Integrated Pest Management Plan for

Ash Meadows National Wildlife Refuge Nye County, Nevada

2006

U.S. Fish and Wildlife Service December 2006

Integrated Pest Management Plan for Ash Meadows National Wildlife Refuge

Nye County, Nevada

Monoculture of Russian knapweed Tamarix spp. bordering Peterson Reservoir. near Bradford Springs.

The Integrated Pest Management Plan for Ash Meadows National Wildlife Refuge was prepared by staff of Ash Meadows National Wildllife Refuge and the Southern Nevada Field Office of the U.S. Fish and Wildlife Service. Marco Buske, Integrated Pest Management Specialist for Klamath Basin NWRC and Bob Wilson, Extension Educator, University of Nevada-Reno Cooperative Extension, reviewed this document. Brian Hobbs, Biologist for the Nevada Department of Wildlife, and Gary Scoppettone, Scientist with the Biological Resources Division of the U.S. Geological Survey, were also consulted.

2 Table of Contents EXECUTIVE SUMMARY ...... 6 I. INTRODUCTION ...... 7 IMPACT OF INVASIVE SPECIES ...... 8 IMPACT OF INVASIVE PLANT SPECIES ON ASH MEADOWS NATIONAL WILDLIFE REFUGE ...... 8 IMPACT OF INVASIVE ANIMAL SPECIES ON ASH MEADOWS NATIONAL WILDLIFE REFUGE ...... 9 ASH MEADOWS NATIONAL WILDLIFE REFUGE MANAGEMENT SETTING ...... 10 MANDATES TO CONTROL NON-NATIVE AND INVASIVE SPECIES ...... 10 FUNDING ...... 11 II. INTEGRATED PEST MANAGEMENT PROGRAM ...... 16 INCORPORATING THE IPM PROGRAM INTO REFUGE MANAGEMENT ...... 16 Endangered Species Management and Recovery ...... 16 Habitat Restoration ...... 17 Resource Protection ...... 17 Wildlife-dependent Recreation, Public Education and Outreach ...... 18 IPM MANAGEMENT STRATEGY ...... 19 ASSESSMENT PROTOCOL ...... 19 Resource-Based Refuge Management Unit Approach ...... 20 Targeted Species Approach ...... 20 III. INVASIVE AND PEST PLANT CONTROL ...... 26 INVASIVE AND PEST PLANT SPECIES MANAGEMENT: STANDARD OPERATING PROCEDURES AND GUIDELINES ...... 26 Prevention and Early Detection of Weeds ...... 26 Inventory and Monitoring ...... 27 Prioritization of Target Management Units and Species ...... 28 Treatment ...... 29 Revegetation ...... 29 INVASIVE AND PEST PLANT CONTROL METHODS ...... 30 Cultural Control ...... 31 Manual Control ...... 32 Mechanical Control ...... 33 Solarization ...... 35 Fire ...... 37 Biological Control ...... 38 Chemical Control ...... 41 Chemicals Currently Approved for Vegetation Management on AMNWR ...... 42 IV. INVASIVE PLANT SPECIES INVENTORY AND PRIORITIZATION ...... 48 INVENTORY ...... 48 CHARACTERIZATION OF INFESTATIONS AND PRIORITIZATION BY MANAGEMENT APPROACH ...... 49 Sub-basin Management Units ...... 49 Spring and Reservoir Management Units ...... 50 Targeted Species ...... 50 CONCLUSIONS AND RECOMMENDATIONS ...... 51

3 TARGET SPECIES ...... 59 Acroptilon repens ...... 59 Bassia hyssopifolia ...... 62 Bromus rubens ...... 63 Cardaria draba ...... 67 Centaurea melitensis and C. solstitialis ...... 72 Elaeagnus angustifolia ...... 79 Phragmites australis ...... 82 Solanum elaeagnifolium ...... 87 Sorghum halepense ...... 88 Tamarix ramosissima and related Tamarix species...... 91 Tribulus terrestris ...... 94 Typha domingensis ...... 95 VI. INVASIVE ANIMAL CONTROL ...... 99 INVASIVE ANIMAL SPECIES MANAGEMENT: STANDARD OPERATING PROCEDURES AND GUIDELINES 99 Prevention and Early Detection of Invasive Animal Species ...... 99 Inventory and Monitoring ...... 100 Prioritization of Target Management Units and Species ...... 100 Treatment ...... 101 INVASIVE ANIMAL CONTROL METHODS...... 102 Cultural Control ...... 102 Physical Control ...... 103 Biological Control ...... 105 Chemical Control ...... 105 VII. INVASIVE ANIMAL SPECIES INVENTORY AND PRIORITIZATION ...... 108 INVENTORY ...... 108 CHARACTERIZATION OF INFESTATIONS AND PRIORITIZATION BY MANAGEMENT APPROACH ...... 108 Sub-basin Management Units ...... 108 Spring and Reservoir Management Units ...... 109 Targeted Species ...... 110 CONCLUSIONS AND RECOMMENDATIONS ...... 110 VIII. INVASIVE ANIMAL SPECIES PROFILES: BIOLOGY AND SPECIES-SPECIFIC CONTROL RECOMMENDATIONS ...... 111 TARGET SPECIES ...... 111 Archocentrus nigrofasciatus (Cichlasoma nigrofasciatum) ...... 111 Gambusia affinis ...... 112 Lepomis cyanellus ...... 113 Marisa cornuarietis ...... 114 Melanoides tuberculata ...... 114 Micropterus salmoides ...... 115 Poecilia latipinna ...... 116 Procambarus clarkii ...... 117 Rana catesbeiana ...... 118 IX. REPORTING AND ADAPTIVE MANAGEMENT ...... 120 REPORTING ...... 120 EFFECTIVENESS MONITORING ...... 120 4 X. REFERENCES ...... 122 APPENDIX A: STANDARD OPERATING PROCEDURES TO MINIMIZE IMPACTS TO SENSITIVE PLANT AND ANIMAL SPECIES AT AMNWR ...... 142 APPENDIX B: LITERATURE REVIEW AND SUMMARY OF POTENTIAL FOR DISEASE TRANSMISSION FROM DOMESTIC GOATS TO DESERT BIGHORN SHEEP AT AMNWR ...... 143 APPENDIX C: BEST MANAGEMENT PRACTICES FOR HERBICIDE USE ...... 148 APPENDIX D: SUMMARY OF RECOMMENDED IPM TREATMENTS ...... 150

LIST OF FIGURES

Figure 1.1: Ash Meadows National Wildlife Refuge Land Status Figure 2.1: Ash Meadows National Wildlife Refuge Management Units Figure 4.1: Ash Meadows National Wildlife Refuge 2005 Vegetation Communities Figure 4.2: North Carson Slough Management Unit: 2005 Saltcedar Mapping Project Figure 4.3: Crystal Spring and Warm Springs Management Units: 2005 Saltcedar Mapping Project Figure 4.4: Jackrabbit-Big Springs Management Units: 2005 Saltcedar Mapping Project Figure 4.5: 2005 Saltcedar Mapping Project Detail

LIST OF TABLES

Table 1.1: Ash Meadows National Wildlife Refuge endemic and special status species Table 2.1: Ash Meadows National Wildlife Refuge management units: Critical Habitat and/or known populations of Federally-listed species. Table 2.2: Ash Meadows National Wildlife Refuge targeted invasive and pest plant species Table 2.3: Ash Meadows National Wildlife Refuge targeted invasive wildlife species Table 4.1: Non-native and pest plant species present in Ash Meadows National Wildlife Refuge

5 Executive Summary

Ash Meadows National Wildlife Refuge (AMNWR, Refuge) is located in Nye County approximately 22 miles northwest of the town of Pahrump in the Amargosa Valley of southwestern Nevada. The Refuge is part of the Desert National Wildlife Refuge Complex and a unit of the National Wildlife Refuge System. AMNWR was established in 1984 to provide for the protection and recovery of threatened and endangered species.

Ash Meadows NWR has been described as “a true oasis” embracing “the type of spring-fed wetlands and alkaline desert uplands that development has rendered rarer than usual in the arid Southwest” (Audubon, June 2003). More than 23,000 acres within AMNWR provide habitat for at least 27 plant and animal species found nowhere else in the world. This distinguishes Ash Meadows as having the largest concentration of endemic species of any terrestrial area in the United States and second greatest in all of North America. Almost half of these endemic species are listed as threatened or endangered.

According to the U.S. Fish and Wildlife Service (FWS), invasive species have become the single greatest threat to the Refuge System. This threat is clearly visible in AMNWR where close to 100 species of nonnative plants and animals have been introduced. The invasive nature of some of these species threatens the listed and endemic species of Ash Meadows, alters ecosystem processes, degrades wildlife habitat, reduces the quality of wildlife-dependent recreation, and prevents habitat restoration, public access, and construction of public facilities in infested areas.

AMNWR is mandated to control or eradicate non-native species. In response, the Refuge initiated an integrated pest management (IPM) program. IPM is a decision-making process for determining if pest suppression treatments are needed, when they are needed, and what strategy and mix of tactics should be used (Olkowski 1980). The elements of AMNWR’s IPM program are described in this Integrated Pest Management Plan.

6 I. Introduction

Ash Meadows National Wildlife Refuge is located in Nye County approximately 22 miles northwest of the town of Pahrump in the Amargosa Valley of southwestern Nevada. The Refuge was established on June 18, 1984 when the U.S. Fish and Wildlife Service (FWS) purchased 12,654 acres of land from The Nature Conservancy. Today, AMNWR includes a total of 23,488 acres of spring-fed wetlands and alkaline desert uplands. Within AMNWR there are approximately 500 acres of private land, 40 acres of land managed by the National Park Service, and 9,460 acres of Bureau of Land Management (BLM) land that is managed by the FWS under a cooperative agreement. The refuge is also surrounded by 27,870 acres designated by the BLM as the Ash Meadows Area of Critical Environmental Concern (ACEC). (Figure 1.1.)

Ash Meadows is a unit of the National Wildlife Refuge System. The mission of the National Wildlife Refuge System as established by the National Wildlife Refuge System Improvement Act of 1997 is “to administer a national network of lands and waters for the conservation, management, and where appropriate, restoration of the fish, wildlife, and plant resources and their habitats within the United States for the benefit of present and future generations of Americans.”

Unlike most FWS refuges, Ash Meadows was created to “conserve and recover listed endangered , proposed endangered, and candidate plant and animal species found in the area” (USFWS 1984). The refuge is unique in that it provides designated critical habitat for seven threatened and endangered plant species, one threatened insect, and four endangered fish – all of which are endemic to Ash Meadows. The refuge also provides habitat for around 100 species of plants and animals that are considered sensitive or are state protected/priority species. With at least 27 plant and animal species found nowhere else in the world, Ash Meadows is distinguished as having the largest concentration of endemic species of any terrestrial area in the United States and second greatest in all of North America. Another nine species are endemic to the larger Death Valley ecoregion. (A list of all endemic species and their status is included in Table 1.1.)

An oasis in the Mojave Desert, the 30+ seeps and springs within AMNWR produce approximately 10,700 gallons of water per minute or 17,000 acre-feet annually. Combined, the seven major springs alone produce flows of about 9,000 gallons per minute year round (Mayer 2003). This unique environment led to Ash Meadows being one of the first four wetlands in the United States to be designated a “Wetland of International Importance” by the Ramsar Convention; an international treaty between 136 countries whose goal is to conserve special wetlands throughout the world. The Refuge has also been designated an Important Bird Area for Nevada, providing habitat for over 200 species of migrating birds. Many native plants that have been lost or reduced elsewhere can be found on the Refuge, making it a valuable source for seeds that have been used in restoration projects throughout southern Nevada.

AMNWR has been inhabited and likely managed by humans since prehistoric times. Early accounts by explorers in the region include descriptions of gallery stands of velvet ash (Fraxinus velutina), for which AMNWR was named. These stands along with pre-1900 hydro-geologic functioning of the springs no longer remain. Cattle grazing, farming and irrigation diversions from the 1950’s through the early 1980’s dramatically altered vegetation composition, surface topography, and the configuration of nearly all the major spring outflow channels and associated wetlands and uplands on the site.

The legacy resulting from over a century of human activity at Ash Meadows is the introduction of approximately 100 non-native species. Human-induced habitat changes have also allowed some native species to spread beyond their normal extent and threaten biodiversity. Recovery efforts and the eventual 7 delisting of some or all of the sensitive species managed at AMNWR are dependent on the long-term management of these non-native and native pest species. This will require (1) identification of invasive and pest species problems, (2) development of a refuge-wide strategy for managing invasive and pest species, (3) prioritization of management actions, and (4) characterization of management tools and techniques available to meet invasive/pest species management needs.

Impact of Invasive Species

Invasive species cause environmental damage and losses worth almost $120 billion per year, and approximately 42% of all threatened and endangered species are at risk primarily because of non-native species (Pimentel et al. 2005). Economic effects are easier to calculate than ecological consequences which are sometimes difficult to perceive, let alone quantify (Hanson and Sytsma 2001). According to the FWS, invasive species have become the single greatest threat to the Refuge System. Rare species with limited ranges, small numbers, and restricted habitat requirements – such as the endemic plant and animal species of Ash Meadows – are often particularly vulnerable.

Impact of Invasive Plant Species on Ash Meadows National Wildlife Refuge

Non-native and pest plant species alter ecosystem structure and function, disrupt food chains and other ecosystem characteristics vital to wildlife (including rare and endangered species), and alter key ecosystem processes such as hydrology, productivity, nutrient cycling, and fire regime (Randall 1996, Brooks and Pyke 2001).

An estimated 4,460 acres within AMNWR were used for agricultural production and livestock grazing. These abandoned fields are now largely monocultures of nonnative species, including: Russian knapweed (Acroptilon repens), hoary cress (Cardaria draba), five hook bassia (Bassia hyssopifolia), Malta starthistle (Centaurea melitensis), yellow starthistle (Centaurea solstitialis), sorghum and Johnson grass (Sorghum bicolor and S. halepense) and red brome (Bromus rubens). In many parts of the Refuge, these monocultures appear to be expanding beyond the historic field into surrounding areas. The extent of this expansion and its threat are just beginning to be understood through preliminary vegetation mapping and research investigations funded by the Refuge. Weed expansion beyond the existing agricultural fields is a concern because of the potential threat they pose to listed plants including the Ash Meadows gumplant (Grindelia fraxino-pratensis), spring-loving centaury (Centaurium namophilum) and Ash Meadows ivesia (Ivesia eremica) which occur in the riparian zone along spring margins.

Currently there are over 750 acres of saltcedar (Tamarix ramosissima, T. parviflora, and T. aphylla) threatening riparian areas within and adjacent to the Refuge. Saltcedar is known to disrupt native communities by monopolizing limited water and lowering water tables, increasing soil salinity and suppressing the germination and establishment of native species, and reducing available forage and access to water for wildlife (Carpenter 1999, Dudley and DeLoach 2004, Dudley et al. 2000, Lovich and DeGouvenain 1998, Vandersande 2001).

A critical concern is the potential effect that non-native species may have on fire regimes at AMNWR. Saltcedar often forms monocultures that increase the fuel load, thereby increasing the frequency and intensity of fires and floods (National Invasive Species Council 2004). In August 2004, AMNWR experienced a fire that was fueled by saltcedar. This fire destroyed habitat for the Southwestern willow flycatcher (Empidonax traillii extimus) and one historic structure. Fires during 2005 within the Jackrabbit 8 and Big springs systems, burned through riparian vegetation and saltcedar, and in the process extirpated Ash Meadows pupfish (Cyprinodon nevadensis mionectes) and Ash Meadows speckled dace (Rhinichthys osculus nevadensis) from channels within the burned areas.

Impact of Invasive Animal Species on Ash Meadows National Wildlife Refuge

Animal invaders threaten native species by competing with and displacing or preying on indigenous wildlife, acting as vectors or reservoirs of disease, and physically altering habitats (Pimentel et al. 2005).

Feral horses and burros graze heavily on native vegetation, allowing non-native invasive annuals to displace native perennials. Burros compete with native bighorn sheep and degrade springs. These species were excluded from Ash Meadows when fencing was installed in 1995. The removal of horses and burros has allowed listed and other native plant species to at least partially recover.

In the United States, non-native species have contributed to 68% of the fish extinctions in the past 100 years, and the decline of 70% of the Federally-listed fish species (Lassuy 1994). Many of the native fish in the desert southwest have evolved in the absence of competitors or predators, and therefore, lack behavioral defense mechanisms. Non-native aquatic species are suspected of causing the extinction of the endemic Ash Meadows killifish (Empetrichthys merriami) by the early 1950’s (G. Scoppetone, pers. comm.). Aquatic species that have been introduced into AMNWR include crayfish (Procambarus clarkii), bullfrogs (Rana catesbeiana), red-rim melania (Melanoides tuberculatus), gambusia (Gambusia affinis), sailfin molly (Poecilia latipinna), convict cichlid (Archocentrus nigrofasciatus), largemouth bass (Micropterus salmoides), and green sunfish (Lepomis cyanellus). All fish species were intentionally introduced by humans. For example, largemouth bass were illegally brought to Crystal Reservoir for sport fishing prior to the establishment of the Refuge. The bass is a voracious predator that can quickly decimate native fish. Bass were discovered in Big Spring in October 2003 by which time they had extirpated the endemic Ash Meadows pupfish (Cyprinodon nevadensis mionectes) and Ash Meadows speckled dace (Rhinichthys osculus nevadensis) from the spring. They are believed to have entered the Big Spring system from a pond on private property within the Refuge. After three years and thousands of dollars in personnel time spent removing more than 70 bass, several bass are believed to have eluded capture as of this writing.

Gambusia are known to prey on the eggs and larvae of desert fishes (Courtenay and Deacon 1983). Convict cichlids may also prey on the eggs and young of native fishes, but a greater threat may come from competition for spawning sites and territorial exclusion (Courtenay et al. 1974, Courtenay and Hensley 1979, 1980).

Crayfish are known to prey on the native fishes of Ash Meadows, and are known to have decimated macroinvertebrate populations in other locations (S. Goodchild, pers. comm.). Recent surveys at AMNWR strongly suggest that crayfish are having a major impact on the endemic springsnails and may result in their loss within the next decade (L. Stevens, pers. comm.).

Not much is known about the impacts of the red-rim melania snail on Ash Meadows’ endemic springsnails, but it is known to be capable of replacing native species of snails in other areas of the country and to host a parasite that can infect the gills of fish such as the speckled dace (Benson et al. 2001, Mitchell et al. 2005, Rader et al. 2003, Wilson 2003).

9 Ash Meadows National Wildlife Refuge Management Setting

The very high biodiversity and presence of listed species in Ash Meadows was the driving force behind the creation of AMNWR. Past land use over the last 100 years introduced non-native species and created conditions favorable for their establishment. Designation as a National Wildlife Refuge has stopped many of the activities that created disturbance and conditions favorable to non-native species.

The relatively remote location of AMNWR and the surrounding Mojave Desert provide a buffer against future invasions by non-native species. This isolation does not mean that weed seed sources from established populations on adjacent federal and private lands are not likely to be problematic. Agriculture and other land disturbances on in-holdings are expected to be a continuous source for agricultural weed species. Private land and watersheds that enter the Refuge from adjacent BLM land are also likely sources for some invasive species, especially saltcedar, bassia, and Malta starthistle. Also, anthropogenic introductions of non-native plant and animal species will likely increase as the explosive population growth in Southern Nevada results in encroaching development and greater visitation to AMNWR.

The high level of endemism in AMNWR and presence of endangered species limits the variety of management options available to the refuge manager. In some cases, biological control agents for specific non-native invasive plant species (i.e., tamarisk and Russian knapweed) have been approved or already released by the U.S. Department of Agriculture (USDA). However, biological control agents are rarely tested on sensitive and listed species. Refuge policy is to minimize risk to listed non-target plants and animals. Biological control agents (other than domestic livestock) will not be used while their effects on Ash Meadows’ listed species are unknown.

The unfortunate reality is that invasive species are now part of the flora and fauna of AMNWR and some will never be eradicated. A long-term integrated pest management (IPM) program will be needed in perpetuity to maintain the refuge as suitable habitat for many of the listed species. If left unmanaged, current problems will only be exacerbated, become more expensive to mitigate, and could lead to an adverse effect on federally listed species and Section 7 involvement.

Mandates to Control Non-native and Invasive Species

Authorization for non-native species management and protection of the environment and human health includes the following:  Reclamation Act of 1902, 32 Stat. 388 (43 U.S.C. 391)  Carlson-Foley Act of 1968, Public Law 90-583 (43 U.S.C. 1241 et seq.), providing for the control of noxious plants on lands under the control or jurisdiction of the Federal Government  Federal Noxious Weed Act of 1974, Public Law 93-629, as amended (7 U.S.C. 2801 et seq.) Federal land management agencies are required by Section 2814 of the Federal Noxious Weed Act to establish and adequately fund a weed management program (Mullin et. al. 2000).  Plant Protection Act (PPA, 7 U.S.C. 7701 et seq.)  Federal Land Policy and Management Act of 1976 as amended, Public Law 94-579 (43 U.S.C. 1701 et seq.)  Public Rangelands Improvement Act of 1978, Public Law 95-514 (43 U.S.C. 1901 et seq.)  Endangered Species Act, Public Law 93-205, as amended by Public Law 100-478 (16 U.S.C. 1531 et seq.)  National Wildlife Refuge System Administration Act (16 U.S.C. 668dd)

10  Nonindigenous Aquatic Nuisance Prevention and Control Act of 1990 (NANPCA; 16 U.S.C. 4701 et seq.)  Executive Order 11514-Protection and Enhancement of Environmental Quality, as amended by Executive Orders 11541 and 11991  Executive Order 11987-Exotic Organisms  Executive Order 13112-Invasive Species  DOI Manual 609 DM 1, Weed Control Program  Noxious Weed Regulations, 7 CFR Part 360  Pesticide Programs, 40 CFR Subchapter E  Departmental Manual, Pesticide Use Policy, 517 DM 1

Nonnative species control and management is sanctioned by FWS policies on exotic species management (7 RM 8.1) and pest control (7 RM 14.1) outlined in the U.S. Fish and Wildlife Refuge Manual for the National Wildlife Refuge System. Service policy on exotic species introduction and management (7 RM 8.1) states that the “National Wildlife Refuge System exists for the protection and management of plants and animals native to the United States.” The two objectives of this policy, as listed, are:  To prevent further introduction of exotic species as noted in Section 8.1…..  To protect native plants and animals from adverse impacts of competing with exotic species (USFWS 2002).

Nevada State weed laws (NRS 555) state that noxious weeds will be eradicated by the owner or occupant of the land including the Federal Government. If the owner or occupier of the land fails or neglects to control noxious weeds, enforcement action can be taken by the Nevada Department of Agriculture.

The Recovery Plan for the Endangered and Threatened Species of Ash Meadows, Nevada lists habit alteration and exotic species as the major threats to the listed species. The primary objective of the Refuge and its Recovery Plan is to recover the listed species and their habitats through an ecosystem approach focusing on habitat restoration and the removal of threats. Restoration of springs and historic stream flows is identified as a key element in the recovery of Ash Meadows species and the Refuge has developed a refuge-wide restoration plan. But due to the invasive nature of some non-native plant species, physical restoration cannot go forward until these species have been eradicated or greatly reduced and controlled.

Integrated pest management will address Tasks 222, 223, 224, and 232 of the Recovery Plan for the Endangered and Threatened species of Ash Meadows, Nevada (remove introduced non-native plant species, prevent reestablishment of wild horse herds, enhance/reestablish native plant communities, and remove non-native competitive/predatory aquatic species.). These four steps will assist in the accomplishment of several other tasks including: reestablish seven listed plant species throughout historic habitats (Task 225), reestablish native aquatic communities (Task 233), and reestablish four listed fish throughout historic range (Task 234). Integrated pest management conforms to the goals of the Comprehensive Conservation Plan for Ash Meadows NWR (in draft) and addresses several objectives within that plan. It will also help the FWS to meet the objectives of the Nevada Partners in Flight Bird Conservation Plan, and Resolution VII.14 of the Ramsar Convention on Wetlands.

Funding

Successful eradication requires an initial treatment, careful monitoring and additional follow-up treatments. All eradication projects must include provisions and a budget for subsequent follow-up 11 eradication efforts otherwise the money on the initial control effort will be wasted. Funding for follow-up monitoring and treatments should be built into proposals and secured prior to implementation. For plants, eradication often takes multiple growing seasons. Depending on the level of infestation up to four years of follow-up treatments may be needed to successfully eradicate non-native weeds from a site. A similar or greater level of effort is needed to eradicate or control invasive animal species.

Invasive species management should be coordinated through multiple funding sources and where possible coupled to a variety of refuge activities including threatened and endangered species recovery, habitat restoration, recreational use, educational initiatives, and refuge maintenance operations.

Contingency funds are needed to deal with invasive species outbreaks. Their biology does not respect annual funding cycles, and like human disease epidemics, invasive species outbreaks are best eradicated by early intervention when the outbreak is small and can be contained. A contingency fund could be used to address this issue. For example, the dumping of non-native aquarium fish into one the Refuge’s springs by humans is unpredictable. Management’s response must be rapid to prevent proliferation of the unwanted species. Unusually wet or warm winters often create boom years for invasive plant species when more seed germinates than is typical. Intervention during these years is imperative. A contingency fund should be available so that the Refuge can adequately address these unusual events when they occur. Since seed set in the desert is directly correlated to rainfall, this sort of fund would also be extremely useful when there are heavy seed set years and large scale seed collections for revegetation purposes can be accomplished.

12 Figure 1.1.

13 Table 1.1. Ash Meadows National Wildlife Refuge endemic and special status species.

ESA1 Scientific Name Common Name Endemism Status Mollusks Pyrgulopsis crystalis Crystal Spring springsnail sensitive Ash Meadows endemic Pyrgulopsis erythropoma Ash Meadows pebblesnail sensitive Ash Meadows endemic Pyrgulopsis fairbanksensis Fairbanks springsnail sensitive Ash Meadows endemic Pyrgulopsis isolatus elongate-gland springsnail sensitive Ash Meadows endemic Pyrgulopsis micrococcus Oasis Valley springsnail sensitive wider endemic Pyrgulopsis nanus distal-gland springsnail sensitive Ash Meadows endemic Pyrgulopsis pisteri median-gland Nevada springsnail sensitive Ash Meadows endemic Tryonia angulata Sportinggoods tryonia sensitive Ash Meadows endemic Tryonia elata Point of Rocks tryonia sensitive Ash Meadows endemic Tryonia ericae minute tryonia sensitive Ash Meadows endemic Tryonia variegata Amargosa tryonia sensitive Ash Meadows endemic Undescribed Virile Amargosa snail ------wider endemic? Crustaceans Undescribed Amphipod ------Ash Meadows endemic? Insects Ambrysus amargosus Ash Meadows naucorid threatened Ash Meadows endemic Ambrysus relictus Warm Springs naucorid ------Ash Meadows endemic Pelocoris shoshone amargosus Amargosa naucorid sensitive wider endemic Pseudocopaeodes eunus alinea Ash Meadows alkali skipperling sensitive wider endemic Stenelmis calida calida Devils Hole warm spring riffle sensitive Ash Meadows endemic beetle Fishes Cyprinodon diabolis Devil's Hole pupfish endangered Ash Meadows endemic Cyprinodon nevadensis mionectes Ash Meadows Amargosa pupfish endangered Ash Meadows endemic Cyprinodon nevadensis pectoralis Warm Springs Amargosa pupfish endangered Ash Meadows endemic Rhinichthys osculus nevadensis Nevada speckled dace endangered Ash Meadows endemic Reptiles Gopherus agassizii Desert tortoise threatened wider ranging Heloderma suspectum cinctum Banded Gila monster sensitive wider ranging Sauromalus ater Chuckwalla sensitive wider ranging Birds Athene cunicularia hypugea Western burrowing owl sensitive wider ranging Chlidonias niger Black tern sensitive wider ranging Contopus borealis Olive-sided flycatcher sensitive wider ranging Empidonax traillii extimus Southwestern willow flycatcher endangered wider ranging Empidonax wrightii Gray flycatcher sensitive wider ranging Falco peregrinus American peregrine falcon sensitive wider ranging Guiraca caerulea Blue grosbeak sensitive wider ranging Haliaeetus leucocephalus Bald eagle threatened wider ranging Ixobrychus exilis hesperis Least bittern sensitive wider ranging Phainopepla nitens Phainopepla sensitive wider ranging Piranga rubra Summer tanager sensitive wider ranging Plegadis chihi White-faced ibis sensitive wider ranging 1 Endangered Species Act 14 Table 1.1 (continued). Ash Meadows National Wildlife Refuge endemic and special status species.

ESA1 Scientific Name Common Name Endemism Status Birds (continued) Pyrocephalus rubinus Vermilion flycatcher sensitive wider ranging Rallus longirostris yumanensis Yuma clapper rail endangered wider ranging Vermivora luciae Lucy’s warbler sensitive wider ranging Vireo bellii arizonae Arizona Bell’s vireo sensitive wider ranging Mammals Corynorhinus townsendii Townsend's big-eared bat sensitive wider ranging Euderma maculatum Spotted bat sensitive wider ranging Eumops perotis californicus Greater western mastiff-bat sensitive wider ranging Idionycteris phyllotis Allen's big-eared bat sensitive wider ranging Macrotus californicus California leaf-nosed bat sensitive wider ranging Microtus montanus nevadensis Ash Meadows montane vole sensitive Ash Meadows endemic Myotis ciliolabrum Small-footed myotis sensitive wider ranging Myotis evotis Long-eared myotis sensitive wider ranging Myotis thysanodes Fringed myotis sensitive wider ranging Myotis velifer Cave myotis sensitive wider ranging Myotis volans Long-legged myotis sensitive wider ranging Myotis yumanensis Yuma myotis sensitive wider ranging Nyctinomops macrotis Big free-tailed bat sensitive wider ranging Plants Arctomecon merriamii White bearpoppy sensitive wider endemic Astragalus phoenix Ash Meadows milkvetch threatened Ash Meadows endemic Calochortus striatus Alkali mariposa lily sensitive wider ranging Centaurium namophilum Spring-loving centaury threatened Ash Meadows endemic Cordylanthus tecopensis Tecopa birdsbeak sensitive Ash Meadows endemic Enceliopsis nudicaulis var. Ash Meadows sunray threatened Ash Meadows endemic corrugata Eriogonum concinnum Darin buckwheat sensitive wider endemic Grindelia fraxino-pratensis Ash Meadows gumplant threatened Ash Meadows endemic Ivesia eremica (= I. kingii var. Ash Meadows ivesia threatened Ash Meadows endemic eremica) Mentzelia leucophylla Ash Meadows blazing star threatened Ash Meadows endemic Nitrophila mohavensis Amargosa niterwort endangered Ash Meadows endemic Phacelia parishii Parish’s phacelia sensitive wider endemic Salvia funerea Death Valley sage sensitive wider endemic Spiranthes infernalis Ash Meadows lady's tresses sensitive Ash Meadows endemic Sysyrinchium funereum Death Valley blue-eyed grass sensitive wider endemic 1 Endangered Species Act

15 II. Integrated Pest Management Program

Integrated pest management (IPM) is a decision making process for determining if pest suppression treatments are needed, when they are needed, and what strategy and mix of tactics should be used. Treatments are chosen and timed to be most effective and least disruptive to natural ecosystem processes (Olkowski 1980). Taking this a step further, AMNWR will be striving toward ecologically-based integrated pest management. Ecologically-based IPM requires that land management agencies describe current plant and animal communities and their ecology, including their potential and how they are affected by the presence of invasive species. They should also describe desired future conditions. Then the processes and management actions necessary to drive those ecological process changes can be incorporated into the efforts to remove or minimize invasive plant and animal populations (B. Wilson, pers. comm.).

The removal of targeted invasive species is an overly simple prescription that does not address the multitude of factors that facilitate the domination of invasive species. Ecological processes can be used to make native communities more resistant to invasion by non-native species. The ultimate objectives for land management should be the focus of the non-native species management plan. The ultimate objective is not simply the removal of invasive species, but instead is a functioning ecological system. Focusing on this more comprehensive objective opens managers to the vast array of opportunities and challenges, control of invasive species being only one of those challenges (B. Wilson, pers. comm.).

Incorporating the IPM Program into Refuge Management

An integrated pest management program must be based on the overall conservation and management goals of the area for which it was designed (Evans et al. 2003). Primary conservation targets and recreational management goals as they relate to invasive species management at AMNWR are described below:

Endangered Species Management and Recovery

The threatened and endangered (T&E) species protection and recovery objective for Ash Meadows is described in the Recovery Plan for the Endangered and Threatened Species of Ash Meadows, Nevada (USFWS 1990). The objective is to restore populations of listed species to a non-listed status. The recovery plan outlines eight conditions that must be met within essential habitat for a period of five years before downlisting of the Devils Hole pupfish (Cyprinodon diabolis ), Warms Springs Amargosa pupfish (Cyprinodon nevadensis pectoralis), Ash Meadows Amargosa pupfish (Cyprinodon nevadensis mionectes), Ash Meadows speckled dace (Rhinichthys osculus nevadensis), Ash Meadows naucorid (Ambrysus amargosus), and Ash Meadows niterwort (Nitrophila mohavensis) can occur. Conditions 1 and 4 include specific provisions for the removal and control of non-native species:

1. All nonnative animals and plant species must be eradicated from essential habitat. These non-native species include sailfin mollies, mosquitofish, largemouth bass, black bullheads, bullfrogs, crayfish, turban snails, wild horses, saltcedar, and Russian olive.

4. The essential habitat must be secure from detrimental human disturbances including mining, off-road vehicles, and the introduction of non-native species.

16 The recovery plan also outlines six conditions for further downlisting (delisting) all of the above species except the Devils Hole pupfish; and delisting the Ash Meadows blazing-star (Mentzelia leucophylla), Ash Meadows milkvetch (Astragalus phoenix), Ash Meadows sunray (Enceliopsis nudicaulis corrugata), spring-loving centaury (Centaurium namophilum), Ash Meadows gumplant (Grindelia fraxino-pratensis), and Ash Meadows ivesia (Ivesia eremica). Conditions 2, 3, 5, and 6 apply to non-native species management in that native communities cannot be reestablished without it. As described above, these criteria must also be met for a five-year period.

2. Secure, protect and maintain natural vegetation corridors and adjacent buffer areas for gene flow and dispersal of listed plant species within the essential habitat.

3. Native plant communities and aquatic communities have been reestablished to historic structure and composition within all essential habitat.

5. The listed Ash Meadows naucorid, the two candidate aquatic insects, and 13 candidate snails are present in all the locales that they have historically occupied as identified in Appendix A, Table XIII.

6. All of the listed plant species and the four candidate plant species are present in all the sites that they have historically occupied as identified in Appendix A Table XV and within each critical habitat unit, the listed plan has a frequency value equal to or greater than the frequency value determined by task number 644 as needed as an indicator of a self sustaining plant population.

Habitat Restoration

The National Wildlife Refuge System Improvement Act of 1997 requires that the FWS complete a Comprehensive Conservation Plan (CCP) for every refuge. The CCP’s purpose is to guide Refuge management for the next 15 years. AMNWR is currently in the process of developing a CCP.

The CCP includes a vision statement, goals, objectives, and strategies. To assist in formulating the goals and objectives of the CCP, and to address the objectives of the Recovery Plan for AMNWR, the Refuge developed a refuge-wide hydro-geomorphic restoration plan. This plan establishes the Refuge’s desired future conditions and prioritizes areas of the Refuge for restoration. Goal 1 of the Draft AMNWR CCP is to “Restore and maintain viable populations of all native, endemic, endangered, and threatened species within the Refuge’s Mojave Desert oasis ecosystem.” Goal 2 is “Restore and maintain suitable habitat for endemic, endangered and threatened species within the Ash Meadows National Wildlife Refuge.” These goals stipulate habitat restoration and restoration cannot occur without pest management. Therefore, objectives under these goals will address pest management.

In 2006, funding was approved through the Southern Nevada Public Lands Management Act (SNPLMA) for restoration of three springs. A portion of the money will be allocated for pest management and monitoring at these sites.

Resource Protection

The goals of the National Wildlife Refuge System are to “Provide for the conservation of fish, wildlife, and plants within the System; ensure that the biological integrity, diversity, and environmental health of the System are maintained for the benefit of present and future generations of Americans…” and 17 “…monitor the status and trends of fish, wildlife, and plants in each refuge.” In addition to specifically managing for Federally-listed species, AMNWR has an obligation to appropriately manage and protect non-listed species and ecosystem integrity on the refuge. These larger scale processes include fire. Fire is a major concern at AMNWR. Although fire is a natural process, the presence of non-native species like saltcedar and Russian knapweed may alter the frequency and/or intensity of fires, resulting in a regime that favors non-native species over natives (Brooks et al. 2004). The refuge has experienced five fires in the past six years. Over those six years more than 2,800 acres and 10% of wetland areas have burned. Recent fires destroyed habitat for the Southwestern willow flycatcher (Empidonax traillii extimus), killed federally listed Ash Meadows pupfish (Cyprinodon nevadensis mionectes) and Ash Meadows speckled dace (Rhinichthys osculus nevadensis) in stream channels within burned areas, and destroyed habitat suitable for supporting the Ash Meadows vole (Goodchild 2005, U.S. Department of the Interior 2004, U.S. Fish and Wildlife Service 2005). At present rates, it is likely that most of the Refuge wetlands will burn in the next 20 years (Otis Bay, Inc. 2006).

The fires in AMNWR appear to be confined to springs, woody riparian areas, and mesic meadows where fuel loading is greatest. The expansion of native pest species like cattail may be adding fuel to the fire. The Meadows fire burned through accumulated cattail litter over the top of standing water (Otis Bay, Inc. 2006). The role of non-native tamarisk in carrying fire at AMNWR is unstudied; however, it also appears to be an important factor. In other parts of the Mojave desert non-native annual grasses, and non-native annual mustards now pose a serious threat to creosote bursage scrub, blackbrush scrub and sagebrush steppe vegetation communities.

In 2004 and 2005, AMNWR secured funding for emergency stabilization and rehabilitation measures through the Burned Area Emergency Response (BAER) program. This funding can be used to support recovery efforts such as herbicide application, seed collection, and revegetation to prevent the establishment of weeds in recently burned areas.

Wildlife-dependent Recreation, Public Education and Outreach

The six priority public uses for the National Wildlife Refuge system include: hunting, fishing, photography, wildlife observation, environmental education, and interpretation. Recreational use on AMNWR includes waterfowl and upland game hunting, photography, wildlife observation, environmental education, and interpretation. Fishing is not an authorized use because of the threat game species such as largemouth bass (Micropterus salmoides) pose to federally-listed aquatic species. Where possible, programs for game management and recreational/visitor use development on the refuge should be used to meet both administrative needs and IPM objectives.

Recreational Hunting Waterfowl and upland game hunting are offered on 22,270 acres (95%) of the refuge. Degraded habitat typically provides fewer resources for wildlife used for recreational hunting and typically has a higher proportion of non-native species. Therefore, managing invasive species is expected to directly improve habitat for game species. For example, the conversion of former agricultural lands which now are infested with Russian knapweed into quailbush (Atriplex confertifolia) shrubland could provide additional habitat for Gambel’s quail (Callipepla gambelii). Allowing the public to trap non-native bullfrog and crayfish is a population control strategy that may be an effective management tool, but must be weighed against the possibility of accidental introductions via trapping equipment and harassment of endangered fishes.

18 Wildlife Viewing and Photography The installation and maintenance of boardwalks and self-guided visitor tours to improve visitor use can also indirectly benefit invasive species management efforts by reducing the level of disturbance associated with visitor foot traffic, and providing regular funding to maintain the areas immediately adjacent to them. Cattails (Typha domingensis) and common reed (Phragmites australis), while native, pose a serious threat to sensitive aquatic wildlife species, choke off visitor access, and threaten scenic views that are the most distinctive feature of AMNWR. If used appropriately, visitor boardwalks and other visitor improvements can meet multiple goals.

Public Education and Outreach Invasive species management can provide an opportunity for public education and outreach. For two years running, volunteers have been used to cut and remove cattails from Crystal spring. This event has attracted wide public attention. Funding has been secured recently through the Southern Nevada Public Lands Management Act (SNPLMA) to develop interpretative displays and visitor brochures to educate the public on invasive species management issues.

IPM Management Strategy

The components of a successful IPM program include:  Identification of pests and natural enemies.  A monitoring and record keeping system for regular sampling of pest and natural enemy populations; monitoring is an ongoing activity throughout any IPM program.  Setting injury levels, or determining the size of the pest population correlated with an injury sufficient to warrant treatment. (In determining injury levels, the amount of aesthetic economic damage that can be tolerated must be correlated with the population size of pests, natural enemies, time in the season, and/or life stage of the pest or host.)  Setting action levels, the pest population size, along with other variables such as weather, from which it can be predicted that injury levels will be reached within a certain time if no treatments are undertaken.  An integration of treatment methods that are effective against the pest, least disruptive to natural controls, and least hazardous to human health and the environment.  An evaluation system to determine the outcome of treatment actions.

The ongoing monitoring of treatments and results of an IPM program is critical to the adaptive management approach. Information provided by the monitoring component will be used to evaluate the effectiveness of treatment methods in light of site conservation goals. Managers will use this information to adjust priorities, modify treatments, and improve planning and budgeting (Evans et al. 2003).

Assessment Protocol

A prioritization strategy is necessary to effectively utilize the limited funds available to eradicate or control the many non-native species found throughout the 23,000 acres of AMNWR. The first step in prioritizing species and treatment sites is to assess all non-native and pest species, ranking them according to their negative impact on natural biodiversity and Refuge management.

19 The following criteria, based on An Invasive Species Assessment Protocol (2004), a collaborative effort of NatureServe and The Nature Conservancy, will be considered when assessing invasive species impacts and prioritizing target species and treatment sites:

 Ecological impact: impacts on native plant and animal populations, ecosystem processes, ecological community structure and composition; and the significance of those species and communities that are threatened (i.e., rare, endemic, keystone, or T&E species; unique ecosystems).  Current distribution and abundance: size of infestation, proximity to valuable resources, and diversity of habitats or ecological systems invaded.  Trend in distribution and abundance: the potential for spread, especially to new, uninfested areas; the rate of spread; reproductive characteristics.  Management difficulty: susceptibility to treatment/difficulty to control, accessibility of sites, potential for control methods to impact non-target species.

A high impact rank does not always translate into a high priority for treatment. Other considerations such as Refuge operations or earmarked funding can change priorities. For instance, a species that is difficult to manage will have a greater chance of causing significant damage, giving it a high impact rank. However, it may be that the difficulty is such that attempting to eradicate it is not the best use of limited funds. On the other hand, a species that may rank low in these areas could be a high priority for treatment if it is a new or small infestation and can be readily eradicated.

This assessment can be applied to a species refuge-wide (targeted species approach) or to one or more species within a management area (resource-based Refuge management unit approach). Integrated pest management at AMNWR will include both a site specific management strategy using management units and a targeted species approach. Both approaches will enable refuge staff to shift management priorities as needed to best address sensitive species management needs and take advantage of a variety of funding opportunities.

Resource-Based Refuge Management Unit Approach

Emergence of the deep carbonate aquifer and subsequent biological and hydrological interactions are the defining features of AMNWR. The Refuge recently completed a geomorphic and biological assessment. This study will provide guidance and a framework for future restoration efforts on the refuge. The sub- basin units outlined in this assessment have been adapted for IPM to delineate management zones based on groupings of springs that are (or were historically) hydrologically-connected, and the surrounding uplands. The sub-basin management units can be further sub-divided into individual spring and reservoir management units. These management units will be used to define invasive species control targets and priorities. In some cases, pest management goals and listed species recovery needs may conflict or need to be tailored to meet the special needs of listed species. This approach will enable AMNWR to balance competing management and recovery needs by setting specific management priorities within individual areas without sacrificing overall management of all special status species on the refuge. The AMNWR management units are listed in Table 2.1 and illustrated in Figure 2.1.

Targeted Species Approach

A targeted species approach will enable the refuge to address management concerns on a refuge-wide basis as well as prioritize individual management units where control might be more or less important for

20 species recovery and for limiting invasive species outbreaks. Non-native invasive and native pest species that threaten federally listed species as well as the habitats that support them will also be targeted.

Table 2.2 and Table 2.3 list the invasive plant and animal species that will be targeted for management at AMNWR. These lists are intended to be living documents that will need to be reviewed and updated biennially or as more information is gained.

The invasive plant inventory in Chapter IV of this plan identifies problem areas on the refuge and recommendations for specific control measures are included in Chapter V. Chapters VII and VIII contain specific biological information regarding non-native animals found in AMNWR.

21 Table 2.1: Ash Meadows National Wildlife Refuge management units: Critical Habitat and/or known populations of Federally-listed species. ASPH (Astragalus phoenix), CENA (Centaurium namophilum), ENNU (Enceliopsis nudicaulis var. corrugata), GRFR (Grindelia fraxino-pratensis), IVER (Ivesia eremica), MELE (Mentzelia leucophylla), NIMO (Nitrophila mohavensis), CYDI (Cyprinodon diabolis), CYMI (Cyprinodon nevadensis mionectes), CYPE (Cyprinodon nevadensis pectoralis), RHOS (Rhinichthys osculus nevadensis), AMAM (Ambrysus amargosus)

Federally-listed Species and/or Designated Critical Habitat Within Unit

IVER

Management Units CYDI

ASPH

CYPE

CYMI

CENA ENNU GRFR NIMO RHOS

MELE

AMAM Sub-basin Upper Carson Slough X X X X X X X Warm Springs X X X X X X Crystal Spring X X X X X X X X X Jackrabbit-Big Springs X X X X X X X X

Individual Spring Fairbanks Spring X * Soda Spring * Rogers Spring X X X X X * Purgatory Spring X X Longstreet Spring X X * Five Springs X X Cold Spring X X X X X X Mary Scott Spring X X X North Scruggs Spring X X X X South Scruggs Spring X X X X X Marsh Spring X X X X X X North Indian Spring X X X X X X South Indian Spring X X X X X * School Spring X X X Crystal Spring X X X X X * Collins Ranch Spring X X X X X X Kings Spring X X X * * Point of Rocks Springs X X X X X Forest Spring * * Davis Spring Tubbs Spring X X X Bradford Springs X X Jackrabbit Spring X X X X X X X Big Spring X X X X Bole Spring X = known populations present or located within Critical Habitat. * = species extirpated from site.

22 Table 2.1 (continued): Ash Meadows National Wildlife Refuge management units: Critical Habitat and/or known populations of Federally-listed species. ASPH (Astragalus phoenix), CENA (Centaurium namophilum), ENNU (Enceliopsis nudicaulis var. corrugata), GRFR (Grindelia fraxino-pratensis), IVER (Ivesia eremica), MELE (Mentzelia leucophylla), NIMO (Nitrophila mohavensis), CYDI (Cyprinodon diabolis), CYMI (Cyprinodon nevadensis mionectes), CYPE (Cyprinodon nevadensis pectoralis), RHOS (Rhinichthys osculus nevadensis), AMAM (Ambrysus amargosus)

Federally-listed Species and/or Designated Critical Habitat Within Unit

MI

IVER

Management Units CYDI

ASPH

CYPE

CY

CENA ENNU GRFR NIMO RHOS

MELE

AMAM Other Mgmt Units Peterson Reservoir X Crystal Reservoir X X X X X X Horseshoe Marsh X X X Crystal Marsh X X X X Refuge Roads + buffer X X X X X X

X = known populations present or located within Critical Habitat. * = species extirpated from site.

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Figure 2.1:

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Table 2.2: Ash Meadows National Wildlife Refuge targeted invasive and pest plant species.

TARGETED INVASIVE AND PEST PLANTS Scientific Name Common Name Acroptilon repens1,2 Russian knapweed Bassia hyssopifolia five-hook bassia, five-horn smother-weed Bromus rubens2 red brome, foxtail brome, foxtail chess Cardaria draba1,2 hoary cress, white top, perennial pepper-grass Centaurea melitensis1 Malta starthistle Centaurea solstitialis1,2 yellow starthistle Elaeagnus angustifolia Russian olive Phragmites australis common reed Solanum elaeagnifolium1 white horse-nettle Sorghum bicolor, Sorghum halepense1 Sorghum, Johnson grass Tamarix ramosissima, Tamarix spp.1,2 saltcedar, athel Tribulus terrestris1 puncture vine Typha domingensis cattail

INVASIVE AND PEST PLANT WATCH LIST Brassica tournefortii3 Sahara mustard 1 State of Nevada Noxious Weed List 2 Nevada State Weed Plan Species of Concern 3 Proposed addition to the Nevada Noxious Weed List pending change in legislation.

Table 2.3. Ash Meadows National Wildlife Refuge targeted invasive wildlife species.

TARGETED INVASIVE WILDLIFE Scientific Name Common Name Archocentrus nigrofasciatus convict cichlid Gambusia affinis mosquitofish Lepomis cyanellus green sunfish Marisa cornuarietis ram’s horn snail Melanoides tuberculatus red-rim melania or red-rimmed melania Micropterus salmoides largemouth bass Poecilia latipinna sailfin molly Procambarus clarkii crayfish Rana catesbeiana bullfrog

INVASIVE WILDLIFE WATCH LIST Apis mellifera scutellata Africanized bee Equus asinus feral burro Equus caballus feral horse Dreissena bugensis quagga mussel

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III. Invasive and Pest Plant Control

Invasive and Pest Plant Species Management: Standard Operating Procedures and Guidelines

Prevention and Early Detection of Weeds

Prevention and early detection is the cheapest and most effective weed control method. Prevention and early detection strategies will lead to a reduction in the number of acres treated for non-native species in the future by reducing or preventing their establishment (USDI BLM 1996).

Because disturbance often encourages or can favor the spread of weeds, actions on AMNWR will include a weed risk assessment as part of the NEPA process when it is determined that an action may introduce or spread noxious weeds. If the risk is moderate or high, AMNWR will modify the project to reduce the likelihood of weeds infesting the site and include, if necessary, follow-up monitoring and identification of specific control measures to be implemented if weeds do infest the site. A review of current refuge policies and standard operating procedures regarding road maintenance and other refuge operations will also be made to identify if these should, or can be, modified to reduce the potential to spread invasive species. Often, simple changes to everyday activities can go a long way toward preventing establishment or spread of invasive species; however, this “cultural control” is often the hardest to accomplish because it involves changing human behavior.

Cultural Control Cultural control can be defined in different ways. In an agricultural setting it can mean managing and manipulating competitive interactions so that weeds are placed at a disadvantage; this aspect of cultural control is discussed in a later section on control methods. It can also mean modifying human behavior or activities. To this end, cultural control as discussed here consists of awareness of the ways seeds are transported, disposal of non-native and pest plant debris, and public and staff education.

Vehicles, clothing, and equipment can disperse seeds great distances. There may be long-lived seeds of species that persist in mud, debris and soils from infested locations. If just one seed germinates and the plant matures to reproductive age, it can start a new population. Before leaving a site where weeds are present, visitors and staff should be encouraged to clean equipment, check boots, tires, etc. for the presence of weed seeds or vegetative parts. Contractors and fire personnel will also be encouraged to wash their vehicles at the Refuge maintenance facility before leaving Ash Meadows or when moving from a weed infested area to a weed-free area.

As a general prevention measure, the amount of existing vegetation that is disturbed or destroyed during refuge operations will be minimized. Additional prevention measures include the use of weed-free seed, hay, pellets, mulch, fill, gravel, soil, and mineral materials. All plant materials used for restoration will be free of weeds and pathogens and from a reputable nursery supplier. Straw and other materials used for erosion control stabilization should be certified weed seed free. In addition, power washing or using compressed air to clean vehicles and equipment before entering AMNWR may be required as needed to reduce the spread of weeds into the Refuge.

A number of construction and restoration projects are ongoing or planned for the near future at AMNWR. These activities have the potential to create a large amount of ground disturbance; and therefore, should incorporate weed prevention measures starting with the planning phase looking at how to minimize the

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area of disturbance. Known weed populations should be treated prior to the start of a project and areas to avoid should be flagged. Construction and restoration contracts can be written with language requiring preventative measures. A few examples provided by the University of Nevada Cooperative Extension (Siegel and Donaldson 2003) include:

 Provide training to construction workers and equipment operators on the identification of weeds to be avoided.  Certify that all construction material sources used for supplies of sand, gravel, rock and mulch are weed-free prior to obtaining or transporting any material from them.  Clean (power or high-pressure cleaning) all vehicles and equipment of mud, dirt, and plant parts prior to bringing them to the Refuge.  Wash, or use an air compressor to blow clean all vehicles (including tires and undercarriage) that may have entered weed-infested areas prior to moving to an uninfested area of the job site.  Revegetate using seed and other plant materials that have been checked and certified as weed- free.

Cultural control extends into how weed debris is managed. It can be removed from the ground and either left on site for consumption during a prescribed burn, or moved to another area for pile burning at a later date. Ultimately, the debris should be burned so that it does not add to solid waste. Extra care is necessary when weed debris is moved off-site in order to avoid contaminating other areas with live plants and seed.

Cultural control includes educating people and encouraging them to adjust their activities and surroundings to minimize the spread of weedy species. By carefully managing recreational use and educating the public on the potential impacts of recreational activities on vegetation, the amount of damage to native vegetation and soil can be minimized at high use areas. Early detection in recreation areas is focused on roads and trails where much of the weed spread occurs.

At AMNWR, information will be provided to the public in the form of signs, interpretive displays, brochures, and programs on the threat of non-native and pest plant species, and the need to control them. Volunteer days spent cutting cattails and pulling weeds are an opportunity to educate the public about invasive species and how they can help reduce the problem.

Cultural control also extends to AMNWR staff. Weed briefings will be held to educate new staff on how to identify both priority weed species as well as Federally-protected species present on the refuge. Refuge staff and contractors will also attend briefings as needed for specific projects on the appropriate best management practices that must be employed.

Inventory and Monitoring

Regular inventory and monitoring will be essential to detecting and addressing invasive weed outbreaks in a timely manner. Currently, there is no comprehensive inventory of weed infestations on the refuge. To date, invasive weed mapping on the refuge has been completed as staff time and resources were available. In 2005, limited GIS mapping of major weed infestations in former agricultural fields within AMNWR was initiated. In late 2005, the Refuge contracted mapping of tamarisk using aerial imagery. This information has been incorporated into Chapter IV of the plan. Also in 2005, 1:10,000 scale vegetation mapping of the entire refuge and 1:2,500 scale mapping of 12 individual springs was completed. This mapping is expected to be a first step towards producing a comprehensive map of weed infestations on AMNWR.

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Funding for refuge-wide invasive species mapping was approved in 2006. Once comprehensive mapping of weed infestations on AMNWR is complete, it will need to be regularly updated every three to five years. Some management units such as roadsides with a higher exposure to novel weed sources might require updating on an annual basis to best detect new infestations. Since refuge-wide reassessments are expected to be time consuming, approximately ⅓ of all management units should be assessed on a rotating basis in any given year. Any changes in status will be incorporated into regular updates of the IPM.

Continued monitoring of treatment sites should be yearly, at a minimum, and preferably twice a year during the first three to four years of treatments.

Prioritization of Target Management Units and Species

There are currently 63 non-native plant species known to be present on AMNWR. A list of these species is included in Chapter IV, Table 4.1. Of these, ten are considered noxious by the Nevada Department of Agriculture. The state of Nevada (NRS 555.005) defines noxious weeds as “any species of plant which is, or is likely to be, detrimental or destructive and difficult to control or eradicate.” All ten noxious weeds are included on the target species list for AMNWR, as is an eleventh species (red brome) that is listed as a Species of Concern in the Nevada State Weed Plan (2000).

The prevention and early detection of all non-native species is the ultimate goal of AMNWR’s IPM program; however, given the resources available the following criteria as described under Assessment Protocol in Chapter II will be used to rank target species and management units:

 Ecological impact  Current distribution and abundance  Trend in distribution and abundance  Management difficulty

Impacts that will be considered include the threat to Ash Meadows’ endemic and Federally-listed species, the threat to ecosystems that support listed species (e.g., increase the risk for wildfire or reduce aquatic productivity), the threat to visitor safety and refuge staff or operations, the threat to previous habitat restoration projects (i.e., the continued success of previous projects), the potential to transform from a local to refuge-wide infestation, and the level of effort needed to eradicate or contain the outbreak (see Eradication vs. Containment below).

These rankings will be combined with other considerations such as funding sources (e.g., BAER funds earmarked for fire stabilization or restoration project areas) to determine the priority for treatment species and sites.

The target species identified in Table 2.2 will typically receive the highest priority; however, the arrival of new species of known noxious or highly invasive plants, such as Sahara mustard, should take precedence because of the level of effort needed to contain the outbreak and the potential to transform into a refuge- wide problem.

A discussion of priority management units and target species is included in Chapters IV and V.

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Treatment

Eradication vs. Containment Some management units and target species may be classified for either “eradication” or “containment” of invasive species. Eradication is defined as the “elimination of pest species at a given site.” These sites represent areas that have small infestation sizes, new infestations, or are high priority sites due to restoration and construction activities on the refuge. Containment is defined as “limitation to the current site with no expansion.” The sites chosen under this category are large, and total eradication will be difficult. The goal of containment sites is to not allow further expansion of the infestation, and to slowly decrease its size, realizing that eradication may not be realized for many years.

Control methods are discussed in the section following Revegetation. Recommendations for specific control measures are discussed in Chapter V.

Revegetation

Following weed control activities, revegetation will be used to stabilize and restore native plant cover on disturbed sites to eliminate or reduce the conditions that favor invasive species. In addition, the establishment of vegetative cover on disturbed or treated sites will help to control erosion and provide habitat for wildlife. The establishment of native vegetation on most sites will take three to five years. Complete recovery may take considerably longer. Reseeding or replanting may be required to revegetate sites in which the soil has been disturbed or vegetation removed, and where there is insufficient native vegetation or soil seed bank for natural succession to revegetate the site. In some cases a revegetation plan that describes specifically the plant palette, seed mixes, and maintenance regime may be necessary to guide revegetation efforts.

All seed, plant materials and methods used for revegetation projects will be approved and implemented under the supervision of the Refuge biologist. Preferably, seed and plant materials from local genetic stock will be used. All planting and seeding will be done at an appropriate time of year and conditions or as directed by the Refuge biologist. Planting and seed mixtures will be adapted for the treatment area and site uses. The seeding and planting palettes will include a variety of species to enhance the value of the site for fish and wildlife and improve aesthetic characteristics. Mixtures of species rather than monocultures can better take advantage of variable soil, terrain, and climatic conditions and are more likely to withstand insect infestations and survive adverse climatic conditions.

Several standard operating procedures for site revegetation include:  Prior to revegetation, all weed infestations must be under control. With heavy infestations, multiple herbicide treatments are expected prior to seeding and planting to ensure follow-up maintenance is reduced. However, reseeding after an initial herbicide treatment that is followed by tilling, may be possible when using competitive native grasses that are tolerant of the herbicide being used.  The soil will be prepared for planting and seeding as necessary. Depending on the site this may include re-contouring to mimic the natural surface contours and decompaction. The soil surface should be textured (pitted, imprinted, trackwalked scarified etc.) so that seed will remain on the site and not be blown away after it is sown. Pre-plant fertilizers are rarely required, as most native species in the Mojave are adapted to grow under lower soil nitrogen conditions and plants that have been fertilized may be preferentially grazed by herbivores.  Follow-up monitoring and maintenance will be required. The success and failure of revegetation projects often depends on these activities. During the first growing season after installation, at

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least three spot spray treatments with herbicide or manual removal should be expected. The amount of follow-up treatments is expected to decrease during subsequent growing seasons.  All follow-up weed maintenance must be done before the weeds have an opportunity to reseed themselves.  Revegetate sites once work is completed or soon after a disturbance.  Use seed that is free of noxious and invasive weeds.  Use clean equipment, free of plants and plant parts, on revegetation projects to prevent the inadvertent introduction of weeds into the site.

During revegetation, clearing or removal of native plant materials should be restricted for a minimum of five years to allow native vegetation to become established and reduce the probability that weeds will reestablish on the site. This includes grazing by domestic and wild animals and brush removal for fire protection.

Revegetation pre-planning is essential. Mature seed must be collected by hand on the Refuge or purchased ahead of time. However, there are a few companies that sell seed of native plants. If seed is obtained from a commercial dealer, seed lots with high purity rates must be used. With commercially grown seed there is the potential for seed lots to contain weedy species and this must be carefully monitored. Because much of the seed applied is likely to be eaten by insects and wildlife, a typical application rate of 30 pounds of pure live seed per acre should be used. If seed is applied by hand, a carrying agent should be used to help evenly distribute the seed as it is being applied. Rice hulls, cracked wheat or bran can be mixed (50% by volume). In smaller areas, after seeding, the surface can be lightly raked to cover the seed.

Salvaged materials, transplants, and container stock can also be used to establish trees, grasses, shrubs, sedges and rushes. The advantage of using these materials is that they provide an immediate visual improvement and can under the right conditions facilitate establishment. All plantings should be done at the end of the winter or beginning of the spring growing season for the best survivorship. Tree shelters or wire cages should be placed around young woody transplants in areas where there is a high risk of grazing from herbivorous animals. If transplants for container stock are used, provisions must be made for irrigation. In remote areas, hand watering and watering with a water truck are practical alternatives. The bottom of planting holes should be filled with some water just prior to planting to reduce transplant shock. Container stock should be hardened off on or near the site for at least a week prior to planting. All transplant material removed from a donor site should not exceed 10% of the total vegetative cover for that area.

Invasive and Pest Plant Control Methods

AMNWR will employ a variety of control methods. Treatment methodologies will be based upon the best information available from pest management literature and professional expertise. The most appropriate treatment for an infestation typically depends on the scale of the infestation and on the biology and ecology of the target species (Evans et al. 2003). Invasive plant management techniques are expected to change and become more refined as more experienced is gained.

A series of standard operating procedures will be followed on a project by project basis to minimize impacts to sensitive plant and animal species as a result of the pest plant and animal control methods described in the IPM. These standard operating procedures are described in Appendix A. Through the adaptive management process it is expected proceedures will be regularly revised as new information is gained.

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Cultural Control

Cultural control methods include a broad range of normal management practices that can be modified or manipulated to manage one or more pest problems, usually by minimizing the conditions those pests need to live (e.g., water, shelter, food). In an agricultural setting, cultural control refers to manipulating the environment at a particular site so that a competitive advantage is shifted away from weeds towards more desirable species. At AMNWR, this means shifting the competitive balance towards native species. Cultural control as discussed in this section is at the heart of integrated pest management at AMNWR because rarely can a single treatment address every invasive species and all situations. Integrated pest management requires the ability to adapt and combine control techniques to meet shifting management needs.

Soil Seedbank The seeds of many plant species are able to persist for many years in the soil. Noxious weeds in particular can produce large quantities of seed that persists in the soil. If a site has had a heavy weed infestation for an extended period of time it may be necessary to deplete weed seed from the soil seed bank prior to actual revegetation work. Depending on the weed species, different methods including non- chemical and chemical techniques can be employed. Non-chemical techniques include tilling, mulching, and solarization. Chemical techniques are treatments with sterilizing agents or herbicides. Depending on the weed species and degree of infestation, it can take one to several growing seasons before a site may be ready for seeding and planting natives.

If the soil seed bank is heavily infested with noxious weeds, it is far more cost effective to begin control and continue to use less precise weed control techniques such as grazing or boom spraying herbicide for a growing season or two. Once revegetation with desirable species has begun, weed control techniques must be shifted to more expensive labor intensive techniques such as flaming, spot spraying, and manual removal. If a site is still heavily infested with weeds it can be a very costly endeavor to target weed species while preserving desirable species.

There are many cultural control techniques that are used to address managing weeds in the soil seed bank. A few are discussed below:

Mulches and soil amendments Mulches can be included as one component of an integrated approach. Mulches can provide a physical barrier that can reduce weed germination and establishment. Mulches can, however, also inhibit native seedlings at the same time. When considering whether or not to use mulch, cost must be considered. For large projects, the benefits may not be worth the added expense. Instead of adding mulches to an entire site, a lower cost alternative would be to place mulches around plantings to improve water relations and establishment, and reduce direct competition with weeds. Weeds within interspaces could then be more easily treated with herbicides. The following considerations regarding mulches and soil amendments are summarized from the Beginners Guide to Desert Restoration (Bainbridge et. al. 1995).

Consider whether mulches are necessary; often they are not. Do not use mulches that may have weed seeds in areas where invasive species are likely to flourish once established. Mulches in desert ecosystems should have a high carbon to nitrogen (C:N) ratio and be added to pits and around planted seedlings and imprinted areas to increase soil moisture and enhance seed germination and plant establishment. Potential mulches include bark, rice hulls, almond shells, straw, and wood chunks. Mulches should be wind resistant or place mulch in pits or protected areas where it cannot be blown away. Large pieces or heavy materials work better since they will deteriorate more slowly and do not blow away as easily as lighter materials. Crimping or punching in straw can make it more wind resistant.

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Do not add mulches that have a low C:N ratio since desert plants are not adapted to high nutrient input and invasive species are more likely to invade. Soil amendments and mulches are often unnecessary in the desert, although adding organic matter may increase germination and establishment. Mulch can provide wind protection, reduce evaporation, increase infiltration and rainwater retention, reduce erosion, and improve plant microclimate. Materials with lots of lignin and a high C:N ratio appear to be desirable in most desert soils, providing a long-term food source for fungi and subsequent grazing by microarthropods. This grazing makes mineral nitrogen available to plants. Mulches can also be used to tie up available nutrients as an "antifertilizer" (St. John 1987) so that the site is less suitable for invasive exotics. Native plants are, in general, adapted to relatively low nutrient sites and do not respond strongly to fertilization. Invasive exotics in contrast, are often from areas of high disturbance and/or high fertility and will respond very strongly to fertilization. Nitrogen and phosphorus in fertilizer can also depress important microbial activity and prevent root inoculation by soil symbionts. High nutrient levels can also decrease the root-to-shoot ratio and limit root spread. These many factors may interact to increase moisture stress on plants and reduce survival. Herbivores also tend to prefer plants with more nitrogen.

Super-absorbent polymers that store many times their own weight in water are often touted for desert planting. While these amendments have proved useful in some cases (primarily where water is available at regular intervals), the polymer chunks may limit root growth and do not reduce plant water use.

Grow and Kill Cycles “Grow and kill cycles” is a management technique where weed seed in the soil seed bank is depleted prior to planting and seeding. Grow and kill refers to allowing weeds to germinate under conditions that encourage maximum germination – then kill the seedlings before they can produce seed. The kill portion of the cycle can be completed using herbicide, biocontrol (such as goat grazing) or a mechanical means. Weed seed germination is generally increased by supplemental irrigation using a water truck or flood irrigation, and tilling the soil. Depending on the weed species being managed chemicals, such as liquid smoke that help break seed dormancy, can be applied. This technique is particularly useful in controlling weed species, like non-native grasses, that produce large quantities of seed and are highly competitive. Depending on the weed species and weather conditions, multiple grow and kill cycles can be applied in a single year. In most cases multiple grow and kill cycles are needed to significantly deplete the seed bank. Following treatment it is imperative that the soil is not tilled or disturbed in such a way as to bring new weed seed to the surface where it can germinate. In heavily infested sites, using a season or two of grow and kill cycles prior to revegetation has the advantage of reducing the level and cost of weed management needed during the first year or two of the project.

Water Management There are several ways that careful irrigation management can be used to help reduce weed competition. The first includes “using irrigation to pre-germinate weeds” as described above however only one cycle is completed before planting. The second is “planting to moisture” where, after irrigation and weeds have been killed and the top 2-3 inches of soil are allowed to dry out, this soil is pushed away and container plants and large seeded species are planted in the moist subsoil. A third technique is the use of buried drip irrigation. This is more expensive and probably most effective in small scale projects.

Manual Control

Manual treatment involves hand-pulling or the use of hand tools and hand-operated power tools to cut, clear, or prune herbaceous and woody species. Treatments include cutting undesired plants above the ground level; pulling, grubbing, or digging out root systems of undesired plants to prevent sprouting and regrowth; cutting at the ground level or removing competing plants around desired species; or placing mulch around desired vegetation to limit competitive growth (USDI BLM 1991).

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Manual treatments, such as hand pulling and hoeing, are most effective where the weed infestation is limited and soil types allow for complete removal of the plant material (Rees et al. 1996). Additionally, pulling works well for annual and biennial plants, shallow-rooted plant species that do not resprout from residual roots, and plants growing in sandy or gravelly soils. Repeated treatments are often necessary due to soil disturbance and residual weed seeds in the seed bank.

Manual techniques can be used in many areas and usually with minimal environmental impacts. Although they have limited value for weed control over a large area, manual techniques can be highly selective. Manual treatment can be used in sensitive habitats such as riparian areas, areas where burning or herbicide application would not be appropriate, and areas that are inaccessible to ground vehicles (USDI BLM 1991a). Ash Meadows employs the use of vinyl flooring knives and hedge trimmers for cutting cattail in spring pools and their outflows where cut portions will be covered with more than three inches of water. The hedge trimmer (Stihl HL 100) has proven to be very efficient for this purpose and for clearing dead cattail biomass from stream banks prior to treating new growth with herbicide.

Manual treatments are expensive and labor intensive compared to other vegetation management methods such as prescribed burning and herbicide application. Manual methods may also be more dangerous for the workers involved in implementation because of the use of sharp tools and the difficulties associated with working conditions (e.g., steep terrain with slippery ground cover). Some weeds may contain potentially toxic or hazardous compounds. While manual techniques may not be very efficient or cost effective over large acreages, they may be very useful for highlighting specific invasive species problems, and for educating public land users. Care must be taken to thoroughly inspect and clean equipment and clothing before moving off-site.

Mechanical Control

Mechanical control can be the sole weed management tool or, more likely, it is used in combination with other methods such as herbicides or cultural practices within an integrated weed management program. At AMNWR, mechanical control is probably most useful in the abandoned agricultural fields and stands of tamarisk on the Refuge. Equipment for mechanical weed control includes chain saws, harrows, rotary hoes, tillage equipment, undercutters, rod weeders, mowers, shovels, and root jacks. One advantage to mechanical control methods is that they are not harmful to sensitive ecosystems in the same way that herbicides can be; however, some mechanical methods will impact non-target vegetation and the use of heavy equipment can damage sensitive soils such as that in the alkaline wet meadows of Ash Meadows. Care must be used with mechanical methods as new disturbance can create additional opportunities for weedy invasive species. A major disadvantage is that often mechanical control takes a long time to become effective and is very labor intensive. It is important to thoroughly clean and inspect all equipment prior to moving it off-site.

The selection of a particular mechanical method is based upon characteristics of the vegetation, seedbed preparation and revegetation needs, topography and terrain, soil characteristics, climatic conditions, and an analysis of the improvement cost compared to the expected productivity (USDI BLM 1991a). Mechanical methods that may be used include root plowing, tilling and drill seeding, mowing, roller chopping and cutting, blading, grubbing, and feller-bunching. As new technologies or techniques are developed, they could be used if their impacts are similar or less than those discussed below.

Tilling involves the use of angled disks (disk tilling) or pointed metal-toothed implements (chisel plowing) to uproot, chop, and mulch vegetation. This technique is best used in situations where complete removal of vegetation or thinning is desired, and in conjunction with seeding operations. Tilling leaves mulched vegetation near the soil surface, which encourages the growth of newly planted seeds. Tilling is usually done with a brushland plow, a single axle with an arrangement of angle disks that covers about

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10-foot swaths. An offset disk plow, which consists of multiple rows of disks set at different angles to each other, is pulled by a crawler-type tractor or a large rubber tire tractor. This method is often used for removal of shrubs and works best on areas with smooth terrain, and deep, rock-free soils. Chisel plowing can be used to break up soils such as hardpan. Tilling may also be used at AMNWR after herbicide treatment of Russian knapweed and prior to revegetation. This helps to remove the allelopathic chemicals produced by Russian knapweed, but care must be taken to ensure that soil turnover does not extend beyond the depth penetrated by the herbicide (B. Wilson, pers. comm.)

Often, drill seeding is conducted along with tilling. The seed drills, which consist of a series of furrow openers, seed metering devices, seed hoppers, and seed covering devices, are either towed by or mounted on a tractor. The seed drill opens a furrow in the seedbed, deposits a measured amount of seed into the furrow, and closes the furrow to cover the seed.

Mowing tools, such as rotary mowers or straight-edged cutter bar mowers, can be used to cut herbaceous and woody vegetation above the ground surface. Mowing is often done along highway right-of-ways (ROW) to reduce fire hazards, improve visibility, prevent snow buildup, or improve the appearance of the area. Mowing is also used in sagebrush habitats to create a mosaic of uneven aged stands and enhance wildlife habitat. Mowing is most effective on annual and biennial plants (Rees et al. 1996). Weeds are rarely killed by mowing, and an area may have to be mowed repeatedly for the treatment to be effective (Colorado Natural Areas Program 2000). However, the use of a “wet blade,” in which an herbicide flows along the mower blade and is applied directly to the cut surface of the treated plant, has greatly improved the control of some species. At AMNWR, mowing will be used to remove above-ground biomass of some species, such as five-hook bassia, prior to manual treatment or treatment with herbicides. Mowing is not recommended on species that can sprout from stem or root fragments unless cut fragments will be collected.

Roller chopping tools are heavy bladed drums that cut and crush vegetation up to 5 inches in diameter with a rolling action. The drums are pulled by crawler-type tractors, farm tractors, or a special type of self-propelled vehicle designed for forested areas or range improvement projects.

During blading, a crawler type tractor blade shears small brush at ground level. The topsoil could be scraped with the brush and piled into windrows during this operation. Blading use is limited to areas where degradation to the soil is acceptable, such as along ROW or in borrow ditches (USDI BLM 1991a).

Grubbing is done with a crawler-type tractor and a brush or root rake attachment. The rake attachment consists of a standard dozer blade adapted with a row of curved teeth projecting forward at the blade base. Brush is uprooted and roots are combed from the soil by placing the base of the blade below the soil surface. Grubbing greatly disturbs perennial grasses, so grubbed areas are usually reseeded to prevent extensive runoff and erosion (USDI BLM 1991a).

Feller-bunchers are machines that grab trees, cut them at the base, pick them up, and move them into a pile or onto the bed of a truck (Bonneville Power Administration 2000). Feller-bunchers are used in forest thinning to remove potential hazardous fuels. Large chippers, or “tub-grinders,” are often used to chip the limbs, bark, and wood of trees to generate mulch or biomass.

AMNWR employs the “extract and grind” method for tamarisk removal. This approach is relatively non- intrusive and should actually reduce the need for herbicide. The extraction portion involves using a low ground pressure (4.5 to 6 pounds per square inch) excavator with a “thumb” attachment to grab the saltcedar. By extracting the entire root ball from the soil, the number of re-sprouts will be reduced drastically; thereby reducing the amount of herbicide required to eradicate it. After the saltcedar is extracted, it is piled or windrowed and ready for grinding. The grinding is accomplished using a Hydro-

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axe 421E or 721E with a Fecon head attachment. The end product is chips ranging from two to six inches in size.

The extensive areas of tamarisk in Ash Meadows that will be treated with herbicide sprayed aerially will also need to have the dead trees removed and chipped prior to revegetation. This may be accomplished with the “extract and grind” method mentioned above or by use of a Magnum 500 mulcher.

Solarization

Soil solarization is a non-chemical method for controlling diseases, pests and weed seed in the seed bank. It has been traditionally used in agricultural settings, but is also applicable to weed management in habitat restoration settings (Bainbridge 1990). This method is usually not 100 % effective; repeated treatments or use integrated with other methods will generally yield the best results. This simple technique captures radiant heat energy from the sun, thereby causing physical, chemical, and biological changes in the soil. Transparent polyethylene plastic placed on moist soil during the hot summer months increases soil temperatures to levels lethal to many soil-borne plant pathogens, weed seeds, and seedlings (including parasitic seed plants), nematodes, and some soil residing mites. Soil solarization also improves plant nutrition by increasing the availability of nitrogen and other essential nutrients. Included below is a discussion and guidelines for soil solarization from a 1999 University of California-Davis cooperative extension technical bulletin intended for agricultural settings:

The area to be solarized should be level and free of weeds, debris, or large clods, which could raise the plastic off the ground. Maximum soil heating occurs when the plastic is close to the soil; therefore, air pockets caused by large clods or deep furrows should be avoided. The soil should be disked, rototilled, or turned over by hand and raked smooth to provide an even surface and to help water penetrate and moisten the soil profile. Transparent (not black or colored) plastic tarps or sheeting 1 to 4 mils (0.001 to 0.004 inch) thick are anchored to the soil by burying the edges in a trench around the treated area. Plastic tarps can be laid by hand for small farms or gardens or by commercial machinery for large farms. To prevent air pockets that retard the soil heating process, there should be a minimum of space between tarps and the soil surface. The soil under the plastic is then soaked with water by inserting one of more hose or pipe outlets under one end of the tarp. If the soaking step is impractical, the soil may be irrigated before laying the plastic, but care should be taken to apply the plastic as soon as possible to avoid water loss. If, however, heavy machinery is used, the soil must be dry enough to avoid soil compaction. The plastic should be left in place 4 to 6 weeks to allow the soil to heat to the greatest depth possible. The plastic should then be removed and the soil allowed to dry to a workable texture. The soil can be planted to a fall or winter crop or left fallow until the next growing season. If the soil must be cultivated for planting, the cultivation should be shallow (less than 2 inches) to avoid moving viable weed seed to the surface.

The highest soil temperatures are obtained when the day lengths are long, air temperatures are high, the sky is clear, and there is no wind. Clear or transparent polyethylene plastic should be used, not black plastic. Transparent plastic results in greater transmission of solar energy to the soil which allows the soil to heat to higher temperatures than when black plastic is used. Polyethylene plastic 1 mil thick is the most efficient and economical for soil heating. However, it is easier to rip or puncture and is less able to withstand high winds than thicker plastic. Users in windy areas may prefer to use plastic 1½ to 2 mils thick. If holes or tears occur in the plastic, they should be patched with clear patching tape or duct tape. Thick transparent plastic (4 to 6 mils)

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reflects more solar energy than does thinner plastic (1 to 2 mils) and results in slightly lower temperatures. Transparent polyethylene plastic containing ultra violet (UV) inhibitors that slow the deterioration of polyethylene can be purchased in large quantities. The use of UV inhibitors may allow the soil to be solarized longer, the plastic to be reused, or the plastic to be left in place and used as a mulch during the following growing season.

Polyethylene tarps may be applied in strips (a minimum of 2 to 3 feet wide) over the planting bed or as continuous sheeting glued, heat-fused, or held in place by soil. If the tarps are glued together, a long-lasting, heat-resistant glue must be used. In some cases strip coverage may be more practical and economical than full soil coverage because less plastic is needed and plastic connection costs are avoided. In addition, if planting beds are covered with tarps with UV inhibitors to avoid plastic deterioration, the tarps may be used as a mulch during the following growing season by planting through the plastic. Partial soil coverage, however, may lose the long-term benefits of soil solarization by leaving substantial amounts of pest-infected soil to contaminate and reinfest treated areas.

Soil must be moist for maximum effect as moisture not only makes organisms more sensitive to heat, but it also conducts heat faster and deeper into the soil. Soil can be moistened by pre-irrigation or by drip or furrow irrigation following laying of the plastic. With machine application of the plastic, irrigation water may be run underneath the tarps in the tractor-wheel depressions, which act as shallow furrows. Irrigation under the plastic usually controls pests slightly faster and to a greater extent than when irrigation is done before the plastic is laid.

Killing of pathogens and pests is related to time and temperature exposure. The longer the soil is heated, the deeper the control. In addition, longer soil coverage increases the opportunity for biological control mechanisms to work. Although some pest organisms are killed within days, 4 to 6 weeks of treatment in full sun during the summer is usually best.

In the California central valley, soil solarized during June or July often reaches temperatures of 140˚ F at 2 inches and 102˚ F as deep as 18 inches. As a result, many diseases-causing organisms are controlled to 18 inches or deeper. Seed and seedlings of many annual and perennial weeds have been controlled with soil solarization. Some weed species are very sensitive to solarization. Others are moderately resistant and require for control optimum soil moisture, tight-fitting plastic close to the soil surface, and high radiation. Control of winter weed species is often evident for more than 1 year after treatment. Winter annual grasses seem to be especially sensitive to solarization, while weeds such as sweet clover (Melilotus alba) or yellow nutsedge (Cyperus esculentus) and purple nutsedge (C. rotundus) are only partially controlled. The summer annuals purslane (Portulaca oleracea) and crabgrass (Digitaria sanguinalis) are also only partially controlled.

Preliminary experiments combining solarization with low application rates of fungicides, fumigants, or herbicides have led to improved control of pathogens, nematodes, and weeds. Solarization chemical combinations may be especially useful in cooler areas, for heat-tolerant organisms, or to increase the long-term benefits of solarization.

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Fire

Prescribed Fire Prescribed fire is the intentional application of fire to wildland fuels under specified conditions of fuels, weather, and other variables. The intent is for the fire to stay within a predetermined area to achieve site- specific resource management objectives. Prescribed fire may be necessary to restore the natural fire regime and is used to control vegetation; enhance the growth, reproduction, or vigor of certain species; manage fuel loads; and maintain vegetation community types that meet management objectives (USDI BLM 1991a). Burning may be used prior to other treatments to remove vegetation that reduces the effectiveness of various treatments, including herbicide applications (Rees et al. 1996).

All fire treatments must be implemented according to FWS fire management policy. The Prescribed Fire Plan is a stand alone and legal document that provides the prescribed fire burn boss all the information needed to implement the project. Prescribed fire projects must be implemented in compliance with the written plan. Several factors are considered when designing a burn plan and implementing a prescribed burn. These include weather conditions, vegetation types and density, slope, fuel moisture content, time of year, risks to dwellings and property, alternative treatment methods, and potential impacts on air quality, land use, cultural resources, and threatened and endangered species.

Hand held tools, such as drip torches, propane torches, diesel flame-throwers, and flares, may be used to start a prescribed fire. Mass ignition techniques include terra-torches and heli-torches. These types of ignition devices release an ignited gelled fuel mixture onto the area to be treated. Helicopters may also be used to drop hollow polystyrene spheres containing potassium permanganate that are injected with ethylene glycol immediately before ignition. The sphere ignition method is best used for spot-firing programs.

Prescribed fire can be used in some situations where some other treatment methods are not feasible due to soil rockiness, slope steepness, or terrain irregularity, although prescribed fire is limited to situations where adequate fuel is available to carry the fire.

The use of prescribed fire comes with a risk of the fire getting out of control and damaging property and endangering human life. Thus, chemical, biological, mechanical and manual methods, instead of fire, are often used to control vegetation near communities.

Some invasive species have underground storage organs that re-sprout vigorously after fire or seeds whose germination is stimulated by fire. In these situations, prescribed fire alone will not control the species, but may be effective if the site is treated with herbicides or revegetated after fire use.

At AMNWR, fire may be of most use in removing biomass, or the remains of the previous year’s growth, prior to treatment with herbicides. A Prescribed Fire Plan will be developed for AMNWR to address the use of prescribed fire to benefit resources.

Flamers Under circumstances where the spot application of herbicides is undesirable, the direct application of fire to individual plants can be used for weed control. Flamers are the method of choice for this technique. Included below is a summary of flamers and the direct application of fire for spot weed control from the University of California Division of Agriculture and Natural Resources Publication 7250:

Flamers are useful for weed control. Propane-fueled models are the most common. Flaming does not burn weeds to ashes; rather, the flame rapidly raises the temperature of

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the weeds to more than 130°F; the sudden increase in temperature causes the plants’ cell sap to expand, rupturing the cell walls. For greatest flaming efficiency, weeds must have fewer than two true leaves. Grasses are difficult to impossible to kill by flaming because the growing point is protected underground. After flaming, weeds that have been killed rapidly change from a glossy appearance to a duller appearance. Typically, flaming can be applied at a speed of 3 to 5 mph through fields, although this depends on the heat output of the unit being used. Best results are obtained under windless conditions, as winds can prevent the heat from reaching the target weeds. The efficiency of flaming is greatly reduced if moisture from dew or rain is present on the plants. Early morning and early evening are the best times to observe the flame patterns and adjust the equipment.

Biological Control

Biological control involves the intentional use of domestic animals, insects, nematodes, mites, or pathogens (agents such as bacteria or fungus that can cause diseases in plants) that weaken or destroy vegetation (USDI BLM 1991a, BPA 2000). Biological control is used to reduce the targeted weed population to an acceptable level by stressing target plants and reducing competition with the desired plant species.

Biocontrol is typically considered to be environmentally safe, energy efficient, and cost-effective. Despite the positive aspects of biocontrol, some risks do exist. Most insects released by the USDA for biocontrol are native to other continents. Little is known of their impacts on the ecosystem as a whole, including on other insect populations. There is also no guarantee that the introduced biocontrol agent will not itself become a pest by changing its food preference from weeds to desirable plants after it is released. For this reason and the fact that most USDA released biocontrol insects are not tested on federally listed species, these agents are not likely to be widely used at AMNWR. However, because much of AMNWR was formerly used for agriculture and much of the surrounding land is in agricultural production, the use of domestic livestock as a biocontrol agent could prove to be a useful and cost efficient management tool.

Livestock Grazing Domestic animals, such as cattle, sheep, or goats, control the top-growth of certain non-native invasive and noxious weeds which can help to weaken the plants and reduce their reproduction potential. The animals benefit by using the weeds as a food source and can, after a brief adjustment period, consume weeds as 50% or more of their daily diet, depending on the animal species (Tu et al. 2001). Grazing is not just consumption of forages. Grazing can also be used to force ecological processes a different direction, but the process needs to be well thought out and full communication is necessary between the livestock operator and the agency so that the desired effect can be achieved and the operator maintains adequate financial incentive to perform to expectations (B. Wilson, pers. comm.).

Cattle primarily eat grass, but also eat some shrubs and forbs. Sheep consume many forbs, as well as grasses and shrubs, but tend not to graze an area uniformly. Goats typically eat large quantities of woody vegetation as well as forbs, and tend to eat a greater variety of plants than sheep (USDI BLM 1991; Tu et al. 2001). Goats and sheep are effective control agents for leafy spurge, Russian knapweed, toadflax, other weed species, and some types of shrubs (Colorado Natural Areas Program 2000).

In order for this treatment to be effective, the right combination of animals, stocking rates, timing, and site rest must be used. Grazing by domestic animals should occur when the target species is palatable and when feeding on the plants can damage them or reduce viable seeds as much as possible. Additionally, grazing should be restricted during critical growth stages of desirable competing species. When desirable

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species are present, there needs to be adequate rest following the treatment to allow the desirable species to recover.

Whenever the use of livestock to control undesirable vegetation is being considered, the needs of the domestic animals as well as the other multiple use objectives for the area must be considered. A herder, fencing, or mineral block may be required to keep the animals within the desired area. Many weed species are less palatable than desired vegetation, so the animals may overgraze desired vegetation rather than the weeds. Additionally, some weeds may be toxic to certain livestock and not to others, which will influence the management option selected (Tu et al. 2001). Proper management of the domestic animals is extremely important if this method of treatment is to be successful (Olson 1999).

Goat Grazing to Control Russian Knapweed Russian knapweed is extremely difficult to control and domestic goats have been shown to effectively graze it. As part of this IPM, goat grazing will be combined with herbicide treatments to control areas that are predominantly Russian knapweed. In full scale treatments, approximately 400-600 goats will be grazed in areas dominated by Russian knapweed between November and April. All sites where grazing will be used were previously agricultural land and are highly disturbed. Goats will be grazed three consecutive years during key periods for maximum weed control. After grazing has had an opportunity to diminish energy reserves stored in root tissue, the areas will be spot sprayed with herbicide. The quantity and concentration of herbicide required to treat problem areas is expected be much lower than without the grazing. The success of combined treatment is expected to be greater and more cost effective than treatments with herbicide alone.

Disease transmission from domestic livestock to bighorn sheep has been documented and wildlife biologists have voiced concerns regarding the potential for domestic livestock in Southern Nevada to spread disease to local bighorn sheep populations. Research studies suggest that domestic sheep pose the most serious threat of disease transmission, however other domestic ungulates including cattle, horses, and goats also have the potential to transmit disease (Foreyt and Lagerquist, 1996). Included in Appendix B is a literature review and discussion of potential disease transmission from domestic goats to the local bighorn sheep population.

Currently, domestic livestock are present and unregulated on private land within AMNWR. There is documented evidence that Russian knapweed is expanding on the refuge and that it poses a serious threat to federally-listed species through direct competition and displacement of native species. There is also mounting evidence that it has the ability to transform fire regimes on the refuge. Russian knapweed presently occupies in excess of 500 acres of the refuge. It is extremely difficult to eradicate. Treatment with conventional herbicides requires elevated concentrations and repeat application. The use of herbicides in this manner poses an unknown, but possibly serious risk to federally listed fish and aquatic insects endemic to the refuge. The desert bighorn sheep is a wide-ranging species. Populations in Nevada are stable and the species does not enjoy Federal protection. Given the extremely limited distribution of protected species at AMNWR and the potential adverse impacts from the quantity of herbicide needed to control Russian knapweed, goat grazing combined with appropriate best management practices to protect the local bighorn sheep population may be the most effective weed treatment.

Best Management Practices for Goat Grazing at AMNWR The following best management practices will be followed to minimize potential disease transmission and adverse affects to desert bighorn sheep from domestic goat grazing at AMNWR:

 Goats will be attended by a monitor 24 hours a day.

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 Goats will be fenced in 5-acre pens using heavy steel mesh panels held together with 5-foot t- posts. (Each panel is 42 inches high by 16 feet long and weighs 34 pounds.) The goats will be excluded from all springs and their adjacent outflow. Water will be brought to the goats and pumped into troughs.  Pens will include portable shelters and goats will be provided supplemental feeding to curb their desire to wander away from the pens.  Problem goats (goats with the ability to escape the pen) are rare. Goats that develop this tendency will be quickly removed from the herd.  Prior to being transported to, or leaving the Refuge, the goats will be fed weed-free sorghum for approximately 5 days to cleanse their digestive tract of weed seeds. (Actual time-frame is dependent on what plant species they were last eating.) If the trailer used for transport does not keep feces from falling out, then the trailer will be kept within a fence for a minimum of 24-hours if it remains on the refuge.  Vacated pens will remain fenced after all goats are removed for a 24 hour period to minimize potential contact between bighorn sheep and any aerosolized saliva or fresh feces.  The goats will be moved roughly every 1½ days (after removing the target weeds) by simply extending the pens. If they must be moved to a new location that is not adjacent to their current site, the goats would be moved by trailer.  Any bighorn sheep detected within sight of the penned animals will be hazed so that there will be no nose to nose contact with the penned goats.  The area immediately surrounding the fence will be monitored every morning for ungulate tracks. If bighorn sheep are detected, monitoring and hazing will be stepped up by increasing the number of monitors and dogs.  Goats in estrus will not be used. If pregnant goats deliver while on the refuge, piles of afterbirth will be removed and any remaining residue sprayed with a disinfectant solution .  Flies in and around the goats will be controlled using strips, dip, CO2 emitters, and traps to minimize the potential to spread Chlamydial conjunctivitis.  All goats used for weed control would be certified by the owner to not have had any contact with other domestic livestock or equipment used for other livestock within the past six months.  Prior to entering the refuge, all goats used for weed control will be checked by a veterinarian and certified to be in good health and to meet federal, state and local agriculture requirements including:

Nevada Department of Agriculture Reg., 55, eff. 9-1-64; A 7-15-71; 10-1-71; 4-1-77]—(NAC A by St. Quarantine Officer, 7-8-92) 1. A person shall not ship, transport or otherwise move goats into Nevada unless each goat is accompanied by a health certificate and an entry permit. 2. In addition to the requirements of subsection 1, a goat imported into Nevada for dairy or breeding purposes must have reacted negatively to tests for tuberculosis and brucellosis within the 30 days before the date of entry.

To enter Nevada all goats require a certificate of veterinary inspection. All breeding and dairy goats 4 months of age and older must have a negative tuberculosis test within 30 days of entry or have certified and accredited herd status. All ANIMALS: Require a certificate of veterinary inspection issued within the last thirty (30) days. Prior entry permit required on cattle, bison, swine, sheep, goats and Mexican steers. Health documents must accompany each animal transport. Call 775- 688-1180, ext 230 for entry permits or other information from 8:00 a.m. to 5:00 p.m. PST on weekdays

NAC 571.025

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(Added to NAC by St. Quarantine Officer, eff. 7-8-92) Performance or confirmation of required tests by official laboratory. (NRS 571.210) All tests required for entry of an animal into Nevada must be performed or confirmed at an official laboratory before a health certificate or an entry permit is issued.

Chemical Control

The size of some infestations and/or the characteristics of some species, which cannot be controlled by physical or mechanical means or by cultural methods alone, will require the use of herbicides. Herbicides are chemicals that kill or injure plants. Herbicides are widely used for controlling weeds, and are generally considered an effective eradication tool under most circumstances. They can be classified by their mode of action, and include growth regulators, amino acid inhibitors, grass meristem destroyers, cell membrane destroyers, root and shoot inhibitors, and amino acid derivatives, all of which interfere with plant metabolism in a variety of ways (Bussan and Dyer 1999). Herbicides can be categorized as selective or non-selective. Selective herbicides kill only a specific type of plant, such as broad-leaved plants. Some herbicides used for noxious weed control are selective for broad-leaved plants so that they can be used to control weeds while maintaining grass species. Other herbicides, such as glyphosate, are nonselective, so must be used carefully around desirable and non-target plants (Rees et al. 1996).

Weeds may develop a resistance to a particular herbicide over time. Varying herbicide use practices or rotating herbicides with different biochemical pathways (from different herbicide groups) will help delay the development of herbicide resistance.

Several herbicide application methods are available. The application method chosen depends upon the treatment objective (removal or reduction); the accessibility, topography, and size of the treatment area; the characteristics of the target species and the desired vegetation; the location of sensitive areas and potential environmental impacts in the immediate vicinity; the anticipated costs and equipment limitations; and the meteorological and vegetative conditions of the treatment area at the time of treatment. Herbicides can be applied with manual application devices, or from vehicles such as ATV’s with a boom sprayer attachment. Manual applications of herbicides are used only in small areas, in areas inaccessible by vehicle, and/or to minimize potential impacts to non-target plants. Herbicides may be applied to green leaves with a backpack applicator or spray bottle, wick (wiped on), or wand (sprayed on). Herbicides can be applied to trees around the circumference of the trunk on the intact bark (basal bark), to cuts in the trunk or stem (frill, or “hack and squirt”), to cut stems and stumps (cut stump), injected into the inner bark, or to the soil before the target species’ seeds germinate and emerge (Tu et al. 2001).

Herbicides can also be applied aerially with helicopters or fixed-wing aircraft. Operation of helicopters is more expensive than operation of fixed-wing aircraft, but helicopters are more maneuverable and more effective in areas with irregular terrain. Helicopters also are more effective for treating target vegetation in areas with multiple vegetation types.

There are several drawbacks and limitations to herbicide use. Herbicides can injure or kill non-target plants even when the herbicide is not applied directly to the plant, through drift, runoff, and possibly through root leakage. Herbicides have the potential to impact all living species, although most herbicides commonly used today block or alter biochemical processes found exclusively in plants. The herbicides the Refuge is considering using are regarded as posing relatively low risk for use in natural areas because they are not likely to contaminate groundwater if used properly and are of low toxicity to animals (Tu, et al. 2001). However, there has been no research on herbicide toxicity specific to the fish and insects endemic to Ash Meadows. Also, if a chemical were to drift into an aquatic habitat, it might kill the aquatic vegetation utilized by these species. With seven federally listed plants, four federally endangered

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fish and one federally threatened aquatic invertebrate, improper use of herbicides resulting in drift and water contamination is a particular concern.

Several factors influence drift, including spray droplet size, wind and air stability, humidity and temperature, physical properties of herbicides and their formulations, and the method of application. Accidental drift is most likely to happen when the chemical is applied by broadcast method, particularly via a boom. Drift is less likely to occur when other methods are used such as basal bark, cut stump, and wick application.

Surface water contamination with herbicides can occur when herbicides are applied intentionally or accidentally into ditches, when buffer zones around water sources are not wide enough, or when soil- applied herbicides are carried away in runoff to surface waters. When treating emergent pest plants (e.g., cattails and Phragmites) or other vegetation located near water (e.g., saltcedar), an herbicide approved by the Environmental Protection Agency (EPA) for aquatic use, such as Habitat™ or Rodeo™, will be used.

To avoid water contamination and impacts to federally-listed species, the best management practices listed in Appendix C will be followed at all times. Herbicide treatments must comply with the U.S. EPA label directions, FWS regulations and pesticide use permit guidance. Application schedules are designed to minimize potential impacts to non-target plants and animals, while remaining consistent with the objective of the vegetation treatment program. The application rates depend upon the target species, the presence and condition of non-target vegetation, weather and site conditions, soil type, depth to the water table, presence of other water sources, the label requirements, approved rates, and sensitivity of non-target species.

Restricted use herbicides must be applied by someone with a Nevada Restricted Use License, or by a person under their direct supervision. Federal law states all herbicides must be applied according to the label.

AMNWR will combine herbicide treatments with other control methods, and will likely use most of the application methods listed above, depending on the situation. Aerial spraying is one of the most cost effective means for controlling extensive infestations, especially monotypic stands of saltcedar. Cut stump herbicide application costs $1,600 - $2,500 per acre, and ground-based foliar herbicide application runs $40 - $300 per acre (U.S. Department of Agriculture 2004). At $260 per acre (including the cost of the more expensive aquatic-approved herbicide Habitat), precision aerial spraying from a helicopter is not only cost-effective, it is the only realistic method for large-scale control, especially since the ability of saltcedar to disperse from a single seed source makes it desirable to remove all of the saltcedar in an area at once. AMNWR will be contracting aerial spraying of approximately 750 acres of tamarisk on the refuge. Aerial spraying will be done by helicopter with Global Positioning System (GPS) capability. The on-board GPS will use the GIS shapefiles created for the saltcedar mapping contract. The GPS unit is linked to a variable flow control system and will also control the automatic shut-off preventing off-target spraying. Loader trucks will have DOT 406 specification-certified tanks and compartments.

Chemicals Currently Approved for Vegetation Management on AMNWR

Due to differences in species tolerance and the variety of habitats within the Refuge, a number of herbicides will be necessary in order to choose the one that is most effective for a particular species in a particular environment. Currently, 12 herbicides (10 different chemicals) are approved for use at AMNWR. One of the herbicides (Milestone) is currently being used in a research trial comparing herbicide effectiveness on Russian knapweed. Summarized below is specific information regarding each product.

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2,4-D Common name: 2,4-D Chemical name: 2, 4-Dichlorophenoxyacetic acid Common product names: 2,4-D LV4, Weedar 64 2,4-D is the most widely used herbicide worldwide and has been used for over 50 years. It is often used in combination with other herbicides such as picloram and clopyralid. 2,4-D is a plant hormone (auxin) mimic that kills the plant by causing rapid cell division and abnormal growth. It is a systemic herbicide and can be absorbed through the roots, although it is most often applied to foliage. Depending on the formulation, 2,4-D is recommended for control of terrestrial and aquatic broadleaf weeds with little or no activity against grasses. Salt formulations are registered for use against aquatic weeds, but ester formulations are toxic to fish and aquatic invertebrates. The World Health Organization (1984) concluded that 2,4-D does not accumulate or persist in the environment. For a more in-depth discussion of the properties of 2,4-D, see The Nature Conservancy Weed Control Methods Handbook (Tu et al. 2001) and the Herbicide Handbook Eighth Edition (Vencill 2002).

Aminopyralid Common name: Aminopyrlid Chemical name: 2-pyradine carboxylic acid, 4-amino-3,6-dichloro-2-pyradinecarboxylic acid Common product names: Milestone

Aminopyrlid is an auxin growth regulator used to control susceptible broadleaf weeds, including Russian knapweed and yellow starthistle, at very low labeled use rates compared to other herbicides with the same mode of action. It translocates throughout the entire plant and accumulates in the meristematic tissues, including the roots, disrupting plant growth metabolic pathways and affecting the growth process of the plant. Broad-leaved species are controlled with little or no injury to cool- and warm-season grasses. This is a new herbicide currently being used at AMNWR only on Russian knapweed in plots as part of a research trial being conducted by Colorado State University and New Mexico State University. However, it has great potential for use at AMNWR due to its low toxicity to animals (practically non-toxic to birds, fish, honeybees, earthworms, and aquatic invertebrates), non-volatile formulation, and low use rates. Milestone™ is registered under the U.S. Environmental Protection Agency (EPA) Reduced Risk Pesticide Initiative. This program is reserved for compounds that demonstrate lower risk to humans and the environment than other available alternatives. It has also demonstrated a low risk of resistance development compared to herbicides with other modes of action.

Chlorsulfuron Common name: Chlorsulfuron Chemical name: 2-chloro-N-[(4-methoxy-6-methly-1,3,5-triazin-2-yl)aminocarbonyl]benzenesulfonamide Common product names: Telar, Glean

Chlorsulfuron is used as a pre- and post-emergent herbicide to control a variety of weeds on cereal grains, pasture and rangeland, industrial sites, and turf grass. It controls many broadleaf weeds including kochia, Russian thistle, mustard spp., pigsweed spp., and lambsquarters. Its effectiveness on Russian knapweed is being tested in AMNWR. Chlorsulfuron is rapidly absorbed through both leaves and roots. It inhibits a key enzyme in the biosynthesis of certain amino acids. Plant death occurs from events that take place in response to the enzyme inhibition, but the actual sequence of processes is unclear.

Chlorsulfuron is likely to be persistent and highly mobile in the environment. It is practically nontoxic to freshwater fish, birds, mammals, and honeybees on an acute exposure basis (Environmental Protection

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Agency 2005). The EPA determined ecological risks to be low except for non-target plants; and therefore, the agency requires that chlorsulfuron be applied in a manner that minimizes spray drift. For a more in-depth discussion of the properties of chlorsulfuron, see the Herbicide Handbook Eighth Edition (Vencill 2002).

Clopyralid Common name: Clopyralid Chemical name: 3,6-dichloro-2-pyridinecarboxylic acid, monoethanolamine salt Common product names: Transline, Stinger. Reclaim Clopyralid is an auxin-mimic type herbicide. It is used to control broadleaf weeds, but is more selective than some other herbicides using the same mode of action. Clopyralid has little effect on grasses and other monocots, but also does little harm to mustard spp. and several other groups of broadleaf plants. It is effective on members of the sunflower (Asteraceae), legume (Fabaceae), nightshade (Solanaceae), knotweed (Polygonaceae), and violet (Violaceae) families. Clopyralid has been used on yellow starthistle with excellent control at low rates when used on seedlings prior to bud stage. On Russian knapweed it provides same season control only; however, new research indicates there may be increased effectiveness when combined with glyphosate.

Clopyralid is considered non-toxic to fish, birds, mammals, and other animals; however, it is relatively persistent in soil, water, and vegetation making it potentially highly mobile and a contamination threat to water. Although of low toxicity to mammals, direct contact with the eye can cause severe eye damage including permanent impairment. For a more in-depth discussion of the properties of clopyralid, see The Nature Conservancy Weed Control Methods Handbook (Tu et al. 2001) and the Herbicide Handbook Eighth Edition (Vencill 2002).

Glyphosate Common name: Glyphosphate Chemical name: N-(phosphonomethyl)glycine Common product names: Rodeo, Roundup, Accord, Aquamaster

Glyphosphate is a broad-spectrum, nonselective, systemic herbicide that kills or suppresses many grasses, herbaceous plants, brush, vines, shrubs, and trees. Applied to foliage, it is absorbed by leaves and rapidly moves through the plant. It can also be applied to green stems and cut-stems (cut-stumps), but cannot penetrate woody bark. It tends to accumulate in plant regions with actively dividing cells and acts by preventing the plant from producing several essential amino acids. This reduces the production of protein in the plant, and inhibits plant growth. Only certain formulations are approved for aquatic use (e.g., Rodeo™). Glyphosate by itself is essentially non-toxic to submersed plants. It is the adjuvants (surfactants) often sold with glyphosate that may be toxic to aquatic plants and animals and these formulations are not registered for aquatic use. Aquatic-approved glyphosate is used to control cattails and Phragmites. Application timing is critical for effectiveness on most broadleaf plant species.

Because glyphosate is a nonselective herbicide, extra care must be taken to prevent it from being applied to desirable, native plants. Glyphosate by itself is of low toxicity to mammals and earthworms; and is practically nontoxic to birds, fish, aquatic invertebrates, and honeybees. The chemical is essentially immobile in soil and is readily degraded by soil microbes (Environmental Protection Agency 1993). When used as an aquatic herbicide in non-flowing water (e.g. ponds, lakes), only ⅓ to ½ of the water body should be treated at any one time to prevent fish kills caused by dissolved oxygen depletion. For a

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ore in-depth discussion of the properties of glyphosate, see The Nature Conservancy Weed Control Methods Handbook (Tu et al. 2001) and the Herbicide Handbook Eighth Edition (Vencill 2002).

Imazapic Common name: Imazapic Chemical name: (±)-2-[4,5-dihydro-4-methyl-4-(1-methlyethly)-5-oxo-1H-imidazol-2-yl]-5-methyl-3- pyridinecarboxylic acid Common product names: Plateau, Cadre

Imazapic is a selective herbicide approved for pre- and post-emergent control of some annual and perennial grasses, and some broadleaf weeds. It is readily absorbed through leaves, stems, and roots; and rapidly translocates throughout the plant, accumulating in the meristematic tissues. Imazapic kills plants by inhibiting the production of certain amino acids which are necessary for protein synthesis and cell growth. It has been used to control Johnson grass, downy brome, and bermudagrass, while allowing establishment of some native legumes. Post-emergent control requires the use of a spray adjuvant such as methlylated seed oil (MSO) or vegetable oil concentrate.

Imazapic is relatively non-toxic to mammals, birds, amphibians, and honey bees. It is moderately toxic to fish, but degrades rapidly in water, rendering it safe to aquatic animals. For a more in-depth discussion of the properties of imazapic, see The Nature Conservancy Weed Control Methods Handbook (Tu et al. 2001) and the Herbicide Handbook Eighth Edition (Vencill 2002).

Imazapyr Common name: Imazapyr Chemical name: (±)-2-[4,5-dihydro-4-methyl-4-(1-methlyethly)-5-oxo-1H-imidazol-2-yl]-3- pyridinecarboxylic acid Common product names: Arsenal, Habitat, Chopper, Stalker

Imazapyr is a broad-spectrum herbicide that controls annual and perennial grasses, broadleaf weeds, and woody species. Like imazapic, it kills plants by inhibiting the production of certain amino acids which are necessary for protein synthesis and cell growth. It is relatively slow-acting, does not readily break down in the plant; and therefore, is particularly good at killing large woody species such as saltcedar. However, it has little to no effect on legumes such as the mesquite trees which are native to Ash Meadows. Some formulations (e.g., Habitat®) are approved for aquatic use. Habitat is a low-volume herbicide; it is effective at low rates of the active ingredient, thereby reducing the chemical load on the environment.

Because imazapyr is a broad-spectrum herbicide that is relatively persistent in soil, care must be taken during application to prevent accidental contact with non-target species. A few studies have reported that imazapyr may be actively exuded from the roots of legumes (such as mesquite), likely as a defense mechanism by those plants and this exudate may therefore adversely affect the surrounding desirable vegetation. Imazapyr is of relatively low toxicity to mammals, birds, fish, and invertebrates, but some formulations (inert ingredients in Chopper® and Stalker®) can cause severe, permanent eye damage in humans.

Picloram Common name: Picloram

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Chemical name: 4-amino-3,5,6-trichloropicolinic acid Common product names: Tordon, Tordon 22K, Grazon, Access, Pathway

Picloram is used to control broadleaved herbs and woody species. This chemical is a systemic herbicide; absorbed through plant roots, leaves and bark. It moves both up and down within the plant, and accumulates in new growth. Picloram acts by interfering with the plant's proteins and nucleic acids. It is a growth regulator herbicide that literally forces the plant to “grow itself to death.” Most grasses are resistant to picloram, making it useful for treating plants like Russian knapweed while allowing native grasses to grow and out-compete the invasive species. It has been used successfully against several knapweed and thistle species, hoary cress, birdsfoot trefoil, toadflax, and Russian olive. Picloram is nontoxic to bees, slightly to practically non-toxic to birds and mammals, and slightly to moderately toxic to aquatic species. Some formulations are highly toxic if inhaled, while others can cause severe eye damage if splashed in the eyes. The herbicide is moderately to highly persistent in the environment and is highly mobile through surface or subsurface runoff. For this reason, it should not be used near water supplies. Leaching potential is greatest in sandy soils low in organic material. (Much of Ash Meadows is overlain with clay soils.) Because of its hazard to non-target plants, picloram is a Restricted Use pesticide and may only be applied by, or under, the direct supervision of certified applicators. Nonetheless, the Environmental Protection Agency (EPA) concluded that picloram and its derivatives can be used without causing unreasonable adverse effects to humans or the environment (EPA 1995). For a more in-depth discussion of the properties of picloram, see The Nature Conservancy Weed Control Methods Handbook (Tu et al. 2001) and the Herbicide Handbook Eighth Edition (Vencill 2002).

Metsulfuron methyl Common name: Metasulfuron Chemical name: methyl 2-[[[[(4-methoxy-6-methyl-1,3,5-triazin-2- yl)amino]carbonyl]amino]sulfonyl]benzoate Common product names: Escort, Ally

Metsulfuron methyl is used as a selective pre- and post-emergence herbicide for broadleaf weeds, brush, and some annual grasses. It is a systemic compound with foliar and soil activity that kills plants by inhibiting the production of certain amino acids which are necessary for protein synthesis and cell growth. This chemical can be used with other foliar herbicides.

Metsulfuron methyl has a higher mobility potential in alkaline soils than in acidic soils; however, it is applied at very low rates and therefore the amount that reaches the soil is quite low. Metsulfuron methyl is of low toxicity to mammals, birds, aquatic organisms, honeybees, and earthworms. For a more in- depth discussion of the properties of metasulfuron, see the Herbicide Handbook Eighth Edition (Vencill 2002).

Triclopyr Common name: Triclopyr Chemical name: 3,5,6-trichloro-2-pyridinyloxyacetic acid, butoxyethel ester Common product names: Garlon 4, Garlon 3A, Turflon

Triclopyr is a selective systemic herbicide used to control woody plants and broadleaf weeds. It has little or no effect on grasses, but is particularly effective on woody species like saltcedar with cut-stump or basal bark treatments. Triclopyr controls weeds by mimicking a plant hormone and causing uncontrolled

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growth that leads to plant death. It may be mixed with picloram, clopyralid, or with 2,4-D to extend its utility range.

There are two formulations of triclopyr – a salt and an ester. Both formulations are relatively non-toxic to terrestrial vertebrates and invertebrates, but the ester formulation is extremely toxic to fish and aquatic invertebrates. The ester is also highly volatile and must be applied at cool temperatures and on days with little wind. The salt formulation (e.g., Garlon 3A®) cannot readily penetrate plant cuticles so is best used in a cut-stump treatment or with a surfactant. This formulation can also cause severe eye damage. For a more in-depth discussion of the properties of triclopyr, see The Nature Conservancy Weed Control Methods Handbook (Tu et al. 2001) and the Herbicide Handbook Eighth Edition (Vencill 2002).

Adjuvants An adjuvant is any compound that is added to an herbicide formulation or tank mix to facilitate the mixing, application, or effectiveness of that herbicide. Spray adjuvants often improve spray retention and absorption by reducing the surface tension of the spray solution, allowing the spray droplet to spread more evenly over the leaf surface. Herbicide absorption may be further enhanced by interacting with the waxy cuticle on the leaf surface. They are sometimes included in the formulations of herbicides (e.g. RoundUp®), or they may be purchased separately and added into a tank mix prior to use (Tu et al. 2001).

Adjuvants are chemically and biologically active, not chemically inert, compounds. Some adjuvants have the potential to be mobile and pollute water. The Material Safety Data Sheet (MSDS) for an adjuvant and the herbicide label (if the adjuvant is included in the formulation) should be checked for conditions in which the adjuvant should not be used.

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IV. Invasive Plant Species Inventory and Prioritization

A comprehensive weed management plan for land management agencies should describe the current plant communities and their ecology, including their potential and how they are affected by the presence of invasive weeds. It should also describe the desired future condition of the plant communities. Then the processes and management actions necessary to drive those ecological process changes can be incorporated into the efforts to remove or minimize invasive weed populations.

The simple removal of targeted invasive weed species is an overly simple prescription that does not address the multitude of factors that facilitate the domination of invasive weeds. Ecological processes can be used to make plant communities more resistant to invasion by invasive plant species. The ultimate objectives for land management should be the focus of the weed management plan. That ultimate objective is not the removal of invasive weeds, but instead is a functioning ecological system. Focusing on this more comprehensive objective opens managers to the vast array of opportunities and challenges, control of invasive weeds being only one of those challenges.

Inventory

Currently, 63 non-native species have been identified within AMNWR as well as two native species that have reached pest status. These species, and the estimated acreages of some, are listed in Table 4.1. With the exception of saltcedar, none of the non-native or pest plants have been systematically surveyed or mapped Refuge-wide. The acreages given are very rough estimates made by biologists while surveying for Federally-listed and endemic species.

In 2004, Burned Area Emergency Response (BAER) funding was obtained to inventory non-native species within the Longstreet Fire perimeter. Funding was used to map Russian knapweed and 16 other species. To date, 1600 acres have been mapped in the Longstreet Fire project area using GPS technology. BAER money was also obtained for weed inventory and treatment in the 2005 Meadows and Ash fires. Seventy acres of the 80-acre Ash Fire have non-native species. The main species of concern are saltcedar (45 acres), bassia (20 acres), and a small population of Malta starthistle.

Outside of fire project areas, Refuge staff has concentrated mostly on the surveying of Russian knapweed. Over 150 acres have been mapped in the area between Bradford and Point of Rocks springs; much of it a monoculture. Russian knapweed was also mapped on the Tubbs Ranch tract near Big Springs and in the Warm Springs complex. Malta starthistle was mapped in the Warm Springs management unit as well.

Vegetation types were mapped by Otis Bay, Inc. and Stevens Ecological Consulting, LLC at the 1:10,000 scale using the 2004 satellite imagery obtained by the Refuge. Ground-truthing via field visits was accomplished to the extent possible in 2005. Seven major vegetation series were identified at this scale. One of the series, classified as non-native oldfield, is a non-native plant species-dominated community that is largely restricted to old agricultural fields. This vegetation series covers 2,000 acres and comprises about 8% of the Refuge. Tamarisk-dominated vegetation was given its own classification type and was estimated to cover about 5% of AMNWR. The map produced by Otis Bay and Stevens Ecological Consulting is presented in Figure 4.1. Otis Bay also completed a human impact analysis by quantifying the combined effects of human disturbance (agricultural activities and infrastructure development such as roads, dams, irrigation ditches, building foundations, mines, etc.) and found that moisture availability- grain size and human disturbance were the most important environmental variables affecting Refuge vegetation (Otis Bay, Inc. 2006).

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In November 2005, Aerial Imagery Services, LLC was hired to map the saltcedar within AMNWR and the land immediately adjacent to the Refuge. The contractor provided ½-meter multispectral imagery and digital ESRI shapefiles of indicated saltcedar. The saltcedar mapping was hand-classified, thereby reducing the high error rate of computer classification. However, even with this method, some error is expected. Single trees, especially when mixed in with ash or mesquite, and very small trees may not be evident even with hand-classification. Over 750 acres of saltcedar were identified with this mapping method. Figures 4.2 – 4.4 display the density of saltcedar within each sub-basin management unit. Figure 4.5 shows the level of detail possible with hand-classified mapping.

A grant proposal submitted through the SNPLMA funding process was approved in 2006. This grant includes money to complete a comprehensive vegetation map to further refine what Otis Bay and Stevens Ecological Consulting accomplished in 2005. This will involve intensive surveying by foot and mapping with GPS. Non-native plant species and endemic species will be the top survey priorities. The grant will also cover refuge-wide aerial spraying of saltcedar, treatment of re-sprouts, mulching of saltcedar skeletons, treatment of 500 acres of Russian knapweed, native seed collection for revegetation, revegetation with native plants, and the production of interpretive/educational signs and brochures.

Characterization of Infestations and Prioritization by Management Approach

Sub-basin Management Units

Warm Springs Management Unit The Warm Springs sub-basin management unit will receive top priority for IPM treatment for several reasons. It is the smallest sub-basin management unit and currently contains the least amount of non- native species making it very manageable. Much of this unit contains the unique alkaline soil where most of the Refuge’s Federally-listed plant species occur, and this is the only sub-basin where the Warm Springs pupfish live. The Warm Springs unit is also the Refuge’s top priority for hydrological restoration and therefore, weeds must be eradicated to prevent spread during restoration activities. The two non- native plant species of concern in this unit are Russian knapweed and Malta starthistle. There are approximately two acres of these species on Refuge-owned land and another 2 ½ acres on a 40-acre in- holding in this unit. The Refuge and the Tri-County Weed Program are working with the private land owner to address this issue.

Jackrabbit-Big Springs Management Unit The Jackrabbit-Big Springs sub-basin management unit is second in priority for hydrological restoration following the springs in the Warm Springs unit. Much of the wetland and riparian vegetation within this unit, including saltcedar, burned during the Ash and Meadows fires of 2005. BAER funds are being used to treat weeds and plant native vegetation. Saltcedar trees have been extracted (large trees) or treated with herbicide (saplings) along the Jackrabbit Spring outflow channel and within the Ash fire project area. Russian knapweed and palm trees have also been treated.

Bassia’s proven ability to spread into disturbed areas of AMNWR and the lack of data on successful control methods ranks it a high priority for treatment in the Jackrabbit-Big Springs management unit. It is crucial to prevent its spread and keep it from becoming the problem it is in the Crystal Springs and North Carson Slough management units. Cattails and Phragmites are also a concern in this unit due to their flammability and the amount of private property at the south end of the sub-basin. The Meadows fire burned through accumulated cattail litter over the top of standing water; burning across emergent wetlands (Otis Bay, Inc. 2006) and threatening at least one home. This area will remain a high priority

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for IPM treatments to prevent the reoccurrence of weeds due to fire/private property issues, and to protect the considerable investment of time and money already committed.

North Carson Slough and Crystal Spring Management Units Both the North Carson Slough and Crystal Spring sub-basin management units have large non-native and pest plant issues and will be extremely difficult to manage. Both units have been heavily impacted by humans, have hundreds of acres of old agricultural fields, and include reservoirs and other areas receiving high recreational visitation with the increased potential for spread of weeds. The largest acreages of five- hook bassia, a particularly problematic species at AMNWR, are found in these two units, as are large expanses of cattails that replace other native vegetation and impact Ash Meadows pupfish. Crystal Springs unit has the largest known concentration of Russian knapweed; approximately 150 acres around the Bradford Springs area (spills over slightly into the Jackrabbit-Big Springs management unit), but the North Carson Slough unit has the largest diversity of weeds forming non-native plant species-dominated communities. Also, there is a breached dam located in the North Carson Slough unit, adjacent to the Refuge on BLM land. This dam sits in the largest single drainage basin feeding into AMNWR. Because the dam has breached, the 55 acres of saltcedar and bassia that have grown in behind the dam are, most likely, the largest single seed source for these species.

Both units contain threatened and endangered species, but the Crystal Springs unit has larger populations of the listed plants and it is the only unit containing the endangered Devils Hole pupfish and Ash Meadows niterwort. Currently, there is no money earmarked for treatments within the Crystal Springs sub-basin. However, AMNWR is participating in a study being conducted by Colorado State University and New Mexico State University, testing several herbicides for effectiveness on Russian knapweed. The National Park Service Exotic Plant Management Team (EPMT) and the U.S. Geological Survey (USGS) are managing the treatment and monitoring of these test plots. The site of this study is near Bradford Springs in the Crystal Springs Management Unit.

Weed treatment is ongoing in the North Carson Slough management unit due to funding acquired through the BAER program.

Spring and Reservoir Management Units

Whenever possible, non-native plant treatments will be considered on a sub-basin scale; however, there are times when it may be necessary to narrow the focus to individual springs or reservoirs, such as when hydrological restoration or facility development is planned. From the perspective of impacts to sensitive species, most of the springs in the Warm Springs complex and Jackrabbit Spring would rank high in priority as do their sub-basin management units. However, Collins Ranch Spring and Crystal Spring in the Crystal Spring management unit, and Cold Spring and the area around Rogers Spring in the North Carson Slough unit would also rank high. Due to funding received through SNPLMA, interpretive facilities (i.e., boardwalk, signs, small seating/viewing area) will be constructed at Longstreet Spring and the King’s Pool – Point of Rocks springs area. Money for weed treatments is included in this funding.

Targeted Species

Tamarisk species and Russian knapweed are the top priorities for IPM treatment. Treatment of these species has already begun, especially in the fire project areas. In 2006, AMNWR received money to begin Refuge-wide treatment of tamarisk and control of approximately 500 acres of Russian knapweed and bassia. Hoary cress, bassia, and the starthistles (Malta and yellow) will remain top priorities for treatment with BAER funds. Pervasive grass species like red brome, Johnson grass, and rabbitfoot grass

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(Polypogon monspeliensis) will be treated only when found in small populations within treatment areas or when mixed in with other high priority species that are being treated.

Conclusions and Recommendations

The comprehensive vegetation survey planned for AMNWR will help to better define current plant communities and their ecology, and will provide a clearer picture of the current status of non-native and pest plant species on the Refuge. It may turn up species not previously documented, and confirm or challenge existing priorities, but it will definitely result in better management decisions. However, it must be remembered that any biological inventory is only a snapshot in time. Invasive plant populations are dynamic and will require monitoring annually at a minimum (Evans et al. 2003).

Ongoing monitoring of invasive species’ response to IPM treatments is also critical in order to evaluate the effectiveness of different treatment methods and apply adaptive management practices. A successful IPM program requires a commitment of funds and adequate staffing year-round (Evans et al 2003). AMNWR must make this a high priority and continue to seek out funding wherever available.

AMNWR must continue to work with private property owners to prevent the spread of weeds between the Refuge and inholdings. The FWS will also work with the BLM to remove the breached Mud Lake dam and the 55 acres of saltcedar and bassia in the major drainage feeding into the Refuge.

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Table 4.1. Non-native and pest plant species present on Ash Meadows National Wildlife Refuge.

Scientific Name Common Name Family Status ~ Acres Acroptilon repens Russian knapweed Asteraceae Noxious 500-1000 Cardaria draba hoary cress Brassicaceae Noxious unknown Centaurea melitensis Malta starthistle Asteraceae Noxious 10-50 Centaurea solstitialis yellow starthistle Asteraceae Noxious unknown Solanum eleagnifolium white horse nettle Solanaceae Noxious 50-100 Sorghum bicolor sorghum Poaceae Noxious 50-100 Sorghum halepense Johnson grass Poaceae Noxious Tamarix parviflora tamarisk Tamariacaceae Noxious 1000 Tamarix ramosissima saltcedar Tamariacaceae Noxious Tribulus terrestris puncture vine Zygophyllaceae Noxious <1-10 Agrostis semivericillata water bent Poaceae introduced unknown Amaranthus albus tumbleweed Amaranthaceae introduced unknown Amaranthus retroflexus Redroot pigweed Amaranthaceae introduced unknown Arundo donax giant reed Poaceae introduced <10 Asparagus officinalis asparagus Liliacae introduced <1-10 Avena sativa cultivated oat Poaceae introduced unknown Bassia hyssopifolia fivehook bassia Amaranthaceae introduced 500-1000 Bromus madritensis var. rubens red brome Poaceae introduced 500-1000 Cenchrus echinatus sandbur Poaceae introduced unknown Chenopodium album lamb's quarters Amaranthaceae introduced unknown Cirsium vulgare bull thistle Asteraceae introduced <1-10 Convolvulus arvensis field bindweed Convolvulaceae introduced 50-100 Conyza Canadensis horseweed Asteraceae introduced 10-50 Cynodon dactylon Bermuda grass Poaceae introduced 500-1000 Descurania Sophia flixweed Brassicaceae introduced 100-500 Echniochloa crusgalli barnyard grass Poaceae introduced unknown Eleagnus angustifolius Russian olive Eleagnaceae introduced <1-10 Elytrigia pontica ssp. Pontica tall wheatgrass Poaceae introduced unknown Erodium cicutarium Redstem filaree Geraniaceae introduced 50-100 Festuca arundinacea tall fescue Poaceae introduced unknown Festuca pratensis Meadow fescue Poaceae introduced unknown Gnaphilum luteo-album weedy cudweed Asteraceae introduced <1-10 Halogeton glomeratus salt weed Amaranthaceae introduced <1-10 Helianthus annuus annual sunflower Asteraceae introduced 100-500 Hordeum murinum ssp. glaucum Barley Poaceae introduced unknown Hordeum vulgare common barley Poaceae introduced unknown Lactuca serriola wild lettuce Asteraceae introduced 10-50 Lepidium perfoliatum shield-cress Brassicaceae introduced unknown Lolium perenne English ryegrass Poaceae introduced unknown Lotus corniculatus birdfoot trefoil Fabaceae introduced 500-1000 Malcolmia Africana African malcomia Brassicaceae introduced unknown Marrubium vulgare horehound Lamiaceae introduced 10-50 Medicago sativa Alfalfa Fabaceae introduced unknown

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Table 4.1. Non-native and pest plant species present on Ash Meadows National Wildlife Refuge.

Scientific Name Common Name Family Status ~ Acres Melilotus alba white sweetclover Fabaceae introduced unknown Melilotus indica sourclover Fabaceae introduced 500-1000 Melilotus officinalis yellow sweetclover Fabaceae introduced unknown Nuphar odorata water lily Nymphaceae introduced unknown Phoenix dactylifera date palm Arecaceae introduced <1-10 Phragmites australis common reed Poaceae native unknown Plantago major broadleaf plantain Plantaginaceae introduced unknown Polygonum argyrocoleon silversheath knotweed Polygonaceae introduced unknown Polypogon monspeliensis rabbitfoot grass Poaceae introduced 100-500 Populus nigra Lombardy poplar Salicaceae introduced <1 Rorippa nasturtium-aquaticum water cress Brassicaceae introduced 50-100 Rumex crispus curly dock Polygonaceae introduced unknown Salsola paulsenii Russian thistle Amaranthaceae introduced 500-1000 Schismus arabicus Arabian grass Poaceae introduced unknown Sisymbrium irio London rocket Brassicaceae introduced unknown Sonchus asper ssp. Asper spiny sowthistle Asteraceae introduced unknown Tamarix aphylla Athel Tamariacaceae introduced <1-10 Trifolium ssp. Clover Fabaceae introduced unknown Typha domingensis Cattail Typhaceae native unknown Veronica anagallis-aquatica water speedwell Plantaginaceae introduced unknown Vulpia octoflora var. ? six weeks fescue Poaceae introduced unknown Washingtonia filifera California fan palm Arecaceae introduced <1-10

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Figure 4.1.

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Figure 4.2.

55

Figure 4.3.

56

Figure 4.4.

57

Figure 4.5.

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V. Invasive Plant Species Profiles: Biology and Species-Specific Control Recommendations

The plant species targeted for treatment were chosen either due to their actual or potential threat to Federally-listed species and ecosystem processes in AMNWR, or their status as noxious weeds in the State of Nevada. With the exception of saltcedar, the full extent (current distribution and abundance) of these species is unknown, but in some cases has been estimated. Mapping of these species is a top priority of AMNWR’s IPM program. The size of an infestation, its pervasiveness, and management difficulty will determine whether the goal is eradication or containment. For instance, relatively small, separated populations of Russian knapweed, such as that in the Warm Springs complex (Warm Springs management unit), will be targeted for eradication. The current goal for the extensive infestation of Russian knapweed at Bradford Springs is containment with a long-term goal of reduction.

A species that is not on the Target Species list may still be considered for treatment, especially if it is found in close proximity to priority species in project areas, or is a new arrival in the Refuge. The list will be reviewed and updated biennially or as more information is gained.

The following brief profiles of targeted species include a discussion of possible treatment methods and priority sites for treatment.

Target Species

Acroptilon repens

Common name: Russian knapweed

Russian knapweed is a long-lived perennial forb in the composite family (Asteraceae) characterized by an extensive, spreading root system and low seed production (Carpenter and Murray 1998a). It is a strong competitor and can form dense colonies in disturbed areas. The plant spreads primarily through a system of creeping horizontal roots. The roots of Russian knapweed can extend to a depth of more than 7 meters with as much as 2.5 meters of growth occurring the first year (Zimmerman 1996). A single plant can cover an area of 12 m2 within two years (Watson 1980).

Russian knapweed’s dense vegetative growth allows the species to quickly colonize and dominate new sites, forming dense single-species stands. It produces an allelopathic compound which may inhibit root growth of neighboring plants (Watson 1980, Stevens 1986), furthering the species competitive advantage. Russian knapweed invades open, disturbed areas, roadsides, agricultural areas, and rangelands. It appears to thrive in riparian areas where soil moisture is somewhat higher than normal; however, recent evidence suggests it is expanding slowly into even the driest habitats (Young and Clements 2002). Russian knapweed infestations crowd out native plant species, reduce forage value for wildlife and range stock, and increase precipitation runoff and soil erosion (Carpenter and Murray 1998a, Roché and Roché 1988). The species can be extremely long-lived and persistent, with clonal stands reported as old as 75-100 years (Carpenter and Murray 1998a).

Mechanical Control Russian knapweed can sprout from root fragments. Therefore, many physical control methods are not highly effective. Hand-pulling can actually contribute to its spread (Roche and Roche 1991, Sheley 1997). A majority of the root system must be removed to effectively eliminate the plant which is

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impossible considering the extent of the taproot (>2.5 meters) and horizontal roots (> 7 meters) (Graham and Johnson 2004). Cutting and mowing several times annually will control existing top growth and may lower plant vigor, but it will not kill Russian knapweed. Because populations will rebound vigorously if just one year is missed, the process would need to be repeated annually which would not allow for the recovery of native vegetation (TNC 2002). Also, mowing is largely ineffective because the plants respond by producing flowers below the mowed height, although this may result in decreased flower and seed production (IVM Technical Bulletin, M. Ryan, pers. comm.). Disking is also not effective since each root fragment can regrow into a new plant (Graham and Johnson 2004, B. Wilson, pers. comm.).

Prescribed Burning Knapweeds are not very flammable, resulting in low temperature fires and patchy, discontinuous burns. Knapweed will rapidly regenerate from rootstalks and fire may actually encourage knapweed establishment and growth. On the other hand, a combination of fire followed by herbicide treatment may result in greater grass cover than non-burned, herbicide-treated sites (IVM Technical Bulletin 2000). Graham and Johnson (2004) do not recommend burning; however, fire may be used to remove the previous year’s top growth and more completely expose new growth to chemical treatment (B. Wilson, pers. comm.).

Biological Control The USDA has approved the use of the Russian knapweed gall nematode (Subanguina picridis) which was introduced in 1984 and has been established successfully in Washington, Colorado, Montana, Oregon, Utah, and Wyoming. This nematode weakens, but does not kill the plant (Graham and Johnson 2004). Refuge policy is to minimize risk to non-target plants and animals and therefore, no biological control agents will be used while their effects on Ash Meadows’ threatened and endangered species are unknown.

Subanguina picridis is a gall forming nematode native to Asia, and is now established in Colorado, Montana, Oregon, Utah, Washington, and Wyoming. The microscopic nematode is worm-like and about 1.5 mm (.06 in) long. It induces the production of galls on the stems, leaves, and root collars of infected plants causing a reduction in plant growth and seed production. Galls on the stems of the plant often visibly distort plant growth.

Larvae of Subanguina picridis feed, mature, and reproduce within the galls. Two or more generations are completed during the growing season, and second-stage larvae become dormant and overwinter in the soil.

In early spring, the infective-stage larvae are activated by moisture, and leave the deteriorating galls. They penetrate immature leaves and stems of new shoots, and galls eventually form at the infected sites. Nematodes multiply within these galls until August when the mature galls contain primarily second-stage larvae. These second-stage larvae disperse and overwinter in the soil as the galls disintegrate. The following spring these larvae usually become infective after at least a month in moist soil (Rees et al. 1996).

Under most conditions, Subanguina picridis needs to overwinter in the soil before it is able to attack its host. Therefore the fall seems to be the best time for application. Subanguina picridis likes moist areas during the winter and spring infection periods and does not flourish in dry areas. The range of Subanguina picridis is limited because the nematodes can not travel far from their host plants. Human intervention is needed to introduce the nematode to a new site. Galls can be collected in the fall and placed upon the soil to permit the nematode larvae to emerge from the wet, disintegrating

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galls and penetrate the young knapweed shoots when they break through the soil in the spring (Rees et al. 1996).

Aceria acroptiloni (Russian knapweed mite) is a gall-forming mite native to Eurasia and the former Soviet Union. The mites form galls in the flower heads of Russian knapweed and feed on the inner bracts, the receptacles of the flowers, and the deformed structures of the flowers. Females lay eggs in the receptacle of the flower and inner bracts.

Two or more generations are formed during a single season. The first generation (spring) females are morphologically different from the summer and winter females that appear later. Male acroptiloni mites do not differ morphologically between generations (Kovalev et al. 1975). The mites overwinter in the upper ends of the inner leaflets and the deformed flower structures.

Plants that have been infested with Aceria acroptiloni are underdeveloped and noticeably stunted. The formation of new shoots ceases and seed production is hindered. (From The Nature Conservancy’s Element Stewardship Abstract on Acroptilon repens)

Cultural Control Cultural control of Russian knapweed by manipulating soil moisture and fertility, grazing, or sowing competitive species is very difficult. Russian knapweed is very tolerant of drought conditions and is a great competitor because its deep rootedness allows it to survive dry surface soils for long periods (Graham and Johnson 2004). Production of an allelopathic chemical by this plant inhibits the growth of competing plants.

Grazing knapweed stands with domestic goats followed by herbicide use has been used with some success (G. Glenne, pers. comm.); however, there is concern that diseases found in goats can be spread to bighorn sheep. The largest Russian knapweed stand in Ash Meadows is found near the Point of Rocks, an area occasionally visited by bighorn. Proper management of goats can minimize the risk to bighorn sheep. (See Appendix.)

Chemical Control Large infestations are best controlled with herbicides, but herbicides alone will not effectively manage Russian knapweed. A combination of chemical and cultural controls works best (Beck 2003). The method of combining an herbicide for weed control with a reseeding program has been tested at the University of Wyoming for 12 years with excellent weed control after only the initial herbicide treatment (Whitson 1997, Bottoms et. al. 1998).

Picloram is most often mentioned as the herbicide of choice, although clopyralid and glyphosate have also been recommended (TNC 2002, Beck 1996, Duncan 1994). Imazapic (Plateau®) and imazapyr (Arsenal® and Habitat®) are newer herbicides that have also been reported to be effective (B. Lee, pers. comm.). Glyphosate (Rodeo®) may be the least effective of these herbicides, but it, along with Habitat®, are the only ones currently approved for aquatic use. A recent trial of several chemicals on Russian knapweed in Ash Meadows shows Milestone to be promising when applied during the dormant season.

Rodeo® only effects the top growth of Russian knapweed. It is rapidly inactivated upon contact with soil and so will not suppress germination or seedling emergence if applied to the soil (Ross and Childs 1998). There will be abundant regrowth from the knapweed root systems when glyphosate is used so the process must be repeated annually for a number of years (TNC 2002, Sirota 1998). Transline® controls the initial top growth and also inhibits regrowth during the same season (same-season control). Higher rates of Transline® may reduce shoot regrowth the following season, but plant response may be inconsistent.

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Tordon® also requires annual retreatment, but at rates at the low end of the rate range. All of these recommended herbicides are applied to Russian knapweed in late summer and/or fall (varies with herbicide). Control with Plateau®, Arsenal®, and Tordon® improves as senescence progresses. Tordon® is reportedly very effective after the first frost (B. Wilson, pers. comm.). Applying a chemical after grasses are dormant and trees have dropped leaves can reduce the potential for non-target injury.

After stressing the plants with herbicide, the treated area should be tilled to get rid of the allelopathic chemical produced by Russian knapweed, followed by seeding or transplanting plugs of competitive plants such as perennial grasses. Salt grass is reported to be tolerant of picloram (Tordon®) (B. Wilson, pers. comm.).

Priority Sites Currently, Russian Knapweed is estimated to cover 500 – 1000 acres of Ash Meadows NWR. Top priority sites for treatment include the Warm Springs Complex, Tubbs Ranch (Jackrabbit-Big Springs management unit), Bradford Springs, and the retired agricultural fields in the Longstreet fire project area (North Carson Slough management unit). The largest acreage is in the Bradford Springs area (at least 150 acres), most of it within the Crystal Springs management unit. Test plots comparing the effectiveness of different herbicides have been established in this area. The National Park Service Exotic Plant Management Team (EPMT) is administering the treatments while the U.S. Geological Survey (USGS) manages the monitoring of the test plots. AMNWR plans to also test the effectiveness of grazing goats seasonally over a period of three years. Although this method will still require the use of herbicide after the third year, the quantity and concentration needed should be less than without the grazing.

Bassia hyssopifolia

Common names: five-hook bassia, five-horn smother-weed

Bassia is originally from Europe. It is common in cultivated fields and probably was introduced to the Refuge through hay. Bassia has been present since at least 1996, but has expanded on the Refuge over the past eight years and is spreading rapidly. Phenologically, it takes advantage of disturbed areas, grows to 5 feet in height with 10 foot diameters, and inhibits growth of other plants within its zone of influence. Bassia has a 5-hooked fruit and spines on its stems that make seed dispersal easy and walking through a stand difficult after maturation. Like tumble weed, it breaks off at maturity and is transported across the landscape disseminating seed. Where native species are prevalent, Bassia is not found. However, Bassia is an opportunistic non-native invasive species and it will infest disturbed sites.

The following is from The Nature Conservancy’s Element Stewardship Abstract for Bassia hyssopifolia (Hoshovsky 1986):

Mechanical Control Hand Pulling: Muenscher (1955) recommends hand weeding of Bassia, done most easily after a rain when the soil is loose. Plants should be pulled as soon as they are large enough to grasp but before they produce seed. The pieces of root remaining in the soil will not sprout again.

Hand Hoeing: Plants can be destroyed readily while they are still small by hand hoeing, either by cutting off their tops or by stirring the surface soil so as to expose the seedlings

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to the drying action of the sun. The object of hoeing is to cut off weeds without going too deeply into the ground and doing damage to the roots of desirable vegetation. Mechanical control requires multiple treatments throughout the growing season and is, therefore, labor intensive.

The following is from Invasive Plants of California’s Wildlands (Bossard et al. 2000):

Prescribed Burning Burning may be a useful control strategy for bassia, though it has not been tried. [The August 2004 Longstreet Fire in Ash Meadows resulted in only patches of burned bassia; however, native salt grass appears to be doing well in those areas that did burn.]

Biological Control No program currently exists for biological control of bassia.

Grazing Livestock readily graze on bassia, although sheep have died after a single feeding (James et al. 1976). Goats are able to utilize bassia (S. Harris, pers. comm.).

Chemical Control Chemical control of bassia has not been reported, although it may be similar to control of other similar species, such as kochia and Russian thistle. Russian thistle can be controlled with dicamba, 2,4-D, and picloram plus 2,4-D at 1 – 1.5 fl oz/acre + 0.75 pt/acre. Kochia can be controlled with dicamba plus MCPA amine at label strengths. With good spray coverage, 2,4-D gives good kochia control. The esters of 2,4-D generally are more effective than the amines for both weeds. Picloram is not effective on kochia; but control is good when it is combined with 2,4-D ester at 0.75 pt/acre (North Dakota State University Extension Service 1998). Herbicides may be applied non- selectively (i.e., broadcast application) or selectively (i.e., spot treatments).

Priority Sites Bassia hyssopifolia is estimated to cover 1000 acres of Ash Meadows NWR. It is located in various size patches throughout the refuge, but is most pervasive in the retired agricultural fields of the North Carson Slough and Crystal Spring management units. The top priority site is in the Warm Springs Complex where bassia is located along the road leading to private property within the Refuge. Other priority sites are those within fire project areas and the interpretive project area at Point of Rocks. When funding is available, the next priority will be other sites within the Jackrabbit-Big Springs management unit.

Bromus rubens

Common names: red brome, foxtail brome, foxtail chess

The following is from The Nature Conservancy’s Element Stewardship Abstract for Bromus rubens (Newman 1992):

Like all annual grasses, the development of Bromus rubens is comprised of six stages: germination, vegetative growth, floral bud development, maturation of flowers, fruiting,

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and senescence (Hufstader 1978). The prevailing environmental conditions influence the various stages of development in different ways. Germination of Bromus rubens seeds is particularly dependent on the moisture level of the soil. The ability to germinate throughout the fall, winter and spring, provide the seeds an opportunity to maximize the utilization of available moisture in order for a vigorous growth phase early in the development of the plant. Vegetative growth commences with germination and terminates in the spring when floral development begins (Hulbert 1955). The growth rate and total standing crop appears to be relatively independent of the amount of precipitation once germination has occurred (Hufstader 1976). Plant development subsequent to germination is more dependent on the genetics of the species than it is on the environmental conditions. Growth proceeds slowly through the winter and reaches its maximum growth rate shortly before flowering (Beatley 1966, Hufstader 1978). Spring germination followed by a rapid growth period results in floral development at approximately the same time as flowering of plants that germinated in the fall (Beatley 1966). Plants that germinate in the fall are susceptible to winter freezes. Bromus rubens is not frost hardy and thus temperatures below 32 F will kill the plants (Hulbert 1955).

Crowding, especially in pure stands of red brome, decreases the survivability of individual plants (Wu and Jain 1979). A lack of reduction in number of seeds produced and a high mortality rate accompany higher density plots (Wu and Jain 1979). The section on Population Dynamics addresses these nonadaptive characteristics of Bromus rubens.

Several reasons, particularly the shallow root system and the lack of shade tolerance, account for the inability of this species to compete with established plants. In certain areas red brome is an understory plant and unable to adequately compete with the larger plants for sunlight because of its delayed initial development relative to the taller species (Hufstader 1978). Competition for nutrients along with competition for light appears to be a determining factor in the size and distribution of Bromus rubens; the shallow root system limits the ability of the plant to search for nutrients deep in the soil (Humphrey 1977). Nitrogen fertilizers, but not mulch, increase the growth rate of red brome (Hulbert 1955, Bartolome et al. 1980). Hulbert (1955) speculates that the readily available nitrogen from fertilizers aids in the production of a more extensive root system; the roots are then able to compete with larger plants for water and nutrient supplies, this, in turn, allows for greater above-ground growth.

Management goals should be to reduce seed production and, if appropriate, to increase competition from native herbaceous plants. The management of annual weeds such as Bromus rubens depends on reducing the size of the seed source. Active management is advised on lands with high densities of Bromus rubens. The high seed production ability results in increased population size, particularly in disturbed land with sparse vegetation cover. However, the density of the population will be limited because of red brome's lowered survivability rate in crowded situations (Wu and Jain 1979). Annual removal of seed heads will significantly decrease the amount of Bromus rubens. Reduction in the number of weed seeds will produce available sites for native seeds to germinate and become established. Encouraging germination of native seeds will decrease the reproductive success of red brome. Bromus rubens is not competitive in vegetated sites and established native plants will out-compete the remaining seedlings. Re-establishing native plants should be relatively easy due to the lack of competitive ability of this species.

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Mechanical Control Clipping of Bromus spp. seedlings only slightly reduces the yield (Hulbert 1955). Mowing the plants prior to seed development results in the development of new culms; however, plants are usually killed when cut at soil level once seeds have developed (Hulbert 1955). Mowing at this stage is pointless since the seeds will be dispersed and the plant left alone would have senesced. Increasing the frequency of mowing throughout the entire growing season decreases the quantity of the yield (Hulbert 1955).

Removal of weeds, especially annuals, can be accomplished by hoeing the plants (Lorenzi and Jeffery 1987). Plants will not reach maturity if the seedlings are uprooted and thus no seed source for the following year will be produced. This repetitive task is time consuming, especially since seeds of Bromus rubens germinate from fall through spring. An alternate approach would be to remove all the Bromus rubens plants at one time during the spring before the majority of flowering occurs. Bromus rubens plants are shallow rooted and can be easily removed from the soil by hand or with tools (Humphrey 1977, Richter pers. comm.). The fire hazard from red brome is reduced with spring raking of the dead stems at Boyce-Thompson Arboretum (Crosswhite pers. comm.). Although this method disturbs the land, the number of plants and the seed source for the following year can be decreased.

Mulching often helps in controlling annual weeds (Lorenzi and Jeffery 1987). Either a thick layer (5 cm to 13 cm) of organic mulch or a layer of black plastic will reduce the number of germinating seeds (Heathman et al. 1986, Lorenzi and Jeffery 1987). The former treatment will aid in rebuilding the often eroded topsoil whereas the latter may become a nuisance when the plastic is broken down by the sun. The effects of mulching can be variable. Due to the possibility that mulch will facilitate the growth of Bromus rubens in certain situations, the beneficial and detrimental characteristics of mulch should be tested for each individual site before attempting a large scale control using this technique. A reduction in seedling emergence of Bromus tectorum from 93% to 14% is seen when the depth of burial increases from 4 cm to 6 cm (Hulbert 1955). Since only 2% of seeds are carried over to the following year (Wu and Jain 1979), a prevention of seed development will reduce the number of mature plants.

Burning and Grazing Burning (in June, October and unknown months) increases the abundance of Bromus rubens, especially in areas where the land had previously undergone disturbances (Beatley 1966, O'Leary and Westman 1988). Experiments conducted with coastal sage vegetation burned one time in June or October resulted in drastic increases in the amount of red brome in the sites where there were few vigorous native perennial plants plus a supply of Bromus rubens seeds present prior to the fire (O'Leary and Westman 1988). In general, burning increases the number of annual weedy plants (Pickford 1932). However, if burning comes at a time that will prevent seed production and if native perennial plants are encouraged to grow, burning may help in changing the balance of the plant community (Johnson and Smathers 1974, O'Leary and Westman 1988). Burns conducted in late-fall may possibly damage Bromus seedlings while encouraging the early growth of perennial grasses.

Limited controlled grazing may be beneficial, in some cases. Sheep grazing in California is used to manage weedy annual Bromus species. However, desirable native species are

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also eaten and soil may be altered by livestock promoting further establishment of red brome (Bossard, et al. 2000).

Chemical Control Due to the annual growth cycle of red brome, the most effective chemical control would be from pre-emergence herbicides. These chemicals would kill the seeds in the soil before they germinated.

Rodeo®, Habitat®, Arsenal®, and Plateau® have been used to treat related Bromus species.

Monitoring Requirements Bromus rubens should be monitored to determine if the number of plants are increasing or decreasing; in particular, monitoring the number of seeds allows for prediction of the invasive potential for the following year. Yearly monitoring of the following parameters will be helpful in assessing various control techniques: aerial extent of brome plants, percent seed and percent cover of competing herbaceous plants.

The area covered by Bromus rubens can be determined using transects or winter aerial photographs (color or CIR). The increase or decrease in the extent of land covered by the weed should be determined yearly. Tagging the outer boundary of the invaded area will allow for rapid visual determination of the effectiveness of the control technique.

Visual inspection of the number and size of inflorescences is needed to determine the success in reducing the seed source. Complete elimination of the inflorescences is necessary for eradication of the species. Visual estimation of the extent and density of competing native herbaceous plants will allow for the prediction of a natural change in plant composition. Thus, only limited human intervention may be necessary.

The following is from Invasive Plants of California’s Wildlands (Bossard et. al. 2000):

Physical Control Seedlings can be pulled before they produce seeds, but this is practical only on a small scale. Hand pulling may be an option to help revegetated plants become established during the initial stages of restoration projects, but seed rain from plants in adjacent areas will recolonize any open habitat.

Grazing Livestock grazing may be used in lieu of hand pulling. Unfortunately, desirable native species are eaten as well, and alterations to the soil caused by livestock may promote further establishment of red brome.

Prescribed Burning Burning aids the establishment of red brome in most cases. One exception is fire occurring in spring before seeds are fully mature or have otherwise dispersed to the ground. Naturally occurring spring wildfires can reduce the above-ground biomass of red brome while enhancing that of native forbs in both coastal and desert regions of southern California. Temperatures in fires in grassland and scrub habitats easily kill foxtail chess seeds suspended in the flame zone, but often are not high enough to kill seeds located at or below the soil surface (Brooks 1998). Some perennial plants are more vulnerable to

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fire in spring than in other seasons. However, the high water content of perennials during spring can provide some protection if the intensity of the fire is low.

Chemical Control Various herbicides, including glyphosate, have controlled red brome in agricultural applications, but they are either not practical to use over the large expanses typically infested by red brome or not currently registered for wildland use.

Priority Sites Currently, red brome is estimated to cover 500 – 1000 acres of Ash Meadows NWR; however since no surveys of red brome have been completed, the actual acreage could be quite different.

Cardaria draba

Common names: hoary cress, white top, perennial pepper-grass, heart-podded hoary cress, pepperwort, pepperweed whitetop, white weed.

Hoary cress is a hardy Eurasian perennial forb in the mustard family (Brassicaceae). The species grows in a variety of habitats, but thrives in disturbed areas where soil moisture is at or near the surface for some part of the growing season. Hoary cress’ dense clonal growth excludes native species and reduces forage quality for wildlife (Chipping and Bossard 2000, Lyons 1998a). It possesses a deep, long-lived taproot that enables plants to spread rapidly, out-compete native vegetation, and resist control efforts. Roots are fast growing and penetrate at least several meters into the soil. Even small fragments of damaged roots left behind after control efforts will resprout (Evans 2003, Lyons 1998a).

The following is from The Nature Conservancy’s Element Stewardship Abstract for Cardaria drab (Lyons and Meyers-Rice 1998):

Management Program & Recovery Potential Because they can regenerate from their extensive root systems, the hoary cresses readily re-establish after eradication measures. Therefore, control must be persistent, and requires at least 2-3 years of follow-up work (Blackman, et al. 1939; Garrad, 1923; Willis, 1950).

Successful control is most likely achieved with a combination of approaches. Selleck (1965) used a combination of mowing and competitive cropping to control C. chalepensis and C. pubescens. O’Brien and O’Brien (1994)--managers for The Nature Conservancy-- controlled C. draba by ceasing its irrigation, removing outlying plants, and increasing the general health of the grasslands they were managing. Other managers for The Nature Conservancy have decreased grazing (Carr, 1995), or developed restoration plans (Hill, 1995).

Prevent new infestations originating from seed sources. Seed may travel in contaminated hay, on farming equipment, and in fresh manure (Carr, 1995). Cardaria seeds have been eliminated from manure after one month of decomposition under very moist, warm conditions in late summer (Anonymous, 1970).

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Biological Control No biological control agents are available for hoary cress (Miller & Callihan, 1991).

Cultural Practices The hoary cresses are most invasive in agriculture when they are irrigated. In less disturbed settings without irrigation, and in competition with other species (particularly perennial shrubs) they are relatively easily controlled. In moist conditions, alfalfa is a better competitor with C. chalepensis than perennial shrubs are, and in a combination of alfalfa cultivation and mowing 2-3 times per year will eradicate C. chalepensis within 5-6 years (Selleck, 1965). Other plants that compete well against C. chalepensis (at least in Saskatchewan, Canada) were Rosa spp., Symphoricarpos occidentalis (western snowberry), and the invasive exotic Centaurea repens (Russian knapweed).

Mechanical Control Cutting is somewhat effective in controlling C. draba. A combination of weed-whacking and applying 2,4-D from a backpack sprayer has provided 50% control at a preserve maintained by The Nature Conservancy (O’Brien & O’Brien, 1994). Meanwhile, a single late-April treatment of cutting plants back to the ground did nothing to control plants in England (Willis, 1950). Cutting in this way, combined with an herbicide application, was no more effective than using herbicides alone. If cutting is to be used, it clearly should be timed properly. Cutting before plants are flowering does little to control plants, while waiting for the plants to be in full flower will result in smaller plants and less seed production (McInnis et al., 1990). However, McInnis et al. 1990 recommend that cutting plants be combined with grazing as a primary or long-term solution for control of C. draba.

Cardaria root systems can be exhausted through repeated cultivation (Kott, 1966; Barr, 1942), resulting in complete elimination if the follow-up occurs within ten days of weed reemergence (Miller & Callihan, 1991). Hulbert et al. (1934) found tilling was a more economical way to remove C. draba than were herbicides. They recommended an initial deep plowing, followed by 10-13cm deep cultivations every five days for the first six to eight weeks of growth, and then less frequent tillings into October. Using this regimen, the plants were killed within two years. By tilling less frequently, Mulligan & Findlay (1974) killed Cardaria after three consecutive years. Even one cultivation before seed set reduced infestations.

Rosenthal and Headley (1944, as referenced by Mulligan & Findlay, 1974) successfully eradicated C. pubescens in one and a half seasons by hoeing every four weeks.

Cultivation is generally more successful when used with a competitive crop, as described above. On irrigated land Selleck (1965) controlled C. chalepensis in six years using summer fallowing combined with disking and planting mixtures of alfalfa and Bromus plants.

Cultivation machinery can spread Cardaria infestations, so all root fragments should be removed from machinery before it is used in other, uninfested fields (Pemberton & Prunster, 1940; Mulligan & Findlay, 1974; Scurfield, 1962).

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Mowing to control hoary cresses is controversial. Under non-irrigated conditions, mowing provides some control but also harms other species, especially perennials (Selleck, 1965), which are important to maintain as competitors.

Grazing Sheep will eat C. draba, and especially like seedlings. Cattle that eat C. draba may have tainted milk (Scurfield, 1962)

Chemical Control Herbicide treatment for C. draba is effective, but in most cases a multi-year commitment is required (Blackman et al., 1939; Garrad, 1923; Robson, 1919; Willis, 1950). Cardaria draba can re-establish rapidly if control measures are stopped too soon (Willis, 1950). Even so, just a year of herbicidal treatment may help in restoration efforts where competitive plants are also being grown (Garrad, 1923).

The timing of herbicide application is important. Most recommend application of herbicides at the bud or flowering stage. In a very thorough study, Blackman et al. (1939) demonstrated that timing was important when using the herbicides MCPA (2 methyl-4- chloro-phenoxyacetic acid) and DCPA (2:4-dichloro-phenoxyacetic acid). Both herbicides were most effective when applied to flowering shoots but MCPA was more effective on plants still in bud (77% control) while DCPA was more effective on plants in full flower (69.4% control). Double spraying in one year did not improve control.

The three species of Cardaria differ in their susceptibility to herbicides, and C. draba is the most resistant. Jenkins & Jackman (1938) found that the application rate of carbon bisulfide to control C. draba was almost 2.5 and 2 times greater than that for C. pubescens and C. chalepensis, respectively. In Alberta, Canada, Sexsmith (1964) found that that the three species, C. chalepensis, C. draba and C. pubescens, differed in their responses to 2,4-D. Furthermore, he found that some strains of C. chalepensis were resistant (this may be because in Canada, C. chalepensis is frequently controlled using herbicides).

[Unless otherwise mentioned, all entries for herbicide use apply to C. draba.]

2,4-D: Apply 2,4-D LV ester or amine at 2.3-3.4kg acid equivalent/ha in non-cropland situations and 1.1kg acid equivalent/ha for selective treatment. Apply the herbicide early in the growth stage, before flowering. 2,4-D can be used in the spring, beforehand, when plowing, but respray new growth in the fall (William et al., 1998). Ester formulations should be sprayed only when the temperature is low, since they can evaporate at temperatures as low as 21ºC (70ºF) and harm non-target plants. Vaporization increases as the temperature rises (Hall et al., 1992).

A program of using a weed-whacker on flowering plants and 2,4-D applied using a backpack sprayer, several times during the growing season, resulted in approximately a 50% control rate (O’Brien & O’Brien, 1994).

In Saskatchewan, Canada, yearly 2,4-D applications at 2.2kg/ha, combined with competition from perennial grasses, eradicated C. chalepensis after three years (Selleck, 1965).

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In England, 2,4-D provided 90% control when applied for two years at .85-1.1kg acid equivalent/ha. Contrary to most other studies, these plants were treated when only several cm tall, to flowering size. A competitive crop that is tolerant to 2,4-D should be used in the third year (Scurfield ,1962).

In Canada, 75-99+% C. chalepensis control is achieved with 2,4-D at 5.6-23kg/ha. C. draba and C. pubescens are controlled to between 90-99% at only 2.25kg/ha. Measurements made one year post-application (Sexsmith 1964).

Amitrol and Amitrol-T: Apply at .7kg ai/100 liters water for spot treatment before first flowers open. Wet foliage thoroughly (William et al., 1998). Commercial use of amitrol is restricted as of 1985. It is not registered for use on crops or grazing lands.

In Canada, all three Cardaria species were controlled by 97-100% using Amitrol at 2.2kg/ha. Twice the application rate did not improve control. Measurements were made one year post-application (Sexsmith, 1964).

Ally: An application at 35gm/ha was effective (Carr, 1995).

Chlorsulfuron (Telar®): This is effective if applied at the pre-bloom to bloom growth stage, or to rosettes in the fall at 26-53gm ai/ha (William et al., 1998). Use this with an 80% ai surfactant. Apply only in sites not used for agriculture.

Metasulfuron (Escort®): This is effective if applied at the pre-bloom to bloom growth stage, or to rosettes in the fall at 21-42gm ai/ha (William et al., 1998). Use this with an 80% ai surfactant. Apply only in sites not used for agriculture.

MCPA (2-methyl, 4-chlorophenoxyactic acid): In England, MCPA applied as a spray at 2.2 or 4.5kg/ha controlled C. draba by 96% in the first year (for both rates). Control for the two rates during the second year was 94% and 98%, respectively. If the follow-up control was not applied during the second year, control was only 85% for both rates (Willis, 1950).

In Victoria, Australia, applications at the early rosette stage of growth provided 42% (for 1.1kg/ha), 28% (for 2.3kg/ha), and 55% (for 5.6kg/ha). Applying at 5.6kg/ha for a second year increased control to 85%. An application rate of 2.8kg/ha may be sufficient if there is competition from other plants (Moore, 1953).

Trials at 0.09kg/100liters/ha (in England) were most effective when applied at the bud stage and for at least two consecutive years. This provided 96% control. Double spraying each year was ineffective and wasteful. A third year of treatment may be required but was not tested in this study (Blackman et al., 1939).

Sulfometuron Methyl (Oust®): This is effective if applied to pre- or post-emergent hoary cress at 0.16-0.27kg ai/ha or 0.21-0.35kg/ha. The best results are obtained if the application is made during early stages of growth. It can only be applied in non-crop areas, and with extreme care if near crops (Hall et al., 1992).

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The following is from Invasive Plants of California’s Wildland (Bossard et. al. 2000):

Mechanical Control Tillage may control infestations if started at flower bud time and continued every ten days throughout the growing season. Slightly longer intervals may be possible at different times of year, but it is essential that no green leaves be allowed to form. This deprives rootstock fragments of energy, but the process may have to be continued for at least three growing seasons to deplete the seed bank. Care should be taken not to spread fragments of the plant out of the infested area on tillage equipment.

Prescribed Burning Cardaria species apparently are favored by fire through removal of competition.

Flooding Flooding to a depth of six to ten inches (15-25 cm) for about three months can produce 90 percent control of the plant (Cook 1987, Fryor and Makepeace 1978, Pryor 1959, Robbins et al. 1974). However, short-term submergence lasting a week has no effect on the plant (Chipping, pers. observation).

Biological Control No USDA recommended biological control agents exist, and potential introductions from the native range are complicated by the large numbers of cruciferous crops.

Grazing Grazing is not effective as Cardaria draba survives and resprouts using energy stored in its rhizome-like rootstock. The plant is actually spread by grazing, as cattle ingest seed heads and may become vectors for plant fragments.

Chemical Control Most research on chemical control has focused on cropland.

Different forms of 2,4-D have been tried with limited success in northern California, although Canadian trials have had success with applications at 1-2 lbs/acre, repeated for three years to remove the seedbank.

Mixes of 2,4-D ester and dicamba have been applied by aircraft, and mixes of 0.50 2,4-D and 0.25 each dicamba and R-11 surfactant have worked in roadside application of one of the mix in 100 gallons of water.

Chlorsulfuron, which is selective for broadleaf plants, has been used on California rangeland at 0.33-1 oz/acre with limited success, but affects non-target species. Glyphosate at 1 pt/acre produces 80 percent control at the budding or flowering stage, but is also non-selective (Cook 1987, Fryor and Makepeace 1978, Pryor 1959, Robbins et al. 1974).

Priority Sites Currently, hoary cress is estimated to cover at least 30-60 acres of Ash Meadows NWR. To date, it has only been found in the retired agricultural fields at the north end of the refuge, and at Point of Rocks, but

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much of the Refuge has never been surveyed. The known populations are included in treatment plans for the Longstreet Fire and the Point of Rocks boardwalk project areas.

Centaurea melitensis and C. solstitialis

Common name: Malta starthistle and yellow starthistle

Little research has been conducted on the biology and control of Malta starthistle. However, there is extensive information concerning its close relative yellow starthistle.

Yellow starthistle is an erect winter annual or occasionally biennial European forb in the composite family (Asteraceae). Yellow starthistle infests more than 15 million acres (6 million ha) in the western U.S. where it can form dense stands in natural areas, rangelands, and elsewhere. This species disperses seeds both in the summer (plumed seeds) and in early winter (non-plumed seeds) (Larson and Sheley 1994). Mature plants are capable of producing as many as 75,000 seeds, which may remain viable in soil for up to 10 years (DiTomaso and Gerlach 1999). Taproots grow vigorously early in the season to soil depths of 1 m or more, giving plants access to deep soil moisture during the dry months of summer and early fall (DiTomaso 2001, Larson and Sheley 1994).

Yellow starthistle infestations can reduce wildlife habitat and forage, displace native plants, and reduce native plant and animal diversity (Sheley and Larson 1994). It significantly depletes soil moisture reserves in both annual and perennial grasslands, and its high water usage threatens human economic interests as well as native ecosystems (DiTomaso 2001). Yellow starthistle is able to invade and coexist within cheatgrass-dominated annual grasslands, further complicating restoration efforts (Evans 2003, Sheley and Larson 1994).

The following is from The Nature Conservancy’s Element Stewardship Abstract for Centaurea solstitialis (DiTomaso 2001):

The goal of any management plan should be not only controlling the invasive weed, but also improving the degraded community, enhancing the utility of that ecosystem, and preventing reinvasion or invasion by other weed species. This usually requires a long- term integrated management plan.

Mechanical, cultural, biological and chemical control options are available for management of C. solstitialis. Mowing can be used as a mechanical option for C. solstitialis control provided it is well timed and used on plants with a high branching pattern. Cultural control options include grazing, prescribed burning, and re-vegetation with competitive species.

Sheep, goats or cattle are effective in reducing C. solstitialis seed production when grazed after plants have bolted but before spines form on the plant. Goats will eat starthistle even in the spiny stage.

In California, burning is best performed at the end of the rainy season when flowers first appear. C. solstitialis should be green at this time and will require desiccated vegetation to burn. Most annual vegetation other than C. solstitialis, particularly grasses, should have dried and shed their seeds by this time. Burning can also increase the recovery and density of perennial grasses.

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Re-vegetation programs using perennial grasses or legumes can be effective for management of C. solstitialis but establishment may be difficult in areas without summer rainfall.

Six biological control agents of C. solstitialis have been imported from Europe and are well established in the western United States. Of these the most effective are the hairy weevil (Eustenopus villosus) and the false peacock fly (Chaetorellia succinea). These insects attack the flower/seed head, and directly or indirectly reduce seed production by 43 to 76%. They do not, by themselves, provide sustainable management of C. solstitialis, but can be an important component of an integrated approach.

Clopyralid and picloram are the most effective herbicides for full season control of C. solstitialis. Unlike most postemergence herbicides, they provide both foliar and soil activity. The best timing for application is when C. solstitialis is in the early rosette stage. Clopyralid gives one season of control and is generally used at 1.5 oz a.e./acre, 4 oz product/acre (110 gm a.e./ha; 290 gm product/ha). Picloram has longer soil residual activity than clopyralid (two to three years) and is applied at 0.25 lb and 0.375 lb a.e./acre (0.28 kg and 0.42 kg a.e./ha). Glyphosate is a non-selective herbicide that is also effective on C. solstitialis. It will control bolted plants at 1 lb a.e./acre, 0.33 gal product/acre (1.1 kg a.e./ha; 9.4 liters product/ha) or 1% solution and can be used as a late season spot treatment to small infestations or escaped plants.

A list of management options for the control of C. solstitialis can be seen at http://wric.ucdavis.edu/yst/.

Mechanical Control Mechanical control options for C. solstitialis typically include hand pulling, hoeing, weed whipping, tillage or mowing.

Hand pulling, hoeing or weed whipping: Manual removal of C. solstitialis is most effective with small patches or in maintenance programs where plants are sporadically located in the grassland system. This usually occurs with a new infestation or in the third year or later in a long-term management program. These methods can also be an important in steep or uneven terrain where other mechanical tools (e.g., mowing) are impossible to use (Woo et al. 1999). To ensure that plants to not recover it is important to detach all above ground stem material. Leaving even a 2 inch (5 cm) piece of the stem can result in recovery if leaves and buds are still attached to the base of the plant (Benefield et al. 1999). The best timing for manual removal is after plants have bolted but before they produce viable seed (i.e., early flowering). At this time, plants are easy to recognize and some or most of the lower leaves have senesced. Hand removal is particularly easy in areas with competing vegetation. Under this condition, C. solstitialis will develop a more erect slender stem with few basal leaves. These plants are relatively brittle and easy to remove. In addition, they usually lack leaves at the base and, consequently, rarely recover even when a portion of the stem is left intact.

Tillage: Tillage is effective, and is occasionally used on roadsides. It is also often used in agricultural lands which probably accounts for the uncommon occurrence of C. solstitialis as a cropland weed. In wildlands and rangelands, tillage is usually not appropriate because it can damage important desirable species, increase erosion, alter soil

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structure, and expose the soil for rapid re-infestation if subsequent rainfall occurs (DiTomaso and Gerlach 2000).

Mowing: Mowing may be an alternative strategy for small landowners that do not wish to use herbicides. It is a popular control technique in recreational areas and has less impact on the environment than tillage. A few land managers have successfully controlled C. solstitialis using continuous mowing over multiple years. However, since mowing is a late season management tool it is best employed in the later years of a long- term management program or in a lightly infested area. This gives the land manager the ability to assess the level of infestation and the flexibility of choosing the most appropriate and cost effective option, which can include mowing. If only a few plants are present, hand pulling may be a better choice than mowing.

Although mowing can be a cost-effective control method, it is not feasible in many locations due to rocks and steep terrain. Even when mowing is employed, it is not always successful and can decrease the reproductive efforts of insect biocontrol agents, injure late growing native forb species (Rusmore 1995), and reduce fall and winter forage for wildlife and livestock (DiTomaso 1997, DiTomaso et al. 2000). In addition, its success depends on proper timing and the growth form of the plant. Mowing too early or late will usually increase the C. solstitialis problem. Plants with an erect, high-branching growth form are effectively controlled by a single mowing at the early flowering stage, while sprawling low-branching plants cannot be controlled even with repeated mowings at the proper timing. Despite its limitations, mowing conducted at the early flowering stage, before viable seed production, can be very effective for C. solstitialis control.

Grazing Properly timed (May and June) intensive grazing by cattle, sheep or goats can reduce growth, canopy cover, survivability, and reproductive capacity of C. solstitialis (Thomsen et al. 1989, 1990, 1993). Grazing should be conducted after the stems bolt but before spiny seedheads develop. Cattle and sheep avoid C. solstitialis once the buds produce spines, whereas goats continue to browse plants even in the flowering stage (Thomsen et al. 1993). For this reason, goats have become a more popular method for controlling C. solstitialis in relatively small infestations.

Grazing the weed during the bolting stage could provide palatable high protein forage (8 to 14%) (Thomsen et al. 1989). This can be particularly useful in late spring and early summer when other annual species have senesced. Grazing alone will not provide long- term management or eradication of C. solstitialis, but can be a valuable tool in an integrated management program.

Prescribed burning Properly timed prescribed burning will control some important noxious annual grasses, such as barbed goatgrass (Aegilops triuncialis), medusahead (Taeniatherum caput- medusae) and ripgut brome (Bromus diandrus), as well as late flowering broadleaf species such as C. solstitialis (DiTomaso et al. 1999a).

Burning should be timed to coincide with the very early C. solstitialis flowering stage. At this time C. solstitialis has yet to produce viable seed, whereas seeds of most desirable species have dispersed and grasses have dried to provide adequate fuel. Fire has little if any impact on seeds in the soil.

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In addition to controlling C. solstitialis, burning will reduce the thatch layer, expose the soil, and recycle nutrients held in the dried vegetation. In the first growing season after the burn, plant diversity will often increase, particularly native perennial grasses and forbs.

Despite its effectiveness, air quality issues can be a significant problem when burns are conducted adjacent to urban areas. A major risk of prescribed burning is the potential of fire escapes. This risk is greatest when burns are conducted during the summer months. In some areas, burning can lead to rapid invasion by other undesirable species with wind- dispersed seeds, particularly members of the sunflower family.

The ability to use repeated burning depends on climatic and environmental conditions. In areas where resources are ample and total plant biomass is abundant, two or three consecutive years of burning may be practical. However, in other environments or years, fuel loads may not be sufficient to allow multiple year burns. Consequently, prescribed burning may be a more appropriate option as part of an integrated approach.

In addition to summer burning, C. solstitialis seedlings have been controlled using winter or early spring flaming techniques (Rusmore 1995). This technique is somewhat non- selective and the control of C. solstitialis is inconsistent. When spring drought follows a flaming treatment, control of C. solstitialis can be excellent (Rusmore 1995). In contrast, a wet spring can lead to complete failure and increased C. solstitialis infestation, particularly since competing species may be dramatically suppressed.

Re-vegetation Re-vegetation programs for C. solstitialis control generally rely on re-seeding with native or high forage non-native perennial grasses (Callihan et al. 1986, DiTomaso et al. 2000, Enloe et al. 2000, Johnson 1988, Larson and McInnis 1989, Lass and Callihan 1995, Northam and Callihan 1988a, 1988b, 1988c, 1990a, 1990b, Prather et al. 1988, Prather and Callihan 1989a, 1989b, 1990, 1991). Re-vegetation with desirable and competitive plant species can be the best long-term sustainable method of suppressing weed invasions, establishment, or dominance, while providing high forage production. Because of the ecological diversity within most grassland ecosystems, no single species or combination of species will be effective under all circumstances. Unfortunately, few studies have been conducted on the restoration of C. solstitialis infested grasslands using a wide diversity of species, particularly natives.

In western states, competitive grasses used in re-vegetation programs for C. solstitialis management include non-native perennial grasses such as crested wheatgrass (Agropyron desertorum), intermediate wheatgrass (Elytrigia intermedia [=Agropyron intermedium]), pubescent wheatgrass (Thinopyrum intermedium), Bozoisky Russian wildrye (Psathyrostachys juncea), sheep fescue (Festuca ovina), tall oatgrass (Arrhenatherum elatius), or orchardgrass (Dactylis glomerata), as well as the native perennial grasses including big bluegrass (Poa ampla) and thickspike wheatgrass (Elymus lanceolatus subsp. lanceolatus [=Agropyron dasystachyum]) (Borman et al. 1991, Enloe et al. 2000, Ferrell et al. 1993, Prather and Callihan 1991, Sheley et al. 1999). These species provide good livestock forage and a sustainable option for rangeland maintenance.

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In those parts of California with a Mediterranean climate, re-vegetation programs for control of C. solstitialis are more difficult that those in other western states where summer rainfall is critical to the establishment and survival of native perennial grasses.

In addition to perennial grasses, non-native crimson clover (Trifolium incarnatum) and subterranean clover (Trifolium subterraneum) were used for re-seeding programs in foothill ranges of Oregon and California (Sheley et al. 1993, Thomas 1997). Used as a sole control option, however, T. subterraneum did not provide adequate seasonal control of C. solstitialis.

Re-vegetation projects for C. solstitialis control nearly always rely on integrated strategies. In most cases, it is difficult to establish desired plants without the management of competing vegetation, including C. solstitialis and annual grasses. The goal of these re-vegetation projects is to develop sustainable high quality range conditions and improved wildlife habitat capable of providing long-term C. solstitialis control without the need for continued herbicide treatments.

Biological control Insects: Six insects have become established for the control of C. solstitialis in the western United States. These include three species of weevils (seed-head weevil [Bangasternus orientalis], flower weevil [Larinus curtus], and the hairy weevil [Eustenopus villosus]), and three species of flies (seed-head fly [Urophora sirunaseva], peacock fly [Chaetorellia australis], and the false peacock fly [Chaetorellia succinea]). All six insects attack the flower heads of C. solstitialis and produce larvae that develop and feed within the seedhead (Balciunas and Villegas 1999).

Of the four insects that are well established in California (Villegas et al. 2000) only two, Eustenopus villosus and Chaetorellia succinea, have any significant impact on reproduction (Pitcairn and DiTomaso 2000, Pitcairn et al. 1999, 2000). The combination of these two insects reduces seed production by 43 to 76% (Pitcairn and DiTomaso 2000). Although this level of suppression is not sufficient to provide long-term C. solstitialis management, the use of biological control agents can be an important component of an integrated management approach. A more successful biological control program will likely require the introduction of plant pathogens or other insects capable of severely damaging or feeding on roots, stems, or foliage. Biocontrol researchers continue to search for such insects or pathogens in C. solstitialis’ native range.

Plant pathogens: The most widely studied pathogen for C. solstitialis control is the Mediterranean rust fungus Puccinia jaceae. It can attack the leaves and stem of C. solstitialis, causing enough stress to reduce flowerhead and seed production. It is well suited to environmental conditions found in California and other areas of infestation in North America (Bennett et al. 1991). The organism is currently under investigation and has not been released for use.

Herbicides Clopyralid (Transline®, Stinger®) and picloram (Tordon®) provide postemergence control of C. solstitialis seedlings and rosettes, as well as soil residual activity for at least one season. These compounds give the best control of C. solstitialis and are the least injurious to grasses.

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Clopyralid gives excellent control of C. solstitialis at very low rates (1.5 to 4 oz a.e./acre; 100-280 g a.e./ha). The timing for application is broad, usually ranging between January and May. Clopyralid is a very selective herbicide and does not injure grasses or most broadleaf species. However, depending on the timing of application, it does damage or kill many species in the legume family (Fabaceae), as well as the sunflower family (Asteraceae). It can also cause some injury to members of the nightshade (Solanaceae), knotweed (Polygonaceae), carrot (Apiaceae), and violet (Violaceae) families. Clopyralid is also effective on plants in the bolting and bud stage, but higher rates (4 oz a.e./acre; 280 g a.e./ha) are required. Applications made after the bud stage will not prevent the development of viable seed (Carrithers et al. 1997, Gaiser et al. 1997). When clopyralid is used to control seedlings a surfactant is not necessary (DiTomaso et al. 1999b). However, when treating older plants or plants exposed to moderate levels of drought stress, surfactants can enhance the activity of the herbicide. A combination of clopyralid and 2,4-D amine (Curtail®) has also been used for C. solstitialis control in western states other than California. It can be used at 0.25 to 1 pint/acre (0.3-1.2 liter/ha) after the majority of C. solstitialis rosettes have emerged but before bud formation.

Picloram is the most widely used herbicide to control C. solstitialis in western states other than California. It acts much like clopyralid, but gives a broader spectrum of control and has much longer soil residual activity. Picloram is applied (usually with a surfactant) at a rate between 0.25 lb and 0.375 lb a.e./acre (0.28-0.42 kg a.e./ha) in late winter to spring when plants are still in the rosette through bud formation stages (Callihan et al. 1989). This treatment can provide effective control for about two to three years. Although well developed grasses are not usually injured by labeled use rates, young grass seedlings with less than four leaves may be killed (Sheley et al. 1999).

A limited number of postemergence herbicides are registered for use in rangelands, pastures, and wildlands. They include 2,4-D (many trade names), dicamba (Banvel®, Vanquish®), triclopyr (Garlon 3A®, Garlon 4®, Remedy®), and glyphosate (Roundup®). These postemergent herbicide treatments generally work best on seedlings. They are not effective for the long-term management of C. solstitialis when used in spring, as they have no soil residual activity and will not control plants germinating after application. The most effective way to use postemergence compounds for C. solstitialis control is to incorporate them into later stages of a long-term management program. In particular, they are effectively used to spot-treat escaped plants or to eradicate small populations in late season when C. solstitialis is easily visible but has yet to produce viable seed.

2,4-D (0.5 to 0.75 lb a.e./acre; 0.56-0.84 kg a.e./ha), dicamba (0.25 to 1.0 lb a.e./acre; 0.28-1.1 kg a.e./ha) and triclopyr (0.5 or 1.5 lb a.e./acre; 0.56-1.7 kg a.e./ha) are growth regulator herbicides that can provide acceptable control of C. solstitialis when applied at the rosette growth stage. Amine forms are as effective as ester forms at the small rosette growth stage, but amine forms reduce the chance of off-target movement. Glyphosate controls C. solstitialis at 1 lb a.e./acre (1.1 kg a.e./ha) (DiTomaso et al. 1999b). Good coverage, clean water, and actively growing C. solstitialis plants are all essential for adequate control. Unlike the growth regulator herbicides, glyphosate is non-selective and controls most plants, including grasses. A 1% solution of glyphosate also provides effective control and is used at this concentration for spot treatment of small patches. Glyphosate is a very effect method of controlling C. solstitialis plants in the bolting, spiny, and early flowering stages at 1 to 2 lb a.e./acre (1.1-2.2 kg a.e./ha). However, it is important to use caution when desirable perennial grasses are present. In late season

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treatments, except with glyphosate and ester formulations, a surfactant should be added to the herbicide formulation.

A number of non-selective preemergence herbicides will control C. solstitialis to some level, including simazine, diuron, atrazine, imazapyr, imazapic, metsulfuron, sulfometuron, chlorsulfuron, bromacil, tebuthiuron, oxyfluorfen and prometone. All these compounds are registered for use on right-of-ways or industrial sites (although not all in California), but few can be used in rangeland, pastures, or wildlands. In rangeland, only metsulfuron (Escort®) and to some degree chlorsulfuron (Telar®) provides selective control of C. solstitialis without injuring desirable grasses. Both these compounds are used at 1 to 2 oz a.i./acre (70-140 g a.i./ha). Chlorsulfuron and metsulfuron do not have postemergence activity on C. solstitialis and therefore, must be used in combination with 2,4-D, dicamba, or triclopyr to provide effective control of C. solstitialis in grasslands.

Integrated approaches Most often a single method is not effective in the sustainable control of C. solstitialis and other range weeds. A successful long-term management program should be designed to include combinations of mechanical, cultural, biological, and chemical control techniques. There are many possible combinations that can achieve the desired objectives, and choices will have to be tailored to the site, economics, and management goals. Sometimes the control techniques must be in a particular sequence to be successful. The most effective sequence includes early season control strategies in the first year or two of a management program, followed by late season options in the later years.

The following is from Invasive Plants of California’s Wildlands (Bossard et al. 2000):

Mechanical Methods Tillage can control this thistle; however, this will expose the soil for rapid reinfestation if subsequent rainfall occurs. Under these conditions, repeated cultivation is necessary (Di’Tomaso et al. 1998). During dry summer months, tillage practices designed to detach roots from shoots prior to seed production are effective. For this reason, the weed is rarely a problem in agricultural crops. Weedeaters or mowing can also be used effectively. However, mowing too early, during the bolting or spiny state, will allow increased light penetration and more vigorous plant growth and high seed production. Mowing is best when conducted at a stage where 2 to 5 percent of the seed heads are flowering (Benefield et al. 1999). Mowing after this period will not prevent seed production, as many flowerheads will already have produced viable seed. In addition, moving is successful only when the lowest branches of plants are above the height of the mower blades. Under this condition, recovery is minimized. Results should be repeatedly monitored, as a second or perhaps a third mowing may be necessary to ensure reduced recovery and seed production (Thomsen et al. 1996).

Grazing Intensive grazing by sheep, goats, or cattle before the spiny stage but after bolting can reduce biomass and seed production in yellow starthistle (Thomsen et al. 1996). To be effective, large numbers of animals must be used for short durations. Grazing is best between May and June, but depends on location. This can be a good forage species.

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Prescribed Burning Under certain conditions, burning can provide effective control and enhance the survival of native forbs and perennial grasses (Robards, unpubl. data, Di’Tomaso et al. 1999). This can be achieved most effectively by burning after native species have dispersed their seeds but before yellow starthistle produces viable seed (June-July). Dried vegetation of senesced plants will serve as fuel for the burn. At one site in California, three consecutive burns provided 98% control, but with no additional control method used in the fourth year, the seedbank of yellow starthistle increased by thirty-fold compared to the previous year (Di’Tomaso unpubl. data).

Plant Competition Revegetation with annual legumes and/or perennial grasses provides some level of control. Control was enhanced when revegetation was combined with repeated mowing (Whitson et al. 1987).

Chemical Control The primary options for control in non-crop areas are post-emergence herbicides; 2,4-D, triclopyr, dicamba, and glyphosate (Di’Tomaso et al. 1998). All but glyphosate are selective and preferably applied in late winter or early spring to control seedlings without harming grasses. Once plants have reached the bolting stage, the most effective control can be achieved with glyphosate (1 percent solution). The best time to treat with glyphosate is after annual grasses or forbs have senesced, but prior to yellow starthistle seed production (May-June). The most effective compound for yellow starthistle control is clopyralid (as Transline®), a broadleaf selective herbicide (Di’Tomaso et al. 1998). Clopyralid provides excellent control, both pre-emergence and post-emergence, at rates between 1.5-4 acid equivalent or 4-10 oz formulated product per acre. Although excellent control was achieved with applications from December through April, earlier applications led to significant increases in quantity of other forage species, particularly grasses.

Priority Sites Malta and yellow starthistle are estimated to cover approximately 100 acres of Ash Meadows NWR. These species are located throughout the refuge alongside roadways and in the retired agricultural fields, old homesteads, and Warm Springs complex. The population of Malta starthistle in the Warms Springs complex is the top priority for treatment with a goal of eradication. Populations of starthistle in all fire project areas will also be treated.

Elaeagnus angustifolia

Common name: Russian olive

Russian olive is a small tree or large shrub (10-25 ft.) in the oleaster family (Eleagnaceae). Long-lived and fast-growing, this deep-rooted European native has been planted widely as an ornamental. The large fruits are readily dispersed by birds. Seeds germinate from fall through spring and may remain viable in the soil for up to three years (Shafroth et al. 1995, Howe and Knopf 1991).

Russian olive invades both disturbed and undisturbed moist pastures, irrigation overflows, wetlands, and riparian areas, often forming dense, monospecific stands (Tu 2003, Whitson et al. 1996). In natural areas

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it can reduce biodiversity by outcompeting and displacing native species and altering stand structure. Dominance by this species alters key ecosystem processes such as nutrient cycling, sediment deposition, and hydrology (Tu 2003). Although Russian olive woodlands are used by many bird and mammal species, species richness is typically reduced compared to communities dominated by native species (Evans 2003, Knopf and Olson 1984).

The following is from The Nature Conservancy’s Element Stewardship Abstract for Elaeagnus angustifolia (Tu 2003):

Large mature stands of E. angustifolia are nearly impossible to eradicate throughout an entire watershed once it becomes well-established, so the early detection and rapid response to treat newly detected populations of E. angustifolia is important. Small patches of E. angustifolia, however, can be adequately controlled using a variety of control methods. All control techniques used to manage E. angustifolia are labor- intensive and expensive, especially in the first year of large-scale E. angustifolia removal. Mowing, cutting, burning, excavation, spraying, girdling, and bulldozing have all been used for E. angustifolia control, and they all work to reduce aboveground biomass, sometimes to varying degrees of success. Successful long-term control of E. angustifolia requires that all control sites to be continually monitored and follow-up treatments vigilantly applied for several years, since E. angustifolia frequently resprouts or develops root suckers from the root crown.

Along regulated-rivers, once E. angustifolia trees have been killed and/or removed, the ensuing restoration of native trees and shrubs can be improved by simulating historic flood regimes and rates of water drawdown at the time of cottonwood seed dispersal (Friedman 1993, in Shafroth et al. 1995). In some situations, the planting of poles or nursery stock of native trees and shrubs can assist in the re-establishment of native riparian communities (Shafroth et al. 1995).

Manual and Mechanical Control E. angustifolia seedlings and sprouts can be hand-pulled or weed wrenched out when soil is moist (Deiter 2000). Saplings with a trunk diameter less than 3.5 inches can be pulled sufficiently with a weed wrench (Deiter 2000). Pulling or digging out larger plants is both extremely labor-intensive and not recommended, since it can leave behind root fragments that can resprout. Seedlings can also be continually mowed for good control, but larger plants respond to cutting or girdling by vigorously resprouting, resulting in thicker, denser growth, unless herbicide is immediately applied to cut surfaces after cutting.

Prescribed Burning Small seedlings of E. angustifolia may be susceptible to fire, but burning alone does not adequately control larger individuals of E. angustifolia, since it can vigorously re-sprout following fire (similar to cutting or mowing). Prescribed burning, however, can be used as either a pretreatment to, or used in combination with another control method, called integrated pest management (IPM).

Chemical Control Seedlings, saplings, and mature E. angustifolia trees can all be effectively killed by the careful, judicious, and targeted application of herbicide. Foliar and basal bark applications can be effective, especially for young individuals or for resprouts, but there

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may be off-target effects (from overspray or drift) if applied as a foliar spray to large stands. The most specific herbicide application technique for large mature trees is the cut-stump application method. First cut the stem/trunk as close to the ground as possible, then immediately (within a few minutes) brush-on or squirt herbicide onto the cambium layer of that cut-stump. Hacking and frilling (“hack and squirt”), girdling plus herbicide, or injection of herbicide, are also all effective at killing mature trees. Glyphosate (e.g. RoundUp®) and triclopyr ester (e.g. Garlon 4®) have both been reported to be effective in killing mature E. angustifolia trees (Parker & Williamson 1996). Caplan (2002) reported excellent kill rates using a 50% solution of Garlon 4® in a cut- stump treatment (herbicide applied within 5 minutes of cutting) on trees with trunks less than 4 inches (10 cm) in diameter in New Mexico. This may not be effective on trees with trunks larger than 8 inches in diameter (Caplan 2002). Caplan (2002) then followed-up the cutting treatments with foliar sprays on root sprouts for the following two years (25% solution of Garlon 4®), and reports that instead of large dense stands of E. angustifolia, he now finds on average, less than 3 sprouts per acre. He adds that continued vigilance, monitoring, and follow-up treatments are necessary for long-term success.

Edelen and Crowder (1997) eliminated E angustifolia trees in Washington State by cutting them in mid-summer, and then mowing the re-sprouts once in late summer the following year. While effective, this non-herbicidal method was labor intensive and costly. They decided that their next efforts would include using herbicide to first kill the trees before removal. They used imazapyr (e.g. Contain® or Arsenal®) at different concentrations, and found that Contain® (used in a 4% solution; 14% active ingredient) damaged about 75% of the trees. Large trees showed damage in the upper half of canopy, while younger trees and sprouts were strongly affected throughout their entire canopy. When Garlon 4® (triclopyr) was applied as an aerial spray (no concentrations given), they reported a 90% kill rate (W. Crowder, pers. comm.).

Parker and Williamson (1996) report that basal bark applications (spraying herbicide directly onto the bottom 60 cm [2 feet] of each stem) with triclopyr (e.g. Garlon 4®or Remedy®) appeared to give effective control. They added that with these basal applications, top-kill is excellent, and this method minimizes soil disturbance and maintains other desirable vegetation. Parker and Williamson (1995) also stressed that it is important that applications completely wet the entire circumference of all stems or clumps of stems, but not to the point of run-off. The basal bark method is effective with small trees with smooth bark. For larger trees, the sprayed area must extend upward to include some smooth bark. Treatment of larger trees with thick, rough bark using this method may provide only about 50% control. The best time to apply herbicide is when the plants are actively growing from May through September. Parker and Williamson (1996) recommend that burning is effective in large stands for first reducing biomass, and then basal applications should be used on resprouts.

Biological Control There are no reported biocontrol agents for the control of E. angustifolia.

Priority Sites Currently Russian olive covers approximately 20 acres of Ash Meadows NWR. It is located on old homesteads where it was planted as an ornamental, and along roadways. Although this species does not

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appear to be expanding at any great rate in Ash Meadows, its difficulty to eradicate once well-established, places it on the target species list. Since the infestation is small, Russian olive will be treated wherever it is found, starting in the fire project areas.

Phragmites australis

Common name: common reed

Common reed is a large perennial rhizomatous grass of worldwide distribution. These emergent wetland plants may produce great quantities of seed. New sites are colonized by waterborne seed or rhizome fragments. The thick rhizomes form dense mats and can reach almost 2 meters below ground. Roots penetrate even more deeply, allowing the plant access to receding water tables (Haslam 1970).

Common reed is an aggressive invader of freshwater and brackish wetlands. Rapid clonal growth and thick litter accumulations crowd out native species and produce dense, monotypic stands, reducing biodiversity, wildlife forage, and overall habitat value. Disturbance and increased nutrients from agricultural runoff and other sources may contribute to common reed dominance, but the species is capable of invading pristine wetlands as well (Marks et al. 1993).

While the species is native to North America, one or more new, more invasive genotypes appear to have been introduced from the Old World (Hauber et al. 1991). Native populations may be difficult to distinguish from invasive populations, but rapidly spreading stands, especially where they occur on disturbed sites, generally indicate the invasive genotype (Evans 2003).

The following is from The Nature Conservancy’s Element Stewardship Abstract for Phragmites australis (Marks (original version), Lapin and Randall 1993 (updated 2/03)):

Management is necessary when evidence indicates that Phragmites has spread, or is spreading and threatening the integrity of rare communities, invading the habitat of rare plants or animals or interfering with the wildlife support function of refuges. Cutting, burning, application of herbicides (in particular Rodeo®), or water management schemes are possible control measures. The measure(s) used will depend on a number of factors including the size and location of the infestation, the presence of sensitive rare species and the work-force available.

Invasive populations of Phragmites must be managed in order to protect rare plants that it might out compete, valued animals whose habitat it might dominate and degrade, and healthy ecosystems that it might greatly alter.

Biological Control Biological control does not appear to be an option at this time. No organisms which significantly damage Phragmites australis but do not feed on other plant species have been identified. Naturally occurring parasites have not proven to be successful controls (Tscharntke 1988, Mook and van der Toorn 1982, van der Toorn and Mook 1982). In addition, some of the arthropods that feed on Phragmites are killed by winter fires and thus would likely be eliminated from the systems where prescribed fires are used. Coots, nutria, and muskrats may feed on Phragmites but appear to have limited impacts on its populations (Cross and Fleming 1989).

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Prescribed Burning Prescribed burning does not reduce the growing ability of Phragmites unless root burn occurs. Root burn seldom occurs, however, because the rhizomes are usually covered by a layer of soil, mud and/or water. Fires in Phragmites stands are dangerous because this species can cause spot-fires over 100 feet away (Beall 1984). Burning does remove accumulated Phragmites leaf litter, giving the seeds of other species area to germinate. Prescribed burning has been used with success after chemical treatment for this purpose at The Brigantine National Wildlife Refuge, NJ (Beall 1984) and in Delaware (Lehman, pers. comm. 1992). Occasional burning has been used in Delaware in conjunction with intensive spraying and water level management. This helps remove old canes and allows other vegetation to grow (Daly, pers. comm. 1991).

According to Cross and Fleming (1989), late summer burns may be effective, but winter and spring burning may in fact increase the densities of spring crops. Thompson and Shay (1985) performed experimental burn treatments on Delta Marsh, Manitoba. The increase in light availability following burns generally appears to benefit Phragmites. A variety of understory responses to these burns was noted. For example, summer burns increased species diversity, richness, and evenness, although certain species declined (Thompson and Shay 1985).

In Connecticut late spring burns followed by manual flooding with salt water was successful in reducing Phragmites height and density (Steinke, pers. comm. 1992). After three years, the fuel load was exhausted; the process was very expensive and self- regulating tide gates were installed instead.

In Europe, experimental removal of litter in winter resulted in doubling the above-ground biomass (Graneli 1989). Increased light availability at the soil surface and aeration of the soil around the rhizomes may have been responsible for this increase. Burning in the winter in an experimental field caused little damage, while burning during the emergence period led to the death of the majority of Phragmites shoots (van der Toorn and Mook 1982).

Chemical Control Rodeo TM, a water solution of the isopropylamine salt of glyphosate is commonly used for Phragmites control. This herbicide is not, however, selective and will kill grasses and broadleaved plants alike. Toxicity tests indicate that it is virtually non-toxic to all aquatic animals tested. It should be noted that many of these tests were performed by or for Monsanto, the company which manufactures Rodeo®. Bioconcentration values for glyphosate in fish tissues were insignificant. Glyphosate biodegrades quickly and completely in the environment into natural products including carbon dioxide, nitrogen, phosphate and water. Finally, since glyphosate does not volatilize, it will not vaporize from a treated site and move to a non-target area (Brandt 1983; Comes, Bruns and Kelly 1976; Folmar, Sanders and Julin 1979; Monsanto 1985).

Rodeo® must be mixed with water and a surfactant which allows it to stick to and subsequently be absorbed by the plant (Beall 1984). Instructions for application, amounts needed per acre, the approved surfactants and ratios for mixing, are on the Rodeo® label. Glyphosate must be mixed with clean or, if possible, distilled water because it binds tightly to sediments and is thus rendered non-toxic to plants (Lefor, pers. Comm. 1992). This limits its effectiveness but also may help prevent it from acting on plants that were

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not originally targeted. Rodeo® should not be applied in windy conditions, as the spray will drift (I. Ailes, pers. comm. 1985). It also should not be applied if rain is forecast within 12 hours because it will wash away before it has a chance to act (Daly 1984). Application rates may vary but, as one example, effective control of Phragmites in a Delaware marsh was achieved with 4 pints/acre of concentrate (Lehman, pers. comm. 1992).

Application of Rodeo® must take place after the tasseling stage when the plant is supplying nutrients to the rhizome. At this time, when Rodeo® is sprayed onto the foliage of aquatic weeds, it translocates into the roots. Rodeo® interferes with essential plant growth processes, causing gradual wilting, yellowing, browning and deterioration of the plant. Studies on tasseling at the Augustine Tidal area, in Port Penn Delaware, indicated that tasseling in a stand is never 100% but that it is possible to spray when 94% of the plants are tasseling. In dense stands, subdominant plants are protected by the thick canopy and thus may not receive adequate herbicide. For these reasons, touch up work will be necessary (Lehman 1984).

At Brigantine National Wildlife Refuge, Rodeo® was applied aerially after the plants tasseled in late August. The application resulted in a 90% success. The following February, a fast moving prescribed burn was carried out to remove litter, exposing the seed bed for re-establishment of marsh vegetation. However funding was not available for several years and Phragmites has returned to 90% of the previously treated areas (Beall, pers. comm. 1991). Treatment was resumed in fall 1991.

In September, 1983, at the Prime Hook Wildlife Refuge in Delaware, 500 acres of freshwater impoundments were sprayed with Rodeo® from a helicopter for Phragmites control. The plants yellowed within 10 days. The following May aerial and ground evaluations of the sprayed area revealed a 98% kill of Phragmites (Daly 1984). In addition to applying herbicide, Prime Hook manipulates water levels with a stop log to stress Phragmites; winter water levels are held at an elevation of 2.8' msl until June, when water would otherwise be held at 2.2 msl. The combined spraying and water management approach was successful and many aquatic plants returned. A regime of spraying in August-September for two years followed by flooding has been used through 1991 (Daly, pers. comm. 1991). Annual costs of Phragmites control are $20K annual at Prime Hook (1,000 acres) and $3K at Bombay Hook (20-60 acres); monitoring costs, which include reading vegetation transects for species presence and density each September are not included in the cost.

Aerial spraying has been used since 1983 in many Delaware state wildlife refuges (Lehman, pers. comm. 1992). Using Rodeo®, the state sprays freshwater and brackish impoundments, brackish marshes, and salt marshes from early September to early October; this is combined with winter burns between the first and second year of spraying.

Mechanical Control Cutting: Cutting has been used successfully to control Phragmites. Since it is a grass, cutting several times during a season, at the wrong times, may increase stand density (Osterbrock 1984). However, if cut just before the end of July, most of the food reserves produced that season are removed with the aerial portion of the plant, reducing the plant's vigor. This regime may eliminate a colony if carried out annually for several years. Care

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must be taken to remove cut shoots to prevent their sprouting and forming stolons (Osterbrock 1984). In the Arcola Creek Preserve in Ohio, cutting reduced the vigor of the Phragmites colony. Also in Ohio, at Morgan Swamp, cutting began in mid to end of July (before tassel set) in 1989 around a gas well in a freshwater wetland (Seidel, pers. comm. 1991). The preferred tool was an old-fashioned hedge trimmer with an 8" flat blade with serrations manufactured by Union Fork and Hoe. The trimmers worked better than loppers and were safer than sickles; a circular blade on a weed whacker was also used and proved to be faster and good for staff but it was more dangerous for volunteers and detracted from the atmosphere of the work-day (Huffman, pers. comm. 1992).

Mowing, Disking, And Pulling: Beall (1984) discourages mowing and disking. Mowing only affects the above ground portion of the plant, so mowing would have to occur annually. To remove the rhizome, disking could be employed. However, discing could potentially result in an increase of Phragmites since pieces of the rhizome can produce new plants. Cross and Fleming (1989) describe successful mowing regimes of several year duration during the summer (August and September) and discing in summer or fall.

In Cape May Meadows, New Jersey, a brackish to freshwater non- tidal sandy area, an attempt was made to remove rhizomes by pulling to a depth of three feet (Johnson, pers. comm. 1991). This resulted in a very sparse Phragmites stand the following year. However it was very labor-intensive (using 130 people- hours to cover a 50 ft2 patch) and could be applied best to sandy soils.

In a private yard, Phragmites was mowed and a thin layer of soil and grass seed were added. This was mowed weekly over the course of the summer. In the second summer shoots of Phragmites occurred around the edges. The rhizomes were decomposing after this treatment (M. Ailes, pers. comm. 1992).

Cultural Control Grazing, Dredging, And Draining: Grazing, dredging, and draining are other methods that have often been used to reduce stand vigor (Howard, Rhodes and Simmers 1978). However, draining and dredging are not appropriate for use on most preserves (Osterbrock, 1984).

Grazing may trample the rhizomes and reduce vigor but the results are limited (Cross and Fleming 1989). Van Deursen and Drost (1990) found that cattle consumed 67-98% of above-ground biomass; in a four year study, they found that reed populations may reach new equilibria under grazing regimes.

Manipulation Of Water Level And Salinity: A self-regulating tide gate which reintroduced saltwater tidal action was used to help restore a diked marsh in Fairfield, Connecticut (Thomas Steinke pers. comm. 1992; Bongiorno et al. 1984). A 1-3 foot reduction in stem height resulted over each of three years . In addition to reduced height, plant density declined dramatically from 11.3 plants m-2 in 1980 to 3.3 plants/ m-2 the following year. In following years, Phragmites continued to decline, although less dramatically. In addition to the decreased height and density of the Phragmites stands, typical marsh flora including Salicornia, Distichlis, Spartina alterniflora Loisel, and S. patens (Aiton) Muhl. returned. Depending on topography and elevation, Phragmites was eliminated in large areas and continues to remain short and sparse in other areas through

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1992. Hence, reintroduced tidal action and salinity can reduce Phragmites vigor and restore the community's integrity.

Flooding can be used to control Phragmites when 3 feet of water covers the rhizome for an extended period during the growing season, usually four months (Beall 1984). However, many areas can not be flooded to such depths. Furthermore, flooding could destroy the communities or plants targeted for protection.

Open Marsh Water Management (OMWM) has been used as a method to control Phragmites. Plugging of ditches and addition of culverts to raise the soil salinities appears to have caused Phragmites die-back over the last four growing seasons at Fireplace Neck, New York (Niniviaggi, pers. comm. 1991; Rozsa, pers. comm. 1992).

Hellings and Gallagher (1992) found that Phragmites was negatively impacted by increasing salinity and increased flooding. They also found that cutting and subsequent flooding also reduced growth and survival in outdoor experiments. They suggest that Phragmites may be controlled by increasing flooding and salinity levels. Matoh, Matsushita and Takahashi (1988) also found reduction in vigor with increased salinity. However death apparently occurred only when cutting was combined with brackish flooding (Hellings and Gallagher 1992).

In Europe, episodic freshwater flooding occurring early in the growing season has been suggested as one of the reasons for reed population declines (Ostendorp 1991). McKee et al. (1989) investigated root metabolic changes due to freshwater flooding and labeled Phragmites as a flood-tolerant species.

Plastic: Clear plastic six-mil thick, 12 x 17 m, weighing 51.8 kg, was carried into a North Carolina marsh by air and held in place by sandbags (Boone et al. 1987, 1988). Plants were initially cut to 6-8" with a hand-pushed bush hog (Boone, pers. comm. 1991) or a weedeater with blade, with an area of 20 x 20 m taking several days to cut. The cut material was left and the plastic put over the area. The high temperatures under the plastic caused die-off of Phragmites in 3-4 days. After 8-10 weeks, the plastic deteriorated. The rhizomes appeared to have died back, but the project was of short duration and the results were not monitored the following year (Boone, pers. comm. 1991). Turner (pers. comm. 1992) noted that follow-ups in subsequent years indicated Phragmites returned but not as densely. Plastic management in each 12 x 12 m plot took an average of 53 hours, compared with 17 hours to cut and three hours to burn (Boone et al. 1987).

Clear plastic in two narrow swaths (70 m x 20 m) was placed along the edge of a tidal brackish pond after hand-cutting the Phragmites at the end of July 1991 (Anderson, pers. comm. 1992). One plot, in total sun, had a complete kill of Phragmites in 10 days, while the plot in partial shade had a partial kill. It is unknown how the plastic was kept in place or what was done with the cut material.

Clear and black plastic were used on 50' circular areas at Constitution Marsh in New York in 1990 and 1991 (Keene, pers. comm. 1991). Although there was difficulty due to tidal influence, the plastic was weighted down with rocks and appeared to kill what is under it. Runners along the edge were treated with a syringe application of Roundup in August. In November 1991, a hole cut in the middle of the black plastic provided the opportunity for cattail shoots to germinate. After the first year there was viable

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Phragmites in the areas covered. It appeared that the black plastic was more effective, due to the higher heat levels attained (Rod, pers. comm. 1992).

Monitoring Requirements Phragmites populations require close monitoring in order to determine whether they are increasing in area or not. Populations that are growing may quickly threaten or even eliminate rare elements. Monitoring provides the data needed in order to decide if control measures are necessary. If and when a control program is begun it is important to monitor targeted populations so that the program's effectiveness can be determined. If it is possible to leave untreated control areas without jeopardizing the success of the control program these should be monitored as well for comparison. It is imperative to continue monitoring even if a control program succeeds initially because Phragmites may reinvade and the sooner this is detected the easier it will be to combat.

To assess if a Phragmites colony is spreading, quantitative measurements should be made of percentage of aerial cover, stem density and culm height, especially at the periphery of the stand. Annual data should be compared to detect if the colony is expanding and the stand gaining vigor. Inventories of the vegetation in and near the colony should also be carried out in order to determine whether declines in species diversity are occurring.

Priority Sites Currently, there is no estimate of the acreage of common reed within AMNWR. It is located wherever marsh-like conditions persist. Due to its flammability, areas near private property with structures (e.g., Big Spring, North Scruggs Spring) will have priority.

Solanum elaeagnifolium

Common names: silverleaf nightshade, white horse nettle

The following is from the Washington State Noxious Weed Control Board (2003):

Silverleaf nightshade is a branched, deep-rooted, perennial herb, 1 to 4 feet tall. Slender, yellow spines occur on the stems or leaf ribs of the plant. The lance-shaped leaves are 1 to 4 inches long by 1 inch wide, with wavy margins; they are covered with short, silvery- white, star-shaped hairs that give the plant a dusky or silvery-gray color. The blue, violet or rarely white flowers have 5 fused petals, ¾ inch across, with bright yellow stamens. Flowers grow on stalks in clusters or singly at the end of stems or branches. The fruits are yellow to brownish, juicy berries, ½ inch in diameter. Seeds are flat, brown and 1/10 to 1/5 inch long (Boyd et al. 1984; Gunn and Gaffney 1974; Roche 1991; Rutherford 1978).

The following information on control methods is from the California Department of Food and Agriculture (2006):

Mechanical Control Tillage may spread rootstocks to new areas, where establishment can occur. Small infestations may be hand pulled or hoed, but must be repeated several times during the growing season. Silverleaf nightshade have sharp spines and gloves should be used for

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hand pulling. Any root material that is dug should be collected, dried and burned. Repeated mowing throughout the summer may nearly eliminate seed production. However, the plants will take on a flat, rosette-like growth form that is capable of replenishing root carbohydrate reserves.

Biological Control There are no currently registered biocontrol agents for use on Solanum elaeagnifolium. There is a great deal of concern since several other species in the Solanaceae family are important agricultural crops in California, such as potato, tomato, eggplant, and peppers. However, researchers have examined a nematode, Orrina phyllobia, which is host specific for silverleaf nightshade. Augmentative releases of this nematode may eventually help reduce silverleaf nightshade populations. Livestock will favor these spiny plants by overgrazing the surrounding palatable vegetation. If the seed are ingested by livestock, up to 10% may remain viable in excreted feces. Mature berries of these weeds also contain high levels of solanine and solanosine, which are toxic to livestock. Animals should be removed from infested areas until control is achieved. Experiments have shown that shading reduces silverleaf nightshade berry production and total nonstructural carbohydrate content of the roots. However, there has been little research examining which native California species would compete well with these nightshades.

Chemical Control There are few herbicides that effectively control Solanum elaeagnifolium, and their application is dependent upon the land use. Herbicide labels should be read and followed in regards to crop rotations and restrictions following application. Herbicides should be applied late bud to early flower. Glyphosate in a 2% solution can be applied as a spot treatment. Dicamba and 2,4-D can be applied at 0.5-1.0 and 1.0-2.0 lb ae/A, respectively. Triclopyr can be applied at 1-3 lb ae/A. Regrowth will occur with any of these treatments and retreatment will be necessary. Picloram has provided excellent control. Glyphosate is non-selective and will injure or kill any foliage it contacts. Dicamba, 2,4- D, and triclopyr will injure or kill most other broadleaf plants. These factors should be considered when applying these herbicides.

Priority Sites The amount of silverleaf nightshade in AMNWR is unknown, but may be 50 or more acres. Known populations are associated with the retired agricultural fields. It has been found in drier areas near Russian knapweed. Until the comprehensive vegetation survey is completed, priority sites will be those in current project areas (e.g., fire project areas, restoration sites).

Sorghum halepense

Common name: Johnson grass

The following is from The Nature Conservancy’s Element Stewardship Abstract for Sorghum halepense (Newman 1990):

Sorghum halepense is considered to be one of the ten worst weeds in the world (Holm et al. 1977). Fifty-three countries, ranging in latitude from 55°N to 45°S report Johnson grass as a major problem; the problem is most serious in the region from the

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Mediterranean to the Middle East and India, Australia, central South America and the Gulf Coast of the United States (Holm et al. 1977).

Sorghum halepense is an invasive and tenacious weed which thrives in disturbed soils. The prolific seed production, extensive rhizome system, sprouting ability of fragmented rhizomes and ability to grow in a wide range of environments make Johnson grass difficult to control. The best time to implement control techniques is during the first two weeks of growth when new rhizome development has not yet begun and when the carbohydrate supply is at its lowest concentration. During the fall the rhizome carbohydrate levels are again low, due to the formation of over- wintering rhizomes, making this an appropriate time for herbicide application. A combination of mowing, tilling, and herbicide applications may provide adequate control of Sorghum halepense and may produce better effects than just one technique alone. Once successful control has been reached, a rapid re-vegetation project should be implemented for the establishment of native plants. If transplants are to be used, plants should be grown during the eradication period (Newman 1989). Subsequent spot control of remaining Johnson grass, that avoids jeopardizing the native plants, may be necessary during the subsequent years to fully eradicate this weed.

Several techniques may be helpful in controlling Sorghum halepense: torching and burning, mowing and grazing, tilling and plowing and herbicide applications. These methods primarily focus on starving the plants by reducing growth, thus limiting photosynthesis which results in a reduction of stored carbohydrates (Oyer et al. 1959, McWhorter 1961a&b, Horowitz 1972b, McWhorter 1974).

A single application of the herbicide glyphosate results in an 85% reduction in Johnson grass (Heathman pers. comm.). The encouraging effects of chemicals on the control of Johnson grass is addressed below.

Mechanical Control Mowing Johnson grass for several seasons weakens the plants and reduces rhizome growth (McWhorter 1981, Hamilton B. pers. comm.). Removing aerial grass shoots close to the ground is a technique used to exhaust the stored carbohydrates of perennial weeds (Horowitz 1972a). Horowitz (1972a) reports that clipping three week old seedlings will kill them, whereas McWhorter (1961b) claims that seedlings must be clipped within 14 days after emergence for death of the plants to occur. As compared to the single clipping of seedlings, plants arising from rhizomes require two clippings within the first two weeks of growth to insure death of the plant (McWhorter 1961b). Because the lowest rhizome carbohydrate concentration occurs in the spring, during initial above- ground growth, and in the fall, during over-wintering rhizome formation, clipping at this time will have the maximum controlling effect by preventing the formation of photosynthates and thus precluding a stored energy supply (Horowitz 1972b).

Repeated clipping is required to control plants which emerged more than 20 days prior to the initial treatment. Slight amounts of rhizome growth occurs even under continuous clipping (McWhorter 1961b). Bi-weekly clipping of potted plants severely reduces growth during that growing season, however, one quarter of clipped plants display renewed growth the following year (Horowitz 1972a). A single clipping of the aerial growth of plants 28 days after germination or sprouting reduces the amount of total carbohydrates in the rhizomes by 25%, however a rapid replenishment of carbohydrates

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is seen within 30 days after clipping (McWhorter 1974). McWhorter (1981) reports maximum growth reduction when plants are allowed to reach 12 to 15 inches in height before cutting them at ground level, whereas Lorenzi and Jefferey (1987) feel that eight inches is the maximum size that Johnson grass should be allowed to reach in order to starve the plants.

Hand hoeing is practical only where the concentration of Johnson grass is low. Shallow cultivation using sharp hoes, shovels, knives or hand pulling will remove the plants and the rhizomes from the upper portion of the soil without dividing or pulling up deep rhizomes (Heathman et al. 1986, Lorenzi and Jefferey 1987). Hoeing early in the season when plants are under three weeks old will be much more effective than hoeing older plants which have larger rhizome systems and greater concentrations of stored carbohydrates (McWhorter 1961b). Six to eight fallow plowings throughout the summer is the most effective tilling routine for large scale problems. Plows break up the rhizomes and bring them to the surface of the soil where they desiccate (McWhorter 1981). A 99% reduction in rhizome production resulted from six thorough tillings at two week intervals (Warwick and Black 1983). However, plowing could spread the rhizomes and increase the problem if contaminated machinery is used in uninfested areas (Cox pers. comm.).

Chemical Control Extensive literature is available on herbicides available for Johnson grass control. The use of soil-active herbicides is not recommended due to the residual activity seen eight years after application (Hunter et al 1978). Herbicides alone will not successfully eradicate Johnson grass (Cox pers. comm.). Yearly applications will be required for an effective control plan.

Many herbicides are recommended for use on Johnson grass. Only two of them are foliar sprays that are mildly toxic and rapidly decay in the soil: glyphosate (commercial name -- roundup) and dalapon (commercial name -- Dowpon). Both of these chemicals are translocated to the underground tissue and act on all of the growing sites (Ross 1986).

Glyphosate is recommended for controlling Johnson grass in natural, non-agricultural sites (Brookbank pers. comm., K. Hamilton pers. comm., Heathman pers. comm., Lorenzi and Jefferey 1987). K. Hamilton (pers. comm.) recommends using spot applications of glyphosate with a knapsack sprayer to control small areas of Johnson grass. Multiple applications for several years will be required. An 85% reduction in Johnson grass is commonly seen during the first year of application using glyphosate. Seeds and nonactive rhizomes account for the 15% regrowth of Johnson grass during herbicide activity (Heathman pers. comm.).

Best results in controlling Johnson grass with glyphosate have been seen when the plants are actively growing, greater than 18 inches tall and have reached the bloom-to-head stage of growth (Silberman pers. comm., McWhorter 1981). The inflorescences should be removed to prevent the dispersal of mature seeds. In southern Arizona maximum control of Johnson grass occurs with fall applications of glyphosate (Brookbank pers. comm.). The low amount of rhizome carbohydrates in the fall may account for the effectiveness of the herbicide during this season of maximum rhizome growth. The land should not be tilled for at least a week after applying the herbicide in order to insure optimal efficiency from the single application (McWhorter 1981).

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Sorghum halepense grown under high salt and low water conditions result in reduced plant growth (Sinha et al. 1986). High salt concentrations have little effect on the overall biomass accumulation when water availability is not reduced. There is however, a decrease in the ratio of growth between shoots and roots with increased salinity (Sinha et al. 1986).

Priority Sites The amount of Johnson grass in AMNWR is unknown. Combined, both sorghum species (S. halepense and S. bicolor) have been estimated to cover 50 – 100 acres. Known populations are associated with the retired agricultural fields. Until the comprehensive vegetation survey is completed, priority sites will be those in current project areas (e.g., fire project areas, restoration sites).

Tamarix ramosissima and related Tamarix species

Common names: saltcedar, athel

Saltcedar is a deep-rooted shrub or small tree (5-20 feet tall) in the tamarisk family (Tamaricaceae).

A single mature saltcedar may produce hundreds of thousands of tiny seeds which are readily dispersed by wind and water. Seed dispersal may occur throughout the spring and summer months. Seedling growth is very rapid. The species can resprout vigorously from buried, submerged, or damaged stems and mature plants spread vegetatively as well (Sudbrock 1993). Once established, even dramatic changes in soil moisture will not eliminate saltcedar, as long as abundant ground water is available (Brotherson and Field 1987, Frasier and Johnson 1991).

Aggressive and long-lived, saltcedar has colonized more than one million acres of floodplains, riparian areas, and wetlands throughout the arid west. Saltcedar outcompetes and crowds out native vegetation and alters patterns of sediment deposition (Carpenter 1999, Sudbrock 1993, Tallent-Halsell and Walker 2002).

Saltcedar uses more water than comparable native plant communities and alters local hydrology by lowering the water table (Hoddenbach 1987 cited in Carpenter 1999). The stems and leaves of mature plants secrete salt, increasing soil salinity and further excluding many native plant species (Sudbrock 1993). Infestations also have detrimental impacts on wildlife. Saltcedar is not favored habitat for most bird species. Saltcedar seeds have almost no protein and are too small to be eaten by most granivores, and the scale-like leaves offer little suitable forage for browsing animals (Anderson et al. 1977). Stands of saltcedar are associated with lower diversity of aquatic invertebrates (Bailey et al. 2001).

Saltcedar-dominated communities experience higher fire frequencies than native cottonwood-willow communities, eventually eliminating the fire-sensitive natives (Busch 1995, Busch and Smith 1993, Evans 2003).

It is likely that hydro-geomorphic restoration in AMNWR will not succeed if tamarisk control is not a primary focus (Otis Bay and Stevens Ecological Consulting 2006).

The following is from The Nature Conservancy’s Element Stewardship Abstract for Tamarix species (Carpenter 1999):

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Tamarisk can be controlled by five principal methods: 1) applying herbicide to foliage of intact plants; 2) removing above ground stems by burning or mechanical means followed by foliar application of herbicide; 3) cutting stems close to the ground followed by application of herbicide to the cut stems; 4) spraying basal bark with herbicide; and 5) digging or pulling plants. In addition, The USDA has tested and proposed the release of two species of insects for tamarisk biocontrol.

Selecting an appropriate control method involves considering the size of the area where tamarisk is to be controlled, restrictions on the use of particular herbicides or herbicides generally, the presence or absence of desirable vegetation where tamarisk is growing, the presence or absence of open water, adjacent land uses that might restrict prescribed burning, and the availability and cost of labor.

For larger areas (> 2 hectares) that are essentially monotypic stands of tamarisk, the best methods would likely be foliar application of imazapyr (Arsenal®) [Also now available in an aquatic-approved formulation called Habitat] herbicide to the intact plants or burning or cutting plants followed by foliar application of imazapyr or triclopyr (e.g. Garlon4® or PathfinderII®) to the resprouted stems. Foliar application of imazapyr or imazapyr in combination with glyphosate (e.g. Rodeo®) can be effective at killing large, established plants. Over 95% control has been achieved in field trials during the late summer or early fall. The herbicide can be applied from the ground using hand-held or truck- mounted equipment or from the air using fixed-wing aircraft [or helicopter (B. Lee, pers. comm.)]. Foliar application of herbicide works especially well in monotypic stands of tamarisk, although experienced persons using ground equipment can spray around native trees and shrubs such as cottonwood and willow. As an alternative to herbicides, prescribed fire or a bulldozer can be used to open up large stands of tamarisk. Once opened, the resprouts can be sprayed when they are 1 to 2 m tall using imazapyr, or imazapyr plus glyphosate, or triclopyr.

Tamarisk eradication in areas that contain significant numbers of interspersed, desirable shrubs and trees is problematic. Depending upon site conditions, it may not be possible to rapidly kill tamarisk plants without also killing desirable shrubs and trees. In such situations, it may be necessary to cut and treat tamarisk stumps with herbicide, as outlined in the next paragraph. While this method is relatively slow and labor-intensive, it will spare desirable woody plants. Alternatively, it may be more cost-effective to kill all woody plants at a site and replant desirable species afterward.

For modest-sized areas (< 2 hectares), cutting the stem and applying herbicide (known as the cut-stump method) is most often employed. The cut-stump method is used in stands where woody native plants are present and where their continued existence is desired. Individual tamarisk plants are cut as close to the ground as possible with chainsaws, loppers or axes, and herbicide is applied immediately thereafter to the perimeters of the cut stems. The herbicides triclopyr (e.g. Garlon4® or PathfinderII®) and imazapyr (Arsenal®) can be very effective when used in this fashion. This treatment appears to be most effective in the fall when plants are translocating materials to their roots. The efficacy of treatments is enhanced by cutting the stems within 5 cm of the soil surface, applying herbicide within one minute of cutting, applying herbicide all around the perimeter of the cut stems, and retreating any resprouts 4 to 12 months following initial treatment.

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No matter how effective initial treatment of tamarisk might be, it is important to re-treat tamarisk that is not killed by initial treatment. It is also essential to continue to monitor and control tamarisk indefinitely because tamarisk is likely to re-invade treated areas. However, follow-up control is likely to require much less labor and materials than the initial control efforts.

The following is from Invasive Plants of California’s Wildlands (Bossard et al. 2000):

Manual/mechanical Control Saltcedar is difficult to kill with mechanical methods, as it is able to resprout vigorously following cutting or burning. Root plowing and cutting are effective ways of clearing heavy infestations initially, but these methods are successful only when combined with follow-up treatment with herbicide. Seedlings and small plants can be uprooted by hand.

Prescribed Burning Fire does not kill saltcedar roots, and plants return quickly after fire if untreated by other methods. Fire is valuable primarily for thinning heavy infestations prior to follow-up application of herbicide.

Flooding Flooding thickets for one to two years can kill most saltcedar plants in a thicket.

Biological Control The USDA is currently using an international team of researchers to test thirteen species of natural enemies to control saltcedar. Of these, two have been recommended for field release in the United States, including a mealybug (Trabutina mannipara) from Israel and a leaf beetle (Diorhabda elongata) from China. Several other species are being tested in quarantine.

Grazing Cattle have been shown to graze significant amounts of sprout growth (Gary 1960).

Chemical Control Six herbicides are commonly used to combat saltcedar, including; imazapyr, triclopyr, and glyphosate (Jackson 1996).

Several proven methods exist for removing tamarisk. Perhaps the best method is to apply an imazapyr marketed as Arsenal® to the foliage. This technique is especially effective when a tank mix is used with a glyphosate herbicide such as Rodeo®. The most frequently used method in California is to cut the shrub off near the ground and apply triclopyr, either as Garlon 4® or Garlon 3A®. This technique usually results in better than a 90 percent kill rate. Triclopyr (as Pathfinder II®) can even be applied directly to the basal bark of stems less than about four inches in diameter without cutting the stem (the bark must be wetted completely around the base of each stem).

Garlon 4® or Pathfinder II® have no timing restrictions, but Garlon 3A® should be applied during the growing season. Resprouts can be treated with foliar application of herbicide. Foliar applications of glyphosate or imazapyr achieve best results when applied in late spring to early fall during good growing conditions.

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Priority Sites Tamarisk species cover approximately 1200 acres of Ash Meadows NWR (750 acres were hand mapped using aerial photography, but this method missed areas of young saplings and individual trees mixed in with ash or mesquite.) Tamarisk is located throughout waterways; both natural and manmade channels. These species are also prevalent along the roadways, at the old homesteads, in marshes, and is even spreading into upland areas.

Funding has been acquired to treat tamarisk refuge-wide. Larger infestations and areas of monoculture will receive foliar treatment with Habitat herbicide applied by helicopter. Tamarisk located in sensitive areas and mixed in with desirable species will continue to be treated using cut-stump and basal bark techniques. Treatment of saltcedar is ongoing in the fire project areas using BAER funds. In the Meadows fire project area, saltcedar has been extracted using a low ground pressure (4.5 to 6 pounds per square inch) excavator with a “thumb” attachment to grab the saltcedar. By extracting the entire root ball from the soil, the number of re-sprouts will be reduced drastically; thereby reducing the amount of herbicide required to eradicate it. After the saltcedar is extracted, it is ground using a Hydro-axe 421E or 721E with a Fecon head attachment. The end product is chips ranging from two to six inches in size. This method will be used in other areas of the Refuge as needed, especially where saltcedar is intermixed with ash trees, but too numerous for the cut-stump method to be feasible.

Tribulus terrestris

Common names: puncturevine, tackweed

Puncturevine is a prostrate summer annual Mediterranean forb in the caltrop (Zygophyllaceae) family. The fruit is a notorious burr with sharp, rigid spines. Puncturevine invades pastures, roadsides, waste places, and cultivated fields. The spines of the fruit can injure the feet and mouths of animals. Puncturevine reproduces completely by seeds, which may germinate throughout the growing season (R. Leonard pers. comm.). Seeds spread by attaching to animals, people, and vehicles and may remain dormant and viable in soil for 4-5 years (Whitson et al. 1996).

The key to controlling puncturevine, as with all annual species, is to prevent seed production and gradually exhaust the seedbank. Puncturevine will germinate from mid-June until frost, so treatments must be repeated several times through the growing season (R. Leonard pers. comm.). Due to seedbank longevity, the site must be monitored for 5 years following apparent eradication before it can be declared clean and restrictions lifted. Because of puncturevines ability to spread via vehicles (at all seasons), infested areas should be quarantined. Vehicle traffic through infested areas should be restricted as much as possible, and recreational and nonessential vehicle traffic should be prohibited until the infestation is eliminated.

Manual and Mechanical Methods Pulling, digging or tilling prior to flower and seed production is effective in controlling new infestations (CNAP 2000). Several years cultivation may be required to exhaust the seedbank in established infestations (NWCB 2003b).

Biological Control Two weevils, Microlarinus lareynii and M. lypriformis, have been introduced into the United States as biocontrol agents. The larvae attack the seed and stems and have reportedly provided reasonably good results (NWCB 2003b).

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Chemical Control Glyphosate at 1.5 lb. a.i./A or picloram at 0.25a.i./A may be used for control of seedlings. 2,4D in either amine or LV ester form, or amitrole (Amitrol-T) at 1.0 - 2.0 lb. a.i./A in 10-20 gal. of water is effective for spot treatments. Dicamba at 0.25a.i./A, may also be used for control of seedlings (William et al. 2002, CNAP 2000). Dicamba should not be used in diverse natural areas, as it has a tendency to eliminate all broadleaved species (Carpenter and Murray 1998b, Evans 2003).

Priority Sites The amount of puncturevine in AMNWR is unknown. The extent of puncturevine has been estimated to be less than 10 acres. Until the comprehensive vegetation survey is completed, priority sites will be those in current project areas (e.g., fire project areas, restoration sites).

Typha domingensis

Common name: cattail

The following is from The Nature Conservancy’s Element Stewardship Abstract for Typha domingensis (Motivans and Apfelbaum 1987):

The cattail genus (Typha spp.) is an erect, perennial freshwater aquatic herb which can grow 3 or more meters in height. The linear cattail leaves are thick, ribbon-like structures which have a spongy cross-section exhibiting air channels. The subterranean stem arises from thick creeping rhizomes. North American cattails have minute, brown colored male flowers (staminate) thickly clustered on a club-like spadix. The lower portion of the spadix bares the female flowers (pistillate). There are three species and several hybrids in the cattail genus which occur in North America (Smith 1961, 1962, 1967).

The tall cattail (Typha domingensis) may be difficult to separate from T. angustifolia. T. domingensis is usually taller and has flattened and more numerous leaves (Apfelbaum 1985). T. angustifolia has 3-8 mm wide leaves that are full green and somewhat convex on back (Agricultural Rea. Service 1971). Hybrids of intermediate appearance have been reported, and are often referred to as the species Typha x glauca.

Specifically, the goals of management should be to:

(1) Control the spread and domination of potential habitat by cattail in and adjacent to natural areas. (2) Circumvent declines in other plant species with cattail proliferation. (3) Prevent development of monotypic cattail growth and loss of habitat heterogeneity (Patten 1975, Martin et al. 1957).

Management of cattails should be site specific and could include such active measures as hand cutting root stalks, burning and flooding, or shading.

Water Level Modification High water conditions in a cattail stand can affect the growth of seedlings, can break off mature stalks, or can be followed by the immigration of muskrats which eat the cattail (Zimmerman pers. comm.). The effect of flooding does not always have negative

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impacts on cattails -- plants have been known to float up and continue growing until water returns to previous lower levels.

As with any control measure, temporary conditions, such as flooding, do not prevent later seed establishment. Cattail seeds can arrive from a great distance, and it doesn't take but a few seeds to germinate and rapidly produce clones as adults. The cost of management actions should be considered when dealing with unknown response variables.

Low water conditions, maintained by draining a wetland, significantly affect the overall community (Mallik and Wein 1985). Harris and Marshall (1963) concluded that draining techniques have possible detrimental effects because the plant composition of a wetland can be radically changed. Draining alone can cause a significant increase in Typha cover under some conditions (Mallik and Wein 1985). However, to inhibit Typha growth, a wetland can be drained and then burned during the summer. If there is no reserve of water over winter cattails will not survive the following spring, according to Zimmerman (pers. comm.) but there have been no controlled experiments to show this.

Two years of 65 cm (26 in) deep flooding was required before established cattail began to die and open water conditions were created at Sinnissippi Marsh. Cattail initially survived flooding from 1973-1977 and became the dominant emergent plant. A light green color, noticeably narrower leaves, and absence of fruiting heads indicated stress in 1976. Cattail stem densities declined 57 percent with all emergent plants dead in 1977. Horicon Marsh, flooded to a depth of 40 cm (16 in), showed declines in emergent and aquatic plants. Cattail required two years before it declined (Wisconsin DNR 1969 and 1971).

Mature T. latifolia and seedlings less than one year old are killed by water depths of 63.5 cm (25 in) and 45 cm (18 in) or more, respectively. Narrow-leaved cattail was unaffected by this degree of flooding. Narrow-leaved cattail establishment was prevented when water levels were maintained at 1.2 m (47 in) or deeper (Steenis et al. 1958). Dryer conditions allowed more clones of T. angustifolia to be spread (McMillan 1959).

Because cattails can transpire significant quantities of water (2-3m of water/acre/year) (Fletcher and Elmendor 1955, Zohary 1962), their establishment may serve to exacerbate water level instability and further contribute to disruptive influences supporting increased cattail. Flooding must account for evapotranspirational losses of water to maintain a level effective in cattail control.

Physical Control Hand or mechanical cutting of cattails followed by submergence of all cattail stems results in high control. Up to 100 percent cattail control was measured two growing seasons after treatment. No visible cattail regrowth occurred in one year and cattail rhizomes were dead. The highest cattail control of any method tested was achieved by two clippings followed by stem submergence to at least 7.5 cm (3 in) (Nelson and Dietz 1966). Control was best if plants were cut in late summer or early fall.

In Iowa (Weller 1975), cutting cattail and reflooding with at least 8 cm (3.1 in) of standing water over plant stems was effective. Weller (1975) also found clipping cattails too early in the growing season (e.g. May) stimulated their growth and resulted in a 25 percent increase in stem counts the following year, with an eventual decline to pre-clip

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levels. August clipping controlled up to 80 percent of cattail only if followed by submergence. It was important to remove all dead and live cattail stems to achieve this control. Cutting shoots below the water surface two or three times in one growing season before flower production reduced a cattail stand by 95-99 percent in Montana and Utah (Stodola 1967). Similar results were demonstrated by Shekhov (1974) and Sale and Wetzel (1983).

When shoots are cut below the water level, nearly all the oxygen is consumed in a short time, necessitating anaerobic respiration. In Typha, ethanol is produced accompanied by tissue breakdown after an oxygen shortage. Typha is ill adapted to deprivation of oxygen. Cuttings later than flowering stage are effective only in preventing regrowth for that year and may have no effect on subsequent years (Shekhov 1974).

Cattail control by injuring developing rhizomes and shoots was investigated (Weller 1975). Crushing and reflooding showed that cattails injured after June had poor recoveries. Success of crushing depended on the load used, number of times an area was crushed, and standing water depths after treatment. Spring and early summer treatments generally created favorable seedbeds for cattail and required a fall crushing to control seedlings. Crushing involved pulling a 55 gallon water filled drum behind a tractor. Deeper water areas showed highest control (up to 100 percent) while regrowth occurred in shallow areas. Although not practical for natural areas management, disking (Weller 1975) and blasting (Nelson and Dietz 1966) have also been investigated as methods of cattail control.

Prescribed Burning Fire alone was found to provide little or no cattail control (Nelson and Dietz 1966). Fires that destroyed cattail roots offered control; however, most fires only burned above- ground biomass and did little to control cattail. Drying in readiness for burning was effective cattail control when done for two years in arid Utah. Water was pumped from wetlands and then cattail stands were allowed to sun dry.

Water level drawdown, burning (spring, fall, and mid-growing season), and reflooding to 20-35 cm (8-18 in) water depth or deeper controlled cattail. Fire was found useful for cattail litter cleanup and assisted access for mowing or hand clipping (Nelson and Dietz 1966, Weller 1975, Mallik and Wein 1985).

Shading Black polyethylene tarps were used to cover cattails in an attempted control measure (Nelson and Dietz 1966). Actively growing cattail tips were killed when completely covered for at least sixty days. Greatest control was achieved in July when food resources of cattail were presumed to be lowest (Linde et al. 1976). Problems with holding tarps down and their degradation confounded this investigation. Cattail is generally not shade tolerant.

Chemical control of Typha domingensis: Glyphosate is a systemic herbicide and systemic herbicides are preferred in the elimination of perennial plants. In treating cattails, a person can walk the shore making sure to spray glyphosate liberally on the portions of the cattails that can be reached. There is no need to spray from multiple directions. Another advantage is that one application can totally (or nearly so) eliminate the cattail stand (Lynch 2002).

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It is recommended that a non-ionic surfactant be added to the solution prior to spraying. Surfactants result in uniform sheeting of the herbicide over the vegetative surface which increases the uptake of the herbicide. Cattails have a thick waxy coating on the leaf which slows down herbicide uptake. Without the surfactant, much of the herbicide would be lost to the liquid beads that would form and roll off the plant. One ounce of surfactant is generally recommended for each gallon of spray solution for controlling cattails (Lynch 2002).

Application timing is critical for cattail control. Glyphosate products should be applied just after the seed head has formed. Energy reserves are at their lowest in the roots and the plant begins to store food in the roots in anticipation of next year’s growth. This food is produced in the leaves and transported to the roots. The application of glyphosate at this time results in its transport to the roots as well, thereby killing the root system (Lynch 2002).

The optimum treatment period is from boot stage (noticeable bulge caused by the flowering structure growing up through its protective sheath) to early flowering (green cattail head freshly emerged from the boot) (Dorn and Janssen 2002).

Imazapyr (Habitat®) should be applied to actively growing, green foliage after full leaf elongation (BASF Habitat® herbicide label).

At this time in AMNWR, cutting of cattail by hand using vinyl flooring knives or with the use a hedge trimmer (Stihl HL 100) is the preferred method in springs and outflows where cut portions can be covered by more than three inches of water. Habitat® herbicide is used on cattail along banks of springs and streams.

Priority Sites Currently, there is no estimate of the acreage of cattail within AMNWR. It is located throughout spring outflow channels, irrigation ditches, and marshes. Besides replacing all other native vegetation in springs and their outflow channels, cattails create favorable conditions for crayfish and other non-native aquatic species which, in turn, have a major impact on the native fish and aquatic invertebrates. Therefore, the top priority sites are spring pools and their outflow channels where Ash Meadows speckled dace, Warm Springs pupfish, and Ash Meadows pupfish occur. Due to its flammability, areas near private property with structures (e.g., Big Spring, North Scruggs Spring) will also have high priority.

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VI. Invasive Animal Control

Invasive Animal Species Management: Standard Operating Procedures and Guidelines

Prevention and Early Detection of Invasive Animal Species

As with weeds, the prevention and early detection of non-native animals is the cheapest and most effective control method. Unfortunately, long time lags between an introduction and an observation of impact, confounded with a poor understanding of the natural history characteristics of some native systems, contribute to the inability to detect problems early in the invasion when control is most likely to be effective. Also, impacts of introduced species may be masked by other changes, such as habitat loss or alteration (Hanson and Sytsma 2001). Since all of Ash Meadows’ endangered endemic animal species are aquatic species, the Refuge’s priority will be on regular monitoring of springs to detect new non- native aquatic species. However, it will also remain important to inspect and maintain the exclusionary fence around AMNWR on a regular basis to ensure that feral horses and burros do not reinvade the Refuge. These animals had a major impact on the native vegetation, especially the endemic species, prior to their exclusion in 1995. They are still present in the surrounding area.

Cultural Control Often, simple changes to everyday activities can go a long way toward preventing establishment or spread of invasive species; however, this “cultural control” is often the hardest to accomplish because it involves changing human behavior.

Cultural control can be defined in different ways. In an agricultural setting it can mean managing and manipulating competitive interactions so that non-native species are placed at a disadvantage; this aspect of cultural control is discussed in a later section on control methods. It can also mean modifying human behavior or activities. To this end, cultural control as discussed here consists of awareness of the ways animal or microbic species are transported and spread, and public and staff education.

Most vertebrate species have been introduced intentionally, while most invertebrate and microbe introductions have been accidental (Pimental et al. 2005). Either way, a public that is informed of the causes of these introductions and the problems associated with them, is more likely to assist in their prevention. Therefore, AMNWR should continue to produce and display interpretive materials on invasive species and their management. Emphasis in programs and publications should be on the value of Nevada’s unique native species.

IPM should also be a part of the Refuge’s outreach program. A brochure could be produced and delivered to aquarium dealers in the local communities enlisting their help in educating the public on the impacts to native species of releasing aquarium fish, plants, and other non-native species into native waters.

IPM education will be extended to hunters and other visitors that use boats in Crystal and Peterson reservoirs. Information should be posted at reservoirs and included in outreach programs to teach the boat-using public how they can help prevent the spread of invasive “hitchhikers” by voluntarily inspecting their watercraft. The following checklist from Vermont’s Aquatic Nuisance Species program (available at www.anr.state.vt.us/dec/waterq/latkes/htm/ans/lp_ans-index.htm) is an example of the type of information that could be posted at the reservoirs in AMNWR:

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 Inspect boat, trailer, motor and other equipment for attached plant or animal material.  Remove all plant and animal material.  Discard removed material in a trash receptacle or on high, dry ground where there is no danger of it washing into any water body.  Drain all water from boat, boat engine, and other equipment.  Rinse all boat and trailer parts with tap water (preferably hot, high pressure).  Dry boat, trailer and equipment out of water and in sun for at least five days prior to launching in another body of water.

Volunteers that participate in cattail-cutting work days are told about the impacts of non-native species and taught to clean and disinfect their shoes prior to entering Refuge waters.

Cultural control also extends to AMNWR employees and contractors. Pest management issues are included in the training for all new staff and for contractors such as the Nevada Conservation Corps (NCC) crews that perform various environmental projects in the Refuge.

Refuge staff is in the process of changing the standard operating procedures for use of traps in native fish inventories and for non-native aquatic species removal because invasive species can be transported from spring to spring in traps. For instance, red-rim melania often get stuck in these traps. This snail is capable of resisting dessication, molluscicides, and disinfectants (up to eight days in a dry pan and 60 minutes in full strength bleach) (Dudgeon 1982, Mitchell et al. 2005). The chance of accidentally transferring unwanted species in traps can be decreased by providing a set of traps dedicated to each major spring. Traps will not be shared between springs without first inspecting, disinfecting, and then drying them for one week between uses.

Currently, the public is allowed to trap crayfish by Special Use Permit using their own traps. Refuge staff has no control over where these traps have been used outside of AMNWR. A review of current refuge policies and standard operating procedures regarding public trapping of crayfish will be made to identify if these should, or can be, modified to reduce the potential to spread invasive species. Possible mitigating measures include requiring training with the Refuge biologist and the use of the Refuge’s crayfish traps.

Inventory and Monitoring

Regular monitoring of Refuge springs is essential to detecting new non-native aquatic species and preventing their spread. The best way to monitor the springs is through a trapping program which also aids in controlling non-native fish and crayfish. Currently, there is no funding that specifically supports a program of trapping on a regular basis. Trapping is conducted as staff and time permit. AMNWR is working with the USGS and the Southern Nevada Field Office of the FWS to develop a non-native aquatic species trapping plan.

Prioritization of Target Management Units and Species

Criteria for Prioritization The prevention and early detection of all non-native species is the ultimate goal of AMNWR’s IPM program; however, given the resources available the following criteria as described under Assessment Protocol in Chapter II will be used to rank target species and management units:

 Ecological impact  Current distribution and abundance  Trend in distribution and abundance

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 Management difficulty

Impacts that will be considered include the threat to Ash Meadows’ endemic and Federally-listed species, the threat to ecosystems that support listed species (e.g., reduce aquatic productivity), the threat to visitor safety and refuge staff or operations, the threat to previous habitat restoration projects (i.e., the continued success of previous projects), the potential to transform from a local to refuge-wide infestation, and the level of effort needed to eradicate or contain the invasive species (see Eradication vs. Containment below).

These rankings will be combined with other considerations such as funding sources (e.g., SNPLMA funds earmarked for restoration of a spring) to determine the priority for treatment species and sites.

The target species identified in Table 2.3 will typically receive the highest priority; however, new infestations of non-native, invasive species should take precedence to contain and, ideally, eradicate the problem.

A discussion of priority management units and target species is included in Chapters VII and VIII.

Treatment

Eradication vs. Containment Some management units and target species may be classified for either “eradication” or “containment” of invasive species. Eradication is defined as the “elimination of pest species at a given site.” These sites represent areas that have a new or small infestation that can easily be eradicated (e.g., removal of one or two koi or bass from a single spring), or are high priority sites due to hydrological restoration activities. Containment is defined as “limitation to the current site/management unit with no expansion.” The sites chosen under this category contain large infestations or species for which total eradication will be difficult or impossible without unacceptable loss of native species. The goal of containment is to not allow further growth of the species’ population or expansion into uninfested areas of the Refuge.

Unlike invasive plants that have formed monocultures where treatments are not likely to affect native species, non-native aquatic species are impossible to eradicate without impacting native species. Research is urgently needed on methods to control/eradicate species such as crayfish and red-rim melania that will not severely impact native fish and aquatic invertebrates.

Non-native species removal in a whole-ecosystem context Care must also be taken when dealing with multiple non-native species at any one site. Because of the sometimes complex relationships between native and non-native species, removal of a single non-native species can lead to an unexpected result – unwanted secondary impacts (Zavaleta et al. 2001). For example, removal of a non-native predator could lead to increases in a non-native prey species. The non- native prey species may, in turn, prey upon or compete with a native species. Or removal of a non-native prey species could shift predation pressure to a native species. Often this knowledge of species interactions is lacking (Kennedy et al. 2005). Therefore, it is critical to develop an understanding of the trophic interactions and functional roles of native and non-native species, so that restoration takes into account the possibility of these secondary effects (Zavaleta et al. 2001). Although at this time there is no known method to eradicate red-rim melania, research is still needed on competitive/trophic interactions between this exotic snail and native endemic snails under predation pressure by crayfish.

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Invasive Animal Control Methods

AMNWR will employ a variety of control methods. Treatment methodologies will be based upon the best information available from pest management literature and professional expertise. The most appropriate treatment for an infestation typically depends on the size of the infestation and on the biology and ecology of the target species (Evans et al. 2003). Non-native animal management techniques are expected to change and become more refined as more experienced is gained.

Cultural Control

Cultural control methods include a broad range of normal management practices that can be modified or manipulated to manage one or more pest problems, usually by minimizing the conditions those pests need to live (e.g., water, shelter, food). The intent of cultural control is to shift the competitive balance towards native species.

During the agricultural period at Ash Meadows, springheads were fitted with pumps and water was diverted into irrigation channels, destroying the natural stream channels and riparian corridors. One of the problems with highly altered spring systems is that native vegetation is often replaced with non-native or pest species. Although native, cattail was not abundant in 1891 when Dr. Frank Coville, a botanist with the Death Valley Expedition first reported on the vegetation in Ash Meadows (Threloff 1992.). The slower-moving water of these disturbed sites promotes cattail growth which has a negative effect on pupfish by reducing outflow velocity further, and by providing hiding spots for exotic species. Cattails create headwater marshes that provide excellent habitat for largemouth bass and crayfish. They also provide protection for sailfin mollies. The Ash Meadows pupfish aggressively defends its territory and when more abundant than mollies, the persistent pupfish reduce molly reproductive output, acting as a biological control agent. However, when mollies can escape by hiding in cattails, the pupfish may expend excessive energy chasing mollies to the detriment of the pupfish and with little impact to mollies (G. Scoppettone, pers. comm.). Removal of cattails shifts the balance in favor of native fish species and, therefore, is a form of cultural control. However, removal of cattails is currently done using manual/mechanical (cutting) and chemical (herbicide via backpack sprayer) methods. Both are labor- intensive and time consuming.

Restoration of the historic hydrology of Ash Meadows is needed to create conditions that discourage cattails and favor native aquatic species. Restoration of springs and their outflows will be the heart of cultural control at AMNWR. As an example Kings Pool, like most of the major springs in Ash Meadows, had been diverted into a concrete channel for irrigation during the agricultural period. By 1989, this channel had deteriorated causing water to spread out and form a cattail marsh where non-native species dominated. In 1996-1997, Kings Pool underwent restoration including excavation of a 1-km meandering channel to simulate a portion of the historic outflow stream (Gourley and Ammon 1997). (Approximately 10 km of the historic stream channel has not yet been restored.) By monitoring fish species composition in various macrohabitats within Ash Meadows, Scoppettone et al. (2005), determined the type of habitat preferred by native fish and found that a channel configuration that retains the spring’s high stable temperature at a mean flow velocity of approximately 30 cm/second favors the native fish of Ash Meadows over sailfin molly and mosquitofish. This information was used to reconstruct the historic Kings Pool outflow channel. Species composition shifted from 23% native fish pre-restoration to 91% native fish post-restoration (Scoppettone et al. 2005).

A study at Jackrabbit Spring in AMNWR found that removal of non-native saltcedar from along the outflow channel resulted in a significant increase in algal productivity and the density of pupfish (most likely due to the algae) and a decrease in crayfish (Kennedy et al. 2005). Although not statistically

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significant, the density of speckled dace also increased while non-native mosquitofish decreased. However, removal of saltcedar also resulted in a significant increase in the non-native red-rim melania (also probably due to the increase in algae), demonstrating the need to be aware of unwanted secondary impacts from management actions where multiple invasive species are present.

Altering the stream banks with the addition of one-inch gravel may interfere with burrowing and prevent crayfish from hiding which would then make them easier to catch and remove (Scoppettone, pers. comm.). Experimentation with different sizes of substrate is warranted to determine the effects on native as well as non-native species.

Water manipulation is a method of control that must be well planned and used carefully since it impacts all aquatic species – native and non-native alike. It may be used in combination with physical and/or chemical control, especially where the impact to native species is minimal. For instance, few native fish are found in Crystal Reservoir due to the numbers of predacious fish (bass and green sunfish) and the water delivery system allows water to be diverted around the reservoir directly to the marshes below, making the reservoir an obvious candidate for water manipulation to control non-natives.

Redirecting water from a springhead into a temporary channel to dry the outflow stream for the eradication of crayfish has also been proposed. This would only be effective in small systems that are isolated from other infested waters and could only be considered where the stream contains no unique species that cannot establish in the temporary channel or be held in a refuge (refugium) until the water is rediverted to the original channel .

Physical Control

Exclusion/Barriers Animal invasives can sometimes be excluded from an area by simple barriers. In the case of feral horses and burros, the installation of an exclosure fence around the Refuge resulted in total elimination of these non-native species from AMNWR. Similarly, fish barriers have been used successfully in Ash Meadows to prevent movement of non-native fish. A fish screen has been installed on the outflow of the siphon pipes at Crystal Reservoir to stop bass and green sunfish from migrating into Lower Crystal Marsh and a fish barrier may be all that is keeping bass in the Big Spring system from moving into the Jackrabbit Spring outflow.

Research is being conducted on the use of electrical barriers for fish and for mitten crabs. Electrical barriers have been installed in Central Arizona Project canals to prevent the movement of Colorado River fishes into the Gila River drainage (Clarkson 2004, Dawson and Kolar 2003). This technology might eventually prove useful at Ash Meadows to control the movements of bass, green sunfish, and perhaps, crayfish.

Fish barriers will be considered in the planning for all hydrological systems undergoing restoration in AMNWR. However, barriers have disadvantages which include construction costs, maintenance costs, environmental impacts, and prevention of native fish migration (Dawson and Kolar 2003), thereby reducing the available gene pool of isolated populations. Since barriers are effective only when intact, another disadvantage as a control method comes from their vulnerability to human tampering. Whether it’s the cutting of a horse exclosure fence by an individual that sees it as a government “lock-out” or the removal of a fish barrier by a vandal or uninformed visitor, it may not take long to undo an exclusion that took months or years to achieve.

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Trapping Trapping is the most common method of non-native aquatic species removal used at AMNWR. When infestations are pervasive, trapping is rarely effective at eliminating all individuals of a species, but keeping the invasive species controlled can give native species a fighting chance until a better method is available. The type of equipment used depends on the species and the habitat being trapped.

Traps Several different types of metal mesh “cages” are used for exotic species removal. All are live traps. The Gee Minnow trap is a ¼ -inch galvanized steel wire trap that is 9” in diameter x 17.5” in length with 1- inch openings on each end. The Gee Exotic trap is similar, but has 1/8-inch mesh. The ¼-inch mesh Gee Crawfish trap has a 9” diameter and is 31” in length (center section can be removed to reduce length to 17.5”) with double entrance openings of 2¼ inches. The Tomahawk Double Door Crayfish trap has a much larger mesh (½” x 1”) that is not as effective for small crayfish, but allows native fish to pass through. Rope is tied to the trap for retrieval from the water.

Traps are used in springs and outflows to catch crayfish, sailfin mollies, convict cichlids, green sunfish, bullfrog tadpoles, and to a lesser extent, mosquitofish. Floating the traps near the surface with blocks of Styrofoam or empty plastic water bottles increases the catch of mosquitofish. The traps are baited with dry cat or dog food, or canned cat food and left in the water for a maximum of three hours to reduce the loss of native fish to crayfish predation while in the traps. The only trap that can be used overnight is the larger mesh Tomahawk crayfish trap that allows native fish to escape. At this time, it is not known how easily native fish can find their way out of the larger entrances of the Gee Crawfish trap, so these traps will not be used longer than three hours at a time.

Nets Dip nets are small nets used to scoop mosquitofish from the surface.

Hoop nets have been used to catch crayfish, but because the crayfish can leave the nets when the bait is gone, the nets must be checked every ½-hour to 1-hour. The advantage of this method is that native fish are not trapped with crayfish so there is no loss of endangered species.

Gill nets and trammel nets have been used in spring pools and streams to capture bass and are most effective when left overnight. Mesh sizes vary, but are large enough that native fish are not caught. However, other non-target species such as diving ducks can become entangled and drown.

Spears Spears have been used in some of the larger spring pools and reservoirs to remove bass, sunfish, and convict cichlids. Adult bullfrogs are also removed by spear (gig). Bullfrog gigging is done at night by first spotlighting and then spearing the frog. Bullfrog gigging is open to the public by Special Use Permit; however, few people have shown an interest in this activity.

Fishing Targeted fishing or overharvesting of specific species of fish has been used to regulate fish populations in other areas, but it has not resulted in elimination of a species (Dawson and Kolar 2003). Although never authorized, bass fishing occurred at Crystal Reservoir on AMNWR, and despite the absence of stocking and limits, bass were never “fished out.”

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Electrofishing Electrofishing was originally used as a means of sampling fish for population estimates. It involves using a power unit, transformer, and electrodes to pass a field of electricity through the water that interferes with the neurological pathway between the brain and muscles of the fish (Allen-Gil 2000). It does not kill the fish, but stuns it, allowing its capture and removal.

Electrofishing is size selective. The smaller the fish, the greater the current necessary to affect it. Increasing the field strength to capture smaller fish will increase mortality due to the higher voltage gradient (Couchman 2006). This size selectivity allows use on bass without impacting Ash Meadows’ native fish. Electrofishing efficiency can also be affected by stream conductivity, temperature, depth, clarity of water, and vegetation.

Biological Control

There are a number of potential biological control methods being investigated for controlling non-native species. These include the use of living organisms, biopesticides, biochemicals, genetic manipulation, and fertility control (Dawson and Kolar 2003).

The use of living organisms involves using natural enemies of the pest species or disease-causing organisms. The use of a disease-causing organism would require that the organism be species-specific and not capable of adaptation to new hosts (Dawson and Kolar 2003). At this time, there are no organisms that meet those requirements for the non-native aquatic species found in Ash Meadows. As for using a natural enemy – it would be difficult to find a predator of a non-native species that would not also impact native species. Therefore, there are no plans to introduce a new living organism to the Ash Meadows ecosystem for the purposes of controlling non-native species.

Biopesticides are materials derived from natural sources and include biochemicals that control non-native species by nontoxic means. Pheromones are one type of biochemical that is species-specific; some are attractants and others are repellents. Pheromones might some day be used to interrupt mating behavior or to lure non-native species into traps (Dawson and Kolar 2003), but that state of knowledge does not yet exist for the species of interest in AMNWR.

Genetic manipulation can potentially be used to create monosex populations of fish, and fertility control using an immuno-contraceptive agent that is species-specific has also been proposed (Dawson and Kolar 2003). Research on the effects of inserting sterilized male crayfish into the population has also been suggested (S. Goodchild, pers. comm.).

Chemical Control

Species that cannot be controlled by a combination of cultural methods, trapping, netting, electrofishing, and barriers may require the use of chemicals. Pesticides used to kill fish are called piscicides and those for snails are molluscicides.

The following factors adapted from Dawson and Kolar (2003) and modified from Wiley and Wydoski (1993) are recommended considerations in planning a chemical treatment to remove undesired fish species:

1) Determine the need for chemical treatment. 2) Obtain and evaluate necessary water quality and fish and invertebrate statistics. 3) Determine the volume (lake or pond) or length and volume (stream) of water to be treated.

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4) Determine the amount of toxicant required to obtain desired treatment (amounts of toxicant may be decreased if lake levels can be lowered or the flow of regulated streams reduced). 5) Determine if the chemical must be detoxified (some chemicals break down to nontoxic components quickly because of water temperature, sunlight, etc.); accurately determine the amount of material required to detoxify the specific concentration of the toxicant. 6) Inform the public and provide an opportunity for public comment on the treatment. 7) Ensure that the treatment will not contaminate potential sources of drinking water. 8) Evaluate the potential adverse impacts on environmentally sensitive species (including threatened and endangered species). 9) Develop a detailed operational plan that completely describes all aspects of the project.

Only four pesticides are currently registered by the EPA for use as piscicides and only two of these are registered for general use: rotenone and antimycin.

Antimycin Common product names: Fintrol-5, Fintrol-15, Fintrol-concentrate

Antimycin is an antibiotic produced in cultures of streptomyces. It is a registered fish toxicant in the United States and Canada, but is also used as a fungicide and miticide. Antimycin is an irreversible inhibitor of cellular respiration that is toxic to fish eggs and all life stages of fish. Although considered a general piscicide, it has been shown that certain species of fish, such as channel catfish, are not harmed.

Antimycin does not cause an avoidance response in fish (as does rotenone) (Antonioni and Baumann 1975, Dawson et al. 1998), but it is pH-sensitive, decreasing in toxicity from pH 6.5 to pH 8.5, and is inactivated within a few hours at a pH of 8.5 and above (Marking 1975). In acid water, it takes 7-10 days to degrade to non-toxic components (Lennon et al. 1970), but is quickly deactivated with potassium permanganate (Gilderhus et al. 1969).

Safety glasses should be worn when using antimycin as it can cause conjunctivitis.

Rotenone Common product names: Noxfish, Pro-Noxfish, NuSyn-Noxfish, Chem-fish Regular, Chem-fish Special, Fish-tox, Derris, Derrin, Nicouline, Tubatoxin, Timbe Powder.

Rotenone is a naturally occurring substance derived from a South American plant, and has been used by South American tribes as a method to capture fish. It has been used as a fisheries management tool since 1934, and has a long history of successful applications. Rotenone is commonly utilized by fisheries managers to eliminate undesirable fish within systems where mechanical means are not efficient. Examples of this include elimination of competitive fish in sport fisheries and removal of harmful non- native fish in systems where native fish are preferred. Rotenone has been successfully used as a management tool throughout the southwest, including Nevada, Arizona, and Utah. It is also used on dairy cows and gardens as an insecticide.

Concentrations of between 0.5 to 10 parts per million (ppm) of rotenone are typically used for fisheries applications. The toxicity of rotenone is affected by water temperature, light, dissolved oxygen, turbidity, and alkalinity (Dawson and Kolar 2003). It breaks down quickly with warm water temperatures and in alkaline water; conditions typically met in Ash Meadows (S. Goodchild, pers. comm.).

When used for fish control according to standardized protocols, there are minimal impacts to non-target organisms although it has some toxicity to all gill-breathing animals including aquatic invertebrates and

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early life stages of amphibians (Sousa et al. 1991). Rotenone is a non-systemic inhibitor of cellular respiration in animals, and is most toxic when taken into the body through absorption into the blood across gill membranes. Due to this route of exposure, it is selective for animals which breathe through gills, or absorb dissolved oxygen in water for respiration. Ingested rotenone at treatment concentrations is typically neutralized within the digestive tract of animals by enzymes, and needs to be directly absorbed into the blood stream to be effective. There are no known effects to non-gilled vertebrates or humans from the application concentrations or residue. Rotenone is relatively nonpersistent in the environment and detoxifies more rapidly in warmer water (Gilderhus et al. 1986). It is naturally rendered non-toxic by sediments in streams, or it can be detoxified by using potassium permanganate.

Rotenone can cause irritation of the eyes and skin; protective clothing should be worn when using the chemical.

Rotenone has been used successfully at Ash Meadows to remove bass and green sunfish from systems above and below Crystal Reservoir after installation of barriers to prevent further movement. Unfortunately, vandalism to the barrier below the reservoir may have allowed these non-native species to reinfest the marshes downstream before the damage was discovered. Prior to the use of rotenone, native fish are trapped and moved to non-treatment areas. Although the impact on springsnails from rotenone is not known, snails can be collected and retained in an aquarium until the water has detoxified.

Potassium permanganate Potassium permanganate is an oxidizing agent that is used to deactivate rotenone and antimycin. It is moderately toxic to fish, but is nonpersistent in the environment.

Molluscicides and other pesticides There are no pesticides registered for aquatic crayfish control and any molluscicides capable of controlling red-rim melania or giant rams-horn snails would, most likely, have a devastating impact on the Refuge’s endemic springsnails and other aquatic invertebrates. Therefore, chemical methods will not be used to control these non-native species at this time.

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VII. Invasive Animal Species Inventory and Prioritization

Inventory

The Recovery Plan for the Endangered and Threatened Species of Ash Meadows, Nevada (USFWS 1990), lists the distribution of non-native aquatic species in 59 springs and other water bodies in Ash Meadows. Monitoring of Ash Meadows’ native fishes has occurred on a relatively regular basis (biennially) since 1989 in at least 14 major springs. These surveys utilize minnow-type traps which also result in the capture (and removal) of crayfish, bullfrog tadpoles, and non-native fish species. Numbers of non-native species are documented, but not used to estimate populations.

In 2004-2005, Otis Bay, Inc., completed a study which included invertebrate sampling at 14 springs within the Refuge. They also documented vertebrate observations although surveys were not conducted.

Since 1990, most non-native species have expanded their distribution and a new species, convict cichlid, was discovered in Fairbanks Spring in 2001. Crayfish, red-rim melania, and mosquitofish are now found in almost all of the major springs. Crayfish and red-rim melania have reached North and South Indian Springs, South Scruggs, and School Spring – all within the isolated Warm Springs Complex. In 1990, School Spring was reported as being free from non-native aquatic species and the two Indian Springs and South Scruggs Spring had only mosquitofish. Currently, Marsh and North Scruggs springs within the Warm Springs Complex are believed to still be free of crayfish.

Largemouth bass were discovered in Big Spring in October 2003, by which time they had already decimated the Ash Meadows pupfish and speckled dace populations. Although over 70 bass have been removed from Big Spring and its outflow, there are believed to be several fish remaining. Largemouth bass were present in Crystal Spring in 1990, but have since been extirpated. However, as long as bass remain in Crystal Reservoir, the threat of bass returning to Crystal Spring remains.

Characterization of Infestations and Prioritization by Management Approach

Sub-basin Management Units

The pervasiveness of non-native aquatic species and the impacts to non-target species from eradication methods require management on a smaller scale. Rarely will management of these species be considered on a sub-basin scale. Instead, a spring by spring approach will be the preferred method. That being said, a management action currently in the planning stages may be considered an exception to this rule. Due to the isolated nature of springs within the Warm Springs complex relative to other springs in the Refuge, an attempt will be made to eradicate crayfish and mosquitofish from three springs at once to prevent spread of these species to the rest of the complex. The Refuge currently has money for restoration work within the Warm Springs complex to correct habitat alteration created during the agricultural period, and SNPLMA funding to construct a refuge (refugium) for the Warm Springs pupfish and Warm Springs endemic invertebrates. Water from North and South Indian Springs, and School Spring will be diverted into temporary channels for up to one year to dry areas presently inhabited by crayfish. Following eradication, the original channels will be recontoured or reconstructed as needed. Gravel substrate will be added that encourages native invertebrates while preventing the reestablishment of crayfish by interfering with their ability to burrow into the banks. A refugium will be constructed at School Spring to replace the three cement pools built as a refugium prior to the establishment of AMNWR. These pools have not

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proven to be productive habitat, but a refugium is still necessary especially as restoration continues on other springs in the complex. The new refugium will more closely resemble the native habitat of Warm Springs endemics.

Spring and Reservoir Management Units

Ash Meadows speckled dace were once wide-spread across Ash Meadows, but are now restricted to the Bradford Springs and Jackrabbit Spring. A small number have been translocated to the Point of Rocks, but the sustainability of this population is not yet certain. The population at Jackrabbit Spring suffered a major blow when a high intensity fire, fueled in part by saltcedar, burned along the outflow in 2005 and deposited a large amount of ash in the stream. Two years earlier, the small population remaining in Big Spring was wiped out by largemouth bass. The Ash Meadows speckled dace are considered to be “highly imperiled” (Otis Bay, Inc. 2006), and therefore, springs currently or recently used by dace will be high priorities for non-native management. These include: Jackrabbit, Big, Bradford, and Point of Rocks springs and associated outflows.

The Warm Springs pupfish are also believed to be on a downward trend, numbering less than 1,000 individuals throughout the entire Warm Springs complex. The last record of a pupfish in South Indian Spring was in 1997. Springs within the complex will be receiving treatment this year as described under Sub-basin Management Units (see above).

Other waters that will be priorities for attention include Fairbanks in order to contain a new species, and Crystal Reservoir, to eradicate a predatory species (largemouth bass) that has the potential to spread to several different springs that are hydrologically connected to the reservoir.

Which springs have priority for treatment also varies with the method used. Trapping exotic species will occur at all springs, but with limited staffing, efforts will be focused on Big Spring (bass), Jackrabbit and Bradford Springs (crayfish and sailfin molly), and Fairbanks (convict cichlids) first; then on Point of Rocks (including Kings Spring) and Crystal Spring (sailfin mollies and crayfish). Trapping is ongoing.

Springs with priority for chemical control include Fairbanks Spring (convict cichlids) and Crystal Reservoir (largemouth bass and green sunfish). These waters will require chemical treatment because the goal is eradication to prevent further spread of exotic species. These projects are in the early planning phase.

The priority springs targeted for habitat restoration and use of cultural control methods (water manipulation, substrate manipulation) are Jackrabbit, School, and North and South Indian springs. Most of these projects are in the planning stages, although restoration along the Jackrabbit outflow is in the implementation phase.

After over two years of using physical control methods from spearing and netting to electrofishing, bass remain in the Big Spring system. The use of rotenone would likely be effective, but there are other considerations here such as Private property owners who obtain their drinking water from Big Springs’ outflow. A proposal is being considered for future submission to SNPLMA to begin restoration work at Big Spring. If successful, planning for this project will include a discussion of the methods to be used to control and/or eradicate non-native species.

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Targeted Species

Crayfish and red-rim melania are found throughout Ash Meadows. Crayfish may eventually eliminate most native invertebrates in Ash Meadows’ springs (Otis Bay, Inc. 2006) and cause the extinction of Ash Meadows’ endemic springsnails within 10 years (L. Stevens, pers. comm.). The impact from the red-rim melania is not yet known, but can be presumed to be negative since the species is capable of replacing native snails. Unfortunately, both species are difficult to impossible to eradicate without decimating native species. Research on methods to control/eradicate these species is urgently needed. Until the solution is found, AMNWR will concentrate on trapping crayfish at those springs where the ecological impact is greatest (see above) and try to monitor trends in red-rim melania density.

Largemouth bass and convict cichlids will continue to be high priority species. Largemouth bass will be eradicated wherever found because they are voracious predators capable of eliminating native fishes in a short period of time. Although at the moment not as critical as the bass in Big Spring, the bass (and green sunfish) in Crystal Reservoir will also be targeted for eradication, possibly using a combination of fishing, netting, water manipulation, and chemical (rotenone) control.

Convict cichlids are currently found only in Fairbanks Spring and several hundred yards of its outflow. This species is a high priority due to its still somewhat limited distribution, but potential to invade Rogers and Longstreet springs, which are hydrologically connected to Fairbanks.

Sailfin molly, mosquitofish, and bullfrogs are widespread and will prove difficult to eradicate. AMNWR’s strategy for dealing with these species will be to prevent population increases by trapping (and gigging) these species, along with crayfish, with the goal of simply lessening their impacts to native species until better methods of control are devised.

The giant rams-horn snail was recently discovered at Marsh Spring. This species competes with native snails, and preys upon their eggs and young. Like the red-rim melania, there is little that currently can be done about them. Care will be taken to prevent their spread to other springs by traps or boots.

Conclusions and Recommendations The rapid proliferation of invasive species such as the recently introduced convict cichlid, and the difficulty in eradicating aquatic species, demonstrate the need for constant vigilance through monitoring of springs and reservoirs. The greatest impediment to accomplishing this is lack of funding for the program. Whereas, the Refuge has been able to secure funding for specific invasive weed projects through BAER and SNPLMA, there is currently no similar source for invasive aquatic animal control. Exotic species trapping is carried out as staffing permits. Also, government agencies in Southern Nevada have convened teams to address invasive plant issues (e.g., Southern Nevada Restoration Team, the National Park Service Exotic Plant Management Team, the Weed Sentry Program, etc.), but again, no similar programs exist for invasive aquatic animal species.

However, habitat restoration projects funded through SNPLMA will benefit aquatic species and help to reduce and control non-native species. Also, the FWS must research other potential funding sources.

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VIII. Invasive Animal Species Profiles: Biology and Species-Specific Control Recommendations

The animal species targeted for treatment were chosen due to their threat to Federally-listed species and ecosystem processes in AMNWR. The size of an infestation, its pervasiveness, and management difficulty will determine whether the goal is eradication or containment. For instance, the relatively confined populations of bass and convict cichlids will be targeted for eradication. The current goal for the ubiquitous mosquitofish and crayfish is containment with a long-term goal of reduction.

A species that is not on the Target Species list may still be considered for treatment, especially if it is a new arrival in the Refuge. The list will be reviewed and updated biennially or as more information is gained.

The following brief profiles of targeted species include a discussion of possible treatment methods and priority sites for treatment.

Target Species

Archocentrus nigrofasciatus (Cichlasoma nigrofasciatum)

Common name: convict cichlid

The convict cichlid, first identified on the Refuge in Fairbanks Spring in 2001, was the result of an illegal introduction. Subsequent surveys have consistently found cichlids within the spring and outflow, where they form well established, self-sustaining populations. The presence of this fish poses a further threat to the endemic aquatic fish and invertebrate species of Ash Meadows. The Recovery Plan for the Endangered and Threatened Species of Ash Meadows, Nevada (USFWS 1990) requires restoring a self- sustaining population of Ash Meadows speckled dace to the Fairbanks Spring system as part of the criteria for delisting of the dace. This would not be possible at this time due to the cichlid infestation.

Convict cichlids are members of the Family Cichlidae, whose native range occurs in Central America from Guatemala to Panama. This cichlid is a common aquarium fish that has become well established at various locations throughout North America, such as Florida. In Nevada, they occur throughout the warmer waters of Pahranagat Valley, Lincoln County; Rogers Spring on Lake Mead National Recreation Area, Clark County; as well as in AMNWR. Full grown males can reach up to six inches; however, this generally only occurs in an aquarium setting. Convict cichlids are also known as zebra cichlids; both good descriptors of their physical appearance due to the black vertical bars on their body. Cichlids have no special requirements when it comes to water conditions. A neutral to slightly alkaline pH and water temperature of 68-82˚ will suffice. They are hardy fish that thrive under most conditions (McEwan 2000). Cichlids are aggressive protectors of their feeding area and their young (Coleman 2006); often attacking fish larger than themselves, making physical contact and wounding them.

The convict cichlid feeds on worms, crustaceans, insects, fish and plant matter. Eggs are laid on rocks and there is a high degree of parental care of the eggs and fry. An average of 30 fry per breeding event has been reported to be reared to independence. They may have several nests per year, producing hundreds of young (McEwan 2006). Hobbyists often refer to cichlids as “rabbits of the fish world” in reference to their prolific breeding habits. Fry and juveniles are piscivorous, feeding on smaller fish.

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Cichlids were discovered in Fairbanks Spring by Peter Unmack of Arizona State University and the Desert Springs Action Committee in 2001. At the time of discovery, the cichlids had already bred, and several juveniles were captured and destroyed. The FWS surveyed the Fairbanks springhead and outflow, and determined that cichlids were well established in the outflow, but in low numbers within the springhead. The FWS then initiated a trapping program (spearing and trapping) which was only modestly effective. Several adults remained trap shy and were able to elude any attempts at spearing. These adults spawned and the FWS was unable to eradicate the cichlid, but was successful in keeping the population small. Nevada Department of Wildlife biologists began to assist with these efforts and were able to maintain the population at low numbers. No attempt has been made to manage the outflow as the population was already well established, there is too much vegetation to effectively remove fish, and the outflow is isolated from the spring pool due to the water monitoring flume which acts as a barrier at the beginning of the outflow.

Priority Sites The application of the chemical piscicide rotenone is the proposed method for removal of cichlids from Fairbanks Spring pool and outflow. The upstream point of application will be the spring issuance and the point where the outflow becomes subterranean will be the downstream termination point of removal efforts. Trapping has been minimally effective at slowing the growth of the cichlid population.

The other aquatic habitats on the Refuge are believed not to contain cichlids at this time and represent key recovery habitats for Ash Meadows Amargosa pupfish, Warm Springs pupfish, Ash Meadows speckled dace, Ash Meadows naucorid, and other endemic species. If cichlids were able to extend their range elsewhere on the Refuge, it is very likely that they would severely negatively impact native species and become established to where they would be virtually impossible to remove.

Gambusia affinis

Common name: mosquitofish

Gambusia affinis, better known as the mosquitofish, is native to the southern and central portions of the United States. The current natural range of G. affinis is from about the eastern border of Mississippi west to eastern Texas. To the west of the Mississippi River their range extends at least into southern Missouri (Hole 1995). The mosquitofish has been introduced into habitats worldwide for mosquito control (Sigler and Sigler 1996), and in Nevada during the 1920's and 1930's (La Rivers 1994). However, there is ongoing debate about whether they are any more effective at controlling mosquitoes than native fish populations. Mosquitofish feed on mosquito larvae; however, almost all native fish of this size do as well, and some such as the pupfish, may be more effective (Scoppettone, pers. comm.). It is difficult to find mosquito larvae where healthy native fish populations are present.

The mosquitofish is greenish grey in color with each scale edged in black giving the appearance of a tiny piece of black lace on a silver fish. The basic body form of the female is similar to the wild-type female guppy. The male is much slimmer and shorter than the female mosquitofish. There are no "fancy" colors in this species (Hole 1995).

Mosquitofish are members of the Poecilioidae family and are live-bearers. They reach sexual maturity between 4-6 weeks of age when they are approximately one inch in length. Three to four generations are possible within a year in ideal conditions. Five broods are thought to be the maximum for an individual, with up to 315 young per brood (Krumholtz 1948). A mosquitofish may live up to 15 months in the wild.

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Mosquitofish rely on vegetation for cover, and typically live at or near the surface of the water. Without cover they are at risk of extirpation by predators (Sigler and Sigler 1996). Due to the high biological potential of this species, they are able to rapidly adjust to population fluctuations. The non-native, predaceous largemouth bass does not seem to have an impact on mosquitofish as evidenced by the number of mosquitofish present in Big Spring even after the extirpation of the Ash Meadows pupfish and speckled dace by bass.

Mosquitofish compete for resources with native fish species, and also prey upon fish and amphibian larvae. This behavior increases the need to remove mosquitofish from the environment at Ash Meadows. While no extinctions of pupfish species due to mosquitofish predation have been recorded, native fish populations that live with mosquitofish tend to be depressed in abundance. Evidence collected in part by Unmack (unpub. data) from Ash Meadows suggests that when gambusia are decreased in abundance by physical removal, significantly higher numbers of pupfish occur within a year (Unmack 1998).

Gambusia are hardy fish and are tolerant of a wide range of water conditions, such as low dissolved oxygen and water temperatures between 40-108˚ Fahrenheit (Sigler and Sigler 1996). Known biological factors that limit the spread of mosquitofish are predation, fast flow rate, cold water, and salinity (Schoenherr 1981, Arthington & Lloyd 1989, Courtenay & Meffe 1989, Congdon 1994, Nordlie and Mirandi 1996). Currently, mosquitofish are thriving at Ash Meadows due to the high amount of slack water created by alterations to the environment during the agricultural period. Therefore, hydrological restoration measures proposed for Ash Meadows may help to favor native fishes at the expense of mosquitofish.

Trapping mosquitofish is moderately effective if the trap openings are placed near the surface of the water. Trapping at Ash Meadows from 1995-2000 resulted in an average of 19.4 mosquitofish per trap (n=64,893 mosquitofish / 3,345 traps). This equates to an average of 31.8 fish per hour in 2,040 hours of trapping. Traps were baited with dry dog food. Other forms of netting, such as seining with long handle dip nets have been effective in the smaller open water spring pools within the Refuge.

Priority Sites Currently, mosquitofish continue to be present throughout Ash Meadows with the exception of a few isolated springs. Trapping, with the goal of keeping numbers low, will continue at Bradford, Jackrabbit, Big, and Fairbank springs. Restoration efforts at three springs in the Warm Springs complex, which will include diverting water from the springhead and drying of the outflow channel, may result in eradication of mosquitofish from these springs. Proposed chemical treatment to eradicate convict cichlids from Fairbanks spring may also result in the eradication of mosquitofish from the spring pool, but likely not the outflow.

Lepomis cyanellus

Common name: green sunfish

Green sunfish are native to east-central North America. They have been introduced throughout much of the United States, in many cases by people who thought they were bluegills (Lepomis macrochirus), a more desirable game fish (La Rivers 1962). Green sunfish occur in Crystal Reservoir and possibly the adjoining systems. Green sunfish have been identified as a serious threat to other fish species due to their large numbers, which eat or out-compete young of other species (La Rivers 1962, Scott and Crossman 1973).

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Green sunfish are relatively small, and occur in great numbers within proper habitats. They feed on insects, crustaceans, mollusks, and small fish. When larger in size, they also eat crayfish. Green sunfish require habitats which are similar to the largemouth bass (Sigler and Sigler 1996). They inhabit water temperatures from approximately 65-86˚ Fahrenheit. Green sunfish also require cover (Sigler and Sigler 1996). They live to 11 years, reach sexual maturity at two to three years, and lay many eggs.

Control of green sunfish is the same as for largemouth bass: water manipulation and piscicides.

Priority Sites Currently, green sunfish have a restricted range within Ash Meadows (Crystal Reservoir and possibly Crsytal Marsh and Horseshoe Reservoir), which should facilitate elimination. This should be done before they spread to other waters.

Marisa cornuarietis

Common name: giant rams-horn snail

The giant rams-horn snail is a native of South and Central America. It was probably introduced into the United States through the aquarium trade. This non-native snail can have a negative impact on native snails through competition and direct predation of eggs and young (Hunt 1958). It has been known to completely denude vegetated areas (Benson et al. 2001).

The giant rams-horn snail has been found in Marsh Spring. Its true extent within the Refuge is not known.

Priority Sites There are no plans to control this species at this time. Any molluscicides that would be effective on the giant rams-horn snail would most likely also eliminate Ash Meadows’ endemic springsnails.

Melanoides tuberculata

Common name: red-rim melania

Red-rim melania is a snail that is native to tropical and subtropical Africa, Asia, India, and Australia. It was probably introduced to the United States in the 1930’s through the aquarium trade (Murray 1971) and was reported in springs in Nevada in the mid-1980’s (Hershler 1998).

Red-rimmed melania have an elongate conical shell with regularly increasing whorls, typically five in number. The last whorl is usually broken (Lee 1973). The shell is light brown, frequently mottled with rust colored spots that may form a spiral bellow the suture. The spiral is usually twice the length of the aperture or more (Morrison 1954).

Red-rim melania are known to be tolerant of a wide range of salinities, and occur in waters between 64˚ and 88˚ degrees Fahrenheit (Murray 1971, Neck 1985). They are known from warmer temperatures at Ash Meadows (91˚ Fahrenheit within School Spring). Melanoides are parthenogenic and viviparous with the number of young per brood varying from 1 to 91 (Berry and Kadri 1974, Morrison 1954, Pointier et al. 1993). They feed on algae and detritus (Rader et al. 2003), and there is thought to be a trophic overlap with the food habits of other snails, which is a problem since red-rim melania can achieve extreme

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densities of up to 37,500 individuals per square meter (Roessler et al. 1977). In addition to displacing native snails, red-rim melania may compete for algal resources with native fishes and invertebrates. Melanoides are also known to serve as a host to a variety of parasites including fish, wildlife, and human parasites. Of particular concern is the parasite Centroces formosanus, often referred to as the “gill trematode.” This parasite is carried by the red-rim melania and is infecting several endangered species throughout the United States. In the spring of 2003, the parasite was observed in western Utah in speckled dace and mosquitofish (Mitchell et al. 2005).

Red-rim melania are resistant to dessication, molluscicides, and disinfectants (Dudgeon 1982). Any molluscicides effective on this exotic snail would most likely decimate the native springsnails and other invertebrates. Due to the hazards associated with chemical treatment to the environment and listed species, more research is needed before developing a management plan for this organism. Rader et al. (2003) concluded that red-rim melania have the potential to alter the entire community structure and function of invaded ecosystems which argues for the urgency of this much needed research.

Priority Sites No sites have been chosen for red-rim melania control due to the lack of information on how to control this species. Restoration activities, including water diversion and drying of the outflow channels at School, North Indian, and South Indian springs, may result in eradication. However, the probability of success is low if the snail cannot be completely removed from the springhead.

Micropterus salmoides

Common name: largemouth bass

Largemouth bass are native to the eastern half of the United States and Canada from Quebec and Ontario to the Gulf Coast. Highly prized by anglers, largemouth bass have been introduced throughout the United States and the world (Lee et al. 1980). Largemouth bass were introduced to Ash Meadows as a game species. They are long-lived, large in size, and primarily piscivorous. They prey upon the endangered Ash Meadows pupfish and the endangered Ash Meadows speckled dace. In addition to fish, largemouth bass also eat crayfish and other vertebrates. Young fish feed on zooplankton. Their habitat requirements include low turbidity, moderate amounts of cover, moderate to high oxygen content, and low alkalinities (Sigler and Sigler 1996). Largemouth bass are extremely territorial. They spawn at age two or three years when they dig and defend a nest. From 2,000 to 90,000 eggs are laid in this nest, which the male defends for approximately two weeks. Their nests are negatively influenced by declining water levels.

Fish distribution and abundance surveys in 1990 (refuge files), found bass present in Crystal Spring, Crystal Reservoir, Point of Rocks Ponds (prior to restoration of this area), Lower Crystal Marsh, and Davis Spring. In 1994, bass were found in Forest Spring and Horseshoe Reservoir. It became apparent at the end of that year that bass were spreading rapidly and increased removal efforts were needed. In 1995, bass were found in the Big Spring outflow stream.

The first large bass removal effort was the draining and filling of the Point of Rocks Ponds in 1995. In 1996, Horseshoe Reservoir was drained, removing bass and green sunfish. In 1997, bass were found in Bradford and Kings Spring systems having spread from the Forest Spring bass population. Rotenone was used in 1998 in Forest Spring and lower portions of Bradford and Kings Stream systems to remove bass. In 1999, rotenone and water diversion was used to remove bass from the lower Big Spring system; then in 2000, Upper Crystal Marsh was drained to remove green sunfish. In 2001, bass were found again in the lower Big Spring system on private property. Bass showed up in Big Spring in the fall of 2003.

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The most effective methods for eliminating largemouth bass are water manipulation and piscicides. Rotenone was used to effectively eliminate largemouth bass from the Big, Bradford, Davis, Forest and Kings Spring systems. Trapping or netting bass is ineffective in the reservoirs and larger spring pools, as bass typically avoid active trapping methods. Gill nets and seines have been successful at removing bass in small streams in Ash Meadows that have had only a few bass. Other methods of control that have proved successful are electroshocking, spearing and standard rod and reel fishing. Currently, largemouth bass are known to exist in Crystal Reservoir and Big Spring.

Priority Sites Largemouth bass will be eradicated wherever found because they are voracious predators capable of eliminating native fishes in a short period of time. Although at the moment not as critical as the bass in Big Spring, the bass (and green sunfish) in Crystal Reservoir will also be targeted for eradication, possibly using a combination of fishing or netting, water manipulation, and chemical (rotenone) control.

Poecilia latipinna

Common name: sailfin molly

The sailfin molly is native to the Atlantic and Gulf coasts of North America (Sublette et al. 1990). Mollies are members of the family Poecilioidae which are characterized as being live-bearers. Males and females mate and the female then carries the developing eggs. The eggs are hatched internally and live young emerge from the female. Mollies produce multiple broods per year, each with 10-140 young. Although sex ratios of the young are balanced, adult populations tend to be largely female as males appear to suffer higher rates of mortality (Robins 2003).

The body of the sailfin molly is essentially oblong with a small head and upturned mouth. The common name of this species comes from the greatly enlarged dorsal fin of mature males (somewhat enlarged in females). Sailfin mollies are most commonly observed in the shallow surface waters along the edges of marshes, lowland streams, ponds, swamps, estuaries and even ephemeral water bodies such as roadside ditches. Small to large aggregations of the species are most commonly found under floating vegetation or near structures in the water, minimizing their chances of being observed by potential predators (Robins 2003). It is a warm-adapted fish, and can withstand salinities as high as 87 ppt. This molly is an opportunistic detritivore, but also forages on small invertebrates. Largemouth bass, also exotic to the Ash Meadows ecosystem, is a predator of the molly. The haploplorid trematode, Saccocoelioides sogandaresi is a known parasite of the sailfin molly (Robbins 2003).

Sailfin mollies are known to have caused a decline in populations of the federally endangered desert pupfish (Cyprinodon macularius) (Robins 2003) and they are believed to have an adverse impact on the Ash Meadows pupfish. Mollies are not only direct competitors, but the Ash Meadows pupfish aggressively defends its territory and when mollies can escape by hiding in cattails, the pupfish may expend excessive energy chasing mollies to the detriment of the pupfish and with little impact to mollies. On the other hand, when more abundant than mollies, the persistent pupfish reduce molly reproductive output, acting as a biological control agent (Scoppettone, pers. comm.).

Trapping mollies is minimally successful. Trapping between 1995-2000 resulted in an average of 1.9 mollies per trap (n=6,458 mollies / 3,345 traps) and an average of 3.1 per hour (baited with dry dog food) in 2,040 hours of trapping. Many mollies that were not captured were seen around the minnow traps which were baited with dry dog food, suggesting a low efficiency. Use of a different bait and trap type

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may increase capture rates. Other forms of netting, such as seining, is unfeasible in heavily vegetated areas within most of Ash Meadows’ channels, but has had some success in open spring pools.

Chemical control of sailfin mollies is only feasible in locations without native fish (or where native fish could be removed temporarily), and without Ash Meadows naucorids. Piscicide selection is critical, since shortfin mollies (P. mexicana) have a large tolerance to rotenone due to either physiological factors or avoidance, and a complete kill is difficult to accomplish (B. Hobbs, per. comm.).

Sailfin mollies are a popular aquarium fish and were most likely introduced to Ash Meadows by visitors. They are present in most of the larger springs. AMNWR’s strategy for dealing with this species will be to prevent population increases by trapping, with the goal of simply lessening their impacts to native species until better methods of control are devised.

Priority Sites Priority sites for trapping include Jackrabbit, Bradford, Point of Rocks, Big, and Crystal springs.

Procambarus clarkii

Common name: red swamp crayfish

The red swamp crayfish is a freshwater crustacean native to the southeastern United States. It has been widely introduced throughout the United States, including Ash Meadows National Wildlife Refuge. Crayfish have a high biotic potential compared to many macroinvertebrates. P. clarkii is able to produce one to three generations per year, depending on water temperature (Huner 1984), with each brood consisting of up to 200-500 offspring. A typical life span is up to two years. Mating usually occurs in spring and fall, but is year-round in warmer climates or only in spring in cooler climates. Incubation of offspring (under the mother’s abdomen) is as short as 2-3 weeks, and they molt into instar two and sometimes three while attached. Generally the offspring leave the mother during the third instar. The offspring are able to reach sexual maturity in three months in favorable conditions. Crayfish commonly dig burrows to escape cold winter temperatures or desiccation. They are capable of migrating considerable distances (Helfrich et al. 2001).

Trapping crayfish is problematic due to the restraints of the trapping method and selectivity of crayfish trapped. Trapping from 1995-2000 resulted in an average of 12.5 crayfish per trap (n=42,117 crayfish / 3,345 traps) and an average of 20.6 crayfish per hour (baited with dry dog food) in 2,040 hours of trapping. The number of crayfish per trap varied considerably. Minnow traps with ¼-inch mesh lined with nylon screen door mesh to prevent young crayfish from escaping were the trap-type most frequently used during this period. Due to the small one-inch entrances of these minnow traps, larger crayfish may not have been able to get into the traps. AMNWR now utilizes crayfish traps with larger 2¼-inch entrances which may prove to be more effective.

Trapping also captures fish, and fish confined in a trap with crayfish are routinely attacked. This increases the labor required to operate a trapping program since traps need to be checked frequently. Trapping also requires relatively deep water so at least half of the trap is submerged, space free of vegetation for placement of traps, and accessibility. Trapping is not effective in removing all of the crayfish, and it selectively traps males, since females are reclusive while holding eggs or young. Regardless of its inefficiencies, systematic trapping has shown to be effective in increasing egg and juvenile survival of native fishes, and is currently the best method to reduce crayfish numbers at AMNWR.

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Biological control of crayfish using predators is not possible in Ash Meadows systems that contain native fish. Largemouth bass are effective in predating crayfish (Stein 1976), but have the tendency to invade other habitats and prey on native fish. Other biological controls of crayfish have not been investigated or are not approved for use in Nevada.

Water level management for crayfish has limited effectiveness as crayfish will dig burrows up to three feet deep to reach the water table and will remain until water level increases. However, the Refuge will try eradicating crayfish in the Warm Springs complex by diverting water from three small springs into temporary ditches, allowing the original channels to remain dry for one year. By beginning in the heat of summer, it is hoped that crayfish will not be able to survive a migration to another spring.

Pesticides are a potential control method. However, there are no pesticides registered for aquatic crayfish control. Since crayfish molt many times per year (up to every 5-10 days in warm water) (Huner 1984), pesticides which inhibit the exoskeleton molt of invertebrates may be useful. Since pesticides affect most invertebrates, including the threatened Ash Meadows naucorid (Ambrysus amargosus), other endemic invertebrates, and prey species for endangered fish, pesticide application should be carefully considered and limited. Also, many pesticides effective on crayfish, such as carbofuran, are extremely harmful to fish.

Two control methods that Ash Meadows will be experimenting with are sterilization and substrate manipulation. Crayfish control research is still in its infancy and there is no accepted method to achieve the goal of eradication. At Ash Meadows, the primary goal is to reduce crayfish numbers to a manageable level where they have a minimal effect on the native species’ populations.

Priority Sites Springs currently or recently used by Ash Meadows speckled dace will be high priorities for crayfish control via trapping. These include: Jackrabbit, Bradford, Big, and Point of Rocks springs and associated outflows. Three springs in the Warm Springs complex (School, North and South Indian) are targeted for eradication using water manipulation to prevent the spread of crayfish to the other springs in the complex.

Rana catesbeiana

Common name: bullfrog

The bullfrog is native to the United States east of the Rocky Mountains. They were widely introduced in the western states in the late 1800's and early 1900's as a game or commercial species (Lawler et al. 1999). The bullfrog is a large raniid and is quite common in proper habitats. Habitat requirements include permanent water, cover in the form of either emergent or submerged vegetation, and abundant prey. They feed on a wide variety of animal life including fish, reptiles, amphibians, small mammals, crayfish, insects, and birds. Bullfrogs readily adapted to western conditions and have widely displaced native species. They either directly predate on native fish and wildlife, or compete with them for resources. Recent research indicates that this species consistently carries a pathogenic fungus – Batrachochytrium dendrobatidis – which has been implicated in global amphibian declines and species extinctions (Garner et al. 2006).

Bullfrogs occur throughout the permanent waters at Ash Meadows. Adult bullfrogs occur in wet areas associated with both flowing and standing water, but tadpoles are typically restricted to slow-moving or standing water.

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Trapping bullfrog tadpoles with minnow traps in spring pools is minimally effective. Trapping between 1995-2000 resulted in an average of 2.6 tadpoles per trap (n=8,864 tadpoles / 3,345 traps) and an average of 4.3 per hour (baited with dry dog food) in 2,040 hours of trapping. Other forms of netting, such as seining, has met with limited success in the open water spring pools within Ash Meadows because the tadpoles will burrow down under the algae and soft bottom sediment. Trapping of adults has not been attempted, but gigging is occasionally conducted. “Frogging” has been allowed as a public use at Ash Meadows since the refuge was established. However, very few visitors partake in this activity at this time.

Future control methods to be explored include: continued gigging and trapping, habitat manipulation, and chemical and biocontrol methods.

Priority Sites No sites have been specifically targeted for bullfrog control due to the lack of information on how to effectively control this species. Tadpoles will continue to be trapped in the process of controlling crayfish and other non-native species. Longstreet Spring has an abundance of tadpoles which may be due to the spring’s flat-bottomed shape; not typical of the springs in Ash Meadows. This spring most likely has been altered more than any other in the Refuge, and may require restoration to control use by bullfrogs.

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IX. Reporting and Adaptive Management

The IPM reporting program is intended to streamline mandated reporting requirements for Refuge operations and T&E species management and provides the basis for the adaptive management strategy described in the IPM. Many of the elements of the IPM annual reporting will be prepared as part of reporting requirements for specific project funding, Refuge System reporting and the AMNWR Annual Accomplishment Report. As such, the IPM annual reporting will likely be a composite of these other reports with specific imformation added to satisfy the adaptive management needs of the IPM.

Reporting

On an annual basis activities conducted under the IPM will be summarized and compiled to assist in record keeping and the adaptive management process.

 Areas on the Refuge treated under the IPM. Either a single map or simply a compilation of project maps.  A summary of the pesticides and quantities used per location treated.  A summary of noxious species and acreages treated.  A summary and acreage estimate of listed species, amount of T&E habitat and take incurred by IPM activities.  A summary and acreage estimate of revegetation or mitigation efforts (if any) implemented to benefit T&E species or project related impacts.  As described in the IPM (pages 27-28) regular weed inventory and monitoring activities are important aspects of the IPM. All weed inventory and monitoring activities conducted during the year will reported.  Summary of IPM effectiveness monitoring.  Summary of changes to techniques, methods, or operating procedures based on field experiences, effectiveness monitoring and post implementation assessments.

Effectiveness monitoring

As described in the IPM (page 19) an evaluation system to determine the outcome of treatment actions is an important part of the IPM strategy. As part of all projects implemented under the IPM annual follow- up monitoring of treated areas will be conducted. This treatment will include the following elements:

 Where IPM treatments impact sensitive plants and wildlife, Refuge staff will conduct a post implementation assessment. This assessment will determine if the proposed impacts to sensitive species in the project description is accurate. For species where state and federal permits authorize take of individuals, this assessment will be used for tracking this information. Observations made during the assessment will also be used to inform and adapt standard operating procedures.

 Sites will be revisited at least once a year following the initial treatment,. Depending on the level of funding, follow up monitoring may be either quantitative or qualitative. At a minimum, Refuge staff will set up photo monitoring points and make a visual estimate of the relative cover

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of target weed species at representative locations. If funding is available quantitative monitoring will be conducted, including but not limited to transects and quadrats.

 Treatment areas will be visited at least once a year at the start of the growing season so that, if necessary, areas may be retreated prior to seed development.

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X. References

Ailes, I. 1985. Biologist, Chincoteague National Wildlife Refuge. Telephone conversation with Marianne Marks.

Ailes, M. 1992. Ecologist, U. S. Navy. Telephone coversation with Beth Lapin. January 1992.

Allen-Gil, S.M., ed. 2000. New Perspectives in Electrofishing. Proceedings of the Western Ecology Division of the National Health and Environmental Effects Research Laboratory of the Environmental Protection Agency Training Workshop. Available at: http://www.ithaca.edu/faculty/sallen/Profile/efishproceedings.pdf

Anderson, B. W., A. Higgins, and R. D. Ohmart. 1977. Avian use of saltcedar communities in the Lower Colorado River Valley. USDA-Forest Service, General Technical Report RM-43:128-136.

Anderson, J. 1992. Biologist, Massachusetts Audubon Society. Telephone conversation with Beth Lapin. January 1992.

Anonymous. 1970. Weeds: Fresh manure can be major source of weeds in cropland. Crops and Soils Magazine 22(8):26.

Antonioni, M.E. and P.C. Baumann. 1975. Antimycin as a management and sampling tool. EIFAC Technical Paper (23) Suppl. 1, Vol. 1: 266-286.

Apfelbaum, S.I. 1985. Cattail (Typha spages.) management. Natural Areas Journal 5(3):9-17.

Arthington, A.H. and L.L. Lloyd. 1989. Introduced poeciliids in Australia and New Zealand. In Ecology and Evolution of Livebearing Fishes (Poeciliidae). G.K. Meffe and F.F. Snelson, eds. Prentice Hall, New Jersey. Pp. 333-348.

Audubon Report. 2003. Cooling the hot spots: protecting America’s birds, wildlife, and natural heritage from invasive species. Available at: www.audubon.org/campaign/invasives/habitat.shtm

Bailey, J.K., J.A. Schweitzer, and T.G. Whitman. 2001. Saltcedar negatively affects biodiversity of aquatic macroinvertebrates. Wetlands 21: 442-447.

Bainbridge, D.A. 1990. Soil solarization for restorationists. Restoration and Management Notes 2: 96- 98.

Bainbridge, D.A., R.A. MacAller, M.F. Fidelibus, R. Franson, A.C. Willians, L. Lippitt. 1995. A Beginners Guide to Desert Restoration. Department of the Interior Publication NPS D-10 72. September.

Barr, C.C. 1942. Reserve food in the roots of whiteweed. Journal of Agricultural Research 64:725-740.

Bartolome, J., M. Stroud and H. Heady. 1980. Influence of natural mulch on forage production on differing California annual range sites. Journal of Range Management 33(1): 4-8.

Beall, D. 1991. Refuge Manager, Brigantine National Wildlife Reguge. Telephone conversation with Beth Lapin. November 1991.

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Beall, D. L. 1984. Brigantine Division - Marsh vegetation rehabilitation - chemical control of Phragmites. U.S. Fish and Wildlife Service. 8 pages.

Beatley, J. 1966 Ecological status of introduced brome grasses (Bromus spages.) in desert vegetation of southern Nevada. Ecology 47(4): 548-554.

Beck, K.G. 1996 (updated 04/2003). Russian knapweed fact sheet no. 3.111. Colorado State University Cooperative Extension natural resources series. http://www.ext.colostate.edu/pubs/natres/03111.html

Benefield, C.B., J.M. DiTomaso, G.B. Kyser, S.B. Orloff, K.R. Churches, D.B. Marcum, and G.A. Nader. 1999. Success of mowing to control yellow starthistle depends on timing and plant's branching form. California Agriculture 53(2):17-21.

Bennett, A.R., W.L. Bruckart, and N. Shishkoff. 1991. Effects of dew, plant age, and leaf position on the susceptibility of yellow starthistle to Puccinia jaceae. Journal of the American Phytopathological Society 75(5): 499-501. Benson, A.J., P.L. Fuller, and C.C. Jacono. 2001. Summary report on nonindigenous aquatic species in U.S. Fish and Wildlife Service Region 4. U.S. Geological Survey, Florida Caribbean Science Center. 27 pages.

Berry, A.J. and A.B. Haji Kadri. 1974. Reproduction in the Malayan freshwater cerithiacean gastropod Melanoides tuberculata. Journal of Zoology 172: 369-381.

Blackman, G.E., M.A. Holly and K. Holly. 1939. The control of hoary pepperwort. Agriculture (Publication of the Great Britain Ministry of Agriculture) 56:6-11.

Bongiorno, S. F., J. R. Trautman, T. J. Steinke, S. Kawa-Raymond and D. Warner. 1984. A study of restoration in Pine Creek Salt Marsh, Fairfield, Connecticut. In F. J. Webb (ed.). Proceedings of the 11th Annual Conference in Wetlands Restoration and Creation. Hillsborough Community College, Tampa, FL.

Bonneville Power Administration. 2000. Transmission System Vegetation Management Program Final Environmental Impact Statement. Portland , Oregon.

Boone, J. 1991. University of Georgia, Athens. Telephone conversation with Beth Lapin. November 1991.

Boone, J., E. Furbish and K. Turner. 1987. Control of Phragmites communis: results of burning, cutting, and covering with plastic in a North Carolina marsh. CPSU technical report 41, National Park Service. 15 pages.

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Appendix A: Standard Operating Procedures to Minimize Impacts to Sensitive Plant and Animal Species at AMNWR

1. During planning and development of AMNWR IPM projects, impacts to Federal and State listed species will be avoided to the maximum extent practical. If impacts are unavoidable they will be minimized and mitigated to provide a net benefit to the species or ecosystem that supports the species. All access routes, staging areas, and work areas will be determined prior to the start of an IPM project activity. Refuge staff will work with contractors to clearly identify these project features and if necessary flag or erect construction fencing to minimize unauthorized impacts. The impact minimization measures described in the IPM are intended to be guidelines. During project planning, Refuge staff or contractors will not be limited to BMP’s indicated in the IPM, and they are encouraged to develop appropriate buffers or other BMP’s as needed to minimize impacts to sensitive plant and animal resources from IPM projects.

2. Prior to the start of IPM projects, a habitat assessment for sensitive biological resources will be made. If appropriate habitat is identified and impacts can not be avoided then surveys will be completed. The number of individuals impacted by the project will be determined. Where annual take authorizations are imposed by State and Federal permit conditions, take will be limited to the permit conditions.

3. Prior to commencing IPM projects, Refuge staff or designee will conduct a briefing to educate all personnel working on the project regarding sensitive species that may be present and project specific BMP’s to minimize impacts.

4. Since many of the endangered plants at AMNWR are long lived perennial species – salvage and translocation of individuals is appropriate under limited circumstances. At a future date, the Refuge will develop guidelines for salvaging rare plants and secure appropriate authorizations. When these have been completed, rare plant and soil salvage will be included as an impact minimization standard operating procedure for IPM projects.

5. Standard operating procedures will be regularly updated and modified through the adaptive management process described in the IPM.

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Appendix B: Literature Review and Summary of Potential for Disease Transmission from Domestic Goats to Desert Bighorn Sheep at AMNWR

The spread of communicable diseases and parasites from domestic goats, used for weed management, to desert bighorn sheep is an important concern. Summarized here are the major concerns regarding disease transmission and best management practices designed to minimize potential risks during weed management activities. Ash Meadows National Wildlife Refuge is adjacent to a small portion of Nevada Department of Wildlife Desert Bighorn Sheep Management Unit 261. Currently this population of desert bighorn sheep is exposed in an unregulated manner each year to domestic livestock in the Amargosa Valley. The use of goats as a tool to regulate noxious weeds on Ash Meadows National Wildlife Refuge poses a negligible risk to the bighorn sheep population, yet presents an effective alternative to excessive herbicide use.

The 2005 bighorn sheep population estimate for Unit 261 is 120 individuals, the probability for direct contact between this population and domestic goats proposed to be used in former agricultural fields for weed control at Ash Meadows National Wildlife Refuge is not known; however, given the best management practices outlined in the IPM, and reiterated here, this risk of contact and disease transmission is expected to be negligible. No management tool is completely divorced from risk. The relatively minor risk of disease transmission to desert bighorn sheep must be balanced against to the very real threat that recalcitrant weeds, such as Russian knapweed, and residual herbicide toxicity poses to the 12 federally listed plant and animal species present on the Refuge. Compared to the unregulated exposure from domestic sheep and other livestock that currently exists, the threat posed by weed-control activities at the Refuge is minimal. A website (http://www.amargosavalley.com/AGRICULTURE/alfalfa.html ) which promotes agriculture in the Amargosa Valley, explains that every winter when irrigation is turned off in the alfalfa fields, shepherds from California bring their flocks to graze on the remaining stubble. The sheep are used to help spread alfalfa within the field so that the crop is more uniform the next year.

Recent literature suggests transmission of two diseases, Pasturella and Chlamydial conjunctivitis, are particularly problematic for desert bighorn sheep. Other disease, including parasites, may also be of concern. Nevada has been declared free of hog cholera, bovine tuberculosis, brucellosis, and pseudorabies In addition, chronic wasting disease has also not been found in Nevada. Further, State law dictates any livestock imported into Nevada should be free of these diseases. As a result, transmission of hog cholera, bovine tuberculosis, brucellosis, pseudorabies, and chronic wasting disease are not expected to pose a threat to bighorn sheep at Ash Meadows.

Pasturella Pasturella is a bacterial infection caused by various serotypes (16 known) of Pasturella (Mannheimia) haemolytica and/or P. multocida. It has a broad spectrum of hosts, including birds and mammals, both wild and domestic. Pasturella commonly occurs in dogs and cats, and is a potential zoonosis. In bighorn sheep, Pasturella may cause respiratory distress which can develop into severe pneumonia and lead to death. Epizootics due to Pasturella have occurred, and Pasturella is a serious threat to bighorn sheep populations. Biovariant strains of Pasturella have different virulence to bighorn sheep depending on physical condition, however it should be considered a potential hazard regardless. The primary vector for the transmission of Pasturella to bighorn sheep and mountain goats is through direct contact with domestic sheep (McDaniel, 2005). Nose to nose contact is the primary method of transmission from domestic sheep to wildlife. However, it could potentially be transmitted several meters as aerosolized saliva when an infected animal sneezes or via soil contact because bacteria may remain viable in moist soil for up to 12 hours (McDaniel 2005).

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The role domestic goats play in transmitting Pasturella to bighorn sheep is based largely on circumstantial evidence, however goats have the ability to harbor the bacteria. Other ungulates: cattle, horses, llamas, domestic sheep, Mouflon sheep, as well as domestic goats, are known to carry strains of Pasturella that are cytotoxic to bighorn sheep, without manifesting the disease. In a 1994 study, Foreyt pastured healthy Rocky Mountain bighorn sheep with llamas, domestic goats, mountain goats, cattle, domestic sheep and Mouflon sheep that were known to be carriers. Only bighorn sheep exposed to domestic sheep and Mouflon sheep died in the experiment, whereas the other bighorns remained clinically healthy. Foreyt concluded domestic goats do not appear to regularly carry strains pathogenic to bighorn sheep. During a Pasturella outbreak in Hells Canyon in December 1995- April 1996 a feral goat, found within the herd, was determined to carry strains of Pasturella haemolytica and P. multocida identical to the bighorn sheep associated with it, including a strain cytotoxic to the bighorn sheep but not to the goat (Cassirer et al. 1996). However since bacterial cultures were not obtained from the animals prior to initial field contact, the route of transmission can not be determined and it remains unclear whether or not the feral goat was the source of the infection (Cassirer et al. 1996). Regardless, Rudolph et al (2003) recommend that goats within bighorn sheep habitat are managed to prevent nose to nose contact.

As per the proposed best management practices, all domestic goats used for weed control at Ash meadows will be healthy and inspected by a veterinarian. This combined with penning and hazing to prevent nose to nose contact is expected to reduce the potential of transmission to a negligible level. Transmission of this disease from domestic goats to bighorn sheep is not expected to be a problem.

Chlamydial conjunctivitis Chlamydial conjunctivitis is a bacterial eye infection commonly referred to as pinkeye. The disease is thought to be vectored by flies landing on the eyes of infected animals (AZGF, 2003). Blindness usually sets in over a week or two period. The infection itself is not usually fatal; however, bighorn sheep inhabit steep cliffs and vision impaired animals can die from falling or become easy prey for mountain lions (AZGF, 2003). In 2003 an outbreak occurred in the Ironwood Forest National Monument near Tucson, Arizona three weeks after approximately 4,800 domestic goats were brought onto state lands on a grazing lease. Out of 22 bighorn sheep captured, 13 had the bacterial infection. These animals were treated and released. As in the Hells Canyon Pasturella outbreak, the case for direct transmission of Chlamydial conjunctivitis from domestic goats to bighorn is circumstantial, and again, the goats were in direct contact with the sheep.

Currently there is no vaccine to prevent Chlamydial conjunctivitis. The most effective method to prevent its spread is to minimize exposure to infected animals and control flies. The diesase is easily identified. In general goat manure does not facilitate maggots and fly breeding to the extent that cattle manure does. As per the best management practices, all domestic goats used for weed control at Ash meadows will be healthy and inspected by a veterinarian. The disease is easily identified and it is unlikely that it would be missed during screening. Transmission of this disease from domestic goats to bighorn sheep is not expected to be a problem.

Parasite transmission and other threats Scabies is a skin disease caused by a parasitic mite which infects the skin and results in a general decline in health which may lead to death. Large bighorn sheep die-offs in the late 1800’s and early 1900’s were attributed to scabies that was transmitted from domestic sheep. In the 1970’s however research showed the mite that causes scabes in bighorns can not survive on domestic sheep (McDaniel, 2005). As per the best management practices, all domestic goats used for weed control at Ash meadows will be healthly and inspected by a veternarian. Transmission of this disease from domestic goats to bighorn sheep is not expected to be a problem.

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Bighorn sheep are susceptible to infection by lungworm. Most wild Rocky Mountain bighorn sheep in northern latitudes are infected with lungworm (Goldstein et al. 2005). Sheep and goats both share some of the same genera of lungworm, therefore transmission between domestic goats and desert bighorn sheep is theoretically possible. Lungworm is transmitted when sheep accidentally ingest snails while they graze, which are hosts for the lungworm larvae. The larvae penetrate the intestinal wall and enter the lungs where they mature and lay eggs which hatch and are in turn coughed up and swallowed back into the digestive tract. Once excreted in feces the larvae seek out a snail to complete the lifecycle (McDaniel 2005). Given the hot and arid conditions where goats would be used and their exclusion from the springs and outflow areas at Ash Meadows it is unlikely that the intermediate snail host is present to complete the lungworm lifecycle. As per the best management practices, all domestic goats used for weed control at Ash meadows will be healthy and inspected by a veterinarian. Transmission of this disease from domestic goats to bighorn sheep is not expected to be occur.

Bluetongue is a viral disease that has been documented in wild and domestic sheep, cattle, deer and pronghorn. It is spread by gnat bites. Animals can not directly contract the disease from other animals. Two cases have been documented in bighorn sheep, one in Texas in 1967 and another in Colorado in 1973 (McDaniel 2005). Animals can be vaccinated against this disease. Goats are more resistant to bluetongue viruses than sheep and cattle (USDA 2003) As per the best management practices, all domestic goats used for weed control at Ash meadows will be healthy and inspected by a veterinarian. Transmission of this disease from domestic goats to bighorn sheep is not expected to be a problem.

Johnes Disease (Micobacterium paratuberculosis) is an easily preventable disease occurring in livestock, including goats, and is surveillance disease in Nevada. It is distributed by feces, and can live extended times in water and soil, albeit less in dry alkaline conditions. Several tests are available for this disease, and only test-negative herd should be used. As per the best management practices, all domestic goats used for weed control at Ash meadows will be healthy and inspected by a veterinarian. Exposure to fresh feces will be controlled. Transmission of this disease from domestic goats to bighorn sheep is not expected to be a problem.

Risks and Benefits for using goats to control invasive weeds at AMNRW. Invasive weeds and the 4,000 acres of abandoned agricultural fields from which they are expanding, pose a significant threat to federally listed and other Ash Meadows endemic species. This threat must be addressed by the refuge. AMNWR proposes to the use of goats followed by chemical control as part of a holistic IPM, as opposed to mechanical control methods and chemical control only options because (1) Mechanical control only exacerbates Russian knapweed infestations because every root and stem fragment is that is severed by plowing or tilling is capable of generating a new plant. (2) The concentration of herbicide as well as number of applications needed to control Russian knapweed pose a significant and largely unknown threat to water quality and listed aquatic species. (3) Given the number of acres that need to be managed, hand pulling or other labor intensive treatments are not practical. Clearing and repeatedly depleting the energy in knapweed roots using over successive growing seasons by goat grazing it is expected by the end of three growing seasons that minimal herbicide would be required to kill any remaining plants.

Based on the literature, sheep are a primary vector of Pasturella to bighorn sheep, not goats. It is reasonable to conclude domestic goats may carry strains of Pasturella if they have been in recent contact with domestic sheep (Service 2003), however vaccines and other minimization measures shall ensure that it would not be prevalent. But goats have not been in contact with sheep, the literature suggests goats do not regularly carry pathogenic strains the disease (Foreyt 1994). The possible introduction of Chlamydial conjunctivitis from goats is a theoretical possibility, but is also one that currently exists because of

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domestic livestock already in and adjacent to Desert Bighorn Sheep Management Unit 261 in the Amargosa Valley.

The possible introduction of Chlamydial conjunctivitis in Arizona was the result of the introduction of 4,800 goats as part of a grazing allotment. These animals were not penned or monitored, and were not kept isolated from bighorn sheep. It is also reasonable to assume that the level of veterinary care for the animals is lower than the 500 animals proposed for weed control at Ash Meadows.

Based on a review of the literature and an analysis of potential transmission routes, the following Best Management Practices and Conditions will be implemented to minimize the potential for disease transmission:  Goats will be attended by a monitor 24 hours a day.  Goats will be fenced in 5-acre pens using heavy steel mesh panels held together with 5-foot t- posts. (Each panel is 42 inches high by 16 feet long and weighs 34 pounds.) The goats will be excluded from all springs and their adjacent outflow. Water will be brought to goats and pumped into troughs.  Pens will include portable shelters and goats will be provided supplemental feeding to curb their desire to wander away from the pens.  Problem goats, goats with the ability to escape the pen, are rare. When they do escape, experience indicates that they tend to stay next to the pen. These goats will be quickly removed from the herd.  The goats will be moved roughly every 1½ days (after removing the target weeds) by simply extending the pens. If they must be moved to a new location that is not adjacent to their current site, the goats would be moved by trailer.  Vacated pens will remain fenced after all goats are removed for a 24 hour period to minimize potential contact between bighorn sheep and any aerosolized saliva or fresh feces.  Prior to being transported to, or leaving the Refuge, the goats will be fed weed-free sorghum for approximately 5 days to cleanse their digestive tract of weed seeds. (Actual time-frame is dependent on what plant species they were last eating.) If trailer does not keep feces from falling out, then the trailer will be kept within a fence for a minimum of 24-hours if it remains on the refuge.  Any bighorn sheep detected within sight of the penned animals will be hazed so that there will be no nose to nose contact with the penned goats. Area immediately surrounding fence will be monitored in the morning for ungulate tracks. If bighorn sheep are detected, monitoring and hazing will be stepped up by increasing the number of monitors and dogs.  Goats in estrus will not be used. If pregnant goats deliver while on the refuge, piles of afterbirth will be removed and any remaining residue sprayed with a disinfectant solution.  Flies in and around the goats will be controlled using strips, dip, CO2 emitters, traps and/or other methods to minimize the potential to spread Chlamydial conjunctivitis.  All goats used for weed control would be certified by the owner to not have had any contact with other domestic livestock or equipment used for other livestock within the past six months.  All goats used for weed control would be checked by a veterinarian and certified to be in good health and meet federal, state and local agriculture requirements including:  Nevada Department of Agriculture Reg., 55, eff. 9-1-64; A 7-15-71; 10-1-71; 4-1-77]—(NAC A by St. Quarantine Officer, 7-8-92) 1. A person shall not ship, transport or otherwise move goats into Nevada unless each goat is accompanied by a health certificate and an entry permit. 2. In addition to the requirements of subsection 1, a goat imported into Nevada for dairy or breeding purposes must have reacted negatively to tests for tuberculosis and brucellosis within the 30 days before the date of entry.

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To enter Nevada all goats require a certificate of veterinary inspection. All breeding and dairy goats 4 months of age and older must had a negative tuberculosis test within 30 days of entry or have certified and accredited herd status. All ANIMALS: Require a certificate of veterinary inspection issued within the last thirty (30) days. Prior entry permit required on cattle, bison, swine, sheep, goats and Mexican steers. Health documents must accompany each animal transport. Call 775- 688-1180, ext 230 for entry permits or other information from 8:00 a.m. to 5:00 p.m. PST on weekdays NAC 571.025 (Added to NAC by St. Quarantine Officer, eff. 7-8-92) Performance or confirmation of required tests by official laboratory. (NRS 571.210) All tests required for entry of an animal into Nevada must be performed or confirmed at an official laboratory before a health certificate or an entry permit is issued.

Literature Cited

Arizonia Game and Fish (AZGF) Interview December 15, 2003. Reported in AZ13 Consulting Network News. AZ13.com website accessed 12/20/2005.

Cassirer, E.F., L.E. Oldenburg, V.L. Coggins, P. Fowler, K. Rudolph, D. L. Hunter and W.J. Foreyt. 1996. Overview and preliminary analysis of a bighorn sheep dieoff, Hells Canyon 1995-1996. Biennial Symposium Northern Wild Sheep and goat Council . 10:78-86.

Foreyt, W.J. 1989. Fatal Pasturella haemolytica pneumonia in bighorn sheep after direct contact with clinically normal domestic sheep . American Journal of Veterinary research 50: 341-344.

Foreyt, 1992. Experimental contact asociation between bighorn sheep, elk and deer with known Pasturella haemolytica infections. Biennial Symposium of the Northern Wild Sheep and Goat Council. 8: 213-218.

Foreyt, 1994. Effects of controlled contact exposure between healthy bighorn sheep and llamas, domestic goats, mountain goats, cattle, domestic sheep or mouflon sheep. Biennial Symposium of the Northern Wild Sheep and Goat Council 9:7-14.

Goldstein, E.J., J.J. Millspaugh, B.E. Washburn, G.C. Brundige, K.J. Raedeke. 2005. Relationships Among Lungworm Loads, Fecal Glucocorticoid Metaboolites in Free Ranging Rocky Mountain Bighorn Sheep. Journal of Wildlife Diseases 41(2) Pp 416-425.

McDaniel, C. 2005. From Me to Ewe: Interactions Between Wild Sheep and Goats and Domestic Livestock. Wild Goats and Sheep. Accessed 12.20.2005 http://www.cnr.uidaho.edu/range456/hot-topics/wildlife-livestock.htm

Rudolph, K.M., D.L. Hunter, W.J. Foreyt, E.F. Cassirer, R.B. Rimler, and A.C.S. Ward. 2003. Sharing of Pasteurella spp. Between Free-Ranging Bighorn Sheep and Feral Goats. J. Wildl. Dis. 39(4):897-903.

U.S. Department of Agriculture, Animal and Plant Health Inspection Service (APHIS). 2003. Fact Sheet.

U.S. Fish and Wildlife Service (Service) 2003. Draft Recovery Plan for the Sierra Nevada Bighorn Sheep. May 2003. http://www.johnes.org/ Recommendations from the State Veterinarian (Dept. of Ag, Livestock Div).

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Appendix C: Best Management Practices for Herbicide Use

 Prior to any treatment, the area will be surveyed for listed and sensitive species.

 Herbicides will only be applied by trained personnel.

 The lowest label rate that gives adequate pest control will be used.

 A dye will be used to avoid overspray and overapplication.

 Herbicide will only be applied when

o there is no precipitation predicted within 48 hours of application;

o the wind is between 5 - 10 mph (dependent on chemical and method used), but not calm due to local temperature inversions; and is blowing away from sensitive areas;

o the temperature is ≤90°F (32°C).

 To avoid the potential for drift when using foliar application

o the herbicide will be applied as a course spray using low nozzle pressure;

o larger droplets will be directed no higher than the tops of target vegetation.

 Precision aerial application will be conducted with a helicopter using sectional booms, precision nozzles, computer drift models, variable rate flow control, GPS, state-of-the-art ground support equipment, and properly trained personnel.

 Herbicides will not be used near surface water or on saturated soil unless they have an EPA- approved aquatic label.

 A spill contingency plan will be prepared in advance of treatment.

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Appendix D: Summary of Recommended IPM Treatments

MANUAL MECHANICAL GRAZING BIOCONTROL FIRE CULTURAL CHEMICAL Hand Mowing/ Tilling Discing Grazing Biocontrol Prescribed Water Shading Revegetation Chemical Pulling hoeing Burn Manipulation Russian No No Only used to No Maybe, goats Only weakens Only for No No Yes, after Yes, along knapweed remove followed by plant; does not previous herbicide with allelopathic herbicide kill it. year’s top use. planting chemical growth competitive grasses bassia Yes Yes, hoeing Maybe, goats No Maybe Yes seedlings followed by herbicide red Yes, Yes, hoeing No, except Maybe, Yes, in Yes, but brome seedlings seedlings possibly in with combination most spring black with other effective before seeds plastic treatments with pre- mature emergence herbicides hoary No Cutting Yes, if done No No No Remove Yes cress when in full every 5-10 irrigation or flower + days for 6-8 flood to a herbicide is weeks; then depth of 6-10 partially less frequent inches for 3 effective until Oct. months yellow/ Yes, if all Partially, if Yes Yes, by cattle, Yes, but not Yes, Yes, in Yes Malta above done at the sheep or goats; sufficient to dependent combination starthistle ground right stage done after provide long- on timing, with other stem stems bolt, but term mgmt. Will c. June - treatments material is before spiny not be used in July detached; seed- heads Refuge. and done form; use with before other methods seed production

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Appendix D: Summary of Recommended IPM Treatments

MANUAL MECHANICAL GRAZING BIOCONTROL FIRE CULTURAL CHEMICAL Hand Mowing/ Tilling Discing Grazing Biocontrol Prescribed Water Shading Revegetation Chemical Pulling hoeing Burn Manipulation Russian Yes, seed- No Resprouts Yes olive lings and after fire sprouts phragmites Mowing is No No No Only for Increased Cover Yes not removal of flooding and with effective; leaf litter, salinity plastic cutting although levels may after before the late spring control; cutting end of burning covering results in July may followed by rhizomes die-off control flooding with 3 ft of may be water for 4 effective in months is reducing effective height and density Johnson Hoeing May be May be High salt Yes grass practical effective in effective in concentra- only when combination combination tion and low population with other with other water is small; treatments treatments conditions mixed reduce plant results growth with clipping; mowing may be effective in com- bination with other treatments

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Appendix D: Summary of Recommended IPM Treatments

MANUAL MECHANICAL GRAZING BIOCONTROL FIRE CULTURAL CHEMICAL Hand Mowing/ Tilling Discing Grazing Biocontrol Prescribed Water Shading Revegetation Chemical Pulling hoeing Burn Manipulation Tamarix Yes, May be helpful Yes, but will not No, plants Flooding Yes spp. seedlings in combination be used in resprout thickets for with other Refuge at this quickly 1-2 years can treatments time. after fire kill most and are less plants in susceptible thicket to other treatments cattail Yes Cutting Fire alone Deep Black Yes followed by provides flooding is plastic submer- little or no somewhat possibly gence to at control; is effective, but effective least 3 useful for could also when inches of all leaf litter result in a used for cattail cleanup change in the at least stems; best prior to native plant 60 days results with mowing or composition during cutting in hand summer late summer clipping or early fall

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