. . CHANNEL ISLANDS NATIONAL PARK . FINAL ENVIRONMENTAL IMPACT STATEMENT .

ANACAPA ISLAND RESTORATION PROJECT

Chapter one CHAPTER ONE PURPOSE AND NEED Need

Chapter Contents

INTRODUCTION ...... 2

GENERAL MANAGEMENT PLAN DIRECTION...... 2

PROPOSED ACTION AND PURPOSE & NEED ...... 3

Purpose...... 3

Need For Action...... 3 Introduced Species and Island Ecosystems...... 3 Introduced Commensal Rats ...... 4 Impacts of Introduced Rats on Island Ecosystems ...... 5 Rats on Anacapa Island...... 5

Proposed Action ...... 6 Anacapa Rat Eradication ...... 6 Emergency Response Plan ...... 7 Prevention ...... 7

SCOPE OF THE PROPOSED ACTION...... 8

DECISIONS TO BE MADE...... 8

CHAPTER ONE - 1 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT

Channel Islands National Park General Management Plan (GMP) provides direction for Introduction management of the Park. Decisions and direction identified in these documents are incorporated by Channel Islands National Park has prepared reference. This EIS is “tiered” to the GMP as this Final Environmental Impact Statement to permitted by 40 CFR 1502.2. document environmental impacts that would be associated with eradication, prevention, and emergency response management actions associated with non-native rat (Rattus) species. General Management Plan Specifically, this FEIS will cover proposed management actions in the following three areas: Direction 1) Eradication of the Black Rat (Rattus rattus) on Anacapa Island; 2) An emergency response plan The General Management Plan (GMP) for dealing with accidental introductions of rats completed in 1985 defines management direction on Anacapa, Santa Barbara, Prince, and Sutil for the natural resources within the Park. In this Islands; and 3) A prevention strategy to reduce GMP specific objectives are stated for Anacapa, the potential for rats to be accidentally introduced San Miguel, and Santa Barbara Islands. to Park islands. This FEIS includes analysis of Objectives from the GMP which support the effects for six alternatives, including the Anacapa Island Restoration Project include: consequences of not eradicating the Black Rats
from the Island, or not reacting to or preventing Restore altered ecosystems as nearly as possible to conditions they would be in today rat introductions to Park islands. had natural ecological processes not been This Final EIS is based on direction contained disturbed. in the National Environmental Policy Act
Develop an awareness of threats that impact (NEPA), Council on Environmental Quality or have the potential to impact Park resources. (CEQ) regulations 40 CFR 1500-1508, and the
Actively respond, as a land management National Park Service NEPA implementation agency, to these potential threats. guideline (NPS-12). In addition to stating general management The Final EIS will also document the Park’s objectives, the plan identifies specific objectives obligation to meet other federal laws including: for island resources. Management guidelines to The National Historic Preservation Act; Federal meet objectives were also described in the Plan. Water Pollution Control Act (Clean Water Act); Black Rats are specifically mentioned in the Clean Air Act; Coastal Zone Management Act; GMP. The objective stated for Black Rat Marine Mammal Protection Act; and the management is “eradication”. The action to meet Endangered Species Act. this objective calls for the Park to initiate an eradication program on East Anacapa Island. CEQ regulations require a Notice of Under the criteria established by the GMP for rat Availability (NOA) be made to the Federal eradication, such a program must: Register that a final EIS has been completed. The a) Be effective Park will wait at least 30 days from the Federal Registers publishing of the NOA before signing a b) Be selective for rats record of decision. c) Have the least possible effect on native mouse populations and other forms of plant and animal life

CHAPTER ONE - 2 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT

d) Present the lowest risk to visitors and staff anthropogenic extinctions can be roughly e) Be economical and simple to maintain divided into four broad categories: non- sustainable use of resources, habitat destruction, Alternatives proposed in this analysis meet pollution, and introduction of non-native these criteria to varying degrees. species. The Resources Management Plan (RMP) also Problems in the first three categories are identifies this project as a necessary action to often acute and can directly affect human perpetuate natural processes and resources within welfare on an observable time scale. These the Park. The RMP flows from the General qualities have made them the focus of public Management Plan (1985) and Statement for environmental concern. The introduction of Management (1991). The RMP is the Park’s non-native species has received less publicity strategic plan for the long-range management of and professional attention (Coblentz 1990, its resources and a tactical plan identifying short- Soulé 1990); however, introduced species are term projects. responsible for 39% of all recorded animal extinctions since 1600 for which a cause could be attributed (World Conservation Monitoring Purpose & Need and Centre 1992). Thus, some impacts of introduced species are irreversible (reviewed Proposed Action by Groves and Burdon 1986; Mooney and Drake 1986; and Hengeveld 1989) and at least Purpose as devastating as the other categories (Atkinson 1985, 1989, Soulé 1990). Once The purpose of the proposed action is to established, introduced species often become eradicate rats from Anacapa Island and keep it and permanent in ecological time unless all Park islands rat-free. Eradicating rats from intentionally removed (Tershy and Croll 1994). Anacapa Island would improve seabird-nesting Island ecosystems are particularly habitat and could aid in the recovery of some vulnerable to both extinctions and the impacts species such as the Xantus’ Murrelet and Ashy of introduced species (Diamond 1985, 1989, Storm-Petrel. Olson 1989). Of the 484 recorded animal extinctions since 1600, 75% have been island Need for Action endemics (World Conservation Monitoring Centre 1992). Introduced species were Introduced Species and the completely or partially responsible for 67% Importance of Island Ecosystems these extinctions (based on the 147 island species for which the cause of extinction is It is now widely accepted that current rates known, calculated from World Conservation of species extinctions are dramatically higher Monitoring Centre 1992). than background rates (Raup 1988), that most current extinctions can be directly attributed to Islands are important to the conservation of human activity (Diamond 1989), and that for biodiversity for four reasons: ethical, cultural, aesthetic, and economic 1) A large percentage of their biota are reasons, this current rate of extinction is cause endemic species and subspecies (Darwin for considerable concern (Ehrlich 1988, Ledec 1859, Elton 1958); and Goodland 1988). The causes of

CHAPTER ONE - 3 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT

Figure 1: Location Map of Anacapa Island.

2) They are important breeding areas for seabirds, pinnipeds, and sea turtles, Introduced Commensal Rats which forage over thousands of square There are three species of rats in the genus kilometers of ocean but are dependent on Rattus which are commensal with humans and relatively small amounts of protected which have been introduced to islands land on islands for breeding and nesting; throughout the world. In order of decreasing 3) Many islands are sparsely inhabited or size they are: the Norway or Brown Rat (R. uninhabited by humans, keeping norvegicus), the ship or Black Rat (R. rattus), socioeconomic costs of protection low; and the Pacific or Polynesian Rat (R. exulans). 4) the species and ecological communities They have different dietary preferences, on islands have evolved in natural distributions and histories of introduction, but all fragments, making them less susceptible three species are omnivorous, behaviorally than continental species to the problems plastic, have high reproductive rates, and can of habitat fragmentation caused by small survive in a variety of habitats (Atkinson 1985, reserve size. Moors et al. 1992). These traits make them In summary, by restoring and protecting ideally suited to survive on a variety of predator islands, functioning unmanaged ecosystems can free islands. At least one of the three species be maintained without large expenditures for occurs on an estimated 82% of all island groups, land acquisition or significant conflict with local with R. rattus being the most common human populations (Tershy and Croll 1994). introduced rat (Atkinson 1985).

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Impacts of Introduced Rats on Island eradicated. The Black Rat was introduced to the Ecosystems Anacapa Islands prior to 1939 (Sumner & Bond 1939) probably in supplies transported onto the The most obvious impacts of introduced rats island for sheep ranching or lighthouse on island ecosystems are extinctions of endemic construction, or from a ship wreck (Collins species. Introduced rats (Rattus spp) are 1980). Research on the Anacapa Island by Main responsible for an estimated 40 - 60% of all bird et al. (1972), Collins (1979), Erickson & and reptile extinctions (ICEG Analysis of World Halvorson (1990), and Howald et al. (1997) Conservation Monitoring Centre Data, Atkinson demonstrate that Black Rats: 1985). They have caused extinctions of endemic mammals and invertebrates on the Galapagos 1) Are most abundant in the coastal areas and canyons on the islands; and elsewhere (Andrews 1909, Brosset 1963, Daniel & Williams 1984, Meads et al. 1984). 2) Breed from April through September; Even if extinctions do not occur, rats can have 3) Feed on native mammals, reptiles, insects, ecosystem wide effects on the distribution and intertidal invertebrates, birds, and plants. abundance of native species through direct and It is believed that the most significant indirect effects. For example, comparisons of rat- impact rats have on Anacapa Island is on the infested and rat-free islands, or pre and post rat breeding populations and breeding success of eradication experiments, have shown that rats the colonial nesting seabirds, the Xantus’ depressed the population size and recruitment of Murrelet (Synthliboramphus hypoleucus) and birds (Thibault 1995, Cambell 1991), reptiles Ashy Storm-Petrel (Oceanodroma homochra). (Whitaker 1973, Towns 1991, Cree et al. 1992), These two species are California Species of plants and terrestrial invertebrates. Rats have also Special Concern been shown to affect the abundance and age (http://www.dfg.ca.gov/endangered/birds.html ) structure of intertidal invertebrates (Navarrete & and a federal (USFWS) Species of Concern Castilla 1993). (http://www.fws.gov/r9mbmo/reports/speccon/tb Each of the three species of commensal lconts.html). Species of concern are a “high Rattus have been implicated in extinctions and priority for additional research and conservation prey populations changes. Due to their different actions,…” natural histories, however, each species has (http://www.fws.gov/r9mbmo/reports/speccon/m slightly different impacts. For example R. gmtrec.html). The California Channel Islands norvegicus tends to have a greater impact on host large proportions of the world populations adult burrow nesting seabirds than does R. rattus, of these rare species. but less of an impact on tree nesting birds Predatory mammals such as rats and cats (Atkinson 1985). Consequently, the introduction have been identified by McChesney and Tershy of new Rattus species should be avoided, even to (1998) as the main cause of long-term decline in islands which already have introduced rats (Moors Xantus’ Murrelet populations. The relatively et al. 1992). small size of the adults and crevice nesting behavior makes them susceptible to predation by rats. Introduced rats prey on adults, chicks and Rats on Anacapa Islands eggs of many seabirds. Recent surveys of Anacapa Island have found abundant evidence The three Anacapa islets have been of rat use of cliffs which coincides with subjected to introduced cats, sheep, rabbits, and preferred murrelet nesting habitat (G. rats. All but the rats have been successfully

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McChesney, pers. comm., Erickson and Proposed Action Halvorson 1990). Evidence of recent nesting activity by murrelets was found at only 0.4% of Anacapa Rat Eradication potential nesting sites investigated on Anacapa The technique proposed for eradicating rats Island (as compared to a 30% success rate on on Anacapa Island is modeled after other island Santa Barbara Island, and with no introduced rat eradication projects that have successfully rats), and all eggs found showed evidence of been completed worldwide. Due to the steep mammalian predation (G. McChesney, unpub. cliffs of the island, an aerial broadcast is data). Murrelets utilizing Anacapa are largely necessary to deliver rodenticide to every rat’s restricted to areas inaccessible to rats, such as territory, a condition that has to be met to sea caves, although abundant nesting habitat is accomplish eradication. The formation of the found elsewhere. The removal of rats from islands through uplifting has made the cliffsides Anacapa Island will provide a substantial of Anacapa Island extremely unstable and increase in nesting habitat available to these dangerous to climb, and thus bait stations cannot species in California. Seabird colonial nesting be safely placed and maintained on the likely has evolved in part from predation cliffsides. The cliffsides harbor the greatest pressure (See McChesney and Tershy 1998), and density of rats and so for eradication to be Anacapa Island is only one of two of the accomplished adequate delivery of bait to California Channel Islands which historically cliffsides must be ensured. The placement of has provided terrestrial predator free breeding rodenticide into every rat’s territory is critical to habitat to seabirds. The other predator free the success of the eradication and cliffsides need island, Santa Barbara Island, currently supports to be treated. Therefore, broadcast application a large colony of Xantus’ Murrelets. Only small (aerial and hand broadcast) would be the numbers of Xantus’ Murrelets breed at the other preferred method. Broadcast of the rodenticide Channel Islands. The abundance of nesting bait would be carried out in all habitats across habitat at Anacapa Island for crevice nesting the island. The rat population size on Anacapa seabirds such as Xantus’ Murrelet and Ashy fluctuates between about 750 – 2,000, depending Storm-Petrel, coupled with Anacapa’s similarity on local conditions. Application of rodenticide to nearby Santa Barbara Island, suggest a would be completed within 1-2 days. potential for Anacapa to support large populations of these species (G. McChesney, A local certified agricultural pesticide pers. comm.). The restoration of Anacapa applicator would be used for conducting the Island to an introduced predator free status likely application. The applicator would have to meet will provide substantial benefits to these species. the following criteria: 1) OAS and California The removal of introduced rats from islands has Department of Agriculture certification for aerial been identified as a priority to ensure the application of rodenticide; 2) Helicopters recovery and long-term viability of Xantus’ equipped with differential GPS units to ensure Murrelet populations (McChesney and Tershy even coverage across the island; 3) Experience 1998). in aerial activities in remote offshore Channel Islands National Park. Bait would be broadcast at a maximum rate of 15 kg of 25 ppm bait/ha. A maximum of two applications is anticipated.

CHAPTER ONE - 6 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT

The chronology of eradication would begin approval for use of rodenticide bait on the with baiting in representative habitat within the island. A complete description of the proposed project area. Representative habitat may include action can be found in Chapter II – Alternatives all of East Islet or smaller area on Middle Islet section. that allows for easy and unobtrusive access. Representative habitat contains prime rat habitat including intertidal areas, and dense vegetation Emergency Response Plan sites. The objective of the initial eradication The emergency response plan (ERP) would treatment is to conduct both effectiveness and be implemented under the following conditions: validation monitoring of the project’s objective and the alternative’s proposed activities 1) When it is suspected that rats may be on including mandated mitigation. This effort Santa Barbara Island. would be followed up with the completion of the 2) After the eradication effort on Anacapa island-wide eradication activities. Island has concluded. The window for bait application is November through December (late fall). Baiting The ERP has three main components with a may begin as early as 2000. The late fall period decision process tied to each component. The offers the optimum time to apply the bait for first component (Detection) focuses on the three reasons: verification of presence of the rat. This is done by intensive initial field investigation using 1) The endangered Brown Pelicans are not normal rat detection techniques (chew bait breeding on the island; blocks and sticks, trapping (live and snap, visual 2) The rats are in decline due to lack of inspections, tracking tiles). available food sources, which would cause them to eat the bait more readily. If rat presence is verified, the second 3) The onset of the rainy season would component (Problem Evaluation) is a field expedite the degradation of any residual bait investigation decision process that determines not consumed by the target species. the extent of the rat problem, the terrain associated with the rat territory, and the affected The chronology of proposed eradication resources within colonized area. activities is as follows: 2000 - 2001: During the application window of The third component (Problem Resolution) Nov-Dec, initiate eradication activities in evaluates all of the factors (extent, terrain, representative habitat within project area. affected resources) and through a decision process makes a recommendation on the course 2001 – 2002: Complete Island-wide eradication of action that is necessary to eradicate the rats. during the Nov/Dec application window. The decision process that takes place in all three After treatment of East Islet and components is fully described in Chapter II – approximately 20 ha of Middle Islet there may Alternatives. be a need to retreat intermittently Middle Islet to prevent rats from re-invading East Island from Prevention Middle Island. All rat introductions to the Channel Islands This proposed action would require Federal have been through the assistance of humans. Environmental Protection Agency (EPA)

CHAPTER ONE - 7 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT

The most common ways rats are introduced to the islands are: Scope of the Proposed

1) Boats moored directly to the island or Action anchored nearby This document focuses on three specific 2) Dinghies or other small boats pulled up on actions: 1) The activities that are necessary to shore eradicate rats from Anacapa Island, and 2) The activities necessary to respond to accidental rat 3) Carried ashore in cargo such as foodstuffs, introductions to Anacapa and Santa Barbara and building materials Island, and 3) Preventing rodent introductions to 4) Rafting ashore in flotsam all Park Islands. 5) Shipwrecks This EIS does not cover the eradication of rats 6) Planes and helicopters from any other Park Island where rats have become established, specifically San Miguel Non-endemic mice are the most likely Island. Any eradication activity on San Miguel species to reach the islands because of their Island would require additional NEPA analysis small size and habit of living in facilities and due to the unique environmental issues associated storerooms, and are more likely to escape with the island. Santa Barbara and Anacapa detection. However, rats may occur more Islands have similar resources and resource issues. frequently on large fishing vessels and other boats. To minimize the risk of rodent introductions Decisions to be Made to the Channel Islands, a set of standards would be implemented by the Park prior to conclusion For this EIS, the official responsible for of eradication activities on Anacapa Island. The making the decision on which alternative is minimum proposed standards for the prevention selected is the National Park Service Regional of rodent invasion to the Islands are as follows: Direction, Pacific West Region. The Regional 1) Rodent proof storage areas. Director, once the Final EIS has been completed, can decide to: 2) Rodent proof containers that haul equipment
and supplies to the Islands. Select one of the alternatives analyzed within the Final EIS, including the No-Action 3) Control rodents at all departure points, alternative; or, including planes, boats, and helicopters that
transport people and materials to the Islands Modify an alternative (for example, combine (Park will work with concessionaires to parts of different alternatives), as long as the accomplish objectives when departure points environmental consequences of the modified are not under the control of the Park). action have been analyzed within the Final EIS. 4) Inform and educate all people who visit the islands. This includes visitors, Factors the Regional Director will take into concessionaires, contractors, employees, consideration in making a decision are: permittees, and researchers.
Does the alternative meet National Park Service guidelines and policies, including the Channel Islands General Management Plan?

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How well does the alternative meet the “Purpose and Need” for this project?
How does the alternative respond to and/or resolve the environmental issues raised for this project?
The nature and extent of public comment to the DEIS.

CHAPTER ONE - 9

. . CHANNEL ISLANDS NATIONAL PARK . FINAL ENVIRONMENTAL IMPACT STATEMENT .

ANACAPA ISLAND RESTORATION PROJECT CHAPTER TWO ALTERNATIVES Chapter Contents INTRODUCTION ...... 11 ALTERNATIVE DEVELOPMENT PROCESS ...... 11 Internal Scoping and Public Involvement...... 11 Significant Environmental Issues...... 12 Issue 1: Efficacy on Target Population ...... 12 Issue 2: Impact to Non-Target Species ...... 12 Sub-issue 1 - Marine Mammals...... 13 Sub-Issue 2 - Invertebrates (Marine/Terrestrial)...... 13 Sub-Issue 3 - Marine Fishes ...... 14 Sub-Issue 4 - Herpetofauna ...... 14 Sub-Issue 5 - Seabirds ...... 14 Sub-Issue 6 - Landbirds...... 14 Sub-Issue 7 - Mammals (Terrestrial) ...... 15 Sub-Issue 8 - Flora ...... 15 Issue 3: Public Safety and Visitation ...... 15 ALTERNATIVES CONSIDERED IN DETAIL...... 16 INTRODUCTION ...... 16 FEATURES COMMON TO ALL ACTION ALTERNATIVES...... 16 Effectiveness and Validation Monitoring ...... 16 Non-native Rodent Introduction Prevention Plan...... 17 Protection of Native Deer Mouse Population ...... 17 Rat Detection Response Plan...... 18 Human Health ...... 18 Timing ...... 18 Permits and Approval...... 18 Public Awareness ...... 18 Visitation Restriction...... 18 ALTERNATIVES……………………………………………………………………………… …………………19 ALTERNATIVE ONE - NO ACTION...... 19 ALTERNATIVE TWO - PROPOSED ACTION AND PREFERRED ALTERNATIVE...... 19 ALTERNATIVE THREE...... 20 ALTERNATIVE FOUR...... 22 ALTERNATIVE FIVE ...... 23 ALTERNATIVE SIX ...... 24 ALTERNATIVES CONSIDERED AND REJECTED ...... 26 BAIT STATIONS ...... 26 ELEVATED BAIT STATIONS ...... 26 ALTERNATE RODENTICIDES...... 26 TRAPPING...... 28 INTRODUCING PREDATORS...... 29 SUMMARY OF ALTERNATIVES...... 29

CHAPTER TWO - 10 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL I MPACT STATEMENT

The alternatives detailed below were Introduction developed to focus on the issues identified by resource specialists with the NPS, rat eradication This chapter describes the six alternatives to experts and other rodent control experts, be considered for implementation and identifies government regulatory agencies, and the general the significant environmental issues used to public. Chapter Five – Consultation and formulate these alternatives. The environmental Coordination lists all individuals, agencies and issues were developed as a result of extensive organizations that provided substantive “scoping” conducted for this analysis. The comment regarding the proposed action. “scoping” actions that were conducted for this analysis are described in detail. In addition, this chapter includes the rationale for dismissing Internal Scoping and Public other methods/alternatives from further Involvement consideration. Chapter Four concludes with a The NEPA “scoping” process [40CFR comparison of alternatives. 1501.7] was used to determine the scope of the analysis and to identify potential issues and opportunities related to the Proposed Action. A Alternative Development summary of the scoping and public involvement Process process for the proposed project and for the release of the Draft EIS is summarized in Chapter Five. Section 102(e) of NEPA states that all Federal agencies shall “study, develop, and Below is a summary of the scoping that was describe appropriate alternatives to recommend conducted to identify the environmental issues courses of action in any proposal which involves to be considered for this project. unresolved conflicts concerning alternative uses of available resources”. In addition to Proposed Action Internal Scoping responding to unresolved conflicts, an EIS must The Park has an extensive record of “rigorously explore and objectively evaluate all controlling rats on East Anacapa Island. reasonable alternatives” [40CFR 1502.14(a)]. Through these efforts, the Park has collectively Taken together, these requirements gained knowledge about the issues surrounding determine the range of alternatives and provide the presence of rats on the island. In addition, the basis for the Deciding Official’s informed the Park has funded scientific studies that focus decision, as required under NEPA. The on the ecology and control of rats within the Proposed Action, as stated in Chapter One, was Park. the result of a resource analysis done by NPS resource management staff in collaboration with Proposed Action External Scoping rodent eradication experts from the Island External scoping refers to the effort the Park Conservation and Ecology Group (ICEG). This made to solicit input from the local public, collaborative effort identified management organizations, other government regulatory actions necessary to respond to rat impacts on agencies. A complete summary of the Park’s the Anacapa Island ecosystem. scoping efforts can be found in Chapter Five.

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The methods the Park used to solicit input category (-and/or sub-issue-) contains a summary included: statement that defines the scope of the issue for this project. In addition, for each issue category • Scoping Letter: A letter describing the (and/or sub-issue), measurement indices are given proposed action was sent to individuals and to provide a preview of how the issue will be organizations who expressed interest in the evaluated for direct, indirect, and cumulative Park’s management, and government effects for each alternative. The “Issue” agencies who might have categories are as follows: oversight/regulatory concerns about the project. • Public Meeting: On December 8, 1999 the
Issue 1: Efficacy on Target Species Park hosted a public meeting. The Park paid
Issue 2: Non-Target Impacts for ads in three local newspapers
announcing the meeting (Los Angeles Issue 3: Public Safety and Visitation Times, Ventura County Star, Santa Barbara Newspress). As part of this meeting the Issue 1: Efficacy on Target Park presented the need for the proposed Population action as well as the proposed action. Efficacy for this analysis is defined as how • Presentations: The Park made presentations well the alternative would meet the 100% eradication objective. to several local organizations. Measurement Indices • Website: The Park posted information
regarding the project on its website. Chemical and toxicological properties of the rodenticide • Direct Communication: The Park made
Composition of the bait and how it is direct communication to regulatory applied government agencies who may have
Local environmental factors. oversight concerns regarding the project. A list of these agencies can be found in Chapter Five. Issue 2: Impact to Non-Target Species Significant Environmental Chapter Four (Environmental Consequences) will analyze both the potential Issues for exposure of non-target species to rodenticide Through the Scoping and Public Involvement residues and any physical disturbance from Process the following significant environmental normal activities of non-target species caused by issues were identified. Significant issues are implementation of the project. those that may require project-specific Physical disturbance may occur due to baiting alternatives, mitigation measures or design activities, and crews walking around the island. elements to address the potential effects of the For example, Malacothrix squalida, a listed proposed activities. species (endangered) under the endangered The issues are grouped into three broad Species Act is located in the project area. As such categories. Because these are broad categories, the Park is required to consult with the USFWS on the “Non-target Impacts Issue” category will potential impacts the project may have on the contain a number of sub-issues. Each issue species. Physical disturbance from monitoring

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activities is the only potential impact that may activities. Efforts would be made to minimize occur to this species Rodenticide exposure, for the purpose of this Table 1. Project Area Species Taxonomic analysis, can occur through direct bait Classification consumption (primary exposure), secondarily (via ______carcasses containing rodenticide residues) and I. Marine possibly tertiary exposure. Primary exposure A. Mammals (Sub-Issue 1) occurs when organisms feed directly on the bait. B. Invertebrates (Sub-Issue 2) Secondary exposure occurs when animals feed on C. Fishes (Sub-Issue 3) primarily exposed organisms with residues in their II. Terrestrial tissue. Tertiary exposure is possible, through A. Fauna consumption of a secondarily exposed organism, 1. Invertebrates (*combined with Sub- but has not been thoroughly documented in the Issue 2) literature (Eason and Murphy 1999). For the 2. Herpetofauna (Sub-Issue 4) purpose of this analysis, only primary and 3. Avian secondary exposure will be evaluated. a. Seabirds (Sub-Issue 5) The first step in the process to determine b. Landbirds (Sub-Issue 6) which non-target species may be impacted by the 4. Mammals (Sub-Issue 7) proposed action was to identify all the known B. Flora (Malacothrix squalida) (Sub-Issue 8) species within the project area. The species were ______then placed in a taxonomic classification to identify logical groups of species. Based on the risk assessments for the rodenticide (and other drift of bait into the marine environment; scientific studies) the groups of species that may however, if bait does enter the ocean, marine be impacted were identified. These identified mammals may be at risk of rodenticide groups (See Table 1) will be carried forward in the exposure. analysis as “Sub-Issues”.
Measurement Indices The taxonomic classification for
Exposure to Residues – the effects identification of sub-issues is necessary to discussion will focus on how the provide a logical layout of “effects” when proposed action and alternatives would evaluating toxicological risk. This is because expose the marine mammals to the toxicology of these rodenticides is consistent rodenticide residues. within the groups that have been identified. The sub-issues as derived from Table 1 is as follows: Sub-Issue 2: Invertebrates Sub-Issue 1: Marine Mammals (Marine/Terrestrial) Two pinniped species (harbor seals, Phoca Terrestrial invertebrates on Anacapa Island vitulina, and California sea lions, Zalophus would likely consume carcasses of vertebrates californianus) haul out on the rocks and beaches exposed to the rodenticide, as well as any around Anacapa Island. Harbor seals breed on residual bait not consumed. Thus, there is the island between January and March. Both potential for the transfer of residues into the species may be disturbed by the baiting activities food chain. and possibly by some of the monitoring

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Rodenticide may enter the marine food of results from eradication programs chain if bait incidentally drifts into the elsewhere. intertidal/subtidal areas and is consumed by marine intertidal invertebrates. Sub-Issue 5: Seabirds
Measurement Indices For the purpose of this analysis, the seabirds
Exposure to Residues – the effects have been subdivided into two groups: the discussion will focus on how the proposed pelagic seabirds and roosting seabirds. The action and alternatives will expose the pelagic seabirds are those birds that reside invertebrate populations to rodenticide offshore from Anacapa Island and only utilize residues, and, will analyze those predators at the island for breeding, outside of the proposed risk. baiting period. The roosting seabirds are those that utilize Anacapa for roosting during the Sub-Issue 3: Marine Fishes proposed baiting period. The relative exposure of gamefish to the
Measurement Indices rodenticide is small; however, there is a risk of
Federally Endangered Seabirds – incidental drift of bait into the marine Roosting and nesting habitat for the environment thus presenting a primary and endangered Brown Pelican exists within possible secondary exposure risk. the analysis area. The effects discussion will describe how the proposed action Measurement Indices and alternatives to the proposed action
Exposure to Residues – the effects affect the Brown Pelican. discussion will focus on how the
Disturbance – the effects discussion in the proposed action and alternatives would effects will focus on how the proposed expose gamefish to the rodenticide via action and alternatives would disturb bait ingestion using recent studies with seabirds. placebo baits.
Exposure to Residues– The effects Sub-Issue 4: Herpetofauna discussion will focus on how the proposed action and alternatives would Anacapa is home to two species of reptiles, impact seabirds, with results from recent the Side-blotched lizard (Uta stansburiana) and studies completed on Anacapa Island. the Southern Alligator lizard (Elgarra multicarinata ), and one species of salamander – the Channel Islands Slender Salamander Sub-Issue 6: Landbirds (Batrachoseps pacificus). These species are Some species of landbirds utilize Anacapa subject to primary and secondary exposure risk. Island seasonally and others year round. For the
Measurement Indices purpose of this analysis, the landbirds have been divided into two groups: the birds of prey,
Exposure to Residues – The effects (raptors); and passerines. Birds of prey are at discussion will focus on how the risk of secondary exposure through consumption proposed action and alternatives would of primarily exposed organisms. The Passerines impact lizards and amphibian were subdivided further based on foraging populations, with emphasis on strategy (i.e. omnivorous, insectivorous, and population level impacts and inclusion

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granivorous). While the insectivorous
Measurement Indices passerines are at risk of secondary exposure and
the granivorous are at risk of primary exposure, Trampling – The effects discussion will the omnivorous passerines are at risk of both focus on how the proposed action and primary and secondary exposure. alternatives would impact the island malacothrix population, with emphasis on
Measurement Indices mitigation against damage.
Exposure to Residues - The effects discussion will describe how the Issue 3: Public Safety and Visitation proposed action and alternatives to the Anacapa Island is the most visited of all proposed action may affect individual islands in the Channel Islands National Park. birds of prey and passerines. Visitors are only allowed access to East Island and Frenchy’s Cove on West Island. East Island Sub-Issue 7: Mammals receives both day visitors and overnight The endemic subspecies (unique to Anacapa campers. With the high visitation to the islands Island) of the Deer Mouse (Peromyscus by the public there are two concerns: 1) potential maniculatus anacapae) co-exists on Anacapa exposure of the public to the rodenticide: and 2) Island with the introduced rats. Mice share impacts to visitors from closing the island many characteristics with rats and thus, are at a during operations of the AIRP. high risk of primary exposure.
Measurement Indices
Measurement Indices
Exposure to Residues: The effects
Exposure to Residues – The effects discussion will focus on how the discussion will focus on how the proposed action and alternatives would proposed action and alternatives would potentially expose the visiting public to impact the Deer Mouse population, with the rodenticide, as well as the associated emphasis on population level impacts health risks of exposure. and include the results of rodent control
Visitor Impacts: The effects discussion operations elsewhere. will focus on how the proposed action and alternatives would potentially impact Sub-Issue 8: Flora visitors’ enjoyment of the Park during The endangered Island Malacothrix AIRP operations. (Malacothrix squalida) is an annual herb from the aster family. It is found on Santa Cruz Issues Dismissed from Analysis Island and Middle Anacapa Island. This annual The analysis considered the social impacts occurs on rocky coastal bluffs in coastal scrub of implementing the proposed project. The (Junak et al. 1995). On Middle Anacapa Island analysis concluded that the proposed project the distribution is very limited. It is found in would not change the local population’s work, two locations, near the east and west end of recreation, or social interactions. As such, Middle Anacapa Island. The presence of island executive order 12898 (environmental justice) malacothrix makes it highly susceptible to does not apply to this analysis. trampling from personnel walking on the island. Similarly, this analysis does not affect floodplains (EO1508.27), or sacred sites

CHAPTER TWO - 15 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL I MPACT STATEMENT

(EO13007). The Park has also determined that Features Common to All Action this analysis does not require analysis of energy requirements (1502.16), nor does it require a Alternatives economic impact analysis (EO11821) Effectiveness and Validation Monitoring Alternatives Considered in Effectiveness and validation monitoring would be required to be done for each action Detail alternative prior to final treatment of Middle and West Islets. Effectiveness monitoring would be conducted to determine if the alternative’s Introduction prescription is effective in meeting the stated eradication objective. Validation monitoring Development of the alternatives was would be conducted to determine if the strongly influenced by the significant environmental effects of implementing the environmental issues. In developing the management action (including mitigation alternatives, the Park consulted many outside measures) are similar to the effects predicted in experts in the field of vertebrate biology, the EIS. toxicology, and avian biology. In addition to the six alternatives described below, many other For each alternative, eradication would alternatives were considered, but were begin with baiting (consistent with the eliminated from further study. These alternative) in a representative habitat within the alternatives, along with the rationale for their project area. Representative habitat would be dismissal, can be found at the end of this chapter limited to East Islet as a whole, or a smaller area under the heading, “Alternatives Considered but on Middle Islet. Dismissed”. Because of the specific objective Analysis of monitoring data would be done of this project, many alternatives were dismissed prior to proceeding with final treatment of because they could not meet the objective of Middle and West Islets. Evaluation of total eradication. monitoring results would determine whether to: Eradicating rats from Anacapa Island, and the • eradication of rats as a result of an accidental Modify the eradication activities introduction are two distinct, but inter-related • Continue the proposed eradication activities activities. The former comprises the actions Monitoring results that lead to a being proposed for the eradication of the known modification of the project may require a and long-term persistent rat population on supplemental EIS. The supplemental EIS and Anacapa Island. The latter comprises the subsequent decision would need to be prepared activities that are being considered in response to prior to resumption of eradication activities. A the accidental introduction of rats to islands within supplemental EIS is necessary when substantial the Park. new information is discovered, and/or when change of activities result in substantial change in environmental effects that were not previously analyzed in the EIS. Monitoring results that are consistent with the analysis provided in the FEIS would allow

CHAPTER TWO - 16 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL I MPACT STATEMENT

for the continuance of the proposed eradication three islets would need to be protected (Pergams activities without additional environmental et al. 2000). Management actions to protect the compliance. Deer Mouse population will include a protection plan that will be implemented prior to the Non-native Rodent Introduction eradication efforts. Consultation with Peromyscus Prevention Plan and genetic experts from the Brookfield Zoo, Illinois and the University of Illinois is underway To minimize the risk of rodent introductions to develop a protection plan that will maintain to the Channel Islands, a set of standards would genetic diversity and ensure a viable population of be implemented by the Park. The minimum mice on each islet post eradication. The proposed prevention actions, which would Effectiveness and Validation Program will aid in become the Park’s prevention plan, are as the development of an effective protection plan follows: for the Anacapa Deer Mouse because it will 1) Rodent-proof storage areas. identify problem areas that would allow changes 2) Rodent-proof containers that haul equipment to the final Deer Mouse protection plan. The and supplies to the Islands. final Deer Mouse protection plan would be implemented prior to completion of the baiting. 3) Control rodents at all departure points, The Deer Mouse protection plan may include one including planes, boats, and helicopters that or a combination of the following: transport people and materials to the Islands. 1. Laboratory captive holding/breeding 4) Inform and educate all people who visit the on/off island: Mice are live captured and islands. This includes visitors, transported to a laboratory holding facility concessionaires, contractors, employees, either on island or on the mainland. About permittees, and researchers. 350 mice from each islet are captured from each island and held. They would be Protection of Native Deer Mouse released back on to the island over time. Population 2. Move mice between islands: Mice are moved from Middle and/or West Island to The presence of the endemic Anacapa Deer East Island in between treatment of East and Mouse represents a unique challenge to rat Middle/West Islands. Thus, a viable eradication. The conservation and management population of mice are available on East of Anacapa Island Deer Mice is a high priority for Island for restocking Middle and West the AIRP. The genetic and morphological status Islands after eradication. of the Anacapa Deer Mouse has been investigated using genetics, morphometrics and computer 3. Fenced enclosures: Mice are maintained modeling (Pergams et al. 2000). The results of in a fenced enclosure where rats are this study has confirmed that the Anacapa Deer prevented from entering, and mice are Mouse is a distinct subspecies that is genetically prevented from entering or leaving. A identical across all three islets. Thus, the Deer complement of mice are maintained with Mouse population can be managed as a whole rodent chow and water for a determinant population (one “evolutionarily significant unit” period of time. Mice are released over time (ESU)) rather than a distinct population on each from the enclosure back into the Anacapa islet. Further, to maintain genetic diversity and environment, restocking the island. The ensure a viable population, 1000 mice across all enclosure area would not be treated.

CHAPTER TWO - 17 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL I MPACT STATEMENT

Rat Detection Response Plan would expedite the degradation of any residual bait not consumed by the target species. Reacting to a “rat-spill” from a shipwreck or some other introduction requires a rapid response, Splitting the treatment of the islands into two as does any appearance of rats on Anacapa Island years is beneficial for several reasons. First, it following eradication, or on Prince, Sutil and allows monitoring for efficacy, i.e. evaluate the Santa Barbara Islands. In the event of a feasibility of eradication at the maximum of 15 shipwreck the Shipwreck Response Plan is a kg/ha sowing rate, and modify and improve decision pathway to implement the Rat Detection operational procedures for year 2. Secondly, the Response Plan (Appendix A) – a plan to evaluate Park can monitor impacts to non-target species the extent of rodent introduction and implement on a smaller scale to identify further necessary an appropriate response. The Rat Detection mitigation measures. Response Plan would be implemented if rats were introduced to the islands via shipment of goods or Permits and Approval equipment. EPA registration and approval would be Human Health required for implementation of any of the alternatives considered in this analysis (except the A buffer of approximately 10 meters around No Action alternative). Under the Federal the campground, buildings and landing area on Insecticide, Fungicide, and Rodenticide Act East Island would be established. This buffer (FIFRA), use of a non-registered rodenticide would not be aerially treated, although, a requires approval from the Federal EPA. A site- perimeter of bait stations would be established specific application label would be prepared for approximately every 10-15 m. Each station the AIRP project. Consultation and registration would be uniquely labeled to identify its with the EPA is required before application. location. An appropriate warning label such as: “Anacapa Island Restoration Project. Rat Public Awareness Poison – Danger, Do Not Disturb. Contact Park Ranger or telephone 805-658-5720” on each Posters outlining the project and warning station and a copy of the product label would visitors of the activities on the island would be also be included at each of these bait stations for posted on the mainland at the visitor center, on reference. island at the landing cove and at the visitor center at East Anacapa Island. Timing To minimize both disturbance and potential Visitation Restriction ecotoxicological impacts, bait application would The operations of the eradication program be restricted to September through December of will require that visitation be restricted for a each year. short period. East Anacapa Island will be The late fall period offers the optimum time closed to all visitors for approximately 2-3 days. to apply the bait for the following reasons: 1) The restriction is necessary to allow the endangered Brown Pelicans are not breeding on operations crews to implement the baiting the island; 2) the rats are in decline due to food operation including helicopter activity, stress and therefore would eat the bait more evaluation, and monitoring of the environment. readily; and 3) the onset of the rainy season After the operations are complete, the island will be open to day use visitors. East Anacapa

CHAPTER TWO - 18 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL I MPACT STATEMENT

will be closed to campers for approximately 5 Alternative Two (Preferred days because the campground will be used for Alternative) housing the post treatment monitoring crews. Aerial broadcast of a Rodent Bait Containing Brodifacoum Alternatives Summary

Alternative One This alternative outlines the use of a rodent bait aerially broadcast from a hopper suspended No Action under a helicopter, and broadcast by hand. Alternative One (no action) continues the East Islet baiting would occur during the existing rat management strategy on Anacapa Nov/Dec treatment window and would be Island. Implementation of this alternative would treated along with approximately 20 ha of occur assuming that future Park budgets are Middle Islet to lower the probability of invasion similar to recent budgets. Analysis of the by rats from Middle Islet to East Islet. The 20 alternative is a requirement of the National ha section of Middle Islet may be treated Environmental Policy Act (NEPA) and National intermittently to prevent re-invasion of East Park Service planning procedures. Islet. Middle Islet (including the section treated The existing management strategy for with East Islet ) and West Islet would be treated managing the species Rattus rattus on Anacapa during the application window of November Island is found in the Park’s General thru December in the year following East Islet Management Plan. Specifically, the GMP states, application. Bait would be applied in the “Based on research and experimentation, following formulation: programs will be implemented to reduce to the Active Ingredient: Brodifacoum extent feasible the impacts of introduced plant and animal species.” From the late 1980’s Concentration of Active Ingredient: 25 ppm through the early 1990’s, concentrated control Brodifacoum activity occurred on Anacapa Island. This Rate of application: Bait would be broadcast at a consisted of widely spaced, elevated bait stations maximum rate of 15 kg /ha using the rodenticide Warfarin. Since that time the Park has concentrated control efforts around Application: Application would be completed the existing structures on East Island. No by hand or aerial broadcast across 100% of the control measures have been taken outside of area of the islands. Hand broadcast would be these areas due to budget, personnel, and carried out by or under the supervision of compliance constraints. licensed applicators spreading bait by hand. Aerial broadcast would be carried out utilizing a hopper (dry slinger) suspended from a helicopter flying along a predetermined pathway programmed into a Differential GPS. Aerial baiting would be carried out using a licensed pesticide applicator. Top of Island: Bait would be spread from a hopper suspended under a helicopter. The helicopter would fly at approximately 50 knots, approximately 25-50 m aboveground with the

CHAPTER TWO - 19 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL I MPACT STATEMENT

hopper open and spreading bait. To ensure even East Islet bait broadcast including 20 ha coverage, the island would be flown twice: once of Middle Islet, subsequent year in an East-West direction sowing at half the rate, treatment of Middle and West Islet, then again on a North-South direction sowing including the 20 ha buffer on Middle bait at half the rate. Bait would be spread from Islet. If rats are detected on East the hopper in a 360-degree pattern. The number Anacapa Island between treatment of passes over the island would be determined periods, the Rat Detection Response Plan by the swath width which is a function of size of may be implemented. If the problem the bait pellet and speed with which it is evaluation demonstrates that rats are propelled out of the hopper. widespread on East Island, the whole island may be re-treated during the Cliffsides: Every effort would be made to treatment of Middle and West Islands. prevent bait from drifting into the marine environment. The helicopter would fly along • Future: If rats are detected, the Rat the top cliff edge to minimize drift of bait into Detection Response Plan would be the marine ecosystem. The helicopter also implemented (See Appendix A). would be used to “trickle” bait to the larger offshore rocks with the helicopter hovering low, Alternative Three hopper turned off- gate open to ensure adequate Bait Stations for Top of Island and Aerial coverage. In some cases, bait would be hand Broadcast the Cliffsides with Brodifacoum broadcast onto the cliffsides from above. In the cases of hard-to-reach offshore rocks and lower Summary reaches of cliffsides, travel by boat for hand The primary objective of this alternative is to broadcast may be required. minimize primary exposure impacts to Number of applications: A maximum of two landbirds. This alternative outlines a stratified applications is anticipated. baiting technique where bait stations would be used on top of Middle and East Islands while Timing aerial broadcast is used on West Island and the • Years 1-2: Initiate eradication by baiting cliffsides of East and Middle Islands. The bait in representative habitat during the stations would be armed for one year prior to November-December application treatment of West Island and cliffsides of East window (either East Islet as a whole, or and Middle Islands. Under this strategy, rats smaller area on Middle Islet) and conduct would have been removed from the top of the implementation and effectiveness islet for one year prior to treating the cliffsides. monitoring. Monitor results and West Island would not be treated with bait determine if changes are necessary. Year stations because of the steep terrain and potential 1 activities may begin during the 2000 disturbance to pelicans with frequent visits by Nov-Dec application window given that operators. necessary compliance measures are The top areas of East and Middle Islets completed. would be initiated in Year 1 with deployment • Years 2-3: If monitoring results prove and arming of bait stations. In Year 2, bait favorable, proceed with island-wide stations would be checked and re-armed, while eradication activities. the cliffsides of East and Middle and all of West Island would be treated by hand and aerial

CHAPTER TWO - 20 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL I MPACT STATEMENT

broadcast with a second generation collected and entered into a database for anticoagulant. analysis. When activity (bait removal or consumption) ceases, bait stations would be Active Ingredient: Brodifacoum checked and re-armed bi-weekly then monthly Concentration of Active Ingredient: 25 ppm for one year, documenting bait take and rat sign Aerial Application: in stations. Timing: • Rate of Application: maximum of 15 • kg/ha Years 1-2: Initiate eradication by baiting as prescribed in representative habitat • Number of Applications: a maximum of during the Nov-Dec application window two applications. (either East Islet as a whole, or smaller Bait Stations Application: area on Middle Islet) and conduct implementation and effectiveness • Rate of Application: 6 bait blocks/station monitoring. Monitor results and • Number of Applications: re-armed until determine if changes are necessary. Year activity ceases 1 activities may begin during the 2000 Nov-Dec application window given that Bait Station Design and Construction: Bait necessary compliance measures are stations would be standard lockable stations, completed. similar to those used by professional pest control operators, but brightly colored to assist locating • Year 2-3: If monitoring results prove in dense shrubbery. favorable, proceed with island-wide eradication activities. Bait Station Locations: Bait stations would be secured in place around the cliff edge at 25-50 m Deploy and arm bait stations on the flat, intervals completely encircling the top of the accessible top of East and Middle Islets. island. The remaining bait stations would be The stations would be checked daily, and secured on top of the island, laid out on a grid re-armed as necessary, until activity (spacing at 50 x 50 m). Each station would be ceases. Continue monitoring stations on a uniquely marked with a tag identifying its bi-weekly then monthly basis. Refresh bait location and an appropriate warning such as in stations on East and Middle Islands, “Anacapa Island Restoration Project: Rat Poison aerially broadcast rodenticide bait – Danger, Do Not Disturb. Contact Park Ranger containing 25 ppm brodifacoum on or phone 805 658 5720”. cliffsides of East and Middle Islands and the 100% aerial broadcast treatment of Bait Station Arming and Checking: Each bait West Island. The application rate would station would be armed on the same day once be up to 15 kg/ha following procedures the program is initiated. Certified pesticide outlined in Alternative Two. Continue to applicators would supervise the arming of each check and re-arm bait stations at bi- station with six bait blocks containing 25-ppm monthly intervals for an additional year. brodifacoum. Each station would be visited daily, checked, and bait replenished to the 6- • Year 2 - Future: If rat sign is found, the block level as necessary until activity ceases Rat Detection Response Plan would be (activity includes bait chewed or taken by rats). implemented (Appendix A). Data (number of blocks taken, chewed, added, or replaced) from each station would be

CHAPTER TWO - 21 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL I MPACT STATEMENT

Alternative Four hopper open and spreading bait. To ensure even Aerial broadcast of a Rodent Bait coverage, the island would be flown twice: once Containing Bromadiolone in an East-West direction sowing at half the rate, then again on a North-South direction sowing Summary bait at half the rate. Bait would be spread from This alternative involved aerial broadcast of the hopper in a 360-degree pattern. The number bromadiolone, a second-generation of passes over the island would be determined anticoagulant similar to brodifacoum. This by the swath width which is a function of size of alternative addresses the issue of potential the bait pellet and speed with which it is impacts to non-target species. propelled out of the hopper. The rodent bait would be aerially broadcast Cliffsides: Every effort would be made to from a hopper suspended under a helicopter, and prevent bait drifting into the marine hand broadcast by workers of the Anacapa environment. The helicopter would fly along Island Restoration Project (AIRP). the top cliff edge to minimize drift of bait into the marine ecosystem. The treated area would be The treatment of Anacapa Island would take a portion of the top of the island and the place over a period of one year. East Anacapa cliffsides. In some cases, hand broadcast bait would be treated in year one along with onto the cliffsides from above, or travel by boat approximately 20 ha of Middle Anacapa Island to service the offshore rocks, islands, and lower to lower the probability of invasion by rats from reaches of the cliffsides may be necessary. The Middle Islet to East Islet. The 20 ha section of helicopter would be used to “trickle” bait the Middle Island may be treated periodically to larger offshore rocks with the helicopter prevent re-invasion of East Island. Middle hovering low, hopper turned off- gate open to Island (including the section treated in year one) ensure adequate coverage. and West Island would be treated in year 2. Number of applications: A maximum of two Active Ingredient: Bromadiolone applications is anticipated. Concentration of Active Ingredient: 50 ppm

Rate of application: Bait would be broadcast at a Timing: maximum rate of 15 kg /ha. • Years 1-2: Initiate eradication by baiting Application: Application would be completed as prescribed in representative habitat by hand or aerial broadcast across 100% of the during the Nov-Dec application window area of the islands. Hand broadcast would be (either East Islet as a whole, or smaller carried out by or under the supervision of area on Middle Islet) and conduct licensed applicators spreading bait by hand. implementation and effectiveness Aerial broadcast would be carried out (by a monitoring. Monitor results and licensed pesticide applicator) utilizing a hopper determine if changes are necessary. Year (dry slinger) suspended from a helicopter flying 1 activities may begin during the 2000 along a predetermined pathway programmed Nov-Dec application window given that into a Differential GPS. necessary compliance measures are completed. Top of Island: Bait would be spread from a hopper suspended under a helicopter. The • Year 2-3: If monitoring results prove helicopter would fly at approximately 50 knots, favorable, proceed with island-wide approximately 25-50 m aboveground with the eradication activities.

CHAPTER TWO - 22 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL I MPACT STATEMENT

Initiate broadcast of bait onto East would not be treated with bait stations because Island and the 20 ha buffer of Middle of the steep terrain and potential disturbance to Island. Initiate broadcast of bait onto pelicans with frequent visits by operators. Middle and West Island including the 20 The top areas of East and Middle Islets would be ha buffer on Middle Island. If rats are initiated in Year 1 with deployment and arming detected on East Anacapa Island of bait stations. In Year 2, bait stations would between year one treatment and year 2 be checked and re-armed, while the cliffsides of treatment, the Rat Detection Response East and Middle and all of West Island would be Plan may be implemented. If the treated by hand and aerial broadcast with a problem evaluation demonstrates that second generation anticoagulant. rats are widespread on East Island, the whole island may be re-treated during Active Ingredient: the treatment of Middle and West • Bait Stations: bromadiolone Islands. The 20 ha section of Middle • Island may be treated periodically Aerial Broadcast: bromadiolone between year one and treatment year 2 Concentration of Active Ingredient: 50 ppm to prevent re-invasion of rats to East Aerial Application: Island. This 20 ha section of Middle Island would be re-treated during the • Rate of Application: 15kg/ha treatment of Middle Island. • Number of Applications: a maximum of 2 • Year 2- Future: If rats are detected, the applications is anticipated Rat Detection Response Plan would be Bait Stations Application: implemented (Appendix A) • Rate of Application: Stations would be Alternative Five armed with 6 bait blocks per station Bait Stations for Top of Island and Aerial • Number of Applications: Stations would Broadcast the Cliffsides with be re-armed until activity ceases. Bromadiolone Bait Station Design and Construction: Bait Summary stations would be standard lockable stations, similar to those used by professional pest control The primary objective of this alternative is to operators, but brightly colored to assist locating minimize primary exposure impacts to landbirds in dense shrubbery. and spatially exclude Deer Mice from gaining access to bait in stations. This alternative Bait Station Locations: Bait stations would be outlines a stratified baiting technique where bait secured in place around the cliff edge at 25 m stations would be used on top of Middle and intervals completely encircling the top of the East Islands while aerial broadcast is used on island. The remaining bait stations would be West Island and the cliffsides of East and secured on top of the island, laid out on a grid Middle Islands. The bait stations would be (spacing at 50 x 50 m). Each station would be armed for one year prior to treatment of West uniquely marked with a tag identifying its Island and cliffsides of East and Middle Islands. location and an appropriate warning such as Under this strategy, rats would have been “Anacapa Island Restoration Project: Rat Poison removed from the top of the islet for one year – Danger, Do Not Disturb. Contact Park Ranger prior to treating the cliffsides. West Island or phone 805 658 5720”.

CHAPTER TWO - 23 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL I MPACT STATEMENT

Bait Station Arming and Checking: Each bait West Island. The application rate would station would be armed on the same day once be up to 15 kg/ha following procedures the program is initiated. Certified pesticide outlined in Alternative Two. Continue to applicators would supervise the arming of each check and re-arm bait stations at bi- station with six bait blocks containing 50-ppm monthly intervals for an additional year. bromadiolone. Each station would be visited • Year 2 - Future: If rat sign is found, the daily, checked, and bait replenished to the 6 Rat Detection Response Plan would be block level as necessary until activity ceases implemented (See Appendix A). (activity includes, bait chewed or taken by rats). Data (number of blocks taken, chewed, added, replaced) from each station would be collected Alternative Six and entered into a database for analysis. When activity (bait removal or consumption) ceases, Aerial broadcast of a Rodent Bait bait stations would be checked and re-armed bi- Containing Diphacinone followed by a Rodent Bait Containing Brodifacoum weekly then monthly for one year, documenting bait take and rat sign in stations. Summary

Timing: This alternative outlines the aerial broadcast • Years 1-2: Initiate eradication by baiting of diphacinone, a first generation anticoagulant as prescribed in representative habitat followed by a bait containing brodifacoum, a during the Nov-Dec application window second-generation anticoagulant. This (either East Islet as a whole, or smaller alternative addresses the issue of potential area on Middle Islet) and conduct primary and secondary exposure impacts to non- implementation and effectiveness target species. monitoring. Monitor results and The rodent baits would be aerially broadcast determine if changes are necessary. Year from a hopper suspended under a helicopter, and 1 activities may begin during the 2000 by hand. Nov-Dec application window given that necessary compliance measures are East Islet baiting would occur during the completed. November thru December window and would be treated along with approximately 20 ha of • Year 2-3: If monitoring results prove Middle Islet to lower the probability of invasion favorable, proceed with island-wide by rats from Middle Islet to East Islet. The 20 eradication activities. ha section of Middle Islet may be treated Deploy and arm bait stations on the flat, intermittently to prevent re-invasion of East accessible top of East and Middle Islets. Islet. Middle Islet (including the section treated The stations would be checked daily, and with East Islet ) and West Islet would be treated re-armed as necessary, until activity during the application window of November ceases. Continue monitoring stations on a thru December in the year following East Islet bi-weekly then monthly basis. Refresh bait application. Bait would be applied in the in stations on East and Middle Islands following formulation: stations, aerially broadcast rodenticide Active Ingredients: Diphacinone and bait containing 25 ppm brodifacoum on Brodifacoum cliffsides of East and Middle Islets and the 100% aerial broadcast treatment of

CHAPTER TWO - 24 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL I MPACT STATEMENT

Concentration of Active Ingredient: a portion of the top of the island and the cliffsides. In some cases, hand broadcast bait • Diphacinone: 50 ppm onto the cliffsides from above, or and travel by • Brodifacoum: 25 ppm boat to service the offshore rocks, islands, and Rate of application: lower reaches of the cliffsides may be necessary. The helicopter would be used to “trickle” bait • Diphacinone: 22-34 kg/ha the larger offshore rocks with the helicopter • Brodifacoum: 5-10 kg/ha hovering low, hopper turned off- gate open to ensure adequate coverage. Application: The first application of diphacinone would be applied in two waves Number of applications: A maximum of two approximately 3-4 weeks apart. applications is anticipated. Three to four weeks after final diphacinone Timing: application, the brodifacoum bait would be • Year 1-2: Initiate eradication by baiting aerially broadcast at a rate of 5-10 kg/ha. as prescribed in representative habitat Application would be completed by hand or during the Nov-Dec application window aerial broadcast across 100% of the area of the (either East Islet as a whole, or smaller islands. Hand broadcast would be carried out area on Middle Islet) and conduct with or under the supervision of licensed effectiveness and validation monitoring. applicators spreading bait by hand. Aerial Monitor results and determine if changes broadcast would be carried out utilizing a hopper are necessary. Year 1 activities may (dry slinger) suspended from a helicopter flying begin during the 2000 Nov-Dec along a predetermined pathway programmed application window given that necessary into a Differential GPS. compliance measures are completed. Top of Island: Bait would be spread from a • Year 2-3: If monitoring results prove hopper suspended under a helicopter. The favorable, proceed with island-wide helicopter would fly at approximately 50 knots, eradication activities. approximately 25-50 m aboveground with the Initiate broadcast of bait onto East hopper open and spreading bait. To ensure even Island and the 20 ha buffer of Middle coverage, the island would be flown twice: once Island. .Initiate broadcast of bait onto in an East-West direction sowing at half the rate, Middle and West Island including the 20 then again on a North-South direction sowing ha buffer on Middle Island. If rats are bait at half the rate. Bait would be spread from detected on East Anacapa Island the hopper in a 360-degree pattern. The number between year one treatment and year 2 of passes over the island would be determined treatment, the Rat Detection Response by the swath width which is a function of size of Plan may be implemented. If the the bait pellet and speed with which it is problem evaluation demonstrates that propelled out of the hopper. rats are widespread on East Island, the Cliffsides: Every effort would be made to whole island may be re-treated during prevent bait drifting into the marine the treatment of Middle and West environment. The helicopter would fly along Islands. the top cliff edge to minimize drift of bait into the marine ecosystem. The treated area would be

CHAPTER TWO - 25 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL I MPACT STATEMENT

• Year 2- Future: If rats are detected, the Elevated Bait Stations Rat Detection Response Plan would be The use of elevated bait stations, designed by implemented (See Appendix A) Erickson (1990) would have been used in any of the alternatives that required bait stations. Erickson’s (1990) laboratory study showed that only 93% (n=30) of roof rats could gain Alternatives Considered access to the bait in the stations. The purpose and Rejected and need dictates that 100% be removed; therefore, elevated bait stations fail to meet the objective. In the field, rats were shown to readily use the stations; however, it was unclear Bait Stations if 100% of rats in the area were exposed to the bait. Although the elevated bait stations show Under this alternative bait stations would promise for rat control where native mice are have been placed on top as well as on cliffsides present, Erickson (1990) did not demonstrate and shorelines of Anacapa Island. This was that rats could be controlled or eradicated from dismissed because of the steep topography and Anacapa Island. unstable cliffsides, would have made stations problematic. Moreover, vegetation would have Using elevated bait stations would require been trampled and nesting pelicans disturbed. personnel to dig PVC piping into the ground to A detailed description of each reason follows. support the stations. Where soil is present, PVC may be easily dug into the ground. However, Anacapa Island is composed of basalt and is Anacapa is very rocky (the majority of the island partially volcanic in origin. As a result, the is exposed rock), thus digging holes for PVC cliffsides are extremely unstable and rockfalls would be near impossible. In addition to the are not uncommon. The placement of bait logistical challenge the placement of stations stations would require project personnel to scale across the islands and cliffsides would present, the cliffs using ropes. The instability of the they also would cause disturbance to native cliffsides and high risk of rocks falling on, and vegetation and disturbance and possible damage severely injuring climbers resulted in this to cultural sites (e.g. Chumash native middens, alternative being dismissed. archaeological sites). Bait stations would have to be serviced frequently by personnel, resulting in a high risk Alternate Rodenticides of erosion and trampling of native vegetation. A network of trails would be created that would The use of the other rodenticides registered result in long-term damage. with the US EPA were considered. The rodenticides were dismissed for one or more of Disturbance to pelicans nesting on West the following reasons: 1) lack of proven Anacapa would be unavoidable because of the effectiveness in island rat eradications; 2) need to service bait stations. The pelicans are potential for development of bait shyness in the protected under the Endangered Species Act and rat population; 3) inability to cope with the regular disturbance could cause nest potential “Warfarin resistant” rats; and 4) the abandonment and nest failure resulting in low unavailability of an antidote in case of human productivity. exposure. Each of these issues and the associated rodenticides are discussed below. For

CHAPTER TWO - 26 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL I MPACT STATEMENT

a summary of the registered rodenticides It is unknown if the population of rats on considered, see Table 2. Anacapa Island contain individuals that would demonstrate bait shyness or are “Warfarin- Previous island wide eradication projects (for resistant”. If rats are resistant to Warfarin, the islands greater than 10 ha) have only utilized amount of bait used would require greater and brodifacoum, bromadiolone, and warfarin (Table greater amounts of warfarin to induce a toxic 2). Bromethalin was used in conjunction with effect. It may be that “Warfarin resistant” brodifacoum on one island. None of the other individuals are insensitive to the other first rodenticides have been used for island generation anticoagulants such as diphacinone eradications. and chlorophacinone (Greaves 1994). Even if The use of bromethalin and zinc phosphide warfarin resistance is not present in a rat if used extensively, could result in the population, the use of first generation development of “bait shyness”. Bait shyness anticoagulants may not induce 100% mortality develops in a rat population when symptoms of of the target species under standard EPA exposure are associated with the bait presented laboratory efficacy studies. such as bromethalin and zinc phosphide. Studies The use of rodenticides in the field does pose have demonstrated that even with pre-baiting, some degree of risk, albeit small (due to the fact only 60- 70% of rats would be controlled with that humans would have to intentionally ingest an acute rodenticide (Lund 1988). Any the bait, in large quantities to do harm), to individual rat that survives a round of exposure humans on the islands. On Anacapa Island, bait is likely to avoid the bait in the future (Record would be applied to East Island, which visitors and Marsh 1988). If rats were to survive a frequent, so there is some potential for visitors to baiting application on Anacapa Island, the effort be exposed to any rodenticide. However, the required to remove those individuals would be exposure to human visitors is extremely low. greater than if a non-acute rodenticide which All of the rodenticides represent a risk of does not induce bait shyness was used. exposure. However, most have an antidote Cholecalciferol may also lead to “bait aversion” (Vitamin K1 for the anticoagulants, and because of the high concentrations in the final calcitonin for cholecalciferol) which counteract bait formulations (Prescott et al. 1992 in the activity of the rodenticide. Of the acute Kaukeinen et al. 2000) rodenticides, symptoms would be measurable An attempt to control and/or eradicate rats soon after ingestion. If sufficient quantities from Anacapa Island was carried out over a were consumed, immediate intervention would number of years in the 1980s and early 1990s. be required including medical evacuation. A Many control methods were attempted including major disadvantage of the acute rodenticides, delivery of Warfarin via bait stations. The from a human health perspective, is the lack of control of rats can be a strong selection agent, an antidote. increasing the frequency of rats that cannot be killed via the control method used. Where populations of rats have been previously exposed to poison, some rats demonstrate bait avoidance behavior and others may be biochemically “resistant” to the anticoagulant used.

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Table 2. Characteristics of rodenticides registered with the US EPA

Previous Ability to Success in Danger to Antidote Rodenticide Category Activity Induce Bait Island Humans Available? Avoidancea Restoration

Second Brodifacoum Generation High Single Feed Very Low Low Yes Anticoagulant

Second Difethialone Generation No Data Single Feed Very Low Low Yes Anticoagulant

Second Bromadiolone Generation Low Single Feed Very Low Low Yes Anticoagulant

First Chlorophacinone Generation No Data Multi-Feed Low Low Yes Anticoagulant

First Diphacinone Generation No Data Multi-Feed Low Low Yes Anticoagulant

First Warfarin Generation Low Multi-Feed Low Low Yes Anticoagulant

Bromethalin Subacute Low Single Feed High High No

Cholecalciferol Subacute No Data Single Feed Possible Moderate Yes

Zinc Phosphide Acute No Data Single Feed High High No

a See text for definition

decreases with the increasing effort of trap Trapping placement. Therefore, a prohibitive financial and time investment would be required to trap This alternative would have used live traps the few remaining rats from Anacapa Island. and/or kill (snap) traps to eradicate rats from This technique has not been successfully used on Anacapa Island. This alternative was dismissed other islands and likely would result in a large because it failed to meet the purpose and need control program that, in effect, would harvest the and is technologically infeasible. surplus rats. The use of live traps and/or kill traps to The implementation of a trapping regime on remove rats from an area is a strong selection Anacapa Island would require substantial labor agent and selects for rats that are “trap shy”. and subsequent financial investment. Traps Thus, the frequency with which rats are trapped

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would have to be laid on the cliffsides and cause of species extinctions on islands (Tershy shoreline of the island to be successful. Staff et al. 1997). servicing traps would be placed at risk of encountering numerous vector bone diseases from handling rodents and used traps. The effects of personnel scaling the cliffs has been Summary of Alternatives discussed in the first alternative considered but dismissed (see above). There is also the high A summary of the major features of each probability of capturing non-target species such alternative can be found in Table 3. The as landbirds, seabirds and mice in the traps. environmental impacts of implementing each Therefore, this alternative is infeasible to alternative are discussed in Chapter Four. The implement. alternatives differ in their approach to distribution of a rodenticide (aerial, bait station) across the island and the active ingredients used Introducing Predators in the rodent bait. This alternative is one form of biological control that was recommended during the scoping period. The introduction of predators such as snakes and cats was recommended; however, this was dismissed because it fails to meet the purpose and need. It also would result in unreasonable damage to the environment, and does not conform to the Park’s General Management Plan. The introduction of cats to islands in order to control introduced rats has been attempted numerous times since European explorers began crossing the Atlantic and Pacific Oceans in search of riches. The introduction of a predator such as cats to control rats usually results in a greater impact on birds than if one or the other were present alone. When seabirds are present, cats have been demonstrated to prey heavily on seabirds (Keitt 1998, Atkinson 1985) taking fewer rats. When the seabirds leave the island, the cats turn to rats which artificially maintain the population at a higher level than if the rats were not present (Atkinson 1985). Thus, birds are impacted by both rats and the larger number of cats present due to the rats. Introduction of another species into an island ecosystem can have severe and permanent consequences (see Quammen 1996). The introduction of non- native species has been identified as the leading

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Table 3. Summary of Alternatives for the Anacapa Island Restoration Project.

Middle Anacapa West Anacapa Active Concentration Alternative East Anacapa Ingredient (ppm) Top Cliff Top Cliff Top Cliff

1 (No Action) NA NA NA NA NA NA NA NA

2 (Preferred) Aerial Aerial Aerial Aerial Aerial Aerial Brodifacoum 25

Bait Bait 3 Aerial Aerial Aerial Aerial Brodifacoum 25 Stn Stn

4 Aerial Aerial Aerial Aerial Aerial Aerial Bromadiolone 50

Bait Bait 5 Aerial Aerial Aerial Aerial Bromadiolone 50 Stn Stn

Diphacinone 50 6 Aerial Aerial Aerial Aerial Aerial Aerial and and Brodifacoum 25

CHAPTER TWO - 30

. . CHANNEL ISLANDS NATIONAL PARK . FINAL ENVIRONMENTAL IMPACT STATEMENT .

ANACAPA ISLAND RESTORATION PROJECT

CHAPTER THREE AFFECTED ENVIRONMENT

Chapter Contents

INTRODUCTION ...... 32 PHYSICAL ENVIRONMENT...... 32 SETTING ...... 32 GEOLOGY...... 32 SOILS...... 34 CLIMATE ...... 34 AIR QUALITY (CLEAN AIR ACT)...... 35 TERRESTRIAL ENVIRONMENT...... 36 INVERTEBRATES ...... 36 HERPETOFAUNA...... 37 AVIAN...... 38 Landbirds...... 38 Seabirds ...... 38 MAMMALS ...... 41

RARE, THREATENED AND ENDANGERED PLANTS...... 41 MARINE ENVIRONMENT ...... 42 MARINE MAMMALS...... 42 California Sea Lion...... 42 Harbor Seal...... 42 MARINE INVERTEBRATES ...... 44 HUMAN USES AND VALUES ...... 45

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Introduction Physical Environment

This chapter focuses on portions of the environment that are directly related to Setting conditions addressed in the alternatives. The Off the coast of Southern California, description of the affected environment is eight ridges in the continental shelf rise not meant to be a complete description of above sea level, forming a series of islands. the project area. Rather, it is intended to The four northern islands are located in the portray the significant conditions and trends Santa Barbara Channel parallel to the coast of the resources that may be affected by the south of Point Conception: the four southern proposed project or its alternatives. islands are scattered offshore between Los Information in this chapter is based Angeles and the Mexican border. primarily on the Natural Resources Study The Channel Islands vary greatly in size, conducted in 1979 by the Santa Barbara distance from each other, and distance to Museum of Natural History, inventory and from the mainland, creating an immense monitoring data from the Park’s resource natural laboratory of isolation and evolution. management staff, independent research Because the islands have escaped much of studies, and studies conducted as part of this the historical human impact on coastal proposed action. Other sources are noted California, they provide an ideal place for a where applicable. National Park. This chapter is organized into four Of all the Channel Islands, the smallest sections, which when taken together provide and closest to the mainland is Anacapa the most complete description of the island Island. Totaling 296 ha, Anacapa Island resources, including the human element. with its three islets (East, Middle, and West) The four major components of this chapter is just over 1 square mile in area. One of the are: northern Channel Islands, it lies southwest
Physical Environment of the City of Ventura, 9 miles across the
Marine Environment Santa Barbara Channel from the nearest mainland point.
Terrestrial Environment
Human Uses and Values. Geology For the most part, geologic and (Adapted from Gustafson, 1999) The climatological conditions, processes, and Channel Islands are but exposed peaks in a disturbances cannot be altered by topographically complex area of submarine management activities. Watershed, soil, and basins and ridges known as the Continental atmosphere conditions and processes, also Borderland. This has been a region of part of the physiographic setting, can be intense geological activity – including modified by certain management activities. crustal deformation, volcanism, faulting, However, the management activities that are uplift, and erosion – caused by local tectonic proposed in this analysis would not affect processes. the physiographic settings.

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The deep wrinkles of today’s Boderland breccias formed largely by underwater began to form in a previously broad eruptions 15-20 million years ago. continental shelf during the Oligocene epoch Geologic reconnaissance conducted by (30 million years ago) in response to stress Johnson (1979) on Anacapa Island described at the boundary of the North American and the bedrock geology, quaternary marine oceanic plates. Widespread volcanic terraces and sediments, and quaternary activity both on and off shore followed in terrestrial sediments. the Miocene epoch (24 to 7 million years ago), as the Farallon Plate was subducted Bedrock Geology under the continental shelf. The bedrock geology of Anacapa Island Among the ranges created by this is comprised of dark colored Miocene Conejo tectonic activity was the Santa Monica volcanics with some modest to significant Mountains Range, which originally ran interbeds of lighter-colored San Onofre north and south. By the end of the Miocene, Breccia, also of Miocene age. Some of the however, this range had rotated into its basalt is of the pillow type indicating present east-to-west orientation, as had submarine eruptions. Various joints, faults, several other mountain chains now known and fractures are seen in the sea cliffs about collectively as the Transverse Ranges. The the island and where these intersect the sea, four northern Channel Islands, including sea caves have formed. Scholl (1960) Anacapa Island, constitute the seaward concluded that Anacapa has tilted to the extension of the Santa Monica Mountains, northward as a unit in the Late Pleistocene or which rise in downtown Los Angeles, Holocene. This tilt is very apparent on each plunge into the ocean at Point Mugu, and of the three islets. continue westward for many miles. During the Pleistocene ice ages, sea Quaternary Marine Terraces and levels dropped enough for the four northern Sediments islands to form a single, vast island now Quaternary marine terraces and sediments known as Santarosae. For decades, scientist occur at various elevations, the most assumed that a landbridge once connected conspicuous of which is the 250-ft. terrace Santarosae to the mainland range as well. which dominates the mesa-like form of But as bathymetric knowledge of the ocean Middle and East Islets. These have been floor improved, geologists concluded that described by several authors (Scholl 1960; even during periods of lowest sea levels Lipps 1964), and occur at 25 and 250 feet (about 17 thousand years ago), the elevations. During the geological connection between the mainland and reconnaissance associated with the present Santarosae remained submerged. As study, beach deposits were found at 25, 250, glaciers melted at the close of the 650, 800, and 840 ft. Pleistocene, rising sea levels flooded lower elevations of Santarosae, leaving the higher Marine sediments occur on all three islets regions exposed and separated. but have been preserved best on Middle and West Islets. On Middle Islet, however, Anacapa Island is mostly made up of fosssiliferous terrace deposits occur at 25-ft. volcanics, miocene basalts, andesites, and

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elevation, and a marine unit some 2.5 – 4.5 and grazing. Prior to becoming a National feet thick veneers at the 250-foot terrace. Monument in 1938, all three islets had been grazed primarily by sheep. East Islet had Quaternary Terrestrial Sediment sheep grazing between 1902-1912, and Middle and West Islets were grazed from Quaternary terrestrial sediments are thin 1902-1937 (Johnson 1979). It is estimated on East Islet, ranging from 0 –8 ft. thick, but that soil resources were significantly on Middle and West Islets range up to 15 – 50 affected during this period, but has since feet thick respectively. At the boat landing at recovered. However, to varying extents the the east-end of West Islet a terrestrial unit islets have been invaded by alien grass and occurs which has yielded many remains of forb species. The impacts to soil resources birds, at least one of which is extinct. as a result of these invasive species are not Soils known. Soil information on Anacapa Island is Cyanobacterial crusts known from a reconnaissance survey Cyanobacterial crusts are important for conducted by Johnson (1979). From eight increased soil stability, water infiltration, hand-dug pits and soil lab analysis it was and fertility of soils. Cyanobacterial crusts determined that the Island has three major are common on the Channel Islands. soil types. Surveys done by Belnap (1994) indicate that Lithic Xerorthents – soils found on cyanobacterial crusts should cover the soil moderately steep to steep recent erosional surfaces in most of the vegetation types slopes. found in the Channel Islands. Typic Chromoxererts – clayey, poorly These soil crusts are impacted by soil horizonated soils that shrink and crack surface disturbance, including grazing, during summers and swell when wetted people and off-road vehicles. The only during winters. Found on gentle to opportunity currently for these crusts to be moderate slopes on all three islets. disturbed on Anacapa Island is through Vertic Argixerolls – clayey, organic matter- trampling by people. rich soils that have shrink-swell Although restricted to hiking trails on characteristics such that it forms significant East Anacapa Islet, authorized activities cracks in summer. Found on the gentlest such as iceplant removal and terrestrial and flattest portions on all three islets. animal monitoring, as well as unauthorized trampling by errant hikers may impact these Status and Trend crusts. Middle and West Islets receive minimal foot traffic. Determination of the status or trend of soil resource conditions for Anacapa Island is difficult because of the lack of monitoring Climate data. Generally, declines in soil quality and Precipitation and Temperature productivity are associated with intensive The Channel Islands enjoy the vegetation management activities, roading, Mediterranean climate typical of the central

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California coast. Rain pelts the islands off that there is decreased soil moisture and and on from November to March, but is stream flow, thereby affecting ecological scarce from late May to October, when a processes and human activities. Drought stable Pacific high-pressure system settles conditions occur frequently on Anacapa off the coast. A shallow coastal marine Island. layer helps ameliorate summer drought conditions on the islands in all but the driest Air Quality (Clean Air Act) of years. Current Status and Trend Northwesterly winds blow throughout The history of air quality monitoring on the the year, picking up speed most afternoons Channel Islands goes back to the period of and dropping off at night. These winds 1988-1992 when a air quality station was drive fog against the islands’ northwestern located on East Anacapa Island. This station slopes, which provide very different climatic

Table 4. Anacapa Island-Lighthouse 1992 Ozone Summary (Ventura County Air Pollution Control District)

1-hr Ozone 8-hr Ozone Number of Days Standard % of Concentrations Concentrations Days Exceeded Year ppm ppm Moni- State 1- Federal 1- Federal 8- 1st 2nd 3rd 4th 1st 2nd 3rd tored EPDC* hour hour hour** High High High High High High High 1992 67% 4 0 2 0.100 0.100 0.100 0.100 0.102 0.094 0.090 0.081 *The Expected Peak Day Concentration (EPDC) is calculated based on data for 3 successive years, listed by the last year of the three year period. The EPDC represents the ozone concentration expected to occur once per year. **Proposed Federal Standard

conditions than the south-facing coastal monitored ozone, sulfur dioxide, slopes of the mainland. Santa Ana winds hydrocarbons, and nitrogen oxides. This occasionally disrupt this pattern, particularly station was removed when the Coast Guard in the fall and early winter. These hot dry converted the Anacapa lighthouse to solar winds blow from the east when high- power, and removed the power supply for pressure systems are present of the interior the air quality station. In 1996, in mainland. cooperation with the Santa Barbara County Air Pollution Control District, an ozone Drought monitoring station was built on Santa Rosa Island. Drought is an important process that affects ecosystems. Drought is defined as an It is probable that the combination of absence of usual precipitation (less than 75 prevailing wind patterns, a low natural fire percent of normal), for a long enough period history, and small human populations has

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allowed for generally good air quality on the not a complete description of the entire island. Following the population and terrestrial environment. This chapter is development boom along coastal southern organized to focus on the sub-issues California, however, poor air quality is identified for the terrestrial environment using the best information available. This widespread, and smog often mars the chapter will also include descriptions of the visibility from and around the islands. significant conditions and trends of the The phenomenon of "Santa Ana" winds resources that may be affected by the that come from a northeasterly, inland proposed project or its alternatives. Listed direction can greatly affect air quality at below are the four terrestrial components that will be described in this section: Anacapa Island. These winds usually occur during fall and winter and are
Invertebrates characteristically warm and dry and may be of
Herpetofauna very high velocity near the mainland shore.
Avian They primarily affect those islands close to
Mammals the mainland by carrying out to sea the air pollution usually found onshore. Satellite Invertebrates images show that Santa Ana winds can carry pollutants several hundred miles offshore and Current Status have the potential to negatively affect all of A natural resources study completed by the park islands. A bigger concern relative to the Santa Barbara Museum of Natural air pollutants in the Channel Islands is a History (Miller and Hochberg 1979) "Catalina eddy" that can bring pollutants up generally described the dominant insects on the coast from the Los Angeles basin and a Anacapa Island. The survey focused on insects that would have been of special post-Santa Ana event where the air pollutants interest to the Park such as, endemics and that were pushed offshore come slowly back pests. Since that time, several studies have to the coast. Another type of pattern that added to the knowledge base of invertebrate would bring moderate levels of air pollutants species for Anacapa Island. In the Parks to the Channel Islands is an eastern Pacific Terrestrial Invertebrate Monitoring high pressure system that causes light winds Handbook (Fellers 1991), the Park provided and poorly dispersed air. Normally, the sea an update of invertebrate fauna that was breeze pushes the air pollutants to the coast known to exist on Anacapa Island. Table 5 and keeps low levels of air pollutants in the shows a comparison of the species identified in 1979 by Hochberg and Miller (1979) and Channel Islands. the current state of knowledge. Table 6 describes the number and proportion of endemic terrestrial invertebrate taxa on Terrestrial Environment Anacapa Island. The Parks report (1989) states that Introduction despite the increasing knowledge of the composition of the terrestrial invertebrate This section provides a description of the terrestrial component of Anacapa Island fauna, there is still an almost complete lack that is directly related to conditions of data on the ecology, distribution and addressed in the alternatives. As such, it is

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abundance of invertebrates on the park Herpetofauna islands. Current Status Herpetofauna for this discussion includes native amphibians and reptiles on Anacapa Table 5. Terrestrial Invertebrates known from Island. Only one native amphibian, the Anacapa in 1979 (Hochberg 1979; Miller 1979) Pacific Slender Salamander (Batrachoseps and 1989. pacificus pacificus) and two native lizards, the Side-blotched Lizard (Uta stansburiana) Taxa 1979 1989 and the Southern Alligator Lizard (Elgaria Snails 2 2 multicarinatus), occur on Anacapa Island. Insects 94 130 In 1988 the Park published a protocol Other Arthropods 3 7 (Fellers et. al. 1988) for monitoring Total 99 139 terrestrial vertebrates within the Park. A significant portion of the monitoring protocol was directed at monitoring the Trend Park’s amphibians and reptiles. The Channel Islands National Park developed a purpose of monitoring was to determine Terrestrial Invertebrate Monitoring population status. Population status was Handbook (Fellers and Drost 1991) for the reported using two parameters; 1) an purpose of detecting significant changes in uncalibrated index of population size and, 2) the diversity, abundance and distribution of weight-length regression. The population terrestrial invertebrates. Because of the index allows the park to track changes in isolation of the Islands, the Park is population size and thus detect both long- especially interested in expansion of non- term trends and sudden, short-term changes. native invertebrates into native plant The weight-length regression provides a communities. Unfortunately, due to measure of the general health of the budgetary and personnel constraints the population. monitoring program has not been implemented. As a result, trend estimates Trend: for the invertebrate population’s “health” on Data collection on the reptiles and Anacapa Island is not known. amphibian monitoring began in 1993. Figure 2 shows the population index for both species. Table 6. Number and proportion of endemic taxa Normal year-to-year changes can be on Anacapa Island (Fellers and Drost 1991). expected for the salamander because their Total activities are strongly moderated by rainfall. No. of Endemic Taxa As shown in Figure 2 the population index Species (percent) for the pacific salamander increased Snails 2 1(50) dramatically during the wet winter season of Arthropods 137 18(13) 1997-98.

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Avian were not included in the transects and could Landbirds have contained breeding landbirds (Austin and Coonan 1998). West Anacapa Islet Current Status provides the best landbird habitat out of the Twenty-two species of landbirds are three Anacapa islets, due to its greater known to breed on Anacapa Island topography and more extensive stands of (Diamond and Jones 1980). Seven of these native shrub vegetation, including coastal taxa are recognized as endemic subspecies, sage scrub and coreopsis scrub. A complete occurring only on Anacapa and one or more list of landbirds found on Anacapa Island of the other Channel Islands (Johnson 1972). can be found in the Appendix. These endemi Trend: Figure 3. East Anacapa Island Fall Landbird Counts c Part of the species 70 terrestrial include monitoring 60 the program at Allen’s 50 Channel Humm 40 Islands is ingbird 30 Number focused on (Selasp 20 monitoring horus 10 landbirds. The sasin objective of the 0 sedent 1993 1994 1996 1997 monitoring arius), Bewick's Wren Black Phoebe European Starling program is to Pacific House Finch House Wren Orange-crowned Warbler provide, on an -slope Rock Wren Red-tailed Hawk Say's Phoebe Savannah Sparrow White-crowned Sparrow Western Meadowlark annual basis, Flycatc Yellow-rumped Warbler species and her numbers of (Empid breeding land onax difficilis insulicola), Horned Lark birds on Park Islands. Counts are made to (Eremophila alpestris insularis), Bewick’s provide information on relative abundance Wren (Thryomanes bewickii newophilus), of all breeding birds on each island during Loggerhead Shrike (Lanius ludovicianus breeding and non-breeding periods each anthonyi), Orange-crowned Warbler year. (Vermivora celata sordida), House Finch (Carpodacus mexicanus frontalis) and Seabirds Rufous-crowned Sparrow (Aimophila ruficeps obscura). Current Status Not all of the species that are known to Currently there are eight species of breed on Anacapa Island were observed nesting seabirds on Anacapa Island. Of the during the 1995-1997 National Park Service eight species, three are classified as being surveys. Middle and West Anacapa Island Species of Special Concern in California. These Species of Special Concern include

CHAPTER THREE - 38 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL I MPACT STATEMENT

Figure 4. Critical Seabird Areas.

the Ashy Storm-Petrel (Oceanodroma be consulting with the U.S. Fish and homochroa), Double-crested Cormorant Wildlife Service on this project. (Phalacrocorax auritus), and the Xantus’ Factors that threaten nesting seabirds on Murrelet (Synthilboramphus hypoleuca) Anacapa Island include predation by (California Department of Fish and Game introduced Black Rats (Rattus rattus), oil 1992). The Xantus’ Murrelet is also listed pollution, organochlorines, and gill nets as a Federal Species of Concern (U.S. Fish (Drost and Lewis 1995). The introduction and Wildlife Service 1998). The Channel of non-native plant species may play a role Islands National Park also provides one in loss of habitat, but the numbers of nesting hundred percent of the state’s population of seabirds on Anacapa Island are still nesting Xantus’ Murrelet. Figure 4 shows relatively low compared to the available the critical seabird areas on Anacapa Island. habitat. One of the breeding seabirds on Anacapa Island is the California Brown Trend Pelican (Pelecanus occidentalis Brown Pelican californicus), which is listed as a federal Endangered species. One hundred percent In the 1950’s the pesticide DDT heavily of the state’s population of nesting impacted Brown Pelicans. The pesticide California Brown Pelican occurs on was concentrated as it moved up the food Anacapa and Santa Barbara Island. Because chain and in Pelicans and other predatory of its significance as a listed species under birds caused the eggshells to be so thin that the Endangered Species Act, the Park will the incubating adult crushed the eggs. By

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1968 the population was so low that only Brown Pelican populations. However, 100 pairs bred on Anacapa Island and only repeated disturbance of non-breeding Brown four chicks fledged. For this reason, Brown Pelicans could have a cumulative impact if it Pelicans were listed as a Federally caused a significant energetic drain or Endangered Species. DDT was banned in significantly reduced time available for the U.S. in 1972 and since then Brown preening. Pelican numbers have increased. Today Species of Special Concern they are close to, or above historical population sizes, making the Brown Pelican Two of the species of concern are sea a conservation success story. cave/crevice nesting seabirds that are susceptible to disturbance. These species Today Brown Pelicans are susceptible to Ashy Storm-Petrel (Oceandodroma pollution (especially oil spills and fishing homochroa) and Xantus’ Murrelet gear entanglement), disturbance, and (Synthliboramphus hypoleucus) nest in predation of eggs and young chicks by similar habitats on Anacapa Island. introduced species. Population decline in both species has been Brown Pelicans are particularly documented by Sydeman et al. (1998). susceptible to disturbance in the early part of The executive committee of the Pacific the breeding season; during incubation and Seabird Group has authorized a committee the first three weeks of chick rearing. to draft a petition to list the Xantus’ During this period, if adults are disturbed Murrelet for protection under the they will fly off the nest leaving the eggs or Endangered Species Act. The Pacific young chicks exposed to heat, cold, or gull Seabird Group, however, has yet to render and raven predation. For this reason, an opinion on the merits or reasons for breeding colonies such as Anacapa Island listing Xantus’ Murrelet. must be strictly protected during the breeding season. Even a single group of In addition to rat impacts on the murrelet, visitors during the breeding season can other disturbance factors such as oil pollution result in complete breeding failure over and the associated impacts (increased large parts of the colony. predation, disorientation, disruption) from bright lights from squid boats who fish During the non-breeding season Brown adjacent to Anacapa Island may be Pelicans are much less susceptible to contributing factors to the decline of the disturbance. They will fly off if approached Xantus’ Murrelet population. closely, but the only impact this has on individuals is the energetic cost of flying An assessment of nesting habitat away and the time lost flying that could be confirmed the impacts of introduced used for preening or resting. In addition, predators on the Xantus’ Murrelet on adults are much less likely to be Anacapa Island. Of the estimated 505 energetically stressed during the non- potential nesting sites accessible to rats, only breeding season when they are non-involved two sites, or 0.4%, had evidence of nesting in courtship or chick rearing. Consequently, murrelets (McChesney et al. 2000). Both during the non-breeding season, single eggs showed evidence of mammalian disturbance events will have little impact on predation and were in areas where rats

CHAPTER THREE - 40 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL I MPACT STATEMENT

appeared to be common. In contrast, on rat- have hypothesized that breeding suppression free Santa Barbara Island similar surveys in is the ultimate factor limiting the Deer 1991 found murrelet eggshells in 29.4% of Mouse population on Santa Barbara Island. potential sites. Murrelets on Anacapa (This fluctuation has resulted in densities Island are mostly limited to nesting in areas from less than 10 mice/ha to over 450 inaccessible to rats or where rats occur mice/ha. Summarized in Figure 5 are the infrequently. mouse densities from Anacapa Island since 1993. Mammals

Current Status Figure 5: Mean Deer Mice Densities (No/ha) Anacapa Island. The Deer Mice on Anacapa 300 (Peromyscus maniculatus anacapae) and 250 Santa Barbara Islands (Peromyscus Fall Spring maniculatus elusus) are the largest native 200 land mammal. Both subspecies are endemic 150

and restricted to their respective island. As Number/ha abundant generalist granivores/predators, 100 they undoubtedly have significant influence 50 on the plants and terrestrial invertebrates on 0 the islands, as prey species, they largely 93 94 95 96 97 98 99Mean Grand Across All determine the numbers of some of the Year TotalYears resident hawks and owls (Fellers et al. 1988). As part of its vertebrate monitoring program, the Park has been monitoring mouse populations on Anacapa since the spring of 1993. Monitoring of Deer Mice Rare, Threatened and employs mark-recapture grids (Fellers et al. Endangered Plants 1988). There are currently 3 grids set up on Anacapa Island, one on each islet. The grids Current Status are monitored in the spring and late There is only one federally endangered summer/fall of each year. plant on Anacapa Island: Island Trend Malacothrix (Malacothrix squalida). It occurs only on Santa Cruz Island and Mouse trapping has been conducted on Middle Anacapa. On Middle Anacapa it is Santa Barbara Island since the early 1980’s. found in two locations: near the Knife’s One of the most significant findings from Edge and on an east facing slope near the this data is that there are large fluctuations in west end of the island. population levels that are related to annual It is an annual herb from the aster rainfall, predation pressure, and season family. It ocurs on rocky coastal bluffs in (Fellers et al. 1988). C. Drost and others, coastal scrub.

CHAPTER THREE - 41 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL I MPACT STATEMENT

Trend at two locations. These locations are both on south shore of the East Islet. Although Island Malacothrix has been pupping has been observed in these two documented from Middle Anacapa Island on areas, overall habitat quality is limited due two occasions: when it was first collected in to the marginal beaches on Anacapa (narrow 1963 and again by Steve Junak in 1998. and rocky and can be completely submerged Local populations of Island Malacothrix on during high tide), and heavy visitation (on- Anacapa Island are impacted by soil, habitat shore and off-shore). alteration, and localized impacts from seabird nesting. Its limited occurrence California Sea Lions are opportunistic makes it highly susceptible to stochastic feeders, and feed in large groups when events which could lead to extirpation from schooling fish or squid are available and Anacapa Island. probably disband when the food source is scattered (Bonnel et al. 1979). Feces analysis of California Sea Lions from San Miguel Island showed squid, Pacific Hake, Marine Environment rockfish, and a variety of other schooling pelagic and demersal fishes (benthic fishes) Marine Mammals to be utilized (Antonelis et al. 1978). Two species of marine mammals Incidental set and drift gillnet fishing utilize habitat areas on or around the shores continues to be the leading human caused of Anacapa Island. These species, the mortality factor. However, for the first three- California Sea Lion (Zalophus quarters of 1994, when compared to the years californianus) and the Harbor Seal (Phoca 1991-93, incidental gillnet kills showed a vitulina), are year round residents. Both large reduction (Barlow et al. 1995). species are abundant and widely distributed throughout the area. Trend California Sea Lion Specific population trends for Anacapa Island is not known. However, population Current Status trends for four southern California rookeries, California Sea Lions are the most which includes rookeries from the Channel conspicuous and abundant pinnipeds in the Islands, were estimated by Barlow et al. coastal waters of southern California. The (1995). With the exception of the El Nino principal breeding rookeries in the Channel events of 1983 and 1992, pup counts Islands are on the western end of San increased at an annual rate of 5.2% between Miguel Island, including Castle Rock, the 1975 and 1994. Pup counts between the El offshore sides of San Clemente and San Nino events increased at 8.8% between 1976 Nicolas Islands, and around Santa Barbara and 1982 and at 8.2 % between 1983 and Island. They haul out on all of the southern 1994 (Barlow et al. 1995). California Islands (Bartholomew et al 1970). Harbor Seal On Anacapa Island California Sea Lions are known to haul out, in varying numbers, Current Status

CHAPTER THREE - 42 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL I MPACT STATEMENT

Figure 6. Marine Mammal Bioregions

Harbor seals are occasionally seen in mortality factor for the Harbor Seal. Barlow and around harbors, such as the Ventura (1995) notes that gillnet mortality may reach Marina, breakwaters and jetty. Traditionally as high as 5-10% of the California Harbor they seek to avoid the disturbance that Seal population. usually accompanies the activities of humans. They are much more wary than Trend any other pinnipeds of the Channel Islands Population size for California Harbor area and can only be approached closely Seals is estimated by counting the number of with great caution (Bartholmew et al. 1970). seals ashore during the peak haul-out period Generally they haul out and breed only on (May/June) and multiplied by a correction the most secluded beaches, rocks, and mud factor that estimates the number of seals on flats available, usually avoiding areas land to those in the water. Harbor seal inhabited by other species of pinnipeds counts have continue to increase each year (Bigg 1969). except during El Nino events of 1983 and Harbor seals occur on inaccessible areas 1993. Annual population has been of the south shores of all three islets. While estimated for the islands, and show a stable pups have been observed on southern West population between 1983 through 1995 Islet the role of Anacapa as a hauling and (Barlow et al. 1995). breeding ground is unclear. Harbor seal movement is usually confined to less than 500 km from their pupping sites. The gillnet fishery is the leading human caused

CHAPTER THREE - 43 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL I MPACT STATEMENT

Marine Invertebrates Trend Current Status For the species that were monitored as part of the intertidal monitoring surveys Intertidal invertebrates have been percent cover did not vary more than 10% monitored by the Park since 1982 with the (See Figure 7). The biggest decline detected following goals: 1) monitor trends in by the monitoring program is for black population dynamics; 2) determine normal abalone. Since 1985 when over 900 black limits of variation; 3) discover abnormal abalone were counted across all Anacapa conditions; 4) provide remedies for monitoring zones, the population declined management problems; and 5) measure the significantly with no individuals being effects of management actions. Fifteen sites counted the last two years (See Figure 8) on four park islands are monitored each spring and fall.

Figure 7. Average Percent Cover of Intertidal Zone, Anacapa Island (Across all Zones)

Bare Rock 45 Barnacle Endocladia 40 Rockweed Mussels 35 Misc Algae Misc Animal 30

25

20 Percent Cover 15

10

5

0 1981 1984 1986 1988 1990 1992 1994 1998 Year

CHAPTER THREE - 44 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL I MPACT STATEMENT

Figure 8. Anacapa Black Abalone Counts people to the islands. In addition to the 1000 16,000 annual visitors to the island, various 900 scientists, and Park personnel frequent the 800 island as well. Not included in this statistic 700

600 is the number of people who recreate with

500 private boats, or who conduct commercial Totals 400 fishing operations around the waters of 300 Anacapa Island. Figure 9 shows the 200 monthly average for the years 1996-99 of 100

0 campers and visitors who come ashore.

6 9 1 2 3 6 8 9 85 87 88 90 95 97 9 9 9 9 9 9 99 1 198 1 1 198 1 199 199 199 1994 1 199 1 1 199 Year Park concessionaires provide most of the public transportation to Anacapa Island. Trips to Anacapa are scheduled almost daily throughout the summer and at least on weekends throughout the rest of the year. Human Uses and Values The trips can last all day or half day. Visitors are only allowed on East Anacapa Channel Islands National Park, and Island or Frenchy’s Cove when conditions specifically Anacapa Island are recognized permit. locally, nationally, and internationally as an area of exceptional scientific value with irreplaceable cultural resources, notable Figure 9. Campers and Visitors Ashore geological and paleontological features and plant and animal communities that have 3000 Average Number evolved in a unique manner because of their 2500 of Campers (96- 99) isolation from the mainland. The waters Average Visitors surrounding the islands contain one of the 2000 Ashore (96-99) most diverse and productive marine 1500 ecosystems in the world.

1000

Anacapa Island and its surrounding Visitors of # Average

waters have status as both a state of 500 California ecological reserve (surrounding waters to 1 nautical mile) and a federal 0

y y il y y t r r r ar ch r be u Ma June Jul gus ober research natural area. As an ecological Ap u em ct Januar Mar A cembe Febr ept O e reserve boating activities close to shore are Month S NovembeD prohibited along parts of West Islet for the protection of nesting pelicans. West and Middle Islet have status as a research natural area and are closed for from public use with the exception of Frenchy’s Cove. As an area of such diverse and important resources, the Park attracts a wide array of

CHAPTER THREE - 45 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL I MPACT STATEMENT

Figure 10. Facilities and Trails.

CHAPTER THREE - 46 . . CHANNEL ISLANDS NATIONAL PARK . FINAL ENVIRONMENTAL IMPACT STATEMENT .

ANACAPA ISLAND RESTORATION PROJECT

CHAPTER FOUR ENVIRONMENTAL CONSEQUENCES

Chapter Contents

INTRODUCTION ...... 48

ISSUE 1: EFFICACY ...... 48

INTRODUCTION ...... 48 THE RODENTICIDE AND TOXICOLOGICAL PROPERTIES ...... 48 COMPOSITION OF BAIT AND HOW IT IS APPLIED...... 50 Alternative 1: No Action Alternative...... 50 Alternatives 3 and 5: Aerial- Bait Station Combination ...... 50 Alternatives 2, 4 and 6: Aerial Broadcast...... 51 LOCAL FACTORS...... 51 SUMMARY...... 52 ISSUE 2: NON-TARGET IMPACTS ...... 52

INTRODUCTION ...... 52 PHYSICAL IMPACTS...... 52 TOXICOLOGICAL IMPACTS ...... 57 RELATIVE COMPARISON OF TOXICOLOGICAL IMPACTS BY ALTERNATIVE...... 58 Alternative 1 – No Action...... 58 Features Common to Alternatives 2, 3, 4, 5 and 6...... 58 Primary Exposure...... 58 Secondary Exposure...... 61 Toxicological Impacts by Sub-Issue...... 64 Sub-Issue 1: Marine Mammals ...... 64 Sub-Issue 2 – Invertebrates ...... 66 Sub-Issue 3 – Fishes...... 66 Sub-Issue 4 – Herpetofauna ...... 67 Sub-Issue 5 and 6 – Seabirds and Landbirds...... 69 Sub-Issue 7 – Terrestrial Mammals...... 74 CUMULATIVE EFFECTS ...... 74 ISSUE 3: PUBLIC SAFETY AND VISITATION ...... 78

EXPOSURE TO THE RODENTICIDE ...... 78 IMPACTS TO VISITOR ENJOYMENT ...... 80 SUSTAINABILITY AND LONG TERM MANAGEMENT ...... 81

CHAPTER FOUR - 47 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL I MPACT STATEMENT

choice, and its delivery into the ecosystem, Introduction must offer the greatest probability of achieving success. The success of the eradication is This chapter discloses the environmental dependent on the rodenticide chosen, the bait consequences of implementing each alternative composition and its delivery into the ecosystem described in Chapter Two. The environmental and awareness of the local conditions that could consequences, or environmental effects will be be exploited to maximize success. These factors categorized in three broad areas. The three will be analyzed for each alternative. categories of effects are direct, indirect, and cumulative. These “effect” categories will form The Rodenticide and the basis of the effects analysis in this chapter. Toxicological Properties Direct effects, as defined by the Council on There are three rodenticides outlined in the Environmental Quality, are those which are alternatives. They are brodifacoum, caused by the action and occur at the same time bromadiolone (second generation anticoagulant) and place. Indirect effects are those which are and diphacinone (first generation anticoagulant). caused by the action and are later in time or All of these chemicals are anticoagulant farther removed in distance. Cumulative effects rodenticides, which cause mortality to the target are those that result from the incremental impact species through hemorrhaging (See of the action when added to other past, present, Biochemistry below for further discussion). In and reasonably foreseeable future actions. general, the difference between the first and Cumulative impacts can result from individually second generation anticoagulants is their acute minor but collectively significant actions taking toxicity to rats, the amount required to kill rats, place over a period of time. and their ability to control a population of rats. The cumulative impacts analysis has been The acute toxicity of the rodenticides are narrowed down to two main issues, the potential presented in Table 7. Acute toxicity (LD ) is repeated exposures of non-target species to the 50 defined as the amount of active ingredient (mg) rodenticide and the cumulative impacts to seabirds per kg body weight, required in a single oral that utilize Anacapa Island for breeding. This dose to kill 50% of a test population. Only the chapter forms the scientific and analytical basis acute toxicity of brodifacoum is known to the for the relative comparison of effects presented target species, Rattus rattus. The other LD towards the end of Chapter 3. 50 data presented are based on Norway rat (laboratory rat) data that may not be representative for Rattus rattus. Following the Issue 1: Efficacy pattern of toxicity for the lab rat across all three anticoagulants, brodifacoum is approximately twice as toxic as bromadiolone, and orders of magnitude more toxic than diphacinone. Introduction Although all the rodenticides are toxic to the target rat species, in practice, the rodenticides This section of the analysis compares the differ in their ability to kill the target species. different alternatives and how well they meet the purpose and need. The objective of this project The rodenticides presented are classed as is to remove 100% of the rat population from either “single feeding” or “multi-feeding” Anacapa Island. Therefore, the rodenticide of rodenticides. The first generation anticoagulant diphacinone is a “multi-feeding” rodenticide in

CHAPTER FOUR - 48 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT

Table 7. Amount of bait required (g) for rats to reach one LD50.

Active Ingredient (Rodenticide)

Brodificoum 25 ppm Bromadiolone 50ppm Diphacinone 50 ppm Alternative 2,3 and 6 Alternatives 4,5 Alternative 6

a LD50 (mg/kg; range) 0.26-0.56 0.56-0.84 2.3 – 7.0 Rat Weight (g)b 150 150 150

mg Active Ingredient 0.039 - 0.084 0.084 – 0.13 0.35 – 1.05

Amount of Bait (g) 1.56 – 3.36 1.68 – 2.52 6.9 - 21

Number of Pellets 0.78 – 1.68 0.84 – 1.30 3.5 – 10.5

Number of Feeding Daysc 0.16 – 0.34 0.17 – 0.25 0.69 – 2.1

a LD50 for black rat (R. rattus) is 0.65-0.73. All LD50 data is for Norway rat (Laboratory). Comparing laboratory rat data across the different rodenticides, bromadiolone is half as toxic as brodifacoum. If the LD50 differences between brodifacoum and bromadiolone for the lab rat follow a similar pattern for the black rat, the LD50 data presented may be too low. Conservatively, the feeding estimates should be considered an absolute minimum to one LD50. b from Erickson (1990) c assumes approximately a 10g daily requirement of dry matter per day based on the allometric equation: Food Ingestion Rate (g/day) = 0.621(Weight)0.564 . Assumes bait is 100% Dry matter and satisfies daily requirements.

that rats are required to feed on the bait over a concentrations (which would still be less amount period of days (estimated around 7 days) to of active ingredient than if a first generation cause death. This is due to the ability of rats to compound were used). From an eradication metabolize and excrete the chemical in a standpoint it is necessary that every individual relatively short period of time negating the toxic exposed to the rodenticide succumbs. Therefore, effect of the initial dose. However, if the rats a bait, able to kill after ingestion a single feed on the bait exclusively for a period of days, mouthful would be most efficient for eradication the toxic effect will take hold and cause death. purposes (Eason 1991 as cited in Taylor 1993). Brodifacoum and bromadiolone are somewhat Variation exists within every rat population insensitive to metabolism, relative to to the susceptibility of the rodenticides. Of most diphacinone. These compounds can cause death interest in an eradication program are those after a “single feeding” if enough of the individuals which require more and more bait to rodenticide is consumed. In other words, rats on induce mortality, or show bait avoidance the island would have to only consume a small behavior. It is those individuals that may cause amount of bait to cause death if brodifacoum or failure and form the founding population in the bromadiolone were used in sufficient

CHAPTER FOUR - 49 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT future, making it that much harder to remove restoration project. The composition of the bait rats from the island because of the inherited would be commercial manufactured baits, either lower susceptibility. Diphacinone, with its in pellet or block form. The application multi-feeding requirement to induce mortality, technique, either bait stations and/or aerial increases the probability of rats surviving post broadcast, would differ in probability of application due to bait avoidance, inadequate eradication, primarily based on the movement bait consumption or other mechanisms. The use of rats on the island. To successfully eradicate of brodifacoum is proposed to “clean up” those rats, bait must be delivered into each rat’s remaining individuals that were not lethally territory across the island (Appendix C). exposed to the diphacinone bait. However, Each of the alternatives outlines the use of under alternative 6, the repeated use of different rodenticides and/or methods of diphacinone bait would select for individuals delivery. In each case, the aerial broadcast that require more and more rodenticide to be would utilize a commercially manufactured killed or show higher bait avoidance behavior compressed grain pellet. Bait stations would be due to previous exposure to diphacinone. If rats armed with commercial grade blocks of that survive show bait avoidance behavior, they approximately 20 g or the 2 g compressed grain may avoid the brodifacoum bait when presented. pellets. The baits would be formulated for high Thus, there is lesser confidence in achieving palatability and acceptance by rats and would be eradication under alternative 6. Bromadiolone, consumed readily by the target species. (alternatives 4 and 5) would increase the probability of killing all target animals because Alternative 1: No Action Alternative of its greater toxicity and its “single-feeding” label. However, bromadiolone has been shown Under the no action alternative, there would to be unable to control 100% of Rattus rattus be no use of rodenticides in the Anacapa after two day’s of feeding on 50 ppm bait environment, except for the localized baiting in (Buckle 1994). After the presentation of equal buildings on east island. With no rodenticide concentration of brodifacoum and bromadiolone application, the rat population would not be to a study population of black rats, only controlled, and the numbers of rats on the island brodifacoum killed 100% of the rats after 1 day would fluctuate within the annual cycle. and 2 days of presentation. Bromadiolone was Efficacy would effectively be 0% on Middle and only effective in killing 47% and 90% after one West Islands, and very small (>0%), on East and two days of feeding (Buckle 1994). Island where control would take place in the few buildings. Only brodifacoum offers the highest probability of achieving the 100% kill of rats, thus, meeting the purpose and need of the Alternatives 3 and 5: Aerial- Bait Anacapa Island Restoration Project. Brodifacoum Station Combination has been the most extensively used rodenticide in The use of bait stations on top of the island island restoration practices worldwide (Appendix as well as aerial broadcast of the rodenticides C). onto the cliffsides was developed to minimize the exposure of non-target species to the Composition of Bait and how it rodenticide through direct bait consumption. is Applied Although it minimizes the primary exposure risks to non-target species, may compromise the This section investigates how the success of the eradication because some composition of the bait and its application method would affect the outcome of the

CHAPTER FOUR - 50 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT individuals possibly would not be exposed to the avoidance and could escape exposure. There is bait. no island rat eradication recorded that used a combination of broadcast and bait stations and Habitat utilization by rats on Anacapa Island thus, there is no precedent for this type of follows an annual cycle. Rats are most abundant operation. Alternatives 3 and 5 offer the lowest along the shoreline during the late dry season, probability of successfully eradicating rats. and in very low density on the slopes and top of the island (Erickson 1990; Howald et al. 1997; Collins 1979). General observations have Alternatives 2, 4 and 6: Aerial suggested that during the wet season, the rat Broadcast populations increase and subordinate individuals The aerial broadcast of the rodenticide are pushed into marginal territories, such as up across the entire island as laid out in alternatives the slopes and on top of the island. As the dry 2, 4 and 6 increases the probability that 100% of season progresses and food availability on top the rats would be exposed to the bait. Rats declines, the abundance of rats on top declines. would encounter pellets during their nightly Rats have been found in very low density on top foraging excursions and neophobic behavior, of the island during the late dry season, but not such as to bait stations, would be minimized. absent (Howald et al. 1997; ICEG 2000). With the use of bait stations, some rats may not enter Local Factors the stations even though they are present in their Warfarin resistance territory. This neophobic behavior, common in rats (Greaves 1994), may prevent some An attempt to control and/or eradicate rats individuals from gaining access to bait in the from Anacapa Island was carried out over a stations. Bait stations deployed only on top of number of years in the 1980s and early 1990s. the island may allow for rats to enter the Many control methods were attempted, rodenticide free cliffsides once the aerial including warfarin delivered from bait stations. application is complete. As most cliff/shore The control of rats can be a strong selection dwelling rats have died, the subordinate rats may agent, increasing the frequency of rats that move off the top of the island down to the cannot be killed via the control method used. shoreline into preferred habitat, where they Where populations of rats have been previously would escape exposure to the rodenticide and exposed to poison, some rats demonstrate bait meet no resistance from territorial rats. These avoidance behavior and others may be individuals could form the founder population. biochemically “resistant” to the anticoagulant To overcome this potential, stations would be used (Greaves 1994). It is unknown if the left armed for over a year before any aerial population of rats on Anacapa Island contain broadcast activity. This could allow for individuals that would demonstrate bait shyness neophobic rats to get used to the stations over or are resistant to warfarin. Thus, it is time, enter, and consume the bait and die. recommended to use an active ingredient that Alternatively, if rats refuse to enter stations, they would be lethal to “warfarin-resistant” may continue their day to day activities and die individuals and is able to provide a lethal dose in naturally without exposure to the rodenticide. a “single-feeding” in case of bait shy Their offspring, if any, would emerge from their individuals. Second-generation anticoagulants dens with the armed stations present in their would kill warfarin-resistant rats and, if in territory and may readily enter the stations and sufficient concentration, would kill rats after a consume bait. Conversely, their offspring may single feeding, thus, dramatically increasing the have inherited the behavior of bait station probability of successful eradication.

CHAPTER FOUR - 51 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT

Timing Physical Impacts Rat eradication programs are most likely to be successful if they take place during the Introduction annual population cycle when no reproduction is This section will analyze the impacts from taking place and when rat numbers are both baiting and crews walking around the declining. This insures that new-born rats would island conducting research and monitoring on not emerge from the dens after all bait has been the project. The analysis is broken down by consumed, and that most rats would be food baiting technique within alternative - aerial or stressed and therefore more likely to consume bait station. Within each category, the direct bait. Based on the population fluctuations and and indirect impact to each sub-issue will be breeding season of black rats on Anacapa analyzed. Islands, October through January is the best period for eradication (Collins 1979, Erickson & Alternative 1: No Action Alternative Halvorson 1990). Each of the alternatives The physical impacts of this alternative would be initiated during the low point in the would be negligible. Physical impacts would be annual cycle. restricted to normal Park activities as well as Summary intermittent Navy and Coast Guard aerial activity around the island. This analysis has demonstrated that Under this alternative, no baiting would take strictly from an efficacy standpoint, Alternative place and therefore, risk of rodenticide exposure 2, the preferred and proposed action (the use of would be restricted to non-target species in an brodifacoum aerially and hand broadcast) would and around buildings where rat control with offer the highest probability of achieving rodenticides would take place. eradication and meeting the purpose and need. Rats would continue to be a major perturbation in the Anacapa ecosystem, continuing to have detrimental impacts on small Issue 2: Non-Target crevice nesting seabirds, the deer mouse, Impacts invertebrates, and plants. The rats would continue to prevent the Introduction smaller pelagic seabirds, such as Xantus’ Non-target species, are those species that murrelet and ashy-storm petrel, from nesting may be negatively affected from the actions of outside of the sea caves. Murrelets would the project, has been broken in to two continue to be restricted to nesting in areas components, the physical impacts and exposure inaccessible to rats, although abundant nesting to rodenticide residues. habitat is found elsewhere. Murrelets utilize only 0.4% of available habitat on Anacapa Physical disturbance may occur from baiting Island compared with 30% on rat-free Santa activities, and crews walking around the island. Barbara Island (G. McChesney, unp. data.). Rodenticide exposure, for the purpose of this Rats would continue to predate nesting seabirds analysis, can occur through direct bait and their eggs, further leading to declining consumption (primary exposure) and population levels of the Xantus’ murrelet. The secondarily (via carcasses containing rodenticide declining population may lead towards residues). protection under the Endangered Species Act.

CHAPTER FOUR - 52 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT

The endemic mouse on Anacapa Island associated with that will be covered in a separate would continue to be at risk of extirpation. Rats section below. The total treated area varies have been implicated in the 20 year extirpation between the alternatives; however, the flight of deer mice from East Anacapa Island, operations may have a net impact to some rediscovered in 1997. Rats had likely preyed species. To ensure even and adequate coverage and outcompeted the mice which resulted in of the island, a crew would circumnavigate the extirpation. The extirpation of mice from the island by boat spreading bait by hand in key islets could re-occur, and could have serious locations. implications for birds of prey which rely on the The project’s efforts in eradication and mice as their primary prey base. subsequent potential impacts to non-target The intertidal zone would continue to be an species and the environment would be important foraging area for rats. The monitored. Crews of varying sizes would invertebrates would continue to be impacted, regularly visit study sites and collect appropriate especially the lined shore crab. The terrestrial data. invertebrates would continue to be an important part of the rat diet. The population of terrestrial Sub-issue 1 – Marine Mammals mollusks on Anacapa Island, which are very Direct - Resting California Sea Lions and rare, would unlikely recover. Harbor Seals would likely be disturbed by the The flora of Anacapa Island would continue helicopter activity and boat traffic to hand to be detrimentally impacted. The rats would broadcast bait. It is likely that these species continue to be an important vector for dispersing would retreat from their resting areas to the seeds of iceplant, a highly invasive non-native ocean. The disturbance to this group is likely to species which “chokes out “ native species. The be short, restricted to three passes of the island oaks and cherry trees on West Island helicopter. The seals and sea lions would likely would continue to have low regeneration which return to the haulouts shortly after the could result in complete failure of regeneration disturbance. This type of activity is somewhat of the species. There is a possible severe common with functions performed by boat economic impact to the National Park Service traffic around the islands daily. with trying to constantly restore native habitat Monitoring activities by research crews due to rodent activities. would not take place in the vicinity of the haulouts and would not result in disturbance or Effects Common to Alternatives 2, 3, other effects. 4, 5, and 6: Aerial Broadcast Indirect - The seals and sea lions would not Under each of the alternatives, a helicopter be subject to any indirect effects as a result of would aerially spread a rodenticide from an disturbance. The disturbance would be of short underslung hopper. The helicopter would fly duration, and there would be plenty of alternate 25-50 m above ground at an airspeed of haul out areas around the islands individuals approximately 50 knots. Under each of the could retreat to. alternatives, bait would be aerially broadcast on the cliffsides and all of West Island would be Sub-issue 2 - Invertebrates treated. Alternatives 2, 4 and 6 propose broadcast of the top of Middle and East Islands No impact to this group is expected from as well. Alternatives 3 and 5 would use bait helicopter or any other physical activities. stations on top of the island and the impact

CHAPTER FOUR - 53 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT

Monitoring on study plots and traversing crews walking around the island, causing along trails would not have a significant impact flushing from nesting areas. Few, if any, pelagic on this group of animals. seabirds would be expected to nest on top of the island due to predation pressure from rats. Sub-issue 3 – Fishes Indirect - There would likely be no indirect Direct - No impact is anticipated other than effects from short duration disturbance. If minor disturbance from intermittent inflatable disturbance was of long duration or chronic, boat traffic. The extent of boat traffic at any one there could be nest abandonment or point along the shoreline would be very susceptibility to predation. However, intermittent. This would result in only minor disturbance is expected to be of short duration, disturbance. The fish would return to normal thus likely having no indirect effect. activities soon after departure. Boat traffic Roosting Seabirds around the Anacapa shoreline is common and frequent. The additional inflatable boat traffic Direct - The effect on the seabirds would be would not be expected to increase disturbance in the form of disturbance. Seabirds that roost outside regular Park traffic. on the island would likely be flushed as the helicopter approaches. The main species of Indirect - No indirect impacts would be concern is the endangered brown pelican. Boat anticipated. activity along the shoreline to dispense bait would likely flush roosting seabirds. Sub-Issue 4 – Herpetofauna Disturbance to roosting pelicans by boat traffic Direct - The impacts to the herpetofauna around the island has been observed on Anacapa would be disturbance associated with foot traffic Island (B. Keitt, pers. comm.). Most pelicans from researchers. The salamander would be return to the same roosting location 10-30 dormant or deep within thick vegetation during minutes after disturbance (B. Keitt, pers. the proposed application period and would be at comm.), or would likely roost elsewhere. Coast low risk of disturbance. There would likely be Guard and Navy helicopter activities occur disturbance to the Side-blotched and Alligator periodically on and around East Anacapa Island Lizards which would be active on most regions with no detrimental impact to roosting Brown of the island at the time of baiting. The visiting Pelicans (F. Gress, pers. comm.) public walking along trails regularly disturb Monitoring activities of research crews may sunning Side-blotched Lizards, that quickly disturb roosting seabirds. However, study return to their spots after the disturbance has protocols have been designed such that only passed. minimal activity would take place around known Indirect - There would be no indirect roosting areas, and therefore, disturbance would impacts to this group. be minimal. Monitoring would occur during the breeding season but no monitoring would take Sub-Issue 5 – Seabirds place in the vicinity of the pelican colony on West Island. Monitoring would be conducted Pelagic Seabirds around breeding Western Gulls. Disturbance is Direct - There would be no impact to the the only direct effect expected; however, it pelagic seabirds during the baiting operation, would be of minor significance as gulls are these species would be foraging offshore. routinely disturbed by visitors on East Island and During the breeding season, these species would nest successfully. be susceptible to disturbance from research

CHAPTER FOUR - 54 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT

Indirect Effects - Disturbance to roosting and would be in their burrows during the aerial seabirds would have a low probability of indirect application of the bait in the daylight hours. effect. The disturbance from both aerial and Minor disturbance to mice may occur while hand-baiting would be short and there is plenty monitoring nocturnal species. However, this of alternative roosting areas available on the disturbance would be restricted to trail and island. building areas and would not have any long term consequences. Repeated or chronic disturbance would not be expected under any alternative. Indirect - No indirect effects are anticipated from helicopter activity or monitoring activities. Sub – Issue 6 - Landbirds Sub - Issue 8 - Flora Direct - The immediate effects on avian species of helicopter use above Anacapa Island Direct – The Island Malacothrix is an annual and the bait drop would involve disturbance of species that would not be growing or in bloom roosting species. This immediate effect would during the application window. It would not be be minimal as the normal response of the land susceptible to the rodenticide and would not birds would be to take cover in surrounding absorb any residues. It may be susceptible to vegetation. The stress associated with this trampling damage during the monitoring period activity is unlikely to be greater than that caused after the bait has been applied and the growing by certain visitor activities on the island or by season has started. helicopter use associated with other Park Indirect - Soil compaction from repeated operations made in the past or future. The foot traffic over the growing areas of the Island helicopter would likely cause birds of prey to Malacothrix could result in increase water flush from roosting areas. Flushing of species is runoff, leading to increased erosion during the a common occurrence with visitors to East rainy season, resulting in degraded habitat Island, and individuals usually return to their impairing productivity of this species. roost after 10 to 30 minutes. These effects are unlikely to exceed those incurred during normal Mitigation – To mitigate against any damage to Park operations. this species, NPS botanists will identify and mark known locations of the malacothrix. Falling bait pellets would unlikely have a Personnel working on Middle Anacapa Island significant effect. The approaching helicopter will be advised of the presence of the plant and would likely cause landbirds to either leave the will be briefed thoroughly on techniques to area or move into areas that offer protection minimize trampling of the area surrounding such as thick vegetation, which in turn would malacothrix locations. offer protection from falling pellets. Indirect - During the baiting operation, Effects Common To Alternatives 3 indirect effects would not be expected and are and 5: Bait Stations insignificant. Nesting landbirds could be The use of bait stations on top of East and disturbed during research and monitoring. No Middle Islands is common to both alternatives 3 chronic activity would be expected. and 5. In these alternatives, bait stations would be placed at equal distances on a grid pattern Sub - Issue 7 - Terrestrial Mammals around the island. The stations would be Direct - No impact to the deer mouse is checked daily until the activity (bait removal) expected. The deer mouse is primarily nocturnal ceases or declines precipitously. Then the

CHAPTER FOUR - 55 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT stations would be checked monthly throughout The impact of the disturbance would be flushing the year until the following year when they from territories, however, this is believed not to would be re-armed and checked during the aerial have a great impact because gulls are routinely broadcast operations. disturbed by visitors to East Anacapa Island with no detrimental impact. Sub-issue 1 – Marine Mammals Roosting Brown Pelicans would be flushed No direct and indirect effects because bait from roosting locations. The use of bait stations stations are on top of island, well away from would require frequent checks and would result flushing distances to the haul-outs. in frequent disturbances to pelicans. Indirect Effects – Daily checks of bait Sub-issue 2 - Invertebrates stations would occur over the winter into the No impact to this group is expected from early spring when nesting by Western Gulls has placing and checking stations. been initiated. Regular station checks could potentially lead to nest abandonment or for Sub-issue 3 – Fishes opportunistic predation by other species as a result of disturbance. No direct or indirect impacts, bait stations are in the terrestrial environment. The chronic disturbance to roosting pelicans could result in roost abandonment. Roost Sub-Issue 4 – Herpetofauna abandonment would be insignificant as there are alternative roosting areas around Anacapa Island Direct - There would likely be disturbance such as on West Island which would not be to those individuals that are along the trail disturbed from bait station use. network used to gain access to bait stations. Indirect - There would be no indirect Sub – Issue 6 - Landbirds impacts to this group. Direct - Repeated disturbance to birds nesting or establishing nesting territories may Sub-Issue 5 – Seabirds cause nest or territory abandonment. However, Pelagic Seabirds it is believed that there would be no significant disturbance to any of the species to cause nest or Direct - There would be no impact to the territory abandonment. During the breeding pelagic seabirds, these species would be season, the checks of the bait stations would be foraging offshore during the initial baiting intermittent. period. The monthly checks of the bait stations would likely overlap with the breeding season. Indirect - There would be no indirect effects If the pelagic birds are nesting on top of the expected because of the low direct impacts. island, crews moving between stations may disturb birds, and cause them to flush. Sub - Issue 7 - Terrestrial Mammals Indirect - The birds would likely return to Direct - No impacts to the deer mouse is their nests once the disturbance is passed. expected. This species is nocturnal, all checks would be conducted during daylight hours. The Roosting Seabirds mice would be in their burrows. Direct - There would be minor disturbance Indirect - No indirect effects are anticipated to nesting Western Gulls on Middle and East from repeated checking of bait stations. Anacapa Island during the bait station checks.

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Sub - Issue 8 - Flora toxicological impacts presented by the respective sub-issue. Direct – The Island Malacothrix is an annual species that would not be growing or in bloom during the application window. It may be Biochemistry susceptible to trampling damage during the The proposed action and alternatives have monitoring period after the bait has been applied outlined the use of second generation and first and the growing season has started. generation anticoagulant rodenticides. The Indirect - Soil compaction from repeated anticoagulants act by blocking the vitamin K foot traffic over the growing areas of the Island oxidation-reduction cycle in the liver Malacothrix could result in increase water microsomes, preventing the production of runoff, leading to increased erosion during the activated clotting factors (Thijssen and Baars rainy season, resulting in degraded habitat 1989). Death results not from the active impairing productivity of this species. ingredient itself, but the uncontrolled bleeding after tissue damage (Brown et al. 1988). For a Mitigation non-target species to be at risk of hemorrhaging, it would have to consume a minimum amount of To mitigate against any damage to this species, the anticoagulant. Before any symptoms of NPS botanists will identify and mark known anticoagulant poisoning are measured, a locations of the malacothrix. Personnel working threshold level (concentration in the liver) must on Middle Anacapa Island will be advised of the be reached. Symptoms include, but are not presence of the plant and will be briefed limited to, increased time to clotting thoroughly on techniques to minimize trampling (prothrombin times (PT) ) leading to of the area surrounding malacothrix locations. hemorrhaging. A minimum amount of active ingredient needs to be consumed, absorbed and Toxicological Impacts bound in the liver, and significantly decrease the Introduction production of active clotting factors resulting in an increased prothrombin time, before an The main toxicological issue associated individual is considered at risk of hemorrhaging. with the Anacapa Island Restoration Project is Thus, organisms are able to tolerate sub-lethal the potential impact to other wildlife species levels of anticoagulants without displaying any from rodenticide exposure. For the purpose of symptoms of poisoning. Above that threshold, this analysis, incidental wildlife species the risk of hemorrhaging is high and measurable potentially at risk of exposure to the rodenticide (eg. increased clotting time). Once at risk of are defined as non-target species. To fully and hemorrhaging, activity is required to induce effectively present the potential toxicological hemorrhaging and subsequently mortality impacts to non-target species, this section is (spontaneous hemorrhaging is possible, i.e., organized to give background into the although low activity, hemorrhaging still biochemistry of the rodenticides, followed by a occurs). Without the presence of enough relative comparison of toxicological impacts by anticoagulant the induction of hemorrhaging, alternative. Within the relative comparison of and subsequently mortality would not occur. toxicological impacts section, the potential Thus, all animals are able to tolerate some level direct (primary) and indirect (secondary) of anticoagulant rodenticide exposure without exposure to the rodenticides is analyzed by risk of hemorrhaging. The level of risk is alternative. In the last section, the analysis determined by the toxicity of the chemical and would focus on the direct and indirect that individual’s exposure. This analysis will

CHAPTER FOUR - 57 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT focus on the potential primary and secondary section will evaluate the variables (toxicology, poisoning risks to the wildlife resources. bait composition, behavior of species and local factors) that contribute to risks of non-target The relative risk of non-target species species exposure to the rodenticide. This section poisoning on Anacapa Island is determined by a will follow with a breakdown of toxicological number of variables including the toxicity and impacts by sub-issue. Where possible, an acute exposure to the rodenticide. Exposure is risk of exposure to the rodenticides was evaluated determined by the availability of the active for each sub-issue and rodenticide. ingredient in both space and time. Primary poisoning occurs when species feed directly on the bait. Secondary poisoning occurs when Alternative 1 – No Action animals feed on primarily poisoned organisms Under this alternative, there would be no application of rodenticides, therefore there would that have rodenticide residues in their tissue. be no toxicological impacts. The potential of tertiary and quaternary poisoning exists (eg. birds or mice that consume Features Common to Alternatives 2, carrion insects, containing residue of active 3, 4, 5 and 6 ingredient after digesting a primarily poisoned mouse, would be tertiarily poisoned) but has not Primary Exposure been thoroughly documented. For the purpose of this analysis, the risks of primary and Toxicology secondary exposure to the rodenticides will be The rodenticides are vertebrate toxicants. investigated as per Record and Marsh (1988). All the rodenticides presented in the alternatives Primary exposure to the rodenticides is are toxic to all the vertebrates, provided they are determined in part by: exposed to the rodenticide in sufficient
Toxicological properties of the quantities. The toxicity to both the target and rodenticide non-target species will determine the relative primary and secondary exposure risks. The risks
Bait composition and delivery into the of exposure to the anticoagulants is determined ecosystem by how well the non-target species is able to
Non-target species behavior and metabolize and excrete the compound, which is foraging strategy
Local environmental factors; ______Secondary exposure to the rodenticides is Table 8. Primary exposure index for each driven by any one species primary exposure to alternative the rodenticides. In addition to the above factors, the behavior and location of death of the Alternative target species will influence secondary 1 2 3 4 5 6 poisoning. Ranking Relative Comparison of (Low to 142653 Toxicological Impacts by Highest) Alternative This section will compare the potential toxicological impacts by alternative. Under the ______features common to alternatives 2 – 6, each

CHAPTER FOUR - 58 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT a function of its acute toxicity. Further analysis the relative primary exposure risks among the will be presented by sub-issue (see below). alternatives. The risk index takes into account bait concealment ( C - scored 1 to 3, high to Bait Composition and Delivery into the low), quantity of bait placed (Q), and numbers Ecosystem of animals present (N). Using these factors, the equation: The bait composition and method of delivery into the ecosystem would influence how and if species are primarily exposed. The 3 (C x Q x N) bait formulation (inert products, size of pellet) and method of dispersal into the Anacapa ecosystem would determine the relative primary can be utilized to evaluate the relative primary exposure risks. For example, granivorous exposure risks. For the purpose of this analysis, species would be more interested in rodent bait the primary poisoning risk index was calculated composed of a compressed grain pellet vs a high for each alternative using: 3 for low concealment protein “meat” bait. The insectivorous, or (aerial) 1 for high concealment (bait stations), carnivorous, species may “avoid” a bait that is bait quantity per hectare applied, and assumes composed of compressed grain. Similarly, size that only one non-target animal is present. For of the bait itself plays an important role in the alternatives with both bait stations and aerial determining if a species may be exposed to the application (alternatives 3 and 5), and alternative bait itself. The smaller species may not be 6 (two different rodenticides), the risk index was physically able to consume the bait due to its calculated for each application technique and/or size, in contrast, the larger species may not be rodenticide, and averaged. The scores were interested in small pelleted bait if available. ranked from lowest primary exposure risk to Thus, some species are “ protected” from highest for comparative purposes (Table 8). feeding on the bait because of its size. Under all alternatives, the bait would consist of a The risk of primary exposure is highest compressed grain pellet and could be attractive under alternative 4 and lowest under alternative to most granivorous/omnivorous species capable 3. The highest risks of primary exposure occurs of ingesting that size pellet. Alternatives 3 and 5 when the rodenticide is broadcast, and lowest would see the use of a block that is larger than when presented in bait stations. Presenting bait the pellets and would limit further species from in tamper proof bait stations limits access of the consuming the bait. bait to rats and species smaller than rats (such as deer mice and invertebrates). The use of bait How bait is delivered into the Anacapa stations would lower the scale of rodenticide Island ecosystem would determine the scale of exposure, but it would not reduce the risk of potential rodenticide exposure. The alternatives exposure to zero. Although the relative outline the use of aerial/hand broadcast and bait exposure risks between the alternatives vary, it stations for delivery of the rodenticide onto would be impossible to preclude the possibility Anacapa Island. The aerial broadcast of the of exposure. The Risk Index is useful as a tool rodenticides has been demonstrated to represent to evaluate the primary exposure risks, alone it a risk of non-target exposures to the rodenticides does not provide an adequate measure of the (Edward et al. 1988). relative risks. A risk index (Edward et al. 1988) to provide a measure of primary exposure risk when evaluating rodenticides was utilized to qualify

CHAPTER FOUR - 59 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT

Behavior of Non-Target Species Consequence of Primary Exposure The behavior of the non-target species and Many variables must be taken into their associated foraging strategy is an important consideration when evaluating the primary determinant in risk evaluation. The hazard of exposure to the rodenticides. The consequence the rodenticide is a function of toxicity and of primary exposure to the rodenticides may be exposure (Record and Marsh 1988). Although an anticoagulated state leading to hemorrhaging the toxicity of a rodenticide is high in some and mortality. To characterize the consequence cases, the non-target species needs to be exposed of primary exposure to the rodenticides, the to the rodenticide to be considered at risk. toxicology data and exposure data (based on Exposure may not occur if the species is not allometric equations (EPA 1993) were used to present during the baiting operation, or does not model the number of LD50s individuals would be feed on the bait or a primarily exposed exposed to if they fed exclusively on the organism, thus avoiding both primary and/or rodenticide bait for one day. secondary exposure. Risk quotients (RQs) were calculated by dividing the exposure estimates with ecotoxicity Local Environmental Factors values: Exposure to the rodenticide, primary or RQ= Exposure/Toxicity secondary, is determined by the availability of the rodenticide in space and time. The For the purpose of this discussion, an conditions of the local environment will estimate of the primary poisoning risk to the influence the availability of the rodenticide by birds and mice were estimated by calculating the enhancing the degradation of any residual bait number of LD50s/day a bird would likely be (or not). The application rate was determined by exposed to if it fed exclusively on the bait, using consumption rates of rats and mice over a 4 day the following formula: period. The majority of the bait will be LD50s/day = mg rodenticide consumed by rats and mice, leaving few pellets consumed/day ÷ [LD50 x weight (kg)] in the environment. The combination of rainfall, fog and invertebrates will degrade the remaining Where mg rodenticide consumed/day = amount bait pellets. The application will take place prior of bait eaten x % active ingredient in the bait. to the rainy season such that any remaining bait Allometric equations were used to estimate will absorb moisture and break up. The amount of bait consumed daily (EPA 1993). If presence of moisture would encourage mold and no LD50 data existed for that species, the LD50 microbial degradation of the rodenticide to its from the species in closest taxonomic base components of water and carbon dioxide. relationship was used consistently for each Bait will not likely be present on Anacapa by the rodenticide (eg. Laboratory rat LD50 data used end of the rainy season. for brodifacoum, bromadiolone and Diphacinone). However, caution must be used Similarly, the timing of the operation will when interpreting this data because phylogenetic influence the scale of potential primary and relationships cannot be used to predict secondary exposure risks. For example, sensitivity to the rodenticides (Hill 1994; migratory species may not be present during the Mineau, 1991). To more precisely present the aerial application window and therefore would relative risks of poisoning to non-target bird not be exposed. Conversely, the use of bait species, the LD50 data was statistically stations over time would potentially put those “corrected” following Mineau et al. (2000). species at higher risk.

CHAPTER FOUR - 60 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT

Table 9. Properties of the rodenticides affecting their potential for secondary poisoning.

Active Ingredient (Rodenticide) Brodifacoum a Bromadiolone Diphacinone Alternative 2, 3 and 6 Alternative 4, 5 Alternative 6

Sensitivity to Low Low High Metabolism

Tissue Retention High High Low

Biological Half-Life Long Long Short 150-200 days (RED 318 days (RED 15-20 days (WHO Estimated time 1998) 1998). 1995)

For regulatory purposes, the EPA evaluates production of active clotting factors. The first the Risk Quotients and compares them to the and second generation anticoagulants both bind Office of Pesticide Programs Level of Concerns at this site and the difference between the (LOCs). LOCs are evaluated as: Acute High chemicals is their binding affinity at this site. Risk (LOC >0.5), Acute Restricted Use (LOC Brodifacoum has a greater affinity than >0.2), and Acute Endangered Species (LOC bromadiolone and both have a much higher >0.1). It is on this evaluation that the EPA affinity than diphacinone. Diagrammatically: restricts certain pesticides from certain use Brodifacoum>Bromadiolone>>>>Diphacinone. patterns or availability to public or professional pest control uses. For the purposes of this This binding affinity may be the reason that discussion, any rodenticide with a RQ >0.5 is the second generation anticoagulants are presumed to put that group of species at risk of significantly more toxic. In general, the stronger lethal poisoning. the binding affinity, the higher the toxicity. The binding affinity is also related to the ability of Secondary Exposure the organism to metabolize and excrete the compound. The stronger the binding affinity, Toxicology the greater the resistance to metabolism once Brodifacoum and bromadiolone are second bound. Thus, the ability to metabolize generation anticoagulants while diphacinone is a Diphacinone>>>>Bromadiolone>Brodifacoum. first generation anticoagulant. In general, the The implications of the sensitivity of difference between the two categories is the metabolism is that relative risks of secondary toxicity and the sensitivity to metabolism which poisoning vary between the rodenticides. For is reflective in the toxicity. Upon ingestion and example, mortality was found in barn owls fed absorption, the anticoagulants bind to a brodifacoum (5/6) and bromadiolone (1/6) dosed “warfarin binding” protein in the liver rats but no mortality was detected in barn owls microsomes where they act to prevent the (0/2) fed diphacinone dosed rats (Mendenhall

CHAPTER FOUR - 61 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT

______

Table 10. Potential for accumulation of the rodenticides for the different sub-issues.

Active Ingredient (Rodenticide) Brodifacoum Bromadiolone Diphacinone Sub-Issue Alternative 2, 3 and 6 Alternative 4, 5 Alternative 6

Marine Mammals High High Low Invertebrates Low Low Low Fishesa High High Low Herpetofaunaa High High Low Birds High High Low Mammals High High Low

a No literature data available, however, estimated to follow similar pattern as for mammals and birds.

and Pank 1980). This is suggestive also of the potentially negating the secondary poisoning potential secondary poisoning impact of single “protection”. In comparison, brodifacoum and versus multiple exposures to the rodenticides. bromadiolone are “single-feeding” Brodifacoum would have a higher potential for anticoagulants and are capable of illiciting a secondary exposure impact after a single toxic response to the target species after a single exposure, while diphacinone may require feed. Table 9 summarizes the factors affecting multiple exposures to illicit the toxic effect. the secondary toxicity of the rodenticides in the With brodifacoum and bromadiolone, because alternatives. death is delayed between 3-10 days (for rodents The low sensitivity to metabolism, high and birds), they would continue to feed on the retention of residues in tissue and long bait long after a lethal dose has been ingested, biological half life of the second generation allowing for accumulation of the rodenticide in anticoagulants present a secondary exposure the carcass and liver. With diphacinone, the hazard to species preying on primarily exposed high rate of excretion and metabolism does not organisms. Godfrey (1985) demonstrated that allow for significant levels of residues to most of brodifacoum administered to rats that accumulate in the carcass, although residues survived the dosing was retained up to 10 days would be present and would present a secondary after administration. Sheep dosed with poisoning hazard. Diphacinone bait requires rats brodifacoum at 2 mg/kg showed liver to feed on the bait over a period of up to 7days concentrations of 2 mg/kg four months later to illicit the toxic response. During that period, (Rammell et al. 1984). However, the biological the rats are rapidly metabolizing the compound. half life must be qualified. For a sub-lethally Because ingestion is believed to be faster than exposed organism, the decline of the metabolism, rats will eventually reach the anticoagulants have been demonstrated to be bi- threshold and a toxic response is measurable,

CHAPTER FOUR - 62 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT phasic – a rapid phase (in which the majority of ______toxicant is excreted) followed by a very slow phase (lower toxicant loading in the tissue) Table 11. The relative secondary poisoning potential (RED 1998). Diphacinone, with its high over time. sensitivity to metabolism, low tissue retention and short biological half-life, would not Alternative accumulate in predators as brodifacoum or 1 2 3 4 5 6 bromadiolone. In other words, diphacinone offers greater secondary exposure protection Temporal NA Short Long Short Long Short than do either bromadiolone and brodifacoum. Thus, the second generation anticoagulants present a short term and long term non-target secondary poisoning potential and have the ______potential to present a poisoning hazard to non- target species especially through cumulative Thus, the concentration of the active ingredient exposures. has a secondary poisoning consequence. The potential for accumulation and retention The delivery of the bait onto Anacapa Island of the rodenticides for each of the species in the would occur by one of two methods: aerial sub-issues is outlined in Table 10. The broadcast and/or in combination with bait invertebrates are expected to accumulate stations. Eradication of rats using the bait minimal if any residue (Pain et al. 2000, Howald station approach would be a saturation baiting 1997). The residues available in the strategy where an “unlimited” supply of bait is invertebrates are believed to be restricted to the offered until activity ceases or slows, then the presence of the chemical in the gut of the frequency of checking and re-arming of bait organism. Thus, digestion time of the bait is the stations is reduced. This allows for the critical period as a secondary exposure hazard. possibility of “overkill” where rats are able to consume as much bait as they desire. Recently, Howald et al. (2000) evaluated the brodifacoum residue levels within Norway rat carcasses after Composition of Bait and how it is Applied an eradication effort from a large seabird colony The above analysis demonstrates that the using bait stations. The residue concentration anticoagulant rodenticides represent a potential levels within the carcass were partitioned secondary poisoning risk to non-target species. equally in the liver (site of activity) and gastro- However, the levels of residues found within intestinal tract (primarily from unassimilated carcasses can be mitigated through alteration of bait). Unassimilated bait found in the gut of rats concentration of active ingredient and its found dead above ground, represented 30-50% application technique. From a secondary of the total brodifacoum residue load, and poisoning perspective, by decreasing the reflected the saturation baiting strategy concentration of active ingredient applied, the employed. The aerial application of the residue body burden found in target species rodenticide may potentially limit the carcasses is lessened. For example, Kaukeinen consumption of bait by rats with less chance of (1982), fed voles 10 ppm and 50 ppm overkill and thus limit the residue loading in any brodifacoum bait. The brodifacoum one carcass (Record and Marsh 1988). The concentrations were 4-10 fold more in those levels of the rodenticides that may be found in voles that fed on the 50 ppm brodifacoum bait.

CHAPTER FOUR - 63 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT rats and mice cannot be readily predicted for up to 50% die in the open (Cox and Smith 1992; each of the alternatives. Gemmeke 1990). Thus, anticoagulant poisoned rats and mice would be available to both diurnal On Anacapa, rats may consume all the bait and nocturnal predators and scavengers. On before mice have access to it, versus in a bait Anacapa, islet wide treatment would yield station where bait would be available in stations numerous dying rats and mice displaying erratic for mice long after rats have been eradicated. behavior and likely would be a significant prey The presence of bait in stations in the long term base because of the ease of catching them. would present a long term secondary poisoning Optimal foraging theory indicates that an potential, possibly outweighing the short term individual would use an area for foraging that secondary poisoning potential (Table 11). In would provide the greatest yield. Similarly, a other words, the window of secondary poisoning number of rats and mice would die above from toxic rats and mice would be shorter with a ground and available for diurnal scavengers. single aerial broadcast, and longer with bait stations. For a successful eradication using bait stations, stations must be armed for well over a Local Environmental Factors year, perhaps two (Kaiser et al. 1997, D. Veitch, The above analysis has demonstrated a risk pers. comm., R. Taylor, pers.comm.). Once rats of secondary exposure to the rodenticides, have been eradicated, and mice begin to use however, it does not consider the local stations and die, other mice would fill those conditions at the time of the application window. territories, enter the stations, and consume bait. The late fall period corresponds to the late dry On Anacapa, the secondary poisoning potential season, which is a time when conditions for from bait station delivery is determined by the most species can be difficult. Both the rat and length of time stations are left armed. mouse population would be at the lowest point in their annual cycle which would limit the Behavior of Target Species on Intoxication numbers of poisoned rats and mice available to and at Death avian hunters and scavengers on the island. The onset of the rainy season soon after the bait has The risk of secondary poisoning to been applied will degrade the bait thus limiting predators/scavengers of rats and mice is limited the potential primary and secondary exposure. by the availability of these prey in space and time. For the aerial predators on Anacapa, their search image is for live prey and thus risk of Toxicological Impacts by Sub-Issue poisoning is during the latent period (after rats The analysis is broken down into the sub- and mice have consumed the bait, but have not issues, and within each sub-issue, broken down yet died) (estimated at 2 weeks). Anticoagulated into primary and secondary exposure. The rats demonstrate altered behavior which consequence of rodenticide exposure for each potentially makes them more susceptible to sub-issue, where possible, was calculated and is predation and scavenging. For example, representative of a “worst-case” scenario. Norway rats exposed to a lethal dose of Where the Level of Concerns (LOC) exceed 0.5, brodifacoum spent significantly more time in suggested mitigation measures are presented. open areas, sitting motionless or staggering about (Cox and Smith 1992, Gemmeke 1990). Sub-Issue 1: Marine Mammals Most Norway rats radio-tagged in the field Primary Exposure (Direct) before baiting died underground in their burrows (87 – 100%) (Howald 1997, Taylor 1993). The risk of primary exposure to the However, laboratory studies have demonstrated pinnipeds is the same across all alternatives

CHAPTER FOUR - 64 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT

because of the aerial broadcast of the ______rodenticides onto the cliffsides. Alternative 6 is a higher risk for exposure because of the Table 12. The 48 hour LC50/EC50 (ppm) for freshwater multiple treatments with both diphacinone and invertebrates (from RED 1998). brodifacoum. Active Ingredient Toxicology - No data exists on the toxicity Species of the rodenticides to marine mammals. If Brodifacoum Bromadiolone Diphacinone consumed in sufficient quantities, the rodenticides are likely toxic to the seals and sea, Water Flea 0.98 0.24-2 1.8 impairing hemostasis as in the other vertebrates. (Daphnia Bait Composition and Delivery - The aerial magna) application of the rodenticides onto the cliffsides ______and shoreline of the islands present a risk that bait may drift into the ocean or land on the other animal species, however, it is unknown if beach areas where marine mammals feed and they would be interested in bait pellets falling haul out. Therefore, this group is at risk of through the water column if they were to drift primary exposure if they were to be attracted to into the marine environment. The bait is a grain the bait. based pellet, that would unlikely be attractive to Behavior and Foraging Strategy - The the seals and sea lions. The primary exposure pinnipeds feed exclusively in the marine of the seals and sea lions to bait while hauled out environment, and only haul out to rest and on shore is believed to be very low. The seals breed. and sea lions would be utilizing the haul-outs around Anacapa Island during the proposed The diet of the California Sea Lions and period of baiting. Harbor Seals is primarily composed of fish and Rodenticide Exposure Risk - The sea lions ______and seals are at low risk of primary exposure Figure 11. Risk Quotients for Harbor Seals because of their foraging strategy. Calculating their risk quotient assuming a “worst case scenario” where they would feed exclusively on 1.0000 the pellets revealed that their exposure falls 0.9000 below the EPA LOC of 0.5 for all rodenticides 0.8000

Theoretical Minimum (Figure 11). 0.7000 Theoretical Maximum EPA LOC (0.5) 0.6000

0.5000 RQ Secondary Exposure (Indirect)

0.4000 The diet of the California Sea Lions and 0.3000

0.2000 Harbor Seals is primarily composed of fish and 0.13 0.13 0.12 0.12 0.1000 other animal species. Sea lions and seals are 0.03 0.03 0.0000 abundant around Anacapa Island during the 25 ppm Brodifacoum 50 ppm Bromadialone 50 ppm Diphacinone Rodenticide proposed application window. If fish, predominantly sheephead, were to be primarily exposed to the rodenticide, the seals and/or sea lions may feed on the fish and be secondarily exposed to the rodenticide. This scenario is

CHAPTER FOUR - 65 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT believed to be an extremely low probability consuming any bait pellets. There would likely because of the low probability of fish primary be no direct impacts to individual species as exposure – see above. their blood clotting mechanisms are comparable to the terrestrial species (Shirer 1992). Sub-Issue 2 – Invertebrates The consequence of rodenticide ingestion appears to be insignificant to the invertebrates. Primary Exposure (Direct) However, the consumption of the bait by Toxicology - Limited data exists on the invertebrates may have significant consequences acute toxicity of the rodenticides to the for species that prey on those species, potentially invertebrates. The EPA released data outlining moving the rodenticide into the ecosystem. the acute toxicity of the rodenticides to the water No RQs were calculated because of lack of flea, a freshwater invertebrate (Table 12). No acute toxicity data and the apparent low other invertebrate toxicology data is available. susceptibility to the anticoagulant rodenticides. The anticoagulant rodenticides are not known to affect the terrestrial and intertidal Secondary Exposure (Indirect) invertebrates because of their different blood The invertebrates would play a significant clotting systems (Shirer 1992). Extensive field role in the removal of carcasses containing and lab trials have shown that beetles (Morgan residues of the rodenticides, thus would be et al. 1996; Eason and Spurr 1995; Stejskal et al. secondarily exposed. The invertebrates would 1994; Tershy et al. 1992), cockroaches ingest the rodenticide, however, they would not (Godfrey 1985), wetas (Morgan et al. 1996), carry significant levels of residues outside the land crabs (Pain et al. 2000; D. Veitch pers. resident time in the gut of the organism (Pain et comm.), snails, slugs, orthopterans, millipedes al. 2000; Morgan et al. 1996). They would (Howald 1997), and ants (Godfrey 1985; Tershy present a risk of movement of the rodenticide unpubl. data) are attracted to rodent baits and into the ecosystem. can survive on a diet of 20-50 ppm brodifacoum. Bait Composition, Delivery and Behavior - Sub-Issue 3 – Fishes This sub-issue combines both the marine and Primary Exposure (Direct) terrestrial invertebrates. The terrestrial invertebrates would play a significant role in the Toxicology - No data is available on the removal of residual bait that is not consumed by toxicity of the rodenticides to marine fishes, rats and mice. A wide range of invertebrate however, data is available for freshwater species species would consume bait and may transport (Table 13). the rodenticide into the ecosystem (see Bait Composition, Delivery and Behavior - Secondary Poisoning). Limited studies on The drift of bait pellets into the marine Anacapa Island in 1999 showed that sowbugs environment from aerial broadcast is possible. are attracted to placebo bait (ICEG 2000). The The fish in the nearshore waters off of Anacapa invertebrates on Anacapa Island would play a Island are at risk of primary exposure through significant role in removal of residual bait that is consumption of bait pellets that may fall through not consumed by rats and mice. the water column. A small study was initiated in There is a risk that some bait may enter into 1999 to identify those fish species that may the intertidal zone and ocean around the consume bait (Table 14; ICEG 2000). Placebo Anacapa Island. If bait were to enter, the marine baits were hand broadcast in small areas, the fauna would likely be a significant factor in species present tallied along with their reaction

CHAPTER FOUR - 66 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT

______rodenticides, are not water soluble and would not readily stay in the water column, Table 13. The 96 hour LC50 (ppm) for freshwater fishes (from RED 1998). rather, begin to bind to available organic matter – such as marine animals and in the Active Ingredient benthic layer. Therefore, the probability of a high enough concentration of rodenticide Species Brodifacoum Bromadiolone Diphacinone to enter into the sea and be of high enough concentration to be absorbed across the Rainbow 0.015 0.24 2.6 Trout gills or skin of fish is low.

Bluegill 0.025 3.0 7.5 Secondary Exposure (Indirect) Sunfish Predatory fish may consume any primary exposed fish and/or other prey and ______are secondarily exposed to the rodenticide. However, this event is not likely to be to the bait pellets. The majority of the pellets extensive and would not likely adversely affect that were falling through the water column any local populations. illicited no response from marine fishes (62%). However, baits falling through the water column Sub-Issue 4 – Herpetofauna illicited an “inspection” response 20% of the time (inspection defined as approaching or Primary Exposure (Direct) following the pellet and/or “kissing” the pellet). Toxicology - No LD50 data exists for the Only sheephead was noted to actually take in herpetofauna, however, studies have and break up the pellet, but did not apparently demonstrated equivocal results. In New consume the bait. Based on these results, Zealand, skinks found dead after an application sheephead is the only species to be considered at of brodifacoum, tested positive for brodifacoum primary exposure risk if bait enters the marine and showed symptoms of anticoagulant environment. However, it is recognized that poisoning (see Eason 1995). This is in contrast other species, or larger individuals of the species to Tershy (pers. comm.) in which lizards were could be interested in bait pellets. Fish may also force fed 50 ppm brodifacoum bait. After two be at risk of exposure through the absorption of weeks, the lizards showed no symptoms of rodenticide residue across their gills if a high poisoning. No lab data is available to evaluate enough concentration is found within the water potential primary exposure. column. All the rodenticides in the alternatives Bait Composition, Delivery and Behavior - are slightly to highly lipophilic and would The three species of herps on Anacapa Island are therefore not be found in significant primarily insectivorous and are at a low risk of concentration in the water column. Any bait primary exposure to the rodenticide. However, falling into the ocean would rapidly absorb during an eradication campaign in New Zealand, moisture and begin to breakdown. Studies with Telfair’s Skinks (Leiolopisma telfairii) placebo baits has shown that a compressed pellet reportedly consumed rain softened bait and lasts up to a “few hours” in calm conditions on succumbed to brodifacoum (Merton 1987 in the ocean floor (B. Keitt, pers.comm.). The Eason and Spurr 1995). The most significant incessant wave action and persistent swells on pathway for rodenticide exposure is likely Anacapa Island would expedite the degradation secondarily via their invertebrate prey base. process. On breakup of the bait pellets, the

CHAPTER FOUR - 67 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT

Table 14. Attraction of marine fishes to placebo baits, Anacapa Island, Spring 2000

Event Inspected Touched Chewed Consumed Bait Bait Bait Bait Common Name a Species Name No action Grand Total b

22% 0% 0% 0% 0% 22% Blacksmith Chromis (11) (391) punctipinnis

Hypsypops 6% 6% 6% 0% 0% 18% Garibaldi rubicundus (9) (19) Paralabrax 6% 2% 2% 0% 0% 10% Kelp bass clathratus (5) (11) Girella 16% 4% 4% 0% 0% 24% Opaleye nigricans (12) (100) Oxyjulis 2% 2% 2% 0% 0% 6% Senorita californica (3) (7) Pimelometopon 6% 0% 2% 2% 0% 10% Sheephead pulchrum (5) (7) Unidentified 2% 2% 2% 0% 0% 6% Unidentified (3) (14) Hermosilla 0% 0% 2% 0% 0% 2% Zebra perch azurea (1) (1) none 2% 0% 0% 0% 0% 2% None (1) (1)

Grand Total 62% 16% 20% 2% 0% 100% (31) (8) (10) (1) (0) (50)

a Total number of individuals of a species during study in brackets. b Number of events in brackets.

If the bait would be attractive to any of the have a bait station within their territory. If an lizards or salamander, the aerial broadcast of the individual was poisoned, that territory would rodenticide would increase the probability that become vacant and could be filled with another greater numbers would be exposed. The use of individual. That individual would then be at bait stations on top of the island would spatially high risk of primary exposure. With an aerial exclude most individuals from exposure, broadcast laid out in the alternatives, the scale of limiting exposure only to those individuals that impact would be a short window in time since

CHAPTER FOUR - 68 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT the bait would be removed from the hand broadcast into the marine environment environment. Bait stations would have the caught the attention of Western Gulls which potential for long term exposure to individuals. subsequently investigated the bait. The attraction of gulls to the bait falling into the No RQs were calculated due to lack of acute water drew more gulls into the area. However, toxicity data. the bait pellets fell through the water column quickly and no gulls were observed to Secondary Exposure (Indirect) successfully “fish” out any pellets. The lizards and salamander are at risk of The timing of the operation is late fall and early secondary exposure through consumption of winter when gull numbers are at their lowest. primarily exposed invertebrates. It is unknown if the diet of the herpetofauna is similar or Brown Pelicans contains species that would degrade residual bait There would be no direct effect of the in the Anacapa environment. rodenticide bait on the pelicans since they are fish eaters. There is no likelihood that they Sub-Issue 5 and 6 – Seabirds and would ingest any bait directly, or secondarily Landbirds from contaminated prey. The bait would be in a Primary Exposure (Direct) pellet form and is not expected to adhere to bird feet or feathers, therefore, it is unlikely that Toxicology - Toxicity data exists for both pelicans will inadvertently ingest the pellets groups of birds (seabirds and landbirds) (Table during preening activities. Pelicans are not 15). Brodifacoum is the most toxic rodenticide scavengers and will not eat dead and poisoned to birds. rodents. (It is expected that most (87-100%) of Bait Composition, Delivery and Behavior - rodents will die underground after consuming (Pelagic Seabirds) The pelagic seabirds are the bait.) Pelican prey species are schooling fish considered to be at low risk of primary such as anchovies and sardines, species which poisoning because of their foraging strategy would not come into contact with the bait. which is almost exclusively offshore. They are (Landbirds) - As a conservative estimate of almost exclusively carnivorous, preferring live primary exposure risks, the granivorous and prey. If during the aerial operations, bait was to omnivorous species are presumed to be at a fall into the water, and a pelagic seabird was in primary exposure risk during the operations. the vicinity, it may mistake a pellet for an Over 47% of the landbirds are either granivorous injured fish and perhaps pursue and consume. or omnivorous and may be subject to primary Most of the pelagic seabirds winter offshore exposure risks on Anacapa Island (Table 16). from Anacapa Island and are at a very low risk However, this is based upon year round of exposure. occurrence of these species on the islands. (Roosting Seabirds) - The roosting seabirds, During the proposed application period, many of those that utilize Anacapa Island for roosting the landbird species would have moved off the and tend to primarily feed offshore, are at islands to their wintering grounds. On Anacapa greater risk of exposure to the rodenticide than Island, this reduces the number of species at risk pelagic seabirds. Recent studies documented from 59 granivorous/omnivorous species to 26. Western Gulls exploring piles of placebo bait Further, recent surveys in November/December deliberately placed near roost sites (ICEG 2000). 1999 on Anacapa Island detected only 14 Similarly, placebo baits that were deliberately species, including carnivorous and insectivorous

CHAPTER FOUR - 69 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT birds (ICEG Table 15. Acute Oral and Dietary Toxicity of Rodenticides to Birds The RQs 2000). The (LD50 mg/kg) (A dash indicates that no data is available) (RED for birds are most abundant 1998). presented in species were Figures 12, 13, the House and 14. The Active Ingredient (Rodenticide) Finch, bird RQs Brodifacoum a Bromadiolone Diphacinone Bewick’s Wren Species exceed the EPA and Says Alternative 2, 3 Alternative 4 Alternative 6 LOC of 0.5 for and 6 and 5 Phoebe. brodifacoum, LD50 LC50 LD50 LC50 LD50 LC50 and The interest bromadiolone, in the bait by Mallard 0.26 2.0 - 158 3158 906 falling below non-target Northern >400 - for species was - 0.8 138 37 >5000 Bobwhite <2000 diphacinone. investigated in Canada This suggests the Fall of 1999 <0.75 - - - - - Goose that under the as part of the Black- proposed pre-eradication <0.75 - - - - - backed Gull alternative, if a research. Laughing bird was to be Placebo bait 0.7 - - - - - Gull primarily pellets were exposed to the placed in California 3.3 - - - - - rodenticide, exposed Quail there is a risk of locations Ring- hemorrhaging around Anacapa necked 10 - - - - - Pheasant and mortality. Island and Harrier observed from a 10 - - - - - The lack of Hawk distance. After interest in the House 62 hours of >6 - - - - - placebo baits on observation Sparrow Anacapa Island time, only one does not pile was a The LD50 for an unknown bird species has been estimated to be above preclude the investigated by 0.56 mg/kg (see Howald et al. 2000) possibility of a Western Gull, primary ______which poisoning to apparently did landbirds. Field not ingest any of the pellets (ICEG 2000). studies have shown that landbirds have been However, during spring trials, placebo baits exposed to rodenticides that have been were investigated by Western Gulls and at least dispensed in both bait stations and by broadcast. one was noted to consume pellets. No landbird Common Ravens, wekas and keas have been species were noted around the pellets during the observed reaching into, or breaking into bait observation period. This data suggests that the stations to gain access to the brodifacoum bait relative risk of primary exposure to the landbirds (Howald et al. 2000, Eason and Spurr 1995, would be lower than suggested by the above Taylor and Thomas 1993). The primary table. exposure in combination with secondary exposure to brodifacoum had a significant

CHAPTER FOUR - 70 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT

1999), to minor and insignificant Figure 12. Risk quotients (RQ) for 20-50 g birds (Robertson et al. 1993; Robertson et al. 1999; Dowding et al. 1999; and

8.00 7.81 Empson and Miskelly 1999). Although

7.00 there were incidences of poisoning in most island eradications, some impacted 6.00 species recovered to population densities Theoretical Maximum 5.00 Theoretical Minimum which were higher than densities before

4.00 RQ rodenticide application. (Empson and 3.13 3.00 Miskelly 1999; Robertson et al. 1999;

EPA LOC (0.5) B. Simmons, pers. comm.) 2.00

1.00 In summary, landbirds will be 0.61 0.24 0.05 0.02 exposed to the rodenticides on Anacapa 0.00 25 50 50 Brodifacoum Bromadialone Diphacinone Island. The consequence of such Concentration (ppm) of Rodenticide exposure would depend on the rodenticide. Brodifacoum and bromadiolone would result in mortality to some individuals, through single and cumulative exposures. The risk of impact on the local populations. These species primary poisoning would be significantly less are large, aggressive and share an omnivorous with the use of diphacinone. diet which contributed to their decline. Primary exposure and some mortality of birds of varying Secondary Exposure (Indirect) sizes, foraging strategies and classifications (Pelagic Seabirds) - The risk of secondary including: Kiwi, South Island Robins, weka, exposure to the pelagic seabirds is through North Island Saddlebacks, blackbirds, consumption of primarily exposed fish. The chaffinches,House Sparrows,H Sparrows, Australian Magpie, Paradise Shelducks, and Pukeko Figure 13. Risk Quotients (RQ) for 100-200g birds have been reported (Empson and Miskelly 1999; Dowding et al. 8.00

1999; Eason and Spurr 1995; 7.00 Morgan et al. 1996). All were 6.00

suspected or confirmed exposed to Theoretical Maximum brodifacoum, applied both aerially 5.00 Theoretical Minimum 4.02 4.00 and in bait stations, and used for rat RQ

eradications from islands. Although 3.00

2.01 the above studies have documented EPA LOC (0.5) 2.00 exposures and some mortality of 1.00 these species from rodenticide 0.31 0.16 0.02 0.01 exposure, the significance of the 0.00 25 50 50 Brodifacoum Bromadialone Diphacinone extent of poisoning was varied Concentration (ppm) of Rodenticide ranging from significant mortality (Howald et al. 2000; Eason and Spurr 1995; Empson and Miskelly

CHAPTER FOUR - 71 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT

… ______are at risk of secondary exposure through Figure 14. Risk quotients (RQ ) for 500-1000 g birds consumption of invertebrates that would

8.00 have rodenticide residues in their digestive tract, 7.00 however, the extent of this

6.00 is believed to be relatively

Theoretical Maximum insignificant. 5.00 Theoretical Minimum

4.00 RQ During the pre-

3.00 eradication research, 11mice and 14 rat EPA LOC (0.5) 2.00 1.61 carcasses were observed

1.00 0.80 for 165 hours to identify

0.13 0.06 0.010 0.005 scavengers. The Common 0.00 25 50 50 Raven and American Brodifacoum Bromadialone Diphacinone Concentration (ppm) of Rodenticide Kestrel were the only landbird species observed to scavenge rats and mice foraging grounds and the size of the prey would (ICEG 2000). On Anacapa, only one pair of limit the potential for exposure. Most of the Common Ravens were observed, and American smaller seabirds take small prey such as sardines Kestrels were in low abundance, not even which would not be able to consume the bait showing up in the bird surveys conducted in pellets. The risk of secondary exposure to these November/December 1999 (ICEG 2000). The species is very low. birds of prey also were in low abundance, a (Roosting Seabirds) - Western Gull is the maximum of 3 Burrowing Owls, 2 Short-eared only species believed to be at risk of secondary Owls, and a pair of Barn Owls were observed on exposure in the terrestrial environment via East Anacapa Island; Red-tailed Hawks and consumption of primarily exposed mice. No Northern Harriers were also in low abundance gulls were observed to consume any snap- during fall surveys. This indicates that although trapped mice placed out in open areas, however, there is a risk of secondary exposure to these one was noted to pick up and drop a mouse species, the relative number of species present carcass (ICEG 2000). on the island during the proposed application period is low. In the marine environment, if fish were to be extensively primarily exposed and were to float It seems reasonable to expect a significant on the surface of the ocean, gulls would likely impact on any species that preys primarily on be an important scavenger that would consume rats and/or mice on Anacapa Island if the fish. brodifacoum is used. The relative risk would be less, although not absent with bromadiolone. (Landbirds)- The birds of prey and The eradication of rats from East Island with a scavengers are at risk of secondary exposure follow up on Middle and West Island may limit through predation/scavenging of live/dead mice secondary poisoning because only a limited part and rats containing rodenticide residues (Table of the island would be treated at any one point in 17). Smaller landbirds such as the insectivores time.

CHAPTER FOUR - 72 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT

Mitigation

Table 16. Occurrence of landbirds in It is recognized that the landbirds are at risk of the Channel Islands National Park and primary and secondary poisoning. To minimize their foraging strategies. visual attractiveness to birds, and thus primary exposure, the bait would be dyed blue or green; colors known to be less preferred by the Passerines. Suggested mitigation measures to minimize or prevent exposure to the rodenticides

Island Granivore Omnivore Insectivore Carnivore Total could include: Live trap and release owls and AI 3 3 diurnal birds of prey on the mainland, or live trap, hold in captivity until the risk period SBI 1 13 5 4 23 passes, and release birds of prey back on to island. AI and 35314878 SBI This mitigation would be difficult to implement because live trapping of specific Other 92314 Islands individual birds can be difficult if not impossible (B. Walton, pers. comm., G. Howald, pers. Total 4 78 21 15 118 obs.). If required to implement, efforts would be made, but no guarantees that all individuals ______would be removed. Similarly, removal of birds of prey from Anacapa, could result in more birds filling the empty territories potentially The risk of secondary poisoning to presenting a greater secondary poisoning risk predators/scavengers of rats and mice is limited because more birds would be present (B. by the availability of these prey in space and Walton, pers. comm.). time. For the aerial predators on Anacapa, their search image is for live prey and thus risk of An alternative approach may be to provide poisoning is during the latent period (after rats and mice have consumed the bait, but have not yet died) (estimated at 2 weeks). Anticoagulated Table 17. The birds of prey and scavengers of poisoned rats and mice could be available to Anacapa Island at risk of secondary exposure both diurnal and nocturnal predators and scavengers. On Anacapa, islet wide treatment Birds of Prey Scavengers would yield numerous dying rats and mice Barn Owls Common Raven displaying erratic behavior and likely would be a significant prey base because of the ease of Burrowing Owls American Kestrel catching them. Similarly, a number of rats and Short-eared Owls mice would die above ground and available for American Kestrel diurnal scavengers. There would be extensive Northern Harrier secondary poisoning of the birds of prey with the use of brodifacoum or bromadiolone. The Red-tailed Hawk risk of secondary poisoning would be significantly less, although present with the use ______of diphacinone.

CHAPTER FOUR - 73 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT the landbirds with supplemental food which in those areas would likely survive for some would be more attractive than the bait pellets time without contacting bait. and/or rodent carcasses. Supplemental feeding The RQ indicates that brodifacoum and stations would have to be established and bromadiolone exceed the EPA Level of Concern regularly maintained before, during and after the of 0.5 (Figure 15). Diphacinone offers some baiting period. protection to deer mice, assuming that the LD50 For those carnivorous species that would for house mice is representative of the sensitivity scavenge dead rodents, carcass searching could of deer mice. Deer mice are at a high risk of be carried out to find, collect and dispose of any poisoning after a single days feed on bait dead rodents. Thus, secondary exposure via containing either brodifacoum or bromadiolone. carcasses is minimized. There would be a high impact to the mouse population. Sub-Issue 7 – Terrestrial Mammals Primary Exposure (Direct) Secondary Exposure (Indirect) Toxicology - Acute oral toxicity data exists The risk of secondary exposure to mice is for mammals (Table 18). Brodifacoum is the believed to be small. The only route of exposure most toxic rodenticide proposed under the would be through the ingestion of an alternatives. invertebrate containing rodenticide residues, or through consumption of poisoned carrion. The Bait Composition, Delivery and Behavior - low retention time of the rodenticides in The presence of the deer mouse on Anacapa invertebrates limits this exposure window. Island presents difficulties for eradication. Alternatives 2, 4, and 6 would limit the temporal The baits are optimized for rodent control, risk. Bait stations in the remaining alternatives and subsequently mice would be attracted to and would increase the probability of secondary would consume the bait. The impact on the exposure over time. mouse population would be heavy. The aerial broadcast of bait into the ecosystem increases Mitigation the probability that any one individual mouse would be exposed to the bait, however, the The endemic subspecies of the deer mouse exposure would be limited to a short window in on Anacapa represents a logistical challenge to time as bait would be removed from territories. eradication of rats. The proposed mitigation for However, it may not result in 100% mortality mice is outlined in Chapter 2. because rats have larger home ranges than mice (Howald et al. 1997) and are competitively Cumulative Effects dominant. Consequently, it can be difficult to This section will analyze how each of the simultaneously eradicate both species because alternatives could have a cumulative impact to the rats consume all the bait before the mice predators and scavengers through repeated have access to it. If all the bait is consumed exposures to the rodenticides, and the potential within the home range of an individual mouse, (non-toxicological) cumulative impacts to that mouse would then escape contact with bait seabirds. Included is a summary of rodenticide (D. Veitch, pers. comm.). If on Anacapa, rats toxicology issues from the Mainland of Southern consume all the bait within an area larger than California which could contribute to non-target the home ranges of male deer mice on Anacapa impacts. Island (Howald et al. 1997), then the mice living

CHAPTER FOUR - 74 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT

Table 18. Acute Oral Toxicity of Rodenticides to Mammals (LD50 mg/kg) (A dash indicates that no data is available) (adapted from Erickson 1999)

Active Ingredient (Rodenticide)

Species Brodifacoum Bromadiolone Diphacinone Alternative 2, 3 and 6 Alternative 4 and 5 Alternative 6 LD50 LD50 LD50

Norway Rat 0.26-0.56 0.56-0.84 2.3-7.0 Black Rat 0.65 a -- Laboratory Mouse 0.4 1.75 50-300 Vole 0.2 - - Dog 0.25-1.0 10-15 0.88-7.5 Coyote --0.6 Rabbit 0.29 1.0 35 Guinea Pig 2.78 2.8 - Mink 9.2 - - Mongoose --0.2

Cat 25 - 14.7 a from Taylor 1993

anticipated to be re-treated for up to a year after Alternative 1 – No Action initial application. However, there may be a requirement for the re-treatment to protect East This alternative would utilize no Island intermittently through the year. Any rodenticides and therefore would have no other areas treated initially would not be re- potential for cumulative exposures. treated between one and two years after the initial application. This analysis is divided into Effects Common to Alternatives 2, 3, 4, 5 primary and secondary exposure. and 6 Middle Island Headland Re-Treatment The use of brodifacoum or bromadiolone could result in predators and scavengers being exposed to the rodenticides through cumulative Primary Exposure exposures. The properties of these chemicals Between each treatment, there will be enough (outlined above) are such that they are relatively time elapsed for degradation of any residual bait insensitive to metabolism in vertebrate tissue that may not have been consumed by the rats or which could result in accumulation of residues mice, thus reducing primary risks between in time. The consequence of re-exposure is treatments to very low or negligible. This determined by how long after the initial negligible period is expected to carry through application the bait is re-applied, the amount of the landbird breeding season, thus allowing birds area re-treated and the rodenticide in the bait. to successfully breed before re-treatment may be The 20 ha headland of Middle Island is not

CHAPTER FOUR - 75 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT

Figure 15. Risk Quotient (RQ) for a 20 g deer mouse.

12.00

10.51

10.00

8.00

6.00 RQ

4.81

4.00

2.00 EPA LOC (0.5)

0.17

0.00 25 50 50 Brodifacoum Bromadialone Diphacinone Concentration (ppm) of Rodenticide necessary. As the rat population grows, and if they re-invade the headland, and the risk of re- Secondary Exposure invading East Island is deemed to be high, the treatment of the headland may be required. The risk of secondary exposure would be greatest Thus, after treatment the primary poisoning risk during the initial application, and less with the would again be high, but not as high during the subsequent re-applications because fewer rats and initial application because fewer rats would mice would be available as prey and there would likely be occupying the territory and thus would be less bait placed into the environment. not require as high a sowing rate to kill them all. Similarly, if baiting of the headland occurs during The application period may cross over into the the gull breeding season, there would be less Western Gull breeding season and may result in overall risks to birds of prey on the islands primary exposure of gulls to the rodenticide. because gulls harass the raptors generally During the spring 2000 field trials, placebo bait, was not found to be attractive to gulls occupying excluding them from the island. During the spring nesting territories. This data suggests that and summer periods, very few, if any, birds of although some gulls may be attracted to and prey were observed and they were not detected consume bait, there will likely not be extensive during bird surveys. Some species, such as the primary exposure of gulls. Burrowing Owl and Short-eared Owl only overwinter on Anacapa Island, thus, they would not be present during the intervening months when the headland on Middle Island would be treated, thus escaping re-exposure. However,

CHAPTER FOUR - 76 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT upon return to the islands, they may be at a greater chronic use pattern extensively around the state risk of being lethally exposed to the rodenticide if in both agricultural and urban settings. they already contain sub-lethal levels of rodenticide residue in their tissues from exposure Alternative 6 on the mainland. In other words, individuals could The use of diphacinone under alternative 6 succumb to smaller and smaller amounts of could represent a risk of poisoning to non-target rodenticides because of the sub-lethal levels in species via the mechanism outlined above. The their tissues. This situation would be dependent relative risk would be less than brodifacoum or on the availability of the rodenticide residues in bromadiolone because of the significantly lower time on the island. Re-application of an area residence time in vertebrate tissue. could result in rodenticide residue being available in time which could lead to cumulative exposure. Seabirds Kaukeinen (1982) reported that no This project objective is to restore the island significant wildlife mortalities have been and as a consequence, free up seabird nesting documented after 30 years of anticoagulant habitat. Pressures on the seabird populations usage. Thus, the consequence of baiting would that utilize or could utilize Anacapa Island for be restricted to non-target species that would be breeding include oil spills and the squid fishery. found on Anacapa Island. Migratory species The squid boats fish at night with high powered that overwinter on Anacapa Island could lights to draw in the squid for harvesting. The potentially be exposed to the rodenticides on light boats cause increased predation to the Anacapa, survive, and on return to breeding adults and juvenile seabirds, and are known to grounds on Mainland California, be exposed to negatively influence normal breeding activities the rodenticide and could succumb to the (B. McIver, pers. comm.). Oil spills cause oiling rodenticide exposure. The anticoagulant of feathers which negates the insulatory rodenticides have been detected in wildlife properties of the feathers and leads to losses on Mainland California (B. Hosea, pers. hypothermia and death. This section of the comm.) and recently in golden eagles trapped on analysis will evaluate the cumulative effects to Santa Cruz Island (T. Coonan, pers. comm.). seabirds for each alternative. The detection of brodifacoum in golden eagles on the islands indicates that species with sub- lethal levels of rodenticide are transporting the Alternative 1 – No Action chemical into the Channel Islands National Park Under this alternative, the negative impacts from the mainland since no vertebrate pest of oil spills and light boat activities would control has taken place. With residues in their continue. Together with the presence of the rats tissues they could be re-exposed to the on Anacapa Island, the reproductive potential of anticoagulants on Anacapa Island, and succumb. the seabird population would be seriously The golden eagles are non-native species to the hindered. islands and are currently being removed from the islands (3-5 total remain). Only one golden Effects Common to Alternatives 2-6 eagle has been observed around East Anacapa Under these alternatives, rats would be removed Island (ICEG 2000). As time passes, the relative from the island. The removal of the rats from exposure risk would decline because limited bait the island should result in an increase in would be applied in a relatively small area of seabirds, particularly the Xantus’ murrelet. The land, at one point in time. On the mainland, the increased population could help offset some of rodenticides are used for control and follow a

CHAPTER FOUR - 77 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT the negative impacts from both oil spills and Exposure to the rodenticide squid fishing. For example, if during the The different application methods of the breeding season and the Xantus’ murrelets were rodenticides could potentially expose the visiting breeding in large numbers on both Anacapa and public to the rodenticide through primary Santa Barbara, and a large oil spill occurred exposure. However, it should be noted that this around either island, only one of the two would need to be an intentional exposure on the populations of birds may be at risk of oiling part of the visitor, i.e., a person would have to (under the broad assumption that each seek out the bait and deliberately consume it. population has a distinct foraging range away Anacapa Island is open to the visiting public from each other). Compare with the occurrence year round. Visitors are allowed access to East of an oil spill around Santa Barbara Island, Island and with permission, to West Island in where a significant portion of the breeding Frenchy’s Cove. Thus, primary exposure to the population is at risk of oiling if rats were not rodenticide is limited to these areas of the island. removed from Anacapa. Similarly, the There is a small possibility that fisherman may increased population of birds could help offset catch fish that could contain trace amounts of the potential impacts from predation due to light rodenticide residue, thus, being secondarily boats around the island. However, the presence exposed. This analysis is organized by of the light boats may also have a detrimental application technique (aerial vs. bait station). A impact on the seabirds such that the seabird summary analysis outlining the health concerns population could not grow even with the rats associated with exposure is presented. removed. Aerial Broadcast (Alternatives 2, 3, 4, 5, and 6) Issue 3: Public Safety and Each of the alternatives would use aerial Visitation broadcast either on the cliffsides or both the cliffsides and top of Middle and East Islands. Introduction The aerial broadcast of a rodenticide bait increases the probability that a bait is found in This section in the analysis will analyze the any one location on the treated area. However, potential exposure of the general public to the the probability of finding a bait pellet would be rodenticides and how the proposed action would small. Bait pellets are about 2 g in size, and potentially impact visitors enjoyment to the park would fall to the ground with enough force to be during the baiting operations. Within the covered by vegetation and out of general sight. exposure to the rodenticide section, the analysis The alternatives would restrict public access will discuss how each method of delivery of the to the island 2-3 days during treatment. This rodenticide may expose the visiting public to the closure period would allow for the rats and mice rodenticide and associated health risks of to consume the majority of the bait within 72 exposure. Within visitor impacts, the effects hours (ICEG 2000). The buffer areas around the discussion will focus on how the alternatives buildings and campground on East Island would could potentially impact enjoyment of the park not be aerially treated, thus reducing the during operations. probability of finding the bait pellets even further because these areas attract the greatest number of visitors. Signs posted at the landing areas indicating that the island has been treated would

CHAPTER FOUR - 78 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT

a Table 19. Number of bait pellets for one LD50 exposure to humans for each rodenticide

Age Weight (kg) Brodifacoum Bromadiolone Diphacinone

Adult 70 364 392 1610

Child 10 52 56 230

a LD50 defined as amount of pellets required for a 50% chance of lethal hemorrhaging . LD50 assumed to be 0.26 mg/kg for brodifacoum, 0.56 mg/kg for bromadiolone and 2.3 mg/kg for diphacinone, based on LD50 data for the Norway rat.

______provide information about the program to visitors stations would provide information as to the bait and warnings about the bait and to avoid it if in the stations and emergency contact numbers encountered. would be provided as well as treatment for exposure. The stations would limit access to the There is a risk of bait pellets drifting into the bait to all but the most persistent visitors, such marine environment from aerial activity. The bait as those that may vandalize stations. pellets may be consumed by fish and potentially representing a secondary poisoning hazard to fisherman consuming the catch. The likelihood of Consequence of Exposure exposure is small, and significant exposure via The exposure to small amounts of the bait is this pathway is believed to be even smaller. The considered to present a very low risk to humans. fish population studied did not consume any bait Warfarin, a relative of brodifacoum and pellets, although sheephead was noted to chew bromadiolone, is a common antithrombin and spit out the bait. The amount of residues medication, administered to human patients as a found within the consumable flesh of fish would drug to “thin” the blood preventing heart attacks likely be of inconsequence relative to the amount and strokes. If sufficient amounts are consumed, required for measurable effects (Table 19). Only exposure to either of the rodenticides would fish around Anacapa could be exposed to the bait, have the same effect as warfarin. In effect, and of those only in the nearshore waters. There “thinning” the blood. If too much was is a fishing restriction to 60 ft depth around the consumed, an antidote would be available. north shore of Anacapa, lowering the probability Treatment is through dietary or daily injections of rodenticide exposure to fisherman even further. of Vitamin K1, a common and readily available vitamin. Studies have shown that workers Bait Stations (Alternatives 3 and 5) handling brodifacoum, the most potent of the three rodenticides presented, over a 9 month In these alternatives, the use of bait stations period did not show any effects suggestive of around the buildings and campground on East significant exposure (ICI, in Taylor 1993). Island would limit the potential for exposure to the rodenticides. The rodent bait would be To demonstrate the relative risks of encased within a lockable station that would be exposure, the number of 2 g bait pellets required appropriately labeled “Rat Poison- Do Not Disturb”. Pesticide labels attached to the

CHAPTER FOUR - 79 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT

to consume one LD50 for an adult and child is Impacts to Visitor Enjoyment presented (Table 19). Visitation to Anacapa Island is highest in the summer and lowest in the fall and winter Summary periods. November and December are the The probability of visitors exposed to the slowest months with relatively minor numbers bait is extremely small. The probability of of visitors to the islands as compared to the peak exposure would be limited by closing the island season (Figure 16). The project plan would be for 2 –3 days, allowing for the vast majority of to divide the islands into two sections, treating the bait to be cleaned up by rats and mice. East Anacapa Island in year one and then Posters would warn visitors of the application, Middle and West Island in year 2, thus always and bait stations around buildings with pesticide leaving one of the two public areas open to warning labels. Additionally, it would be rather visitors at any one point in time. Similarly, the difficult for one to find and consume enough other Park islands would be open to visitors bait to be of any consequence. Effective throughout the project period. Therefore, medical treatment would be available because of closure of the island for 2-3 day period post the slow onset of toxicosis and availability of an application would have no significant impact to antidote (Vitamin K1). visitor enjoyment.

Mitigation The bait could contain a bittering agent Figure 16. Visitor use during proposed treatment period. (bitrex) at a concentration known to deter human 16000 consumption, yet still be highly attractive to rats. However, there are data which suggest that 14000 bitrex could have a detrimental impact on 12000 eradications because some rats may be sensitive 10000 to the bittering agent (D. Veitch, B. Simmons, 8000 96-99 Sum of pers. comm.). The bait would be dyed a blue or Average Visitor Use Jan-Sept, green color that may be diluted out of the bait 6000 December (90% of Total) when exposed to water such as saliva and /or 4000 96-99 Sum of

Avg Annual Visitor Use (96-99) Average Visitor Use sweat making it a good indicator for someone Oct & Nov (10% of 2000 who may have incidentally eaten or picked up Total) the bait. Hospitals would be notified prior to the 0 operation that anticoagulants have been used, and to not overlook symptoms of anticoagulant exposure. Public areas on East Anacapa Island – trails, picnic areas and campgrounds would be inspected for any exposed bait, which would be removed before the island is open to the public. All employees and other park staff would be instructed about any hazards concerning the rodenticide before they are allowed on the island after application.

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appropriately protected from extirpation or Sustainability and Long extinction as outlined in Chapter 2. The benefit Term Management of rat eradication would be the recovery of the nesting seabirds, increased mouse populations, increased populations of intertidal invertebrates and terrestrial invertebrates. This increase in This section of the analysis will focus in native species populations could potentially on the relationship between local short-term uses support greater numbers of those species that of the environment and the maintenance and were incidentally poisoned with the rodenticide. enhancement of long term productivity, In other words, the benefits outweigh the costs. irreversible and irretrievable commitments of resources, and adverse impacts that cannot be Irreversible and Irretrievable Commitments of avoided. The analysis is divided into the no Resources action alternative and rats eradicated The irreversible commitments are those which (Alternatives 2-6) since the impacts across all cannot be reversed, except perhaps in the alternatives will be similar. The difference extreme long term . An example, extinction of a between the alternatives would be the scale of species is an irreversible loss. Irretrievable impact to the resources. commitments are those that are lost for a period Relationship between Local Short-term uses of of time, e.g., restriction of visitor use while an the Environment and the Maintenance and area is temporarily closed would be an ongoing Enhancement of Long-Term Productivity irretrievable loss. The following describes irreversible and irretrievable commitments of Alternative 1 – No Action resources resulting from affirmative actions identified in the various alternatives. Under this alternative, no short term uses of the Anacapa environment would take place. The Alternative 1 – No Action Island would continue with normal Park operations as it has in the past. As a result, there Under this alternative, continued rat predation of would be no new existing short-term uses that seabirds would represent an irretrievable loss. would affect long term productivity. An irreversible loss could be the lack of regeneration of the island oaks and cherries on Alternatives 2-6 – Rats Eradicated West Island. Similarly, the financial commitment of the American Trader Trust Under these alternatives, rats would be removed Council would be an irreversible loss since the from the islands with the use of a rodenticide. funds are dedicated towards seabird habitat The alternatives differ by rodenticide choice, restoration. intensity, and duration of application, however, the end result – rats eradicated - remains the Alternatives 2-6 – Rats Eradicated same. The use of the rodenticides in the Anacapa ecosystem represents a risk of non- Under each of the alternatives there would be no target poisoning to birds and mice causing irreversible loss of resources. There would be reductions in population sizes. However, the irretrievable loss of resources, in particular, mice actions would be of short duration which would and landbirds. However, these resources are result in short term declines of some species but proposed for mitigation and protection before those species would recover. Mitigation the operations would begin. measures to minimize those impacts have been developed for landbirds. Deer mice have been

CHAPTER FOUR - 81 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT

Unavoidable Adverse Impacts The impacts identified below for each alternative are those for which there are no mitigating measures or which could not be mitigated to a level of insignificance.

Alternative 1 – No Action The No Action alternative, by definition, contains no measures to mitigate impacts to resources. The presence of rats in the Anacapa ecosystem will continue to result in significant, unmitigated, adverse impacts to seabirds, landbirds, mice, invertebrates, and plants.

Alternative 2-6 – Rats Eradicated Under each of the alternatives, the level of mitigation should be sufficient for a level of insignificance.

CHAPTER FOUR - 82 . . CHANNEL ISLANDS NATIONAL PARK . FINAL ENVIRONMENTAL IMPACT STATEMENT .

ANACAPA ISLAND RESTORATION PROJECT

Chapter one CHAPTER FIVE CONSULTATION AND COORDINATION Need

Chapter Contents

COORDINATION ...... 84

PUBLIC INVOLVEMENT...... 84 INTERNAL SCOPING...... 84 EXTERNAL SCOPING ...... 84

LIST OF PREPARERS...... 85

LIST OF RECIPIENTS...... 86

RESPONSE TO COMMENTS...... 87

DEIS RESPONSE TO COMMENTS……………………………………………………………87

CHAPTER FIVE- 83 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT

summary of the scoping and public involvement Coordination process for the proposed project is as follows: Internal Scoping Although Channel Islands National Park has The Park has an extensive record of identified Anacapa Island rat eradication as a controlling rats on EAI. Through these efforts, priority for management with its inclusion in the the Park has collectively gained knowledge 1985 GMP, it was not until the Island about the issues surrounding the presence of rats Conservation and Ecology Group (ICEG) on the island. In addition, the Park has funded submitted a rat eradication proposal (Tershey et. scientific studies that focus on the ecology and al 1997) to the Park that a specific action was control of rats within the Park. developed. Because the primary benefactors of rat External Scoping eradication on Anacapa Island are seabirds, the Island Conservation and Ecology Park found support for the planning of the Group(ICEG) project through the American Traders Trustee Council (ATTC). The ATTC was formed as a ICEG is a non-profit conservation group result of an oil spill off of the Huntington Beach made up of American and Mexican conservation shore from the single-hull tanker American biologists, educators, and public officials working Trader in 1990. The ATTC is responsible for to protect biological communities on the over 250 the dissemination of settlement monies paid by islands in northwest Mexico and California. the oil carrier. Since 1996, ICEG biologists have been studying the rat infestation on Anacapa Island and have The ATTC was able to support the restoration advised the Park on ecological issues associated planning for this project because the proposed with rats on the island. activity primarily benefits seabirds and seabird habitat. Monetary support of the planning of this Vertebrate Pest Experts project was disseminated through a cooperative agreement between ATTC, NPS, and ICEG. The As part of the Vertebrate Pest Conference cooperative agreement outlined responsibilities of held in San Diego, CA (3/6-9, 2000) vertebrate each party during the planning phase of this pest experts made a site visit to Anacapa Island project. The Park will seek funding through to discuss the rat eradication project. Their ATTC to implement the decision that results from comments and concerns were recorded and this analysis. have been considered in this analysis.

General Public and Government Public Involvement Regulatory Agencies The Park has made extensive efforts to The NEPA “scoping” process [40CFR inform and seek input from the general public 1501.7] was used to determine the scope of the and government regulatory agencies regarding analysis and to identify potential issues and the need to eradicate rats from Anacapa Island. opportunities related to the Proposed Action. A These efforts include the following:

CHAPTER FIVE - 84 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT

11/18/99 - Scoping letter sent to all the project and the release of DEIS for interested publics who expressed an interest comments (Santa Barbara Free Press and the in Channel Islands National Park. This LA Times). included all government regulatory agencies
that may have oversight authority regarding 9/5/2000 – This date ended the review the proposed action. period for the DEIS. At the end of this chapter is the Park’s response to the
11/19/1999 – Park press release sent to all substantive comments that were sent local media outlets. This resulted in stories regarding the DEIS. Included is a full regarding the proposed project in three local reprint of the letters the Park received on the newspapers (Ventura Co. Star, Santa DEIS. Barbara Newspress, and LA Times). Several out of area newspapers printed the article when the Associated Press distributed it on its AP wire. A Santa Barbara local TV List of Preparers station (Channel 6 KSBY) aired a story regarding the proposed project. FEIS Preparation
11/20/1999 – Park posted information on its World Wide Web (www) site. This included a Frequently Asked Question Steve Ortega Restoration Channel (FAQ) summary regarding this project. Specialist Islands National Park
11/26/1999 – Notice of Intent (NOI) to prepare and Environmental Impact Gregg Wildlife Island Statement for this project was published in Howald Biologist Conservation the Federal Register. [Ecotoxicology] and Ecology Group
12/8/1999 – Public meeting held at the Park. Paid for ads and public notices announcing the meeting were published in three local newspapers (Santa Barbara Free Press, FEIS Review Ventura County Star, and the Los Angeles Kate Natural Resources Channel Times). A local radio station (KVEN 1520) Faulkner Division Chief Islands covered the meeting and aired its story the National Park following day. Tim Branch Chief for Channel
7/7/2000 - Notice of Availability for the Coonan Terrestrial Islands Draft EIS appeared in the Federal Register. Monitoring and National Park Combined, the Park widely distributed paper Restoration copies or CD-ROM disks to over 100 government agencies, organizations, and Allen Environmental Pacific West individuals. In addition, the DEIS was made Schmierer Compliance Region – available on the Park’s website. The Park Specialist National Park also issued a press release to 50 local media Service outlets announcing the release of the DEIS. This resulted in at least two articles about

CHAPTER FIVE - 85 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT

FEIS Technical Assistance • Honorable Elton Gallegly • City of Ventura Cathy Schwemm GIS Channel Specialist Islands Organizations and Businesses National Park • Santa Barbara Museum of Natural History • National Wildlife Research Center • Institute for Wildlife Studies • The Nature Conservancy List of Recipients • Santa Barbara Botanic Garden • Catalina Island Conservancy • Environmental Defense Center Below is a list of all agencies, organizations, • National Parks and Conservation and individuals that will receive a copy of the Association FEIS. • California Native Plant Society In addition, the Park will notify the general • National Fish and Wildlife Federation • public that the FEIS is available for comment Pacific Seabird Group • by: American Trader Trustee Council • Island Packers • Issuing a press release to the 50+ local • National Audubon Society, Seabird media outlets that are part of the Park’s Restoration Program Public Relations mailing list • Ventura Audubon Society • • Placement of a legal notice in both the Santa Cruz Island Foundation Santa Barbara News Press and the Ventura County Star Individuals • Post the FEIS on the Park’s website in • Peter Triem PDF format • Bruce Colvin • Gillian Keys Government • Deborah Jaques • • California Department of Fish & Game Charles Drost • • U.S. Fish and Wildlife Service (Ventura Desley Whisson Office) • Frank Gress • Environmental Protection Agency • Dan Anderson (Washington Office) • Lyndal Laughrin • California Environmental Protection Agency • William Everett • Central Coast Regional Water Quality • Dick Veitch Control Board • Buck Hull • California Coastal Commission • Ole Barre • National Marine Fisheries Service • Jack Gillooly • Channel Islands National Marine Sanctuary • Eiji Imamaura • U.S. Army Corps of Engineers • Steve Junak • U.S. Geological Survey • Cristina Bren • Canadian Wildlife Service • John Cloud • U.S. Coast Guard • Scott Cooper • National Wildlife Research Center, U.S. • Department of Agriculture Jack Engle • • Honorable Lois Capps John Gherini • Tom Gherini

CHAPTER FIVE - 86 ANACAPA ISLAND RESTORATION PROJECT FINAL ENVIRONMENTAL IMPACT STATEMENT

• Michael A. Glassow the analysis include impact analysis for the • Jeff Howarth following species: • Julie Tumamait-Stensile • Raptors • Adrian M. Wenner • Anacapa Deer Mouse The Park maintains a mailing list of • individuals and organizations interested in the Pinnipeds activities of Channel Islands National Park. A The Environmental Consequences section in notice will be sent to this mailing list that Chapter Four address impacts to these species notifies them of the availability of the FEIS. and others. The notice will give instructions on how to request a copy of the FEIS or view it at the Park’s website. DEIS Comments and Response to Scoping Responses Comments

The following are letters that were received At the public meeting comments were given on the DEIS and the Park’s response to the regarding the project. In addition, the Park received five written comments on the proposal. comments. The comments received on the proposal were either asking the Park to consider a certain alternative, or to consider certain impacts which may occur as a result of implementing the proposed action. Alternatives Three alternatives were recommended during the scoping period:

• Introduce predatory snakes • Introduce neutered/spayed cats from animal shelters • Use less toxic rodenticides

Each of these alternatives are discussed in Chapter II. The use of less toxic rodenticides was an alternative put forth to address the issue of non-target species poisoning. The issue of non-target species poisoning is discussed in Chapter IV Environmental Consequences. Impacts The comments the Park received on potential impacts to wildlife species asked that

CHAPTER FIVE - 87