Everglades Consolidated Report Chapter 14: Exotic Plants in the Everglades

CHAPTER 14: EXOTIC PLANTS IN THE EVERGLADES

Dan Thayer, Amy Ferriter, Mike Bodle, Ken Langeland, Kristina Serbesoff, David Jones and Bob Doren

SUMMARY

THE EXOTICS PROBLEM dium microphyllum as the four most dominant plant species in the EPA. Today, invasive exotic plants pose one of the world’s most serious environmental threats. Eco- Management tools are being used as needed nomic losses from this problem are now estimated and appropriate. These include biological control, at $20 billion annually in the United States alone. herbicide applications, mechanical and physical In 1999, President Clinton issued an Executive controls, including fire, along with education out- Order on Invasive Species that calls for the devel- reach aiming to increase societal awareness of the opment and funding of national management strat- problems. The District must coordinate invasive egies. Aquatic pest plants have been consistently plant management funds and efforts as much as managed in the southern coastal states, especially possible as mandated by the EFA. Control has been Florida, since late in the 19th century. Upland plant under way in the EPA since 1990. Management management has developed more recently, espe- programs on other public areas of the EPA con- cially as more public lands have been purchased tinue in Everglades National Park, Big Cypress for environmental protection, only to be threatened National Preserve, and Loxahatchee National by dozens of non-native plants. The South Florida Wildlife Refuge. All these programs strive to share Ecosystem Restoration Task Force’s identified research developments regarding the most current invasive plants as one of the most serious threats to controls, and to a degree, are limited by current the restoration of the South Florida ecosystem. policies, resources, and equipment.

Diverse management authorities and regula- The specific ecological characteristics of inva- tions have mainly sought to limit the spread of sive species must be understood to guide manage- invasive plants having adverse effects on agricul- ment actions. Primary exotic species described in ture and navigation. Today, new regulations aim to detail are: Melaleuca quinquenervia, Lygodium stem the loss in biodiversity in natural areas caused microphyllum, Schinus terebinthifolius, Casuarina by these plants. spp., Colubrina asiatica, Eichhornia crassipes, Pistia stratiotes, along with a brief listing of the In the Everglades, more than 220 exotic spe- species currently of secondary concern. cies have been identified; of these, almost 50 per- cent are listed as either Category I or II of the most In Florida, components for basic plant manage- invasive plants in Florida by the Florida Exotic ment initiatives have been in place for years, espe- Pest Plant Council. Legislative mandates of the cially for the plants of primary importance. The Everglades Forever Act require biennial surveys of secondary plants of concern pose relatively exotic plants in the Everglades region. This initia- unknown degrees of risk. tive has focused upon Casuarina spp., Melaleuca quinquenervia, Schinus terebinthifolius,andLygo- Plant importations into Florida occur by the hundreds of millions annually at Miami Interna-

14-1 Chapter 14: Exotic Plants in the Everglades Everglades Consolidated Report

tional Airport alone. Because of policy and Management tools also suffer from a lack of resource limitations, these importations are subject both knowledge and resources. Basic research does to only the most cursory inspections. State regula- not describe ecological impacts of many individual tions of invasive exotic plants still focus primarily pest plants in the EPA. Biological control is well upon those plants threatening agriculture, not understood, but tedious methods, approval pro- native ecosystems. Limited knowledge is incorpo- cesses, and inadequate quarantine space limits the rated in plans for the South Florida Ecosystem Res- rate at which biocontrol research can progress. toration. A true scope of the threat during Resources cannot readily be used across property restoration is not known and may only be seen as lines, limiting effective regional plant manage- restoration proceeds, but plans and funding sources ment. must be in hand as plant problems manifest them- selves. No certain predictions can be drawn from existing literature.

INTRODUCTION TO INVASIVE PLANT MANAGEMENT IN FLORIDA

Invasive exotic plants have become one of the Since the late 1970s, Florida has spent more most serious global environmental problems today than $300 million of state and federal dollars to (IUCN, 1998). Yearly economic losses from weeds manage aquatic plant problems (DEP, 1999). Since in the U.S. are more than $20 billion, while almost 1982, varying amounts of state funds have been $200 million was spent managing invasive plants available for aquatic plant treatments in public in 1997 (Westbrooks, 1998). Such losses and costs waters. Florida DEP’s centralized grants program will inevitably continue along strongly upward makes awards based on a framework of priorities, trends, especially if efforts are scattered. Planning, with the highest rank going to waters with waterhy- resources, and actions must be integrated effec- acinth or water lettuce, hydrilla and/or single or tively to turn back the overwhelming invasions of multiple aquatic uses such as navigation, water numerous non-native plants. management, or critical wildlife habitat. Waterhya- cinth, water lettuce, and hydrilla are not new to the In the southeastern coastal plain and South Everglades system, but mainly occur in manmade Florida, one invasive aquatic plant, the floating canals and perimeter connections where they have waterhyacinth (Eichhornia crassipes), has been presented relatively minimal intrusions. While under attack for much of this century. Introduced to present, they have not posed serious problems in the U.S. in the 1880s, its overwhelmingly rapid the interior Everglades. growth completely blocked boat traffic in many southern navigation arteries by the 1890s. Con- Clearly, aquatic plant management has a long gress has consistently funded its management ever history in the state. Upland invasive plant problems since. Since the 1970s, numerous other aquatic in natural environments have achieved increased plants have been targeted, including water lettuce levels of attention only during the past 10 to 15 (Pistia stratiotes), hydrilla (Hydrilla verticillata), years. Today, governments, both globally and and hygrophila (Hygrophila polysperma)asthey locally, have begun to understand the proven and impeded navigation, blocked flows critical for potential losses from upland invasive plant species. flood protection, and overwhelmed aquatic habitats During the same period in Florida, awareness of with dense monocultures. Many of these plants plant problems above the waterline has been grow- were imported in the 20th century for the aquarium ing. In 1984, the Florida Exotic Pest Plant Council plant trade. (FLEPPC) was formed to focus attention on the

14-2 Everglades Consolidated Report Chapter 14: Exotic Plants in the Everglades

increasingly severe problems posed by invasive ecosystem and, in 1998, authorized a Noxious exotic plants that threaten the survival of Florida’s Exotic Weed Task Team to develop a strategy to upland and wetland native plant communities. Its reduce the impact of invasive weeds in South Flor- public and private sector members, from wide- ida. As the South Florida Ecosystem restoration ranging backgrounds, seek to facilitate communi- proceeds, the team’s recommendations will be cation, education, research, and management of included with other components critical for the exotic pest plants. Since the Council’s startup, success of the project. other similar committees have formed in Califor- nia, Tennessee, the Mid-Atlantic, Kentucky, North On a national level, President Clinton’s 1999 Carolina, and Georgia with other chapters under Executive Order on Invasive Species (EOIS) fur- development. ther recognizes the threats posed by invasive plants and authorizes a national invasive species council More recently, in conjunction with the restora- which shall, among other duties, prepare a national tion of the Everglades ecosystem, the South Florida management plan for invasive species, including Ecosystem Restoration Task Force (SFERTF) has plants. States’ inputs to this plan will include infor- served as an interagency group authorized by Con- mation like that assembled for South Florida in the gress to integrate research and planning for South Task Team document during the mandated “review Florida ecosystem restoration. The Task Force has of existing and prospective approaches... for pre- identified invasive species as one of the most seri- venting the … spread of invasive species (EOIS, ous threats to the restoration of South Florida’s 1999).”

MANAGEMENT AUTHORITIES AND REGULATIONS

There are numerous laws, ordinances, regula- specific authorities, rules, regulations, laws, and tions, rules, policies and programs pertaining to relevant agencies. management of invasive exotic plants in the Ever- glades, Florida and throughout the United States. FEDERAL REGULATIONS Many, if not all, state and federal invasive exotic plant laws have come about because of threats to In 1977, President Carter issued an Executive agriculture and navigation. Historically, it is only Order that instructed executive agencies to restrict when a plant becomes a commercial or economic introductions of “exotic” species into U.S. ecosys- nuisance that it becomes important to regulate its tems, encourage state and local governments and spread. Very few regulations have been initiated private citizens to prevent introductions, and because of invasive species threats to natural areas. restrict the export of indigenous species for intro- Loss of biodiversity has not been fully recognized duction into ecosystems outside of the United as an economic threat. However, large sums of States. money are spent every year by local, state, and fed- eral agencies for the management of invasive With such an unprecedented, far-reaching exotic species on publicly owned lands and natural national policy, the United States is expected to be areas. The following is a general discussion of advanced in efforts to control invasive exotic spe- management authorities and regulations of federal cies. In practice, however, the Executive Order of and state agencies that have jurisdiction over exotic 1977 has been ignored by most federal agencies invasive plants in the Everglades Protection Area (OTA, 1993). This is most likely due to the fact (EPA). Appendix 14-1 includes tables that outline that it was weak, gave no specific direction to

14-3 Chapter 14: Exotic Plants in the Everglades Everglades Consolidated Report

agencies on how or when to implement it, and did United States Department of Treasury/U.S. not identify a funding source. On February 3, 1999, Customs Service: President Clinton signed an Executive Order that created an Invasive Species Council and charged it U.S. Customs Service (Customs) personnel with developing a comprehensive plan within 18 inspect passengers, baggage and cargo at U.S. ports months. The Council can then develop and recom- of entry to enforce the regulations of other federal mend to the President legislative proposals for nec- agencies including APHIS. Customs has the essary changes in authority. Clinton’s budget for authority to detain the passenger carrying a listed fiscal year 2000 proposes an increase of more than noxious weed or to confiscate the weed itself for $28.8 million in funding to combat invasive spe- inspection by APHIS. cies. United States Department of The current federal effort to control invasive Transportation/U.S. Coast Guard exotic plants is a conglomeration of laws, regula- The U.S. Coast Guard, under the Nonindige- tions, policies and programs of at least 20 different nous Aquatic Nuisance Prevention and Control Act agencies. Of the various agencies, only five, which of 1990, was mandated to create ballast regulations have regulation that can be enforced, are discussed that apply to vessels that enter a U.S. port on the here. Great Lakes. The National Invasive Species Act of 1996 expanded the scope of the Coast Guard’s United States Department of Agriculture authority to include all United States waters. Any ship that enters U.S. waters from outside the Exclu- An important mission of the United States sive Economic Zone (area extending from the Department of Agriculture (USDA) is to limit the baseline of the territorial sea of the United States) impact of invasive exotic weeds in agricultural sys- will be subject to voluntary ballast water guide- tems and aquatic, wetland, and terrestrial ecosys- lines. Mandatory monitoring reports will be tems. The USDA regulates the introduction and required and spot checks for compliance will be control of invasive exotic plants primarily through made. These guidelines went into effect in May the Animal and Plant Health Inspection Service - 1999. If compliance with the voluntary guidelines Plant Protection and Quarantine (APHIS - PPQ). is found to be inadequate, they will become man- Of all the federal agencies that have authority over datory. the spread of nonindigenous species, APHIS plays the largest role with a sizeable inspection staff The potential for the spread of invasive exotic located at all major ports of entry to the United plants (mainly aquatics) through the introduction States. APHIS' historic focus, with regards to from the ballast systems of seagoing vessels is plants, has been to keep plant pests and diseases great. The effectiveness of this act has the poten- from entering the United States. Except for certain tial to greatly influence the reduction of non-indig- listed species (Federal Noxious Weed list), the enous species in Florida. plant species themselves are not prohibited from entry even if they are recognized as a species that is known to be an invasive weed in the U.S. or else- STATE REGULATIONS where. Though the bulk of USDA’s regulations (and really all federal regulations) fall under the Florida Department of Agriculture and jurisdiction of APHIS, the Agricultural Marketing Consumer Services (FDACS) Service and the Farm Services Agency also play a The mission statement for FDACS Division of role in the regulatory control of nonindigenous spe- Plant Industry is, “To protect Florida’s native and cies by enforcing the Federal Seed Act, state weed commercially grown plants and the State’s apiary lists and the Conservation Reserve Program.

14-4 Everglades Consolidated Report Chapter 14: Exotic Plants in the Everglades

industry from harmful pests and diseases.” The weeds or plants in waters of the state unless a per- Division does this by regulating plant pests includ- mit for such activity has been issued by DEP or ing insects, mites, nematodes, slugs, snails, proto- unlesstheactivityisinwatersexpresslyexempted zoa, bacteria, fungi, viruses, arthropods, biological by department rule. In addition, anyone importing, control agents and noxious weeds. It maintains one transporting, non-nursery cultivating, collecting or of two weed lists in the State of Florida. FDACS possessing aquatic plants for business purposes also has review and approval authority over the must also obtain a permit from the DEP. Regional Florida Department of Environmental Protection biologists with DEP perform the same duties as (DEP) list of Prohibited Aquatic Weeds. FDACS nursery inspectors with respect to non- nursery businesses such as pet stores that may sell Another regulatory arm of FDACS is the aquatic plants. DEP, similar to FDACS, maintains Office of Agriculture Law Enforcement. This a list of prohibited aquatic plants, authorized by office maintains the Agricultural Inspection Sta- Chapter 62C-52, Florida Administrative Code, tions along the highway system that examine which may not be possessed by anyone without a incoming commercial vehicles to determine if agri- permit. cultural products are property certified for entry into the state and for compliance with the FDACS South Florida Water Management District Noxious Weed List and the DEP list. The office can also inspect plants listed on the Federal Nox- When the Central and South Florida Flood ious Weed List. This is an important extension of Control Project works were turned over to the FDACS' authority, because the federal govern- South Florida Water Management District's (Dis- ment, through USDA APHIS or otherwise, does trict’s) predecessor organization (The Central and not have the authority to halt interstate traffic of Southern Florida Flood Control District), the Dis- Federal Noxious Weeds unless they are on one of trict inherited an obligation to maintain the project the state weed lists. works at peak efficiency. This obligation included aquatic weed control in canals and nuisance vege- Within the FDACS Agricultural Environmen- tation along canal levees. These obligations are tal Service, the Bureau of Compliance Monitoring detailed in the Flood Control Act of 1948, House Seed Section is responsible for enforcing the Document 643, 80th Congress, 2nd Section, and in requirements of the Florida Seed Law, which regu- Chapters 25270 and 378 F.S., 1949, which require lates the sale and distribution of all seed sold in maintenance of Project works necessary for flood Florida. protection and water supply.

Florida Department of Environmental In 1994, the Florida legislature passed the Protection Everglades Forever Act. The Act states in part, “It is the intent of the Legislature to pursue compre- The DEP regional biologists in the Bureau of hensive and innovative solutions to issues of water Invasive Plant Management issue permits to con- quality, water quantity, hydroperiod, and invasion trol noxious aquatic plants and prevent the spread of exotic species which face the Everglades eco- of invasive, noxious aquatic plants. Aquatic plant system.” In regard to exotic species, the Act control that does not qualify for reimbursement requires that the District shall “establish a biologi- under state or federal funding is permitted under cal monitoring network throughout the Everglades Chapter 62C-20, Florida Administrative Code Protection Area and shall prepare a survey of (Aquatic Plant Management Permit), as authorized exotic species at least every 2 years.” In addition, by Section 369.20, Florida Statutes. The law pro- the District shall “establish a program to coordinate vides that no person or public agency shall control, with Federal, State, or other governmental entities eradicate, remove, or otherwise alter any aquatic the control of continued expansion and the removal

14-5 Chapter 14: Exotic Plants in the Everglades Everglades Consolidated Report

of these exotic species. The District’s program trict. Conditions for issuance of these permits shall give high priority to species affecting the restrict the permittee from discharging debris or largest areal extent within the Everglades Protec- aquatic weeds into works of the District and limits tion Area.” whichplantspeciesareallowedtobeusedonDis- trict rights-of-ways. The District maintains a list of The District enforces the discharge of aquatic plants permittable on District rights-of-way. This weeds from private property into District lands and list is not considered all-inclusive, but as a guide in into works of the District through its right-of-way selectingvegetationtobeusedwithinvariousDis- permitting program. Occupancy permits are trict properties when applications are made for an required prior to connecting with, placing struc- occupancy permit. The District maintains this list tures in or across, discharging into or making use due to its interest in eliminating invasive exotic or of the works of the District and any additional otherwise objectionable plant species from its lands or real property interest owned by the Dis- properties.

STATEWIDE COOPERATION AND COORDINATION EFFORTS

The Exotic Pest Plant Council (EPPC) was charge in developing a statewide management plan formed in South Florida in 1984 in response to the for melaleuca. increasingly severe problems caused by exotic plants in the Everglades region. Florida EPPC is a In early 1990, EPPC and the District jointly professional organization made up of public and convened a task force of federal, state, and local private sector members from more than 40 agen- land managers, scientists, and others. The goal of cies and corporations and include botanists, ecolo- this “Melaleuca Task Force” was to develop a com- gists, biocontrol researchers, entomologists, prehensive plan for managing melaleuca. The chemists, plant physiologists, land managers and Melaleuca Management Plan for Florida (1990) others. The wide-ranging backgrounds of the mem- was a first in the field of exotic plant management bers have allowed the Council to facilitate commu- in the state. It serves as a framework for facilitating nication and education, provide a forum for interagency cooperation and coordination of con- discussion, provide advice on research, manage- trol efforts, improving resource sharing, enhancing ment and control, and serve as an advisory body to public awareness, and inspiring legislative support. other groups or agencies. By bringing agencies and organizations From the beginning, the No. 1 enemy of Flor- together, EPPC provided an unparalleled forum for ida EPPC was melaleuca (Melaleuca quinquen- the development of this species-based management ervia) in the Everglades. Much of the initial plan. Based on the success achieved through the progress made in controlling melaleuca in South Melaleuca Management Plan, a Brazilian pepper Florida stemmed from the coordination provided (Schinus terebinthifolius) Management Plan for by the Council. A successful effort led by the Florida has been developed (1997), and a statewide Council resulted in the listing of melaleuca as a management plan for lygodium (Lygodium spp.) is Federal Noxious Weed by the USDA. The Council under development. These plans are key to suc- petitioned the USDA to begin research on the use cessful species-specific regional management of biological control agents to control melaleuca. efforts. Perhaps, most importantly, the Council led the

14-6 Everglades Consolidated Report Chapter 14: Exotic Plants in the Everglades

EVERGLADES RESTORATION and Working Group, the Noxious Exotic Weed EFFORTS AND INVASIVE PLANTS Task Team was established and funded in 1999. The Team is a direct working group of the South Several organized efforts and mandates have Florida Ecosystem Restoration Task Force and highlighted the problems associated with exotic Working Group. The task team is made up only of plants in the Everglades region. Control and man- government agencies—federal, state, and local—to agement of invasive exotics is one of the priorities comply with the Federal Advisory Committee Act established by the South Florida Ecosystem Resto- and Florida’s Sunshine laws. All meetings are open ration Task Force in 1993. The Everglades Forever to the public. While non-governmental organiza- Act of 1994 requires the South Florida Water Man- tionsarenotanofficialpartoftheTeam,Florida’s agement to establish a program to coordinate with Exotic Pest Plant Council provides advice and peer other federal, state, and local governmental entities review. Task team members are land managers and to manage exotic pest plants with emphasis in the scientists from key federal, state, and local govern- Everglades Protection Area. The Governor’s Com- ment agencies that in some way deal with exotic mission for a Sustainable South Florida (1995) pest plant issues. incorporated exotic plant management as one of its restoration objectives. In 1998, control of mela- The Task Team has been charged with devel- leuca and other exotics were ranked as the third oping a comprehensive strategic plan covering the highest projects in the Critical Ecosystems Studies issues and problems of exotic pest plants in Florida Initiative established by the Task Force’s Working with programmatic and management focus on the Group and Governor’s Commission for a sustain- Everglades. A statewide perspective has been used able South Florida. in developing this strategic plan, however, because any plan that addresses the issues of exotic pest There were two main directives from the Task plants cannot do so in a fragmented geographic or Force. The first was the development of an assess- political framework. Federal, state and local gov- ment to characterize the current problems with ernmental policies affect, interact and sometimes invasive exotic plants in southern Florida and iden- contradict one another and must be addressed syn- tify the highest priority invasive species for con- thetically. In addition the issues and experiences trol. The second directive called for the learned regionally regarding control method devel- development of a comprehensive interagency strat- opment, research results, public education, tech- egy for the elimination or control of the highest pri- nology transfer, policy, regulation, and funding, ority species and management to control and affect all agencies and programs throughout the minimize the spread of other pest plant species. state. In turn, national level issues related to exotic pest plants affect state and local policies and pro- Noxious Exotic Weed Task Team grams.

As a result of the priorities established by the South Florida Everglades Restoration Task Force

14-7 Chapter 14: Exotic Plants in the Everglades Everglades Consolidated Report

MANAGEMENT TOOLS

During this same period of planning and strat- 3. Identify the best potential biocontrol agents egy development, invasive plant management has based on field observations, preliminary lab necessarily continued in the EPA. Control pro- tests, and information from local scientists. grams for specific plants that were underway prior 4. Conduct preliminary host-range tests on the to development of management plans have contin- most promising candidate in its native country uedorbeenmodifiedinkeepingwithrecommen- to obtain permission to import to U.S. quaran- dations from the plans. A primary recommendation tine. of every management plan is the integrated use of all available management tools including biologi- 5. Complete host-range tests in U.S. quarantine to cal, herbicidal, physical and cultural as detailed ensure the safety of the organism relative to here. local native plants, agricultural crops, and ornamentals. BIOLOGICAL CONTROL 6. Petition the Technical Advisory Group of USDA-APHIS for permission to release in the Plants are often prevented from becoming seri- U.S. Also, obtain permission from necessary ous weeds in their native range by a complex state agencies. assortment of insects and other herbivorous organ- isms. When a plant is brought into the United 7. Culture agents that are approved to have suffi- States, the associated pests are thoroughly screened cient numbers to release at field sites. Test by government regulations on plant pest importa- release strategies to determine best method. tion. Favorable growing conditions and the 8. Monitor field populations of pest plants to: absence of these associated pest species has a)Determine if biocontrol agent establishes allowed some plants to become serious weeds out- self-perpetuating field populations. side of their native range. b)Understand plant population dynamics to “Classical” biological control seeks to locate have a baseline to measure bioagent effects, such insects and import host-specific species to especially if they are sublethal and subtle, attack and control the plant in regions where it has and know what portions of life history to become a weed. The “classical” approach has a watch. proven safety record (none of the approximately 9. Study the effectiveness of the agents for con- 300 insect species imported specifically for this trolling the target plant. Monitor plant popula- purposehaveeverbecomepeststhemselves)and tions, with the agent and without, to determine has been effective in controlling almost 50 species impacts of agent. of weeds. 10.Study the means of integrating biocontrol into The following are the performance steps of a overall management plans for the target plant. classical biological control investigation: In Florida, classical biological control of inva- 1. Identify the target pest and prepare a report sive non-native plants in non-agricultural areas has outlining the problem conflicts, potential for focused on aquatic weeds. The first biocontrol successful program, etc. agent introduced was the alligatorweed flea beetle (Agasicles hygrophila) in 1964 for the control of 2. Survey and identify the pest’s native range for alligatorweed (Alternanthera philoxeroides). Sub- a list of herbivores that attack the pest plant.

14-8 Everglades Consolidated Report Chapter 14: Exotic Plants in the Everglades

sequently, the alligatorweed thrips (Aminothrips a solid such as clay. Formulations often include an andersoni) was released in 1967 and the alligator- adjuvant that facilitates spreading, sticking, wet- weed stem borer (Vogtia malloi) in 1971. The flea ting, and other modifying characteristics of the beetle and stem borer proved to be fairly effective spray solution. Special ingredients may also for suppressing the growth of alligatorweed, improve the safety, handling, measuring, and appli- although harsh winters can reduce their popula- cation of the herbicide. The active ingredients tions. Less effective have been introductions of the 2,4-D amine, triclopyr amine, imazapyr, and waterhyacinth weevils (Neochotina eichhorniae hexazinone are formulated as water soluble liquids. and N. bruchi), released in 1972 and 1974, and the They are not compatible with oil based diluents waterhyacinth borer, released in 1977 (Sameodes and are diluted in water for foliar applications and albigutalis) for waterhyacinth control. Likewise, diluted in water or applied in their concentrated effectiveness of a weevil (Neohydronomous affinis) form for cut stump applications. They are not nor- and a moth (Namangama pectinicornis) released mally used for basal bark applications. for control of water lettuce has been unpredictable. Waterhyacinth and water lettuce continue to be Triclopyr ester, imazapyr, and fluazifop are problems that require management by other meth- formulated as emulsifiable concentrates. Emulsifi- ods. Current biological control research is focused able concentrates are compatible with oil based on hydrilla, waterhyacinth, melaleuca, Brazilian diluents and also contain emulsifiers that allow the pepper, and Old World climbing fern. formulation to mix with water. They may be diluted in water for foliar applications or mixed The introduction of animals such as cattle, with oil based diluents for low volume applications sheep, goats or weed-eating fish may also be used (e.g., basal bark). Hexazinone is also formulated as to control certain invasive plants. However, the an ultra low weight soluble granule formulation. environmental impacts of using such nonselective This formulation is broadcast with specialized herbivores in natural areas should be carefully con- ground or aerial equipment. sidered before implementation. Important rules and product chemistry affect HERBICIDES the use of herbicides. No pesticide may be sold in the United States until the U.S. Environmental Pro- A pesticide, or some of its uses, is classified as tection Agency (USEPA) has reviewed the manu- restricted if it could cause harm to humans or to the facturer’s application for registration and environment unless it is applied by certified appli- determined that the use of the product will not cators who have the knowledge to use these pesti- present unreasonable risk to humans or the envi- cides safely and effectively. Although none of the ronment. herbicides commonly used for invasive plant con- trol in the Everglades is classified as restricted-use, The USEPA approves the use of pesticides on the basic knowledge of herbicide technology and specific sites, i.e., individual crops, terrestrial non- application techniques that are needed for safe han- crop areas or aquatic settings. Only those herbi- dling and effective use of any herbicides can be cides registered by the USEPA specifically for use obtained from restricted use pesticide certification in aquatic sites can be applied to plants growing in training. All District applicators and contractor lakes, rivers, canals, etc. For terrestrial uses, supervisors are required to obtain this certification USEPA requires herbicide labels to have the state- before they apply herbicides in the EPA. ment: “Do not apply directly to water, to areas where surface water is present, or to intertidal areas A herbicide formulation, or product, consists below the mean high-water mark.” Rodeo® is reg- of the herbicide active ingredient dissolved in a istered for aquatic use and can be applied directly solvent (e.g., oil, water, or alcohol), or adsorbed to to water. Certain but not all products that contain

14-9 Chapter 14: Exotic Plants in the Everglades Everglades Consolidated Report

2,4-D can also be applied directly to water. The lations that contain the active ingredients 2,4-D or state supplemental special local need label for the triclopyr can often be used selectively because imazapyr-containing product, Arsenal® (EPA SLN many broadleaf species are more sensitive to them NO. FL-940004), allows government agencies and than the perennial grasses. Because 2,4-D, triclo- their contractors to use it for injection, frill/girdle pyr and glyhosate have negligible root activity and or cut stump applications to control melaleuca and break down quickly, they have little potential for Brazilian pepper growing in water. causing non-target damage due to root absorption, when carefully applied to target vegetation. In con- Absorption properties are an important aspect trast, caution must be used with root-active herbi- of herbicide chemistry. Systemic herbicides move cides (i.e., hexazinone and imazapyr) to minimize within the plant to the site where they are active damage to non-target vegetation by root absorp- after being absorbed by foliage, roots or bark. Tri- tion. clopyr, 2,4-D, imazapyr, and glyphosate can be absorbed by plant leaves and are effective for foliar Caremustbetakentoavoidunwantedcontact applications. Triclopyr, 2,4-D, and glyphosate are of herbicide spray (drift) to foliage of non-target adsorbed by soils or broken down quickly in soil plants when broadcast applications of the foliar and are not absorbed effectively by plant roots, active herbicides, 2,4-D, triclopyr, glyphosate, or whereas imazapyr and hexazinone are readily imazapyr are made. Particulate drift can be mini- absorbed by plant roots. Only oil soluble herbicide mized by avoiding windy conditions when spray- formulations, i.e., emulsifiable concentrates, are ing and using low pressures and large nozzle absorbed readily through tree bark. orifices. Volatile compounds such as ester formula- tions may cause non-target damage due to vapor Herbicides used for invasive plant control vary drift when applied on very hot days. This damage, in their persistence and sorption to soils. The most which may be observed as wilting or curling important factor is the ability of various soil types leaves, has been minimal and has not caused per- to chemically bind herbicides. Soil applied herbi- manent harm to woody non-target plants. cides, such as hexazinone, have label recommenda- tions that vary the application rate for different Invasive plant management is often conducted types of soils. In general, soils with more organic in natural areas with the purpose of maintaining or matter and/or clay have greater capacities for bind- restoring wildlife habitat. Therefore, it is essential ing herbicides than coarse, sandy soils and require that the herbicides themselves are not toxic to wild- higher application rates. life. Risk assessment to wildlife is conducted as part of the registration procedure for herbicides and Selectivity is determined as the product of hazard and expo- sure. Hazard is measured as the toxicity of the her- The ability to selectively control target vegeta- bicide to test animals and exposure depends on the tion with herbicides without harming non-target use and persistence of the compound. Herbicides plants is related to the relative sensitivities of target used for invasive plant control in the Everglades and non-target plants, absorption and chemical have shown very low toxicity to wildlife that they characteristics of the herbicides, and placement. have been tested on, with the exception of the rela- Herbicides vary in their potential to damage non- tively low LC50 (0.87 ppm) of triclopyr ester and target vegetation, and unwanted results can be pre- fluazifop (0.57 ppm) for fish, neither of which can vented or minimized by making the best choice of be applied directly to water. Ester formulations are herbicides in conjunction with careful applica- toxic to fish because of irritation to fishes’ gill sur- tion. Fluazifop, which kills many grasses, can be faces. However, because triclopyr ester and fluazi- used to selectively manage invasive grass species fop are not applied directly to water, are adsorbed among non-target broad-leaf plant species. Formu- by soil particles, and have low persistence, expo-

14-10 Everglades Consolidated Report Chapter 14: Exotic Plants in the Everglades

sure is low, which results in low risk when properly cambium is next to the bark around the entire cir- used. cumference of the stump. When using dilute solu- tions, the entire stump is sometimes flooded Herbicide Application Methods (depending on label instructions) with herbicide solution. Five approaches are used to apply herbicides in South Florida: Soil applications. Granular herbicide for- mulations are applied by hand-held spreaders, by Foliar applications. A herbicide is diluted specially designed blowers, or aerially. Herbicides in water and applied to the leaves with aerial or are absorbed by plant roots and translocated ground equipment. Foliar applications can either through the vascular system. be directed to minimize damage to non-target veg- etation, or broadcast. Broadcast applications are MANUAL AND MECHANICAL PLANT used where damage to non-target vegetation is not REMOVAL aconcernorwhereaselectiveherbicideisused. Time of year for application can also provide selec- Manual removal is very time consuming but tivity with broadcast spraying. Many of Florida’s often a major component of effective invasive native trees are deciduous, thus winter applications plant control. Seedlings and small saplings can to exotic evergreens is an effective option. sometimes be pulled from the ground but even small seedlings of some plants have tenacious roots Basal bark applications. A herbicide is that will prevent extraction or cause them to break applied, commonly with a backpack sprayer, at the root collar. Plants that break off at the ground directly to the bark around the circumference of will often resprout and even small root fragments each stem/tree up to 15 inches above the ground. left in the ground may sprout. Therefore, repeated The herbicide is absorbed through the bark and hand pulling or follow-up with herbicide applica- translocated through the plant’s vascular system. tions are often necessary.

Frill or girdle (sometimes called hack- Removal of uprooted plant material is impor- and-squirt) applications. Cuts into the cam- tant. Stems and branches of certain species (i.e, bium are made completely around the circumfer- melaleuca) that are laid on the ground can sprout ence of the tree with no more than 3-inch intervals roots, and attached seeds can germinate. If material between cut edges. Continuous cuts (girdle) are cannot be destroyed by methods such as burning, it sometimes used for difficult-to-control species and should be piled in a secure area that could be moni- large trees. Herbicide (concentrated or diluted) is tored and new plants killed as they appear. applied to each cut until the exposed area is thor- Mechanical removal involves the use of bulldoz- oughly wet. Frill or girdle treatments are slow and ers, or specialized logging equipment to remove labor intensive but sometimes necessary in mixed woody plants. Intense follow up with other control communities to kill target vegetation and minimize methods is essential after the use of heavy equip- impact to desirable vegetation. ment, because disturbance of the soil creates favor- able conditions for regrowth from seeds and root Stump treatments. After cutting and fragments, and re-colonization by invasive non- removing large trees or brush, a herbicide (concen- native plants. Mechanical removal may not be trated or diluted) is sprayed or painted on to the cut appropriate in natural areas because of disturbance surface. The herbicide is usually concentrated on to soils and non-target vegetation caused by heavy the cambium layer on large stumps, especially equipment. when using concentrated herbicide solutions. The

14-11 Chapter 14: Exotic Plants in the Everglades Everglades Consolidated Report

In aquatic environments, mechanical controls of fire has altered historical plant communities. include self-propelled harvesting machines, dra- Within these communities, the fire-tolerant woody glines, cutting boats and other machines, most of species have lingered in smaller numbers, and less which remove vegetation from the waterbody. fire-tolerant species have replaced ephemeral These systems generally are used for clearing boat herbs. Little is known about the amount, frequency, trails, high-use areas, or locations where immediate timing, and intensity of fire that would best control is required, such as in flood control canals enhance the historically fire tolerant plant species, and around water control structures. and less is known about how such a fire manage- ment regime could be best used to suppress inva- CULTURAL CONTROL PRACTICES. sive species. Single fires in areas with many years of fire suppression are unlikely to restore historical Prescribed burning and water level manipula- species composition. Periodic fires in frequently tion are cultural practices that are used in the man- burned areas do little to alter native species compo- agement of pastures, rangeland, and commercial sition. forests and may be appropriate for vegetation man- agement in natural areas in some situations. Land Invasion of tree stands by exotic vines and use history is critical in understanding the effects other climbing plants – such as Old World climb- of fire and flooding on the resulting plant species ingfernonEvergladestreeislands–hasgreatly composition. Past practices affect soil structure, increased the danger of canopy (crown) fires and organic content, seed bank (both native and inva- the resulting death to mature trees. The added bio- sive exotic species), and species composition. mass by invasive plants can result in hotter fires, While there is evidence that past farming and tim- and can greatly increase the risk of fires spreading ber management practices will greatly influence to inhabited areas. In these situations, use of fire to the outcome of cultural management, very little is reduce standing biomass of invasive species may known about effects of specific historical practices. better protect the remaining plant populations than Similar management practices conducted in areas doing nothing, even though impacts to non-target with dissimilar histories may achieve very different native species will occur. Under these conditions, results. Even less is known about the effects of the expense of reducing standing biomass of inva- invasives entering these communities, and the sub- sive plant species might be justified by the savings sequent management effects of fire on the altered on subsequent fire suppression. communities. Water level manipulation can also be an impor- Understanding the reproductive biology of the tant method of control. Some success has been target and non-target plant species is critical to the achieved regulating water levels to reduce invasive effective use of any control methods, but particu- plant species in aquatic and wetland habitats. Dew- larly so, with methods such as fire management, atering aquatic sites reduces standing biomass, but which often require significant preparation time. little else is usually achieved unless the site is ren- Important opportunities exist when management dered less susceptible to repeated invasion when tools can be applied to habitats when non-native rewatered. Planting native species may reduce the invasive species flower or set seed at different susceptibility of aquatic and wetland sites in some times than the native species. cases.

Prescribed burning can be an important means In most situations, water level manipulation in of vegetation control. Fire is a normal part of most reservoirs has not provided the level of invasive of Florida’s ecosystems and native species have plant control that was once thought achievable. evolved with varying degrees of fire tolerance. Ponds and reservoirs can be constructed with steep Throughout much of the Everglades, suppression sides to reduce invadable habitat, and levels can be

14-12 Everglades Consolidated Report Chapter 14: Exotic Plants in the Everglades

avoided that promote invasive species, but rarely or fire management of invasive species can some- are these management options adaptable to natural times control subsequent germination, and, with areas. Carefully timed water level increases fol- some exotic species, resprouting. lowing herbicide treatments, mechanical removal

INVASIVE EXOTIC PLANTS OF EVERGLADES PROTECTION AREA

The Florida Exotic Pest Plant Council pub- (Whiteaker and Doren 1989; Avery and Loope, lishes a list of Florida’s most invasive plant species 1997), nearly 50 species (23 percent) belong to (Appendix 14-2). The listing committee is made EPPC’s Categories I and II. The majority of these up of botanists from various agencies and each species occur in limited areas, and do not pose a major university in the state. This list was devel- direct threat to native plant communities. However, oped to help land managers focus and prioritize plants such as melaleuca, Brazilian pepper, Austra- management efforts related to natural area weeds lian pine (Casuarina spp.), and Old World climb- (Langeland and Burks 1997). The list is comprised ingfern(Lygodium microphyllum) are causing of two plant categories. Category I plants are non- widespread damage to native communities native species known to have invaded Florida natu- throughout South Florida. These plants are consid- ral areas – they are displacing native plants or oth- ered species of primary concern because they have erwise disrupting the natural community structure invaded a widespread area and have the potential to and/or function. Placement in this category is severely disrupt native plant communities and/or derived from observed ecological damage and does water delivery systems. not depend on the economic severity of the prob- lem or its geographic extent. Category II species The biannual publication of EPPC’s list of are plants that are considered to have a real poten- Florida’s most invasive plant species (begun in the tial to become Category I problems, but are not yet 1980s), the Park’s list of exotic pest plants in prior- known to be disrupting natural area communities. itized categories by Whiteaker and Doren (1989), The list is revised every two years by consensus of and regional exotic plant surveys have resulted in the committee members. greater interagency efforts to manage exotic spe- cies regionally. There has been increased funding The 1999 EPPC list includes 65 Category I and volunteers in the field (e.g., the Park’s Volun- plants. Some of these plants have only been teers-in-the-Parks Program, Miami-Dade County observed as invasive in regional areas. Chinese tal- Service Corps Program, and the Student Conserva- low (Sapium sebiferum), for example, is a major tion Association’s Americorps program). There- pest in central and northern Florida, but it has not fore, there has been a greater availability of been reported as widespread in natural areas in improved GPS/GIS technologies for mapping and south Florida. In contrast, melaleuca is generally remote sensing work. There also has been regarded, almost exclusively, as a South Florida increased regional cooperation among government problem. agencies and non-governmental organizations. Some of the most disruptive and potentially disrup- In the entire Everglades region, there are hun- tive species, known to occur in the Everglades dreds of exotic plant species. In WCA-2 alone, 52 region, are now being controlled and/or monitored. exotic plant species have been identified as natural- ized (Bradley et al., 1997). Of the approximately Detection of relatively new (not widespread) 220 species of exotic plant species recorded in invasive species or small infestations of invasive Everglades National Park (the Park) today exotic plants is key to developing successful man-

14-13 Chapter 14: Exotic Plants in the Everglades Everglades Consolidated Report

agement plans. The Everglades Forever Act man- ing size and occur in natural, cultural (artificial), dates that the District conduct biannual surveys of disturbed, and undisturbed landscapes. The most exotic plants in the Everglades region. Since 1993, widespread (on both local and regional scales) and the District has tracked four target species region- disruptive of these species have received the great- ally. This program attempts to document the status, est attention. distribution, rates of expansion, and habitat prefer- ences of Old World climbing fern, melaleuca, Bra- MANAGEMENT EFFORTS IN EPA zilian pepper and Australian pine region-wide (excepting large metropolitan areas). Aerial The Act also requires that the District coordi- transects are flown across the state to record the nate with federal, state, and other government enti- presence of primary exotic species, the primary ties the control of exotic species within the EPA. species’ relative density, and the presence of sec- The Act further requires that the District’s program ondary exotic species, if any, and relative density. give highest priority to the species affecting the Observers also note areas where treatment programs largest areal extent within the EPA. have been implemented. Surveying large regional areas allows resource managers to establish trends in The District has been closely coordinating all exotic plant populations. These data can be used to vegetation management efforts with other agencies prioritize the allocation of management funds and within the EPA since 1990. The primary forum for assess management success for the entire South this coordination has been through the Florida Florida region. Exotic Pest Plant Council. This close coordination has resulted in detailed species-based management The first park-wide distribution maps of major plans (Melaleuca Management Plan, Brazilian exotic plant species – melaleuca, Brazilian pepper, Pepper Management Plan, Lygodium Emergency Australian pine, and latherleaf (Colubrina asiatica) Action Plan), and a maximization of all available – were produced in 1988 using color infrared pho- management resources. In addition, the District tographs (1:10,000 scale) recorded in 1987 (Rose has been required to get a permit from the DEP for and Doren, 1988). A recent effort to map these all vegetation management activities in public same species, with the addition of shoebutton ardi- waters since 1979. The permit process has helped sia (Ardisia elliptica), uses 1994-95 USGS NAPP to bring peer review and consistency to manage- color infrared photography (1:40,000 scale) and is ment approaches statewide. Within the EPA, float- part of a cooperative vegetation classification and ing aquatic plant control in canals has been mapping effort between the National Park Service coordinated with the U.S. Fish and Wildlife Ser- and The University of Georgia (Welch et al., 1995). vice and Everglades National Park since the early Seventy percent of the park has been mapped; 1970s. The plant control relates to waterhyacinth mapping is in progress for the northern portion of and water lettuce spraying and/or harvesting in and the Northwest District, parts of Shark River Slough around the S-10 and S-12 structures, and within the and the Whitewater Bay area, and eastern portions L-7, L-39, L-40, and the L-29 canals. of the Park. As required by the Act, the District assembled Other exotic species have not been tracked a meeting with representatives from the DEP, the regionally because their population sizes, densities, USMCE, the U.S. Fish and Wildlife Service, and spatial extents, and environmental impacts are sig- the National Park Service (Everglades National nificantly lower or unknown. Based on field obser- Park and the Big Cypress National Preserve) in vations and published information, particularly 1996. The group discussed a collective list of “pri- Whiteaker and Doren (1989), these species are ority species” for the Everglades Protection Area. widely scattered and range from single individuals Melaleuca, Brazilian pepper, and Australian pine to dense, generally localized populations of vary- are problematic throughout the EPA and are a col-

14-14 Everglades Consolidated Report Chapter 14: Exotic Plants in the Everglades

lective top three problematic plants. Melaleuca has most resource managers are resigned to carrying long been recognized as public enemy No. 1;how- out only control actions. For every exotic control ever, aggressive management efforts in recent project successfully completed, there are a dozen years have reduced the melaleuca population on more to replace it. Detailed summaries of agency public lands resulting in a shift in concern to the management efforts are located in Appendix 14-3. Old World climbing fern. There is consensus among South Florida land managers that the Old PRIMARY EXOTIC SPECIES OF World climbing fern now represents the single CONCERN IN EPA greatest threat to the greater Everglades ecosystem (Ferriter, 1999). Waterhyacinth and water lettuce Melaleuca are mostly confined to canals and areas around water control structures. As such, these two float- Scientific Name: Melaleuca quinquenervia ingexoticaquaticplantsaremostlyawatercon- veyance issue and are only priority species for the Common Names: Melaleuca, paper-bark, U.S. Fish and Wildlife Service, and the District. cajeput, punk tree, white bottlebrush tree While these aquatic weeds can be found down- (Figure 14-1) stream of the S-12 structures within Everglades National Park (the Park), they have not expanded their range and are not currently being managed there. Latherleaf is considered a high priority spe- cies for the Park, but is not presently found in the greater Everglades ecosystem.

Smaller populations of other invasive exotic species are also treated when discovered. For example, a highly-invasive vine, kudzu (Pueraria montana), was identified growing on the L-36 levee in Broward County in 1992 (Bodle, 1994). An eradication program was immediately imple- mented by the District and appears to have been successful.

The ecological effects of exotic pest plants on native areas are generally known to include an alteration of species composition and community structure. Also, there is a diminishment of natural habitats and food sources of native animals. Inter- ference with ecological and geological processes, such as water and nutrient cycling, and species interactions also occurs. Unfortunately, most resource managers are typically not afforded the opportunity to record these changes. Minimally, determining the responses of native plant commu- Figure 14-1. Melaleuca quinquenervia, nities to exotic pest plant removal, by sampling (Cav.) Blake (Melaleuca). before and after control treatments, is desirable, but (Illustration used by permission this too often falls beyond the time and resource of the University of Florida.) capabilities of most management programs. Hence,

14-15 Chapter 14: Exotic Plants in the Everglades Everglades Consolidated Report

Synonymy: Melaleuca leucadendron (L.) L. Life History: Melaleuca prefers seasonally misapplied wet sites, but also flourishes in standing water and well-drained uplands (Laroche, 1994b). Saplings Origin: Australia, New Guinea, and Solomon are often killed by fire, but mature trees can sur- Islands vive fire and severe frost damage (Woodall, 1981). Melaleuca grows 1 to 2 m per year, resprouts easily Family: Myrtaceae, Myrtle Family from stumps and roots, and is capable of flowering within two years from seed (Laroche, 1994b). Botanical Description: Evergreen tree to Melaleuca flowers and fruits all year, producing up 33 m tall, with a slender crown and soft, whitish, to 20 million windborne seeds per year per tree, many-layered, peeling bark. Leaves alternate, sim- and is able to hold viable seed for a massive all-at- ple, grayish green, narrowly lance shaped, to 10 cm once release when stressed (Woodall, 1983). Mela- long and 2 cm wide, with a smell of camphor when leuca releases volatile oils into the air, especially crushed. Flowers in creamy white “bottle brush” when blooming, which cause respiratory irritation, spikes to 16 cm long. Fruit a round, woody cap- asthma attacks, headaches, and/or rashes in some sule, about 3 mm wide, in clusters surrounding people (Morton, 1971b). young stems, each capsule holding 200 to 300 tiny seeds. Distribution: Melaleuca has been found nat- uralized in Florida as far north as Hernando, Lake, Ecological Significance: In its native and Brevard counties (Wunderlin et al., 1995; range, melaleuca grows in low-lying flooded areas Mason, 1997). It is reported from natural areas in and is especially well-adapted to ecosystems that 16 Central and South Florida counties (EPPC, are periodically swept by fire. These are common 1996) (Figure 14-2). Melaleuca grows equally conditions in South Florida, making the region an well in the deep peat soil of WCA1 and the inor- ideal habitat for colonization. ganic, calcareous soil of Everglades National Park. In general, wetland areas such as sawgrass prairie Melaleuca was introduced to Florida in 1906 are more susceptible than drier, upland areas. (Fairchild, 1947) - and scattered aerially over the Everglades in the 1930s, to dry up “useless swamp- Before state and federal control operations land” (Austin, 1978). It is hardy and fast-growing - were initiated in 1990, melaleuca was distributed these characteristics spurred its use as an ornamen- throughout South Florida. Pioneering or “outlier” tal landscape tree, as agricultural windrows and melaleuca had invaded the Holy Land, the interior protective living “guard rails,” and soil stabilizers of Everglades National Park and WCA-2A. Light along canals. Melaleuca was recommended as late to moderate infestations occurred in WCA-3 and as 1970 as “one of Florida’s best landscape trees” the western edge of the East Everglades Acquisi- (Watkins, 1970). tion Area. Moderate to heavy infestations occurred in the Loxahatchee National Wildlife Refuge, Big Melaleuca readily invades canal banks, pine Cypress National Preserve, WCA-2B, Lake flatwoods, cypress swamps, and uninterrupted Okeechobee and wetlands in Miami-Dade, Bro- sawgrass prairies of South Florida (Nelson, 1994; ward, Lee and Collier counties. Initial survey Myers, 1975; Austin, 1978; Duever et al., 1986; results showed that melaleuca had invaded approx- Wade et al., 1981; Woodall, 1981b, 1983). It grows imately 197,640 hectares in South Florida (Ferriter, extremely fast, producing dense stands that dis- 1999). Through regional control efforts, steady place native plants, diminish animal habitat, and progress has been made in these areas, and today, provide little food for wildlife (Laroche and Fer- large untreated monocultures of melaleuca are lim- riter, 1992). ited to WCA-2B, the Loxahatchee National Wild- life Refuge, the East Everglades Acquisition area,

14-16 Everglades Consolidated Report Chapter 14: Exotic Plants in the Everglades

Figure 14-2. 1999 Melaleuca distribution area.

14-17 Chapter 14: Exotic Plants in the Everglades Everglades Consolidated Report

the Everglades buffer strip and wetlands in Miami- Once introduced, several years are generally Dade, Broward and Lee counties. Control efforts required for introduced populations to build to by local, state and federal land management agen- effective levels. In the interim, and throughout the cies have resulted in a decrease in melaleuca acres. biocontrol introduction phase, herbicidal and By 1997, survey results showed that melaleuca mechanical controls will be required to reduce cur- occupied approximately 158,355 hectares (Ferriter, rent infestations and prevent their spread into cur- 1999). rently uninfested areas. Manual removal of seedlings in combination with single tree herbicide Control: There are differing perspectives on applications is the most conservative approach in the role of melaleuca in South Florida. Melaleuca’s natural areas. However, individual tree treatments potential spread in South Florida is considered by are costly. Thus, less costly methods of herbicide some experts to be unlimited, ultimately encroach- application are constantly being investigated. ing upon all open land (Hofstetter, 1991a), or lim- ited to underutilized niches in the relatively young Single tree herbicide applications are most Florida landscape (Myers, 1975). Yet, acknowledg- commonly delivered as a frill-girdle or cut-stump ment of such alternative views embraces their com- treatment. The Refuge and Park programs favor the mon thread—melaleuca needs to be controlled— cut-stump technique because trees are felled, limit- whether or not it could ultimately cover the penin- ing the subsequent seed dissemination. The District sula. uses a combination of the two individual tree treat- ment techniques. The approach is to leave a ring of The integrated management of melaleuca trees standing at each work location and then fell requires a combination of control techniques to be the remaining trees. In this matter, stumps are not effective. Essential elements of effective manage- hidden from the recreating public, mitigating navi- ment include herbicidal, mechanical, physical, and gation hazards. The disadvantage is seed pods dry, biological control. Comprehensive descriptions for and seeds can be wind blown for several hundred each of these management techniques are located feet from the treatment site. in the Management Tools section of this chapter. Direct herbicide application can still result in The key to an effective and long-lasting man- non-target effects where tree densities are high. agement program for melaleuca is the introduction Aerial application of herbicides may, in some of biological control agents. Without biological cases, cause less non-target damage to native and control, melaleuca elimination will be much more herbaceous groundcover. It also may result in less expensive and could not be truly integrated. The herbicide being used on a site and, in some situa- current investigation into biological organisms will tions, may lower the cost of initial treatment. Man- most likely result in the introduction of seed and ual removal of seedlings may not be advisable in sapling feeders. The first introductions of a mela- all situations due to the percentage of roots broken leuca snout beetle (Oxyops vitiosa) began in April below the ground surface. In addition, the soil dis- 1997. By June 1998, over 21,550 adults and 6,700 turbance that results may stimulate more seeds to larvae were released at 13 sites in six counties. Pre- germinate. Mechanical removal using heavy equip- liminary results show that the insect is causing ment is best suited for rights-of-way and other sim- damage to new growth on melaleuca at several ilar areas where routine maintenance follows, and release sites. The melaleuca snout beetle is the first site disturbance is not a concern. of a suite of insects that are being studied for release. Entomologists analyzing the problem esti- A melaleuca management program should be mate that at least five insect species will be based on the quarantine strategy as described by required to effectively suppress melaleuca’s repro- Woodall, 1981a. The least infested areas (outliers) ductive capacities. are addressed first in order to stop the progression

14-18 Everglades Consolidated Report Chapter 14: Exotic Plants in the Everglades

of the existing population. The first phase of con- Ecological Significance: There are two trol targets consists of all existing trees and seed- species of exotic climbing fern naturalized in Flor- lings in a given area. Using navigational ida. Old World climbing fern is native to wet tropi- equipment, crews return to the same site in the fol- cal and subtropical regions of Asia, Africa, and lowing years to remove any resulting seedlings Australia. It has become a serious threat to South from control activities of previous years. Florida natural areas, especially the Everglades, where it is increasing in density and range. Japa- A successful control operation consists of three nese climbing fern (Lygodium japonicum)isnative phases. Phase I focuses on the elimination of all to temperate and tropical Asia. It occurs from east- mature trees and seedlings present in an area. In ern Texas through the southern States to North Phase II, previously treated sites are revisited for Carolina and North Florida. Japanese climbing fern follow-up treatment to control trees previously has not yet been found within the EPA. Old World missed and remove seedlings which may have climbing fern has reached a critical mass in South resulted from control activities of the preceding Florida such that new populations, presumably year. Phase III entails the long-term management from wind-borne spores, are constantly being of melaleuca, surveillance, and inspection of previ- reported by natural resource managers and private ously treated sites to monitor the effectiveness of landowners throughout the southern peninsula. the melaleuca control program and maintain rein- festation levels as low as possible. Old World climbing fern invades many fresh- water and moist habitats in Florida. It is common Old World climbing fern in cypress swamps, pine flatwoods, wet prairies, sawgrass marshes, mangrove communities, and Scientific Name: Lygodium microphyllum, Everglades tree islands (Pemberton and Ferriter, Old World climbing fern (Figure 14-3). 1998; Jewell, 1996). This plant seriously alters fire ecology, which is important to maintaining Florida Common Name: Old World climbing fern habitats. Prescribed burns and wildfires that nor- mally stop at the margins of flooded cypress Synonymy: Lygodium scandens (L.) Sw., sloughs will burn through areas infested with this Ugena microphylla Cav. fern. Burning mats of the light-weight fern break free during fires, and are kited away by heat Origin: Tropical Asia, Africa and Australia plumes, leading to distant fire-spotting. Addition- ally, the plant acts as a flame ladder, carrying fire Family: Lygodiaceae, Climbing Fern Family high into native tree canopies. Under natural condi- tions fire rarely enters the tree canopy. Canopy Botanical Description: Fern with dark fires are deadly to native cypress forests and pine brown, wiry rhizomes and climbing, twining flatwoods. Old World climbing fern has caused the fronds of indeterminate growth, to 30 m long; main loss of some canopy trees with such crown fires, as rachis (leaf stalk above petiole) wiry, stemlike. well as a loss of native epiphytes and bromeliads Leafy branches off main rachis (constituting the residing on tree trunks (S. Farnsworth, Palm Beach pinnae) once compound, oblongish in overall out- County, 1995, Personal Communication; Roberts, line, 5-12 cm long. Leaflets (pinnules) usually 1996). unlobed, stalked, articulate (leaving wiry stalks when detached). Leaf-blade tissue usually glabrous Old World climbing fern forms dense mats of below. Fertile leaflets of similar size, fringed with rachis plant material. These thick, spongy mats are tiny lobes of enrolled leaf tissue covering the spo- slow to decompose, exclude native understory rangia along the leaf margin. plants and can act as a site for additional fern colo- nization. It is difficult for other plant species to

14-19 Chapter 14: Exotic Plants in the Everglades Everglades Consolidated Report

Figure 14-3. Lygodium microphyllum (Cav.) R.Brown (Old World climbing fern). (Illustration used by permission of the University of Florida.) grow through the dense mat made by this fern, retain an 80 percent germination rate (Brown, reducing plant diversity. Large expanses of fern 1984). Fertile pinnules are usually produced where material also may alter drainage and water move- plants receive sunlight. Such exposed locations ment. also aid windborne dispersal of the spores. Old World climbing fern often establishes first at pine- Life History: Wiry Old World climbing fern land/wetland ecotones. It is usually killed back by rhizomes are able to accumulate into dense mats fire, but not eliminated, and re-growth is common one meter or more thick above native soil (J. Street, (Maithani et al., 1986). Palm Beach County, 1996, Personal Communica- tion). Vegetative growth and production of fertile Distribution: The center of dispersal in Flor- pinnules continue throughout the year. Spores can ida is reported by Beckner, 1968; and Nauman and germinate in 6-7 days, and 5-month-old spores Austin, 1978; as the Loxahatchee River Basin in

14-20 Everglades Consolidated Report Chapter 14: Exotic Plants in the Everglades

southern Martin and northern Palm Beach coun- significantly impacted by Old World climbing fern. ties. By 1993, the fern expanded into western Mar- Large tree islands are completely blanketed with tin County, and central Palm Beach County. It is this plant. Recent reports indicate that the fern is now spreading rapidly throughout the southern part spreading south through WCA-2 and WCA-3, Big of the state. Results from the 1993 District regional Cypress National Preserve, and Lee, Collier and survey showed that Old World climbing fern occu- Miami-Dade counties. Everglades National Park pied an estimated 10,935 hectares in South Florida. staff recently found a three-acre patch of the fern By 1997, this number had climbed to 15,800 hect- growing in the Ten Thousand Islands area of the ares (Pemberton and Ferriter, 1998). The tree Park near Broad River (Pernas, 1999) islands of the northern Everglades (WCA-1) are (Figure 14-4).

Figure 14-4. 1999 Old World Climbing fern distribution area.

14-21 Chapter 14: Exotic Plants in the Everglades Everglades Consolidated Report

Increased hydroperiod does not seem to have faces dark green (lateral veins obvious, lighter in an effect on this species as it has expanded greatly color), lower surfaces paler, and leaflet margins in areas that have experienced several years of often somewhat toothed. Leaves aromatic when higher-than-normal water levels. This species is crushed, smelling peppery or like turpentine. Flow- not restricted to elevated Everglades tree islands, as ers unisexual (dioecious), small, in short branched it has been noted growing in open, flooded clusters at leaf axils of current-season stems; petals sawgrass marshes in Loxahatchee National Wild- five, white to 2 mm long. Fruit a small, bright-red life Refuge (Jewell, 1996). Old World climbing spherical drupe. fern threatens to dominate many native plant com- munities in south and central Florida within the Ecological Significance: Brazilian pepper next decade (Ferriter, 1999). was imported as an ornamental in the 1840s (Bark- ley, 1944). It has bright red fruits and shiny green Control: Control options are only now being leaves that increased its popularity as a substitute explored. A biological control program funded by for holly in Florida, quickly earning the misnomer the District has been implemented, but it could be Florida holly (Morton, 1969). Its fruits are com- years before any control agents are introduced monly consumed by frugivorous birds. The dis- (Pemberton, 1998). Fire and flooding do not appear persal of seeds by these birds; namely, mocking- to be stand-alone options based on preliminary birds, cedar-birds, and especially migrating robins studies. When fire kills most above ground por- has been responsible for the spread of this species tions of this vine, it does not kill the plant. It also into outlying, non-Brazilian pepper dominated eco- appears that flooding will not kill this plant, systems, especially those that include perches, such although flooded soils may limit establishment. as trees and utility lines (Ewel et al., 1982). Rac- Herbicides and herbicide application techniques coons and opossums are known to ingest the fruits, are currently being evaluated (Stocker et al., 1998) their stools providing additional nutrients for seed The District intends be begin implementing a lim- germination and seedling growth. Brazilian pepper ited management program within the EPA in 2000. has invaded a variety of areas including, but not limited to, fallow farmland, pinelands, hardwood Brazilian Pepper hammocks, roadsides, and mangrove forests, in areas with a high degree of disturbance and natural Scientific Names: Schinus terebinthifolius, areas with little disturbance (Woodall, 1982; Fer- Brazilian pepper (Figure 14-5). riter, 1997). Brazilian pepper forms dense thickets of tangled woody stems that completely shade out Common Names: Brazilian pepper, Florida and displace native vegetation. It has displaced holly, Christmas berry, pepper tree some populations of rare listed species, such as the Beach Jacquemontia (Jacquemontia reclinata Synonymy: None House, U.S. and Fla. Endangered), and Beach Star (Remirea maritima Aubl., Fla. Endangered) (D.F. Origin: Brazil, Argentina, Paraguay Austin, Florida Atlantic University, personal obser- vations). Family: Anacardiaceae, Cashew family Life History: Brazilian pepper sprouts easily Botanical Description: Evergreen shrub or from the trunk and roots, even if the plant is tree to 13 m tall, often with multi-stemmed trunks undamaged. It flowers in every month of the year and branches arching and crossing, forming tan- in Florida, with the most intense period of flower- gled masses. Leaves alternate, odd-pinnately com- ing in the fall season, September through Novem- pound with 3 to 11 (usually 7 to 9) leaflets, these ber. Brazilian pepper fruits profusely in southern elliptic-oblong, 2.5 to 5 cm long, with upper sur- and central Florida, with wildlife consumption of

14-22 Everglades Consolidated Report Chapter 14: Exotic Plants in the Everglades

Figure 14-5. Schinus terebinthifolius, Raddi (Brazilian pepper). (Illustration used by permission of the University of Florida.) fruits contributing in large part to the spread of United States, it occurs in Hawaii, California, seeds (Ewel et al., 1982). It produces chemicals in southern Arizona, and Florida (as far north as Levy leaves, flowers, and fruits that irritate human skin and St. Johns counties, and as far west as Santa and respiratory passages (Ewel et al., 1982, Mor- Rosa County) (EPPC, 1996). ton, 1978). Brazilian pepper does not become established Distribution: Brazilian pepper is naturalized in deeper wetland communities and rarely grows in most tropical and subtropical regions, including on sites inundated longer than three to six months. other South American countries, parts of Central In the Park, for example, it is absent from marshes America, Bermuda, the Bahama islands, the West and prairies with hydroperiods exceeding six Indies, Guam, Mediterranean Europe, North months, as well as from tree islands with closed Africa, southern Asia, and South Africa. In the canopies (LaRosa et al., 1992). Once established,

14-23 Chapter 14: Exotic Plants in the Everglades Everglades Consolidated Report

however, Brazilian pepper can tolerate extended Control: Park scientists have researched a periods of shallow water inundation. It is unclear number of restoration techniques over the years. what effects deep water flooding has upon estab- Only the complete removal of the disturbed sub- lished Brazilian pepper populations. strate has resulted in recolonization by native vege- tation to the exclusion of Brazilian pepper. The Concern over the occurrence of Brazilian pep- Park initiated a full-scale substrate removal project per in salt-tolerant plant communities, e.g., man- for the entire HID in 1996. To date, 8 percent of the grove forests in southern Florida, especially in the Brazilian pepper forest has been restored. The Park, led Mytinger and Williamson (1987) to project is funded through 2016. investigate the tolerance to saline conditions. Seed germination and transplanted seedlings did not suc- Along canal levee, highway, and powerline ceed at salinities of 5 ppt or greater, which would rights-of-way, most of the control work involves largely exclude it from becoming established in the selected use of herbicides or the use of heavy mangrove forests. Invasion of saline communities equipment to physically remove Brazilian pepper can occur, however, if salinity declines due to followed up with a herbicide application. Large changes in drainage patterns resulting from natural single trees are mostly treated with a basal bark phenomena or human activities. herbicide application. This treatment provides for the greatest selectivity with no non-target effects. Within the EPA, Brazilian pepper has invaded In dense stands, foliar herbicides may be used and most of the canal levees and much of the powerline are most effective when applied aerially. Selectiv- rights-of-way. Some of the tree islands of WCA 1 ity with an aerial herbicide application can be have been colonized to varying degrees by this pest achieved by treating Brazilian pepper among tree. By far the greatest areal coverage of Brazilian deciduous vegetation in the winter. pepper within the EPA is an area called the Hole- in-the-Doughnut (HID). Situated within the bound- Biological controls have not yet been approved aries of Everglades National Park, the HID com- for general release against Brazilian pepper, prises approximately 4,000 hectares of previously although research is ongoing. The University of farmed lands (farming ceased in 1975). More than Florida, Department of Entomology and Nematol- 40 percent (1,600-plus hectares) of this area has ogy, has been investigating insect vectors of Brazil- been invaded by a dense forest of Brazilian pepper. ian pepper since 1994. Several insects have been This species also has infested more than 40,000 identified from exploratory surveys conducted in hectares in the isolated Ten Thousand Islands, and Brazil as potential biological control agents. Three is widely scattered throughout the Park, occurring insect species: a thrips (Pseudophilothrips ichini), in all habitats, particularly disturbed areas. Brazil- asawfly(Heteroperreyia hubrichi)andaleafroller ian pepper is now estimated to occupy over (Episimus utilis) have been selected for further 283,400 ha in central and South Florida (Ferriter, study (Cuda et al., 1999). Host specificity testing 1997; Wunderlin et al., 1995) (Figure 14-6). for the sawfly are completed, and a petition to release this species has been submitted. A permit to release is expected in 2000.

14-24 Everglades Consolidated Report Chapter 14: Exotic Plants in the Everglades

f‚esvsex2€i€€i‚ vERH

vEU

‡ge2I ƒEIHi 5 vEQW

ƒEIHh 5 ƒEIHg 5 ƒEIHe5 ‡ge2Pe

vEQT

ƒEIIg 5 sEUS222ƒ‚2VR ƒEIIf 5 ‡ge2 ƒEIIe 5 Pf

gEII ‡ge2Qe

gEW2

gET ƒ‚2RI ‡ge2 Qf ƒEIPe ƒEIPf ƒEIPg gER 555 5 55 vEPW ƒEIPi i—st ƒEIPp ƒEIPh ivergl—des

i†i‚qvehiƒ prog xe„syxev €ond €e‚u gEIII

roleEinEthe honut

5 ƒtru™tures ƒp‡wh2g—n—ls gounty2vines ‡ges ix€ S H S IH wiles fr—zili—n2 €epper

Figure 14-6. 1999 Brazilian pepper distribution area.

14-25 Chapter 14: Exotic Plants in the Everglades Everglades Consolidated Report

Australian Pine Three species of Australian pine trees invade Florida’s wild lands. Since their introduction in the Scientific Names: Casuarina equisetifolia, late 1800s, they have been widely planted through- Casuarina glauca, Casuarina cunninghamiana, out the southern peninsula. It was not until 1992 Australian pine (Figure 14-8) that the state banned the further propagation and sale of these trees as ornamentals. Australian pine Common Names: Australian pine, beef- grows very fast (1-3 meters per year), is salt-toler- wood, ironwood, she-oak, horsetail tree ant, and readily colonizes rocky coasts, dunes, sandbars, islands, and invades far inland moist hab- Synonymy: Casuarina littorea L. ex Fosberg itats, such as the East Everglades Area of Ever- &Sachet,C. litorea Rumpheus ex Stickman glades National Park (Morton, 1980). It forms dense forests, crowding out all other plant species. Origin: Australia, south Pacific Islands, It has crowded out vast areas of natural vegetation southeast Asia along Florida’s coastline where the public vehe- mently opposes any removal efforts. Family: Casuarinaceae, Beefwood Family Life History: Australian pine is not freeze- Botanical Description: Evergreen tree to tolerant and is sensitive to fire (Morton, 1980). It 46 m tall, usually with single trunk and open, irreg- loses branches easily and topples in high winds ular crown. Bark reddish-brown to gray, rough, (Morton, 1980). Australian pine produces allelo- brittle, peeling. Branchlets pine-needle-like, gray- pathic compounds that inhibit growth of other veg- ish green, jointed, thin (<1 mm wide), 10 to 20 cm etation (Morton, 1980), and can colonize nutrient- long, minutely ridged, hairy in furrows. Leaves poor soils easily by nitrogen-fixing microbial asso- reduced to tiny scales, 6 to 8 in whorls encircling ciations (Wilson, 1997). It reproduces prolifically joints of branchlets. Flowers unisexual (monoe- by seed - as many as 600,000 to the kilogram with cious), inconspicuous, female in small axillary seeds dispersed by birds (especially exotic parrots clusters, male in small terminal spikes. Fruit a tiny, and parakeets), water, and wind (Morton, 1980). one-seeded, winged nutlet (samara), formed in The fruiting heads of this species float (Maxwell, woody cone-like clusters (fruiting heads), these 1984). brown, to 2 cm long and 1.3 cm wide. Distribution: Australian pine occurs through- Ecological Significance: Australian pine out South Florida, from Orlando south, on sandy was introduced to Florida in the late 1800s (Mor- shores and in pinelands. It occurs as far north as ton, 1980). It naturalized since the early 1900s Dixie County on the west coast and Volusia County along coastal dunes (Small, 1927). Australian pine on the east (Wunderlin et al., 1995). It frequently was planted extensively in the southern half of the colonizes disturbed sites, such as filled wetlands, stateaswindbreaksandshadetrees(Morton, road shoulders, cleared land, and undeveloped lots 1980). It is salt-tolerant and seeds freely through- (Maxwell, 1984). out the area, growing even in front-line dunes (Long and Lakela, 1971; Watkins, 1970). Its rapid Australian pine is mainly a problem along growth, dense shade, dense litter accumulation, levee berms in the WCAs. A large portion of the and other competitive advantages are extremely East Everglades and the southern saline glades destructive to native vegetation (Nelson, 1994). (C-111 basin), and coastal areas of the Park are Australian pine can encourage beach erosion by heavily impacted. The seeds are wind blown, car- displacing deep-rooted native vegetation, and ried by birds, and probably moved throughout the interfere with the nesting of endangered sea turtles EPA via water flow in canals. Australian pine has a and the American crocodile (Klukas, 1969). microbial association with nitrogen-fixing organ-

14-26 Everglades Consolidated Report Chapter 14: Exotic Plants in the Everglades

Figure 14-7. Casuarina spp. (Australian pine). (Illustration used by permission of the University of Florida.) isms that allow it to colonize and grow prolifically Control: Fire is sometimes effective in dense in nutrient impoverished soils. With this nitrogen- stands with sufficient fuel on the ground. Larger fixing capacity and a lack of natural enemies, Aus- trees usually resprout from the bases and require tralian pine has a tremendous competitive edge some form of follow-up herbicide treatment. There over natural vegetation. Until recently, Australian is no biological control research being conducted at pine was the dominant tree species growing along this time, even though it is a good candidate for the canal levees of the EPA. The largest remaining this control method. It is not likely that biological populations of Australian pine in the EPA are orig- control will be an option in the near future due to inal plantings growing along S.R. 27 in Broward the tree's popularity in urban landscapes and County and wild populations growing in the East coastal communities. Everglades Area (Figure 14-8)

14-27 Chapter 14: Exotic Plants in the Everglades Everglades Consolidated Report

The primary method of control is selective use along canal levees of the EPA. Periodic followup is of herbicides. Although several soil-active herbi- required to treat seedlings that arise from the resid- cides are effective, the most common control tech- ual seedbank. Retreatment is conducted prior to niques involve basal bark and cut-stump herbicide saplings maturing and flowering in order to deplete applications. The District has nearly completed its the existing seed bank and avoid creating a new control of mature Australian pine trees growing one.

Figure 14-8. 1999 Australian pine distribution area.

14-28 Everglades Consolidated Report Chapter 14: Exotic Plants in the Everglades

Leatherleaf

Scientific Name: Colubrina asiatica,lather- leaf (Figure 14-9)

Common Names: Latherleaf, Asiatic or common colubrina, hoop withe, Asian snakeroot

Synonymy: None

Origin: Old World

Family: Rhamnaceae, Buckthorn Family

Botanical Description: Glabrous, ever- green, scrambling shrub with diffuse, slender branches to 5 m long; in older plants, stems to 15 m long. Leaves alternate, with slender petioles to 2 cm long; blades oval, shiny dark green above, 4 to 9cmlongand2.5to5cmwide,withtoothedmar- gins and producing a thin lather when crushed and rubbed in water. Flowers small, greenish white, in short branched, few-flowered clusters at leaf axils; each with a nectar disc, five sepals, five hooded petals, and five stamens. Fruit a globose capsule, Figure 14-9. Colubrina asiatica (L.) Brogn green and fleshy at first and turning brown upon (Latherleaf. (Illustration used drying, about 8 mm wide, with three grayish seeds. by permission of the University of Florida.) Ecological Significance: Latherleaf is thought to have been brought to Jamaica in the 1850s by East Asian immigrants for traditional use hammocks, where it threatens a number of rare, as medicine, food, fish poison, and soap substitute listed native plant species, such as mahogany, (Burkill, 1935; Perry, 1980). It is noted as natural- thatch palm, wild cinnamon, manchineel, cacti, ized in the Keys and Everglades by Small, 1933, bromeliads, and orchids (Jones, 1996). It is also and as aggressively spreading along these coasts by now in every park in the Florida Keys, where it (Morton, 1976; Austin, 1978). Latherleaf invades threatens rare natives such as bay cedar and beach marly coastal ridges just above the mean high tide star (J. Duquesnel, Florida Park Service, 1994 per- line (Russell et al., 1982), in tropical hammocks, sonal communication). buttonwood and mangrove forests, and tidal marshes (Schultz, 1992). It also forms thickets on Life History: Latherleaf requires consider- disturbed coastal roadsides. Latherleaf can invade able light, with seedling growth rate increasing disturbed and undisturbed forest sites (Olmsted et where shade is removed; stems may grow 10 m in a al., 1981; Jones, 1996), forming thick mats of single year (Schultz 1992). It forms adventitious entangled stems up to several feet deep, and grow- roots where branches touch the ground, and vigor- ing over and shading out native vegetation, includ- ously resprouts from cut or injured stems. This spe- ing trees (Langeland, 1990; Jones, 1996). This cies may reach seed-producing maturity within a species is of particular concern in Florida’s coastal year (Russell et al., 1982, Schultz 1992). It flowers

14-29 Chapter 14: Exotic Plants in the Everglades Everglades Consolidated Report

in Florida most often in July, with fruits maturing ther facilitate its spread inland. Storms and extreme in September (Jones, 1996), but is reported as tides appear to be the only dispersal agents. flowering year-round (Long and Lakela, 1971; Wunderlin, 1982). Loose soil is usually required Latherleaf was casually noted as existing in the for germination, with seeds able to retain viability Park until the 1970s when large monotypic stands in soil for at least several years (Russell et al., up to one hectare in area were observed along the 1982). Long-distance dispersal is aided primarily coast of Florida Bay (Russell et al., 1982). In 1974, by storms and extreme tides, which allow ocean Park staff reported 130 ha of latherleaf growing at currents to carry away the buoyant, salt-tolerant sites along the coast from Christian Point to Santini fruits and seeds (Carlquist, 1966). Bight, including some of the offshore keys (Harold Werner, Everglades National Park, unpublished Distribution: Latherleaf is found naturally memo). In 1980, a detailed vegetation and map- from eastern Africa to India, Southeast Asia, tropi- ping study of the coast between Flamingo and Joe cal Australia, and the Pacific Islands, including Bay revealed 50 ha of high density stands (Olmsted Hawaii, where it typically occurs as scattered et al., 1981). Interpretation of 1987 color infrared plants on sandy and rock seashores (Brizicky, aerial photographs (1:10,000 scale) of the Park by 1964; Johnston, 1971; Tomlinson, 1980). From Rose and Doren, 1988 showed that the areal extent Jamaica, it has spread in the New World to other of medium to high-density latherleaf along the Caribbean islands, Mexico, and Florida, with the same stretch of coastline (Snake Bight to Joe Bay) aid of ocean currents and storm tides (Russell et al., was 230 ha. Photo-interpretation of 1994/95 USGS 1982). In Florida, it is now naturalized in coastal NAPP color infrared photographs (1:40,000 scale) areas from Key West north to Hutchinson Island in by the University of Georgia’s Center for Remote St. Lucie County (Schultz, 1992). Sensing and Mapping Science has provided the lat- est information on the distribution of latherleaf in Nowhere in Florida are the ecological effects the park. Low to high-density infestations of lath- of latherleaf more noticeable than in Everglades erleaf covered nearly 420 ha for the same area. An National Park (Jones, 1997). Latherleaf is well dis- 84 percent increase in latherleaf extent over the 7- tributed throughout the Park’s coastal areas. It year period was reported. From this mapping data, occurs from the Ten Thousand Islands south to it can be estimated that the areal extent of latherleaf Cape Sable along the Gulf Coast and east along the may double every 10 years, spreading at the rate of northern fringe of Florida Bay to the Florida Keys. approximately 25 ha per year (Figure 14-10). Latherleaf occupies approximately 500 hectares of the most remote areas of the Park. Coastal hard- Control: Latherleaf has been successfully wood forests are among the most threatened plant managed in Biscayne National Park as well as on communities in southern Florida. The aggressive other public lands. Uprooting the young, shallow- colonization nature of latherleaf and continued rooted plants, cutting scandent stems, and applying expansion into these areas is especially disconcert- herbicides, either cut-stump or basal bark, have ing. proven effective (Langeland, 1990). Biological control is not currently available—a situation not Fortunately, there is no evidence of long dis- likely to change anytime soon. To date, manage- tance dispersal mechanisms on land that could fur- ment efforts within the Park have been restricted due to funding limitations.

14-30 Everglades Consolidated Report Chapter 14: Exotic Plants in the Everglades

Figure 14-10.1999 latherleaf distribution area

14-31 Chapter 14: Exotic Plants in the Everglades Everglades Consolidated Report

Waterhyacinth Botanical Description: Floating aquatic herb, rooting in mud if stranded, usually in dense Scientific Name: Eichhornia crassipes, mats with new plantlets attached on floating green waterhyacinth (Figure 14-11) stolons. Submersed roots blue-black to dark purple, feathery, dense near root crown, tips with long dark Common Names: Waterhyacinth, water- root caps. Leaves formed in rosettes; petioles to 30 orchid cm or more, spongy, usually inflated or bulbous, especially near base; leaf blades roundish or Synonymy: Piaropus crassipes (Mart.) Britt. broadly elliptic, glossy green, to 15 cm wide. Inflo- rescence a showy spike above rosette, to 30 cm Origin: Amazon basin long. Flowers lavender-blue with a yellow blotch, to 5 cm wide, somewhat two-lipped; petals 6, sta- Family: Pontederiaceae, Pickerelweed Family mens 6. Fruit a three-celled capsule with many seeds.

Figure 14-11.Eichhornia crassipes (Mart.) Solms-Laub. (Waterhyacinth). (Illustration used by permission of the University of Florida.)

14-32 Everglades Consolidated Report Chapter 14: Exotic Plants in the Everglades

Ecological Significance: Waterhyacinth is canals and around most of the water control struc- reported as a weed in 56 countries (Holm et al., tures. In addition, they can often be found growing 1979). It was introduced to the United States in at the mouth of airboat trails that transect the 1884 at an exposition in New Orleans, reaching canals. However, they do not appear to compete Florida in 1890 (Gopal and Sharma, 1981). By the with native vegetation in the EPA away from these late 1950s, waterhyacinth occupied about 51,000 disturbed environments (Figure 14-13). ha of Florida’s waterways (Schmitz et al., 1993). It grows at explosive rates exceeding any other tested Control: Waterhyacinth and water lettuce are vascular plant (Wolverton and McDonald, 1979); both free-floating aquatic plants. They cause simi- doubling its populations in as little as 6 to 18 days lar problems and are managed in a like manner. (Mitchell, 1976). In large mats it degrades water Consequently, control methods for both species quality and dramatically alters native plant and ani- will be discussed together. mal communities (Gowanloch, 1944; Penfound and Earle, 1948). Large mats of waterhyacinth can The District conducts operations under permit collect around water control structures and impede from the DEP and performs all work in accordance flow. with both federal and state regulations. The Dis- trict’s primary goal is to implement a “maintenance Life History: Waterhyacinth reproduces both control program.” Florida State Statute, Chapter vegetatively and sexually (Penfound and Earle, 372.925, defines maintenance control as “... a 1948; Gopal and Sharma, 1981). It quickly forms method of managing exotic aquatic plants in which new rosettes on floating stolons, with stolons easily control techniques are utilized in a coordinated broken, the plants and mats are transported by manner on a continuous basis to maintain a plant wind and water. Leaves are killed back by moder- population at the lowest feasible level.” Mainte- ate freezes, but regrow quickly from the stem tip nance control results in the use of less herbicides, protected beneath the water surface. It flowers the deposition of less organic matter (from dead year-round in mild climates, producing abundant leaves and plants), less overall environmental seeds in developed mats (Penfound and Earle, impact by weeds, and reduced management costs. 1948). Numerous seedlings are seen in conjunction with lake drawdowns (K.A. Langeland, University The primary method of floating exotic aquatic of Florida, personal observations). weed control for the EPA has been with herbicides. The herbicides used for management of these Distribution: Waterhyacinth now occurs glo- plants are diquat and 2,4-D. Both are fully bally in the tropics and subtropics, and further approved by the U.S. Environmental Protection north and south where it can escape severe cold Agency for application to aquatic sites. Mechanical (Holm et al., 1977). It is found throughout Florida, controls have been generally limited to work in and northtoVirginia(andNewYork)andwesttoCali- around structures where plants have modified dis- fornia and Hawaii, 16 states in all (USDA, 1997). charge capacities and need to be physically removed. The process of mechanically harvesting Under ideal growing conditions, these plants waterhyacinth and water lettuce is slow and expen- can increase their surface coverage by 25 percent sive (10-15 times more than herbicide controls). per month when not managed (IFAS maintenance Harvested plant biomass must be removed from the control flyer from Langeland). The thick floating water to be effective, and near-shore disposal mats of vegetation block boating access within the options are often limited, adding considerable costs EPA, clog water control structures, negatively to mechanical removal. impact water quality, and reduce native plant spe- cies. These plants are almost exclusively located in Mechanical harvesting cannot be considered a artificial environments. They are common in all stand-alone option for floating weed management

14-33 Chapter 14: Exotic Plants in the Everglades Everglades Consolidated Report

in the EPA canals. While insects have been intro- pleted field assessments in Peru searching for and duced as biological controls for both species, they identifying candidate insects for study in U. S. have not yet introduced the compliment of insect quarantine. Herbicides applications remain the pri- vectors to “control” plant growth. USDA-ARS bio- mary control method and are either applied by boat control researchers have recently (May 1999) com- or helicopter.

‡e„i‚r‰egsx„r vERH

vEU

‡ge2I ƒEIHi 5 vEQW

ƒEIHh 5 5 ƒEIHg 5 ƒEIHe ‡ge2Pe

vEQT

ƒEIIg 5 sEUS222ƒ‚2VR ƒEIIf 5 ‡ge2 ƒEIIe 5 Pf

gEII ‡ge2Qe

gEW2

gET ƒ‚2RI ‡ge2 Qf ƒEIPe ƒEIPf ƒEIPg gER 555 5 55 vEPW ƒEIPi i—st ƒEIPp ƒEIPh ivergl—des

i†i‚qvehiƒ prog xe„syxev €ond €e‚u gEIII

roleEinEthe honut

5 ƒtru™tures ƒp‡wh2g—n—ls gounty2vines ‡ges ix€ S H S IH wiles ‡—terhy—™inth

Figure 14-12.1999 Waterhyacinth distribution area.

14-34 Everglades Consolidated Report Chapter 14: Exotic Plants in the Everglades

Water Lettuce Botanical Description: Floating herb in rosettes of gray-green leaves, rosettes occurring Scientific Name: Pistia stratiotes, water let- singly or connected to others by short stolons. tuce (Figure 14-14) Roots numerous, feathery. Leaves often spongy near base, densely soft pubescent with obvious par- Common Name: Water lettuce allel veins, slightly broader than long, widest at apex, to 15 cm long. Flowers inconspicuous, clus- Synonymy: None teredonsmallfleshystalknearlyhiddeninleaf axils, with single female flower below and whorl Origin: Africa or South America of male flowers above. Fruit arising from female flower as a many-seeded green berry. Family: Araceae, Arum Family

Figure 14-13. Pistia stratiotes, L. (water lettuce). Illustration used by permission of the University of Florida.)

14-35 Chapter 14: Exotic Plants in the Everglades Everglades Consolidated Report

Ecological Significance: Water lettuce Secondary Species: Other exotic species may have been introduced to North America by of concern in the WCAs are mainly restricted to the natural means or humans (Stoddard, 1989). It was levee berms. These plants include: Java plum seen as early as 1774 by William Bartram, in “vast (Syzygium cumini), earleaf acacia, (Acacia auricul- quantities” several miles in length, and in some forms), ficus (Ficus microcarpa), bishopwood places a quarter of a mile in breadth in the St. Johns (Bischofia javanica), guava (Psidium guajava), River (Van Doren, 1928). It has been suggested Surinam cherry (Eugenia uniflora), lead tree (Leu- that trade via St. Augustine, founded in 1565, may caena leucocephala), climbing cassia (Senna pen- have provided an early avenue for introduction into dula), wild taro (Colocasia esculenta), lantana the St. Johns watershed (Stuckey and Les, 1984). (Lantana camara), Burma reed (Neyraudia rey- Water lettuce is capable of forming vast mats that naudiana), napiergrass (Pennisetum purpureum), disrupt submersed plant and animal communities. kudzu (Pueraria montana), schefflera (Schefflera These mats can collect around water control struc- actinophylla) and torpedograss (Panicum repens). tures and interfere with water movement and navi- Hydrilla and hygrophila are submersed aquatic gation (Bruner, 1982; Attionu, 1976; Sharma, plants that are found mainly in canals and around 1984; Holm et al., 1977). It is considered a serious water control structures. weed in Ceylon, Ghana, Indonesia, and Thailand and at least present as a weed in 40 other countries Shoebutton ardisia is a shade-loving shrub that (Holm et al., 1979). was originally reported from the Hole-in-the- Doughnut. It has spread into adjacent tropical hard- Life History: Water lettuce reproduces rap- wood hammocks in the Long Pine Key area of the idly by vegetative offshoots formed on short, brittle Park (Seavey and Seavey, 1994) and was observed stolons. Rosette density varies seasonally, from to have spread to the Flamingo Bay area in 1995 less than 100 to over 1,000 per square meter in (Doren and Jones, 1997). Other species of concern South Florida (Dewald and Lounibos, 1990). Seed in the Park are less widespread and extremely vari- production, once thought not to occur in North able in their distributions, the habitats they invade, America, is now considered important to reproduc- and the sizes of their infestations. Several of these tion and dispersal (Dray and Center, 1989). Water species have persisted from cultivation and have lettuce is not cold-tolerant (Holm et al., 1977). It shown the ability to spread from their points of can survive for extended periods of time on moist introduction: sisal hemp (Agave sisalana), muck, sandbars, and banks (Holm et al., 1977). woman’s tongue (Albizia lebbeck), orchid tree (Bauhinia variegata), mast wood (Calophyllum Distribution: Water lettuce is now one of the antillanum), Surinam cherry, lantana, lead tree, most widely distributed hydrophytes in the tropics tuberous sword fern (Nephrolepis cordifolia), half (Holm et al., 1977). In North America, it occurs in flower (Scaevola taccada), ground orchid (Oeceo- peninsular Florida and locally westward to Texas clades maculata), guava, oyster plant (Rhoeo (Godfrey and Wooten, 1979). It is also found per- spathacea), bowstring hemp (Sansevieria hya- sisting in coastal South Carolina (Nelson, 1993). cinthoides), shefflera, arrowhead vine (Syngonium Water lettuce occurred in 68 public water bodies in podophyllum), and tropical almond (Terminalia Florida by 1982 and in 128 waterbodies by 1989 catappa). Infestations consist of scattered indi- (Schardt and Schmitz, 1990). In the Everglades viduals, except in the case of sisal hemp, tuberous region, water lettuce is mainly restricted to canals sword fern, ground orchid, oyster plant, bowstring and around water control structures. It also occurs hemp, and arrowhead vine - all species that spread in the artificial waterbodies of the Park vegetatively and produce locally dense popula- (Figure 14-14). tions. The coastal species, mahoe (Hibiscus tilia- ceus)andseasidemahoe(Thespesia populnea), Control: See waterhyacinth control section. and the grasses, cogongrass (Imperata cylindrica),

14-36 Everglades Consolidated Report Chapter 14: Exotic Plants in the Everglades

Burma reed and napiergrass, have reached the Park by natural expansion from outside sources and are represented by single plants and dense clones.

Figure 14-14. 1999 water lettuce distribution area.

14-37 Chapter 14: Exotic Plants in the Everglades Everglades Consolidated Report

INFORMATION GAPS AND FUTURE NEEDS

Rudimentary elements of a good invasive On the state level, the Department of Agricul- exotic plant management strategy—legislation, ture and Consumer Services Division of Plant coordination, planning, research, education, train- Industry's staff does much to assist in the control of ing, and resource input—have been in place in invasive exotic plants in natural areas. However, in Florida for many years. The plants that are recog- a regulatory context, plants on the FDACS Nox- nized as primary species in the Everglades region ious Weed List are primarily listed because of their are all being controlled to some extent by state or threat to agriculture, not to native ecosystems. federal agencies. Unfortunately, there are dozens of While FDACS (Division of Forestry) fights a other exotic species growing in the Everglades whole host of invasive exotic plants in its state for- with unknown invasive potential. Invasiveness is ests, most of the plants they control are not on their often somewhat slow to develop. Plants that appear own agency’s list. benign for many years, or even decades, can sud- denly spread rapidly following certain events, such In the summer of 1999, FDACS amended their as flood, fire, drought, long-term commercial list to include 11 new species that are threats to nat- availability, or some other factor. There is a need to ural areas. The species are: carrotwood (Cupaniop- recognize these species during their incipient phase sis anacardioides), dioscorea (Dioscorea alata and or even prior to introduction to maximize available Dioscorea bulbifera), Japanese climbing fern, Old management resources. World climbing fern, Burma reed, sewer vine (Pae- deria cruddasiana), skunkvine (Paederia foetida), MANAGEMENT AUTHORITIES AND kudzu, downy myrtle (Rhodomyrtus tomentosa) REGULATIONS and wetland nightshade (Solanum tampicense). The addition of these plants is a good indicator of a Although U.S. regulations on the import of growing shift in agricultural rules and regulations exotic species in general are extensive, there is vir- to incorporate the protection of natural areas in tually no regulation against bringing many exotic their regulatory focus. plant species into the United States. Barring the primarily agricultural weeds on the Federal Nox- EVERGLADES RESTORATION AND ious Weed List, importation laws focus on plant INVASIVE EXOTIC PLANTS pests, not pest plants. Insects and pathogens are screened extensively at ports of entry, but plants It is tempting to assume that once restoration are allowed to enter this country virtually unim- efforts “get the water right,” there will be a reduced peded. Upfront screening methods need to be need to control exotic plants in the Everglades. developed for new plant species. In Australia and Although it is true that the spread of some exotic New Zealand, there are strict regulations regarding plant species can be reduced by increasing hydro- exotic plant importation. These countries have periods (i.e., Brazilian pepper), there has been little developed comprehensive “white lists” of plants or no research done to determine what effects long that are permitted for import. If the plant is not on range hydrologic changes will have on most of the the list, it cannot enter the country without a Risk other exotic plant species throughout the system. Assessment. At a minimum, state and federal agen- Ongoing tree island research has focused on the cies importing plants for food, fiber, or forage eval- effects of high water but has completely ignored uation should have a protocol, which screens for the effects of exotic plants like Old World climbing invasiveness prior to recommending new plant spe- fern. Exotic plant communities in the Everglades cies for cultivation. Stormwater Treatment Areas (STAs) will need to

14-38 Everglades Consolidated Report Chapter 14: Exotic Plants in the Everglades

be monitored and measured as changes to the tant opportunity to assess the plant community hydrology are made. response to cessation of agriculture. The Univer- sity of Florida, Center for Aquatic and Invasive A more comprehensive approach needs to be Plants has begun tracking the vegetational changes taken when looking at the long-term restoration through time in the western sections of the property process in regard to the exotic plant species com- (Stocker, 1999). Lessons learned from this assess- position response. For example, the District pur- ment should assist future decision-making pro- chased the Frog Pond in May 1995, in an effort to cesses as other agriculturally-based lands are improve water delivery into Everglades National considered for Everglades restoration. Park and Florida Bay through Taylor Slough. Cur- rent restoration plans for the Frog Pond call for a NOXIOUSEXOTICWEEDTASKTEAM floodway that will simulate natural water delivery REPORT into Taylor Slough, use natural vegetation and soil microbial processes to cleanse runoff, and restore There is a clear need for more a comprehensive the connection between Taylor Slough and its plan that incorporates broad and consistent strate- headwaters. gies, reduces agency inconsistencies, and takes into account differing agency mandates in order to Agriculture, consisting of rock-plowing the achieve the goal of controlling invasive plants. surface of limestone formations to produce tillable This would result in a strategy that is appropriate rock fragments and annual production of vegeta- and applicable to and coordinated with the broader bles, started at various times in the 1970s and state and federal efforts to manage invasive exotic 1980s throughout the area. Experience in the Park plants, and supports each agency in conducting its indicates that when rock-plowed land is released role in the broader program of invasive plant con- from farming, it is vulnerable to colonization by trol. It is hoped that when complete, the NEWTT exotic species. One important colonizer of these Assessment and Strategy will fill this need. rock-plowed lands is Brazilian pepper. Other exotic plant colonizers include Australian pine, MANAGEMENT EFFORTS melaleuca, Burma reed, cogongrass, napiergrass, and wild taro. Formerly plowed and planted fields Economic impacts of plant invasions in the in the western sections of the Frog Pond are cur- EPA cannot be directly drawn from the literature. rently dominated by native and introduced grasses, Studies documenting the expansion of some spe- herbaceous species, and several introduced woody cies imply that control would be cheaper when vines and shrubs. Plant species composition in populations are small (Laroche and Ferriter, 1992). some fields appears very uniform with only a few But no direct analyses of the environmental and species present, while other fields are more vari- cultural costs and benefits of invasive plant control able, possibly reflecting historical vegetation pat- in the Everglades are available in the literature. The terns, historical seed bank patterns, differences in lack of such background information limits the past agricultural practice (crops planted, fertilizer strength of arguments to control these pest species. applied, herbicides used, etc.), or differences in A few citations quantify the costs, impacts, and hydrology, rock fragment depth, fire history, or any benefits resulting from control of aquatic weeds in of a number of possible unknown impacts. a few Florida waterbodies (Colle, 1987; Milon, 1986), but none for wetlands like the EPA. Further, Pressure to maintain and restore wetland habi- it might be argued that there should be no need to tats like the Frog Pond has increased the need to study obvious catastrophes. Yet, basic foundational develop scientifically-based methods to manage research is often needed to construct convincing both agricultural, formerly-agricultural, and wild- arguments for exotics control. land resources. The Frog Pond provides an impor-

14-39 Chapter 14: Exotic Plants in the Everglades Everglades Consolidated Report

For many of upland exotic plants, research has PUBLIC/PRIVATE PARTNERSHIPS not focused upon the most effective and current control methods. Specific controls for melaleuca, Invasive exotic pest plants recognize no politi- Brazilian pepper, and a very few others have been cal boundaries. Natural resource managers increas- the subject of formal and informal research. For the ingly recognize that parochial management majority of other species, only general guidelines approaches to these problems are ineffective. With- of herbicide use or physical attack apply. A wide out a regional approach, effective containment of a range of unknowns remains for each species. pest plant is impossible. This strategy has proven Research might show, as examples, how best to successful with the management of melaleuca on control each plant in different settings, how to min- public lands. However, adjacent privately-held imize non-target damage, or whether treatments lands continue to harbor melaleuca. Without incen- during different seasons or stages of growth of tives for private landowners to remove melaleuca, each plant will affect results. these contaminated lands will be a seed source for neighboring public lands for years to come. This BIOLOGICAL CONTROL issue needs to be addressed when dealing with plants like Old World climbing fern. Spores of this Isolating, testing, and releasing a host-specific plant can easily be spread from the source for insect to control an invasive exotic plant in the miles. Until control efforts effectively involve all United States can take more than a decade as in the of the affected populace, control will not be practi- case of the melaleuca snout beetle. Once an insect cable. This may require the expenditure of public has been properly selected and screened, it must be monies on private lands or property tax breaks that approved by a Federal Technical Advisory Group provide a financial incentive for control. (TAG) and, in Florida, a State Arthopod Commit- tee. Although the process is necessary, it can be ECOLOGICAL IMPACTS OF INVASIVE extremely slow, as there are no deadlines for PLANTS review set by the committee(s), and the review pro- cess for each request for release does not seem to Relatively little work has been done investigat- be a priority for staff at participating agencies— ing the ecological impacts of invasive species in especially in the case of agents that target natural the EPA. Without specific published proof, area weeds. The process needs to be streamlined resource managers can be somewhat “out on a and formalized. limb” when arguing for support to manage invasive plants. Compounding the problem is a lack of specific biological control quarantine facility space in Flor- While melaleuca (O’Hare, 1997; Sowder, ida for environmental weeds. The only quarantine 1985; Ostrenko, 1981) and Brazilian pepper (Cur- facility currently available for this work in Florida nutt, 1989; Gogue, 1974) have been found to is a small, out-dated lab located in Gainesville. decrease wildlife species diversity, such studies are Available space is shared with researchers screen- rare in the literature published on these species. ing biological controls for agricultural pests. This More publications have come from management, space limitation has restricted the number of agents monitoring, or botanical investigations (Ferriter, the researchers can study, creating a serious bottle- 1997; Laroche, 1999). For most of the other inva- neck. sive plants found in the EPA, very few publications are available of even a general nature, and virtually none of these formally assesses the ecological impacts of each species.

14-40 Everglades Consolidated Report Chapter 14: Exotic Plants in the Everglades

LITERATURE CITED

Adams, C.D., 1972. Flowering Plants of Bradley, K., S. Woodmansee and G. Gann, Jamaica, University of the West Indies, Mona, 1997. Ground Truthing of Exotic Species Monitor- Jamaica, 848 pp. ing on District-Managed Lands in South Florida. Final Report. Attionu, R.H., 1976. Some effects of water let- tuce (Pistia stratiotes, L.) on its habitat. Hydrobio- Brown, V.M., 1984. A biosystematic study of logia 50:245-254. the fern genus Lygodium in Eastern North Amer- ica. MS Thesis. Univ. of Central Fla., Orlando. 81 Austin, D.F., 1978. Exotic plants and their pp. effects in southeastern Florida. Environ. Conserv. 5:25-34. Brunner, M.C., 1982. Water-lettuce, Pistia stratiotes L. Aquatics 4:4-14. Austin, D.F., 1998. Invasive exotic climbers in Florida: Biogeography, ecology, and problems. Fla. Canfield, D.E. Jr., K.A. Langeland, and M.J. Scientist 61: 106-117. Maceina, 1983. Trophic state classification of lakes with aquatic macrophytes. Can. J. Fish. Aquatic. Bailey, L.H., and E.Z. Bailey, 1947. Hortus Sci. 40: 1713-18. Second. Macmillan Co., New York. 778 pp. Coble, H.D., 1993. Weed. In The World Book Bailey, L.H., and E.Z. Bailey, 1976. Hortus Encyclopedia. World Book, Inc., Chicago, London, Third (Bailey Hortatorium staff, eds.). Macmillan Sidney, Toronto, Vol. 21: 179-180. Pub. Co, New York, NY. 1290 pp. Coile, N.C., 1996b. Preface, Invasion of the Barkley, F.A., 1944. Schinus L. Brittonia South symposium proceedings. Castanea 61: 209- 5:160-198. 213.

Barrett, M.F., 1956. Common Exotic Trees of Colle, Douglas E., J.V. Shireman, et al., 1987. South Florida. Univ. of Florida Press, Gainesville. Influence of hydrilla on harvestable sport-fish pop- 414 pp. ulations, angler use, and angler expenditure at Orange Lake, FL. N. Amer. Jour. of Fish. Mgmt. 7, Bar-Zvi, D., 1996. Tropical Gardening. Pan- 410-417. theon Books, New York. 223 pp. Cook, C.D.K., B.J. Gut, E.M. Rix, J. Schneller, Beckner, J., 1968. Lygodium microphyllum, and M. Seitz, 1974. Water Plants of the World. Dr. another fern escaped in Florida. Amer. Fern J. 58: W. Junk Pub., The Hague, Netherlands. 561 pp. 93-94. Correll, D.S., and H. B. Correll, 1982. Flora of Bodle, J.M., 1994. Does the scourge of the the Bahama Archipelago. J. Cramer, Vaduz. 1692 South threaten the Everglades? In Schmitz, D.C. pp. and T.C. Brown (eds.). An Assessment of Invasive Non-indigenous Species in Florida’s Public Lands. Correll, D.S., and M.C. Johnston, 1970. Man- Tech. Report TSS-94-100. Florida Department of ual of the Vascular Plants of Texas. Texas Research Environmental Protection, Tallahassee. 303 pp. Foundation, Renner, TX. 1881 pp.

14-41 Chapter 14: Exotic Plants in the Everglades Everglades Consolidated Report

Cox News Service. 1997. Second insect found Dray, F.A. Jr., and T.D. Center, 1989. Seed pro- to bug melaleuca. Tampa Tribune, Dec. 22, Fla./ duction by Pistia stratiotes L. (water lettuce) in the Metro: 4. United States. Aq. Bot. 33: 155-160.

Cronk, Q.C.B., and J.L. Fuller, 1995. Plant Dressler, R.L., D.W. Hall, K.D. Perkins, and Invaders. Chapman and Hall, London. 241 pp. N.H. Williams, 1987. Identification Manual for Wetland Plant Species of Florida. Publication SP- Cuda, J. P., J. C. Medal, D.H. Habeck, J.H. 35. Institute of Food and Agricultural Sciences, Pedrosa-Macedo and M. Vitorino, 1999. Classical University of Florida, Gainesville. 297 pp. Biological Control of Brazilian Peppertree in Flor- ida. EN-820. University of Florida. Gainesville, Duever, M.J., J.E. Carlson, J.F. Meeder, L.C. Florida. Duever, L.H. Gunderson, L.A. Riopelle, T.R. Alex- ander, R.L. Myers, and D.P. Spangler, 1986. The Cunningham, P. M. 1991. Exotic plant control Big Cypress National Preserve. Research Report. and restoration management of a South Florida 8, Natl. Audubon Soc., New York. 455 pp. hammock. In Center, T.D., R.F. Doren, R.L. Hoff- stetter, R.L Myers and L.D. Whiteaker (eds). Pro- Elmore, C.D., 1986. Weed survey--Southern ceedings of Symposium on Exotic Pest Plants states. Res. Rep. South. Weed Sci. Soc. 39:136- (Miami, FL, 1988) Tech. Report NP/NVEVER/ 158. NRTR-91-06. Natl. Park Service, Dept. of the Inte- rior, Washington, D.C. 387 pp. EPPC, 1996. Florida Exotic Pest Plant Council Occurrence Database. Unpublished. Data available Curnutt, J.L., 1989. Breeding bird use of a by requests via Web site: http://www.fleppc.org/ mature stand of Brazilian pepper. Fl. Ornithol. Soc., 17, 53-76. Ewel, J.J., D.S. Ojima, D.A. Karl, and W.F. DeBusk, 1982. Schinus in successional ecosystems Dassanayke, M.D., and F. R. Forsberg (eds.), of Everglades National Park. Report T-676. South 1981. A Revised Handbook to the Flora of Ceylon, Florida Research Center, Homestead. 141 pp. Vo. 2. Emerind Pub., New Delhi. 511 pp. Fairchild, D., 1938. The World Was My Gar- DeBrahm, W.G., 1773. DeBrahm's Report of den. Scribner’s, New York. 494 pp. the General Survey in the Southern District of North America. Tricentennial edition (L. Fairchild, D., 1947. The World Grows around DeVorsey,Jr.,ed.),No.3,1971.Univ.ofSo.Caro- My Door. Scribner’s Sons, New York. 347 pp. lina Press, Columbia. 325 pp. As cited in Austin, D.F., 1978. Exotic plants and their effects in south- Ferriter, A.P. (ed.), 1997. Brazilian Pepper easternFlorida.Env.Conserv.5:25-34. Management Plan for Florida. Florida EPPC, W. Palm Beach. 38 pp. Dewald, L.B., and L.P. Lounibos, 1990. Sea- sonal growth of Pistia stratiotes L. in South Flor- Ferriter, A.P., 1999. Lygodium Emergency ida. Aquatic Bot. 36: 263-275. Action Plan for Florida. A Report from Florida EPPC’s Lygodium Task Force. Florida EPPC, 22 p. Dickey, R.D., 1968. Ornamental Vines for Florida. IFAS Bulletin 172B. University of Florida, Ferriter, A.P., 1999. The Extent of Melaleuca Gainesville. 72 pp. Infestation in Florida In: Melaleuca Management Plan for Florida. Task Force Report. Florida Exotic Pest Plant Council, W. Palm Beach. 88 pp.

14-42 Everglades Consolidated Report Chapter 14: Exotic Plants in the Everglades

Gangstadt. E.O., 1976. Potential growth of sive Exotic Vines. Hobe Sound, FL. Available from aquatic plants in Republic of the Philippines and South Florida Water Management District, West projected methods of control. J. Aquat. Plant Man- Palm Beach, FL 33415. age. 14:10-14. Johnston, M.C., 1971. Revision of Colubrina Gill, H.S., and I.P. Abrol, 1991. Salt affected asiatica (Rhamnaceae). Brittonia 23: 2-53. soils, their afforestation, and its ameliorating influ- ence. Internat. Tree Crops J. 6:239-260. Jones, D.T., 1996. The Status and Management of Colubrina asiatica (Latherleaf) in Everglades Godfrey, R.K., 1988. Trees, Shrubs, and National Park. Tech. Report. South Florida Natural Woody Vines of Northern Florida and Adjacent Resources Center, Everglades National Park, Georgia and Alabama. Univ. of Ga. Press. Athens. Homestead. 7 pp. 734 pp. Jones, D., 1997. Ecological Consequences of Godfrey, R.K., and J.W. Wooten, 1979. Latherleaf (Colubrina asiatica)inSouthernFlor- Aquatic and Wetland Plants of Southeastern United ida. Wildland Weeds, Vol. 1, No. 1. States, Monocots. Univ. of Ga. Press, Athens, 712 pp. Kenoyer, L.A., 1928. Fern Ecology of Barro Colorado Island, Panama Canal Zone. Amer. Fern Godfrey, R.K., and J.W. Wooten, 1981. J. 18: 6-14. Aquatic and Wetland Plants of Southeastern United States, Dicots. Univ. of Ga. Press, Athens, 933 pp. Klukas, R.W., 1969. Exotic Terrestrial Plants in South Florida with Emphasis on Australian Pine Gogue,G.J.,C.J.Hurst,andL.Bancroft,1974. (Casuarina equisetifolia). Tech. Report. Ever- Growth inhibition by Schinus terebinthifolius. glades National Park, Homestead, FL. 8 pp. As Amer. Soc. Hort. Sci. 9, 45. cited in Austin, 1978.

Gopal, B., and K.P. Sharma, 1981. Water-Hya- Lakela, O., and F.C. Craighead, 1965. Anno- cinth (Eichhornia crassipes), Most Troublesome tated Checklist of the Vascular Plants of Dade, Col- Weed of the World. Hindasia Publishers, C.C. Col- lier and Monroe Counties, Florida. Fairchild ony, Delhi, India. 219 pp. Tropical Garden and Univ. of Miami Press, Miami, 95 pp. Gowanloch, J.N., 1944. The economic status of waterhyacinth in Louisiana. La. Conserv. 2: 3-8. Langeland, K.A., 1988. Maintenance Control of Water Hyacinths and Water Lettuce on Lake Hall, D.W., 1993. Illustrated Plants of Florida Okeechobee, Answers to Frequently Asked Ques- and the Coastal Plain. Maupin House Publishing, tions. University of Florida. Gainesville, Florida. Gainesvlle, FL. 431 pp. Langeland, K (ed.), 1990. Exotic Woody Plant Hall, D. W., and V.V. Vandiver Jr., 1990. Control. Circular 912. Institute of Food and Agri- Weeds in Florida. Florida Coop. Ext. Service, cultural Sciences, University of Florida, Gaines- IFAS, University of Florida, Gainesville. 43 pp. ville. 16 pp.

Jewell, S.P., 1996. Lygodium microphyllum's Langeland, K.A., and R.K. Stocker, 1997. coverage and apparent spread at A.R. Marshall Control of Non-Native Plants in Natural Areas of Loxahatchee National Wildlife Refuge. Paper pre- Florida. SP 242. University of Florida. Gainesville, sented to Workshop on Climbing Ferns and Inva- Florida.

14-43 Chapter 14: Exotic Plants in the Everglades Everglades Consolidated Report

Laroche, F.B., and A.P. Ferriter, 1992. Estimat- Maxwell, L., and B.M. Maxwell, 1961. Florida ing Expansion Rates of Melaleuca in South Flor- Plant Selector. Maxwell Publ., Tampa. 116 pp. ida. Journal of Aquatic Plant Management 30:62- 65 McCann, J.A., L.N. Arkin, and J.D. Williams. 1996. Nonindigenous Aquatic and Selected Terres- Laroche, F.B. (ed.), 1994. Melaleuca Manage- trial Species of Florida: Status, Pathway and Time ment Plan for Florida. Task Force Report. Florida of Introduction, Present Distribution, and Signifi- Exotic Pest Plant Council, W. Palm Beach. 88 pp. cant Ecological and Economic Effects. Report, National Biological Service, Southeastern Biologi- Lellinger, D.B., 1985. A Field Manual of the cal Science Center, Gainesville. 256 pp. Online via Ferns and Fern-allies of the United States and Can- Univ. of Florida, Center for Aquatic Plants Web ada. Smithsonian Instit. Press, Washington DC. site: http:\\aquatic1.ifas.ufl.edu\ 389 pp. McKnight, B.N. (ed.), 1993. Biological Pollu- Little, E.L. Jr., and F.H. Wadsworth, 1964. tion--The Control and Impact of Invasive Exotic Common Trees of Puerto Rico and the Virgin Species. Indiana Acad. of Science, Indianapolis. Islands. Agric. Handbk. 249. Forest Service, 261 pp. USDA, Washington, DC. 556 pp. (1989 reprint by authors.) Menninger, E.A., 1964. Seaside Plants of the World. Hearthside Press Inc., New York. 303 pp. Little, E.L. Jr., R.O. Woodbury, and F.H. Wad- sworth, 1974. Trees of Puerto Rico and the Virgin Menninger, E.A., 1970. Flowering Vines of the Islands. Agric. Handbk. 449. Forest Service, World, an Encyclopedia of Climbing Plants. USDA, Washington, D.C. 1024 pp. Hearthside Press Inc., New York. 410 pp.

Long, R.W., and O. Lakela, 1971. A Flora of Meyer, F.G., P.M. Mazzeo, and D.H. Voss, Tropical Florida. University of Miami Press. Coral 1994. A Catalog of Cultivated Woody Plants of the Gables, Florida. 962 pp. Southeastern U.S. National Arboretum Contribu- tion 7. USDA, Washington, DC. 330 pp. Long, R.W., and O. Lakela, 1976. Ferns of Florida. Banyan Books, Miami. 178 pp. Milon, J. Walter, J. Yingling, et al., 1986. An economic analysis of the benefits of aquatic weed Mahendra, K.J., B.Yu, J.M. Rogers, A.E. control in North-Central Florida. Univ. of Fla. Inst. Smith, E.T.A. Boger, R.L. Ostrander, and A.L. of Food and Agri. Sciences, Economics Report Rheingold, 1995. Specific competitive inhibitor of 113. secreted phospholipase A2 from berries of Schinus terebinthifolius. Phytochemistry 39:537-547. Mitchell, D.S., 1976. The growth and manage- ment of Eichhornia crassipes and Salvinia spp. In Maithani, G. P., V.K. Bahuguna, and P. Lal, their native environment and in alien situations. In 1986. Effect of forest fires on the ground vegeta- C.K. Varshney and J.Rzoska (eds.). Aquatic Weeds tion of the moist deciduous sal forest. India For- in South East Asia. Dr. W. Junk b.v., Publishers, ester 112: 646-667. The Hague. 396 pp.

Manks, D.S. (ed.), 1968. Handbook on Origins Morton, J.F., 1971a. Exotic Plants. Golden of American Horticulture (Plants and Gardens Vol. Press, New York. 160 pp. 23, No. 3). Brooklyn Botanic Garden, Brooklyn, NY. 90 pp.

14-44 Everglades Consolidated Report Chapter 14: Exotic Plants in the Everglades

Morton, J.F., 1971b. Plants Poisonous to Peo- Nellis, D.N., 1994. Seashore Plants of South ple in Florida and Other Warm Areas. Hurricane Florida and the Caribbean. Pineapple Press Inc., House, Miami. 116 pp. Sarasota. 160 pp.

Morton, J.F., 1974. 500 Plants of South Flor- Nelson, G., 1994. The Trees of Florida. Pineap- ida, E.A. Seamann Publishing, Miami, 163 pp. ple Press Inc., Sarasota. 338 pp.

Morton, J.F., 1976. Pestiferous spread of many Nelson, G., 1996. The Shrubs and Woody ornamental and fruit species in South Florida. Proc. Vines of Florida. Pineapple Press Inc., Sarasota. Fla. State Hort. Soc. 89: 348-353. 391 pp.

Morton, J.F., 1978. Brazilian Pepper, its impact Nelson, J.B., 1993. Noteworthy Collections: on people, animals and the environment. Econ. South Carolina. Castanea 58: 59-63. Bot. 32:353-359. Office of Technology Assessment, 1993. Morton, J.F., 1980. The Australian pine or Harmful non-indigenous species in the United beefwood (Casaurina equisetifolia L.) an invasive States. OTA-F-565. Government Printing Office, “weed” tree in Florida. Proc. Fla. State Hort. Soc. Washington, D.C. 93:87-95. O’Hare, Nancy K and G.H. Dalrymple, 1997. Morton, J.F., 1981. Atlas of Medicinal Plants Wildlife in southern Everglades wetlands invaded of Middle America, Bahamas to Yucatan. Charles by melaleuca (Melaleuca quinquenervia). Bull. C. Thomas Publisher, Springfield, IL. 1420 pp. Fla. Mus. of Nat. Hist. 41(1), 1-68.

Morton, J.F., 1982. Plants Poisonous To Peo- Olmsted, I., L. Loope, and R. Russell, 1981. ple. Southeast Printing Co., Stuart, FL. 116 pp. Vegetation of the Southern Coastal Region of Ever- glades National Park Between Flamingo and Joe Morton, J.F., and R.B. Ledin, 1952. 400 Plants Bay. Report T-260. South Florida Research Center, of South Florida. Text House Inc., Coral Gables, Everglades National Park, Homestead. 18 pp. FL. 134 pp. Oommachan, M. 1977. The Flora of Bhopal Myster, R.W., and S.T.A. Pickett, 1992. (Angiosperms). J.K. Jain Brothers, Bhopal. 475 pp. Dynamics of associations between plants in ten old fields during 31 years of succession. J. of Ecology Ostrenko, W. and F. Mazzotti, 1981. Small 80: 291-302. mammal populations in Melaleuca quinquenervia communities in the eastern Florida Everglades. In Nauman, C.E., 1978. A checklist of the ferns Geiger, R.K., ed., Proc. Melaleuca Symp., Fla of southeastern Florida, Castanea 43: 155-162. Dept.ofAg.andConsumerSvcs.,Div.ofForestry, Tallahassee, 91-98. Nauman, C.E., 1993a. Lygodiaceae C. Presl. In Flora of North America, Vol. 2. Oxford Univ. Pemberton, R., 1998. The Potential of Biologi- Press, New York. 475 pp. (pp. 114-116). cal Control to Manage Old World Climbing Fern (Lygodium microphyllum), an Invasive Weed in Nauman, C.F., and D.F. Austin, 1978. Spread Florida. American Fern Journal 88(4):176-182. oftheexoticfernLygodium microphyllum in Flor- ida. Amer. Fern J. 68:65-66. Pemberton, R., and Ferriter, A. 1998. Old World Climbing Fern (Lygodium microphyllum), a

14-45 Chapter 14: Exotic Plants in the Everglades Everglades Consolidated Report

Dangerous Invasive Weed in Florida. American pest species in South Florida’s wetlands, some Fern Journal 88(4):165-175. management considerations. Paper presented at Florida Exotic Pest Plant Council Symposium at Penfound, W.T., and T.T. Earle, 1948. The Clearwater Beach, FL. biology of the water hyacinth. Eco. Monog. 18:449-472. Royal Palm Nurseries, 1900. Annual mail- order catalogue. Oneco, Florida. 56 pp. Pernas, A., 1999. Everglades National Park. Personal communication. Russell, R.L., L. Loope, and I. Olmsted, 1982. Colubrina asiatica in Southern Florida. Tech. Popenoe, W., 1939. Manual of Tropical and Report. So. Fla. Research Center, Everglades Subtropical Fruits. Macmillan Co., New York. 474 National Park, Homestead. 18 pp. pp. Sainty, G.R., and S.W.L. Jacobs, 1981. Water Purseglove, J.W., 1975. Tropical Crops: Mono- plants of New South Wales. Stanley Owens and cotyledons I. Longman, London. 334 pp. Sons, Alexandria, New South Wales. 550 pp.

Radford, A.E., E.H. Ahles, and C.R. Bell, Schardt, J.D., 1994. Florida Aquatic Plant Sur- 1964. Guide to the Vascular Flora of the Carolinas. vey 1992. Tech. Report 942-CGA. Florida Dept. of Univ. of North Carolina Press, Chapel Hill, 383 pp. Environmental Protection, Tallahassee. 83 pp.

Radford, A.E., E.H. Ahles, and C.R. Bell, Schardt, J.D., 1997. Florida Aquatic Plant Sur- 1968. Manual of the Vascular Flora of the Caroli- vey 1994. Tech. Report 972-CGA, Fla. Dept. of nas. Univ. of North Carolina Press, Chapel Hill, Environmental Protection, Tallahassee. 86 pp. 1183 pp. Schardt, J.D., and D.C. Schmitz, 1991. Florida Randall, J. M., and J. Marinelli, 1996. Invasive Aquatic Plant Survey 1990. Tech. Report 91-CGA. Plants: Weeds of the Global Garden. Handbook Florida Dept. of Natural Resources, Tallahassee. 89 #149. Brooklyn Botanic Garden, Inc., New York. pp. 111 pp. Schmitz, D.C., and T.C. Brown (eds.), 1994. Reed, C.F., 1977. Economically Important For- An Assessment of Invasive Nonindigenous Species eign Weeds: Potential Problems in the United in Florida’s Public Lands. Tech. Report TSS-94- States. Ag. Handbook No. 498. APHIS, USDA, 100. Florida Department of Environmental Protec- Washington, D.C. 746 pp. tion, Tallahassee. 303 pp.

Rehm, S., and G. Espig, 1991. The Cultivated Schmitz,D.C.,J.D.Schardt,A.J.Leslie,F.A. Plants of the Tropics and Subtropics. Verlag Josef Dray, J.A. Osborne, and B.V. Nelson. 1993. The Margraf, Berlin. 552 pp. ecological impact and management history of three invasive alien aquatic plant species in Florida. In Roberts, R.E., 1996. The monster of Hobe McKnight, B. N. (ed.). Biological Pollution, The Sound. In Bodle, M. (ed.). Proceedings of Invasive Control and Impact of Invasive Exotic Species. Vines Workshop (1996), W. Palm Beach. 35 pp. Indiana Academy of Science, Indianapolis. 261 pp. (Available from So. Fla. Water Mgt. District.) Schmitz, D.C., D. Simberloff, R.H. Hofstetter, Roberts, R.E., and D.R. Richardson, 1995. W. Haller, and D. Sutton. 1997. The ecological Exotic climbing fern, Lygodium microphyllum, a impacts of nonindigenous plants. In Simberloff,

14-46 Everglades Consolidated Report Chapter 14: Exotic Plants in the Everglades

D.,D.C.Schmitz,andT.C.Brown(eds.),Strangers Press, Chapel Hill. 1554 pp. (Facsimile reprint in Paradise: Impact and Management of Nonindig- 1972, Hafner Publishing, New York.) enous Species in Florida. Island Press, Washington, D.C. 467 pp. Sowder, A. and S. Woodall, 1985. Small mam- mals of melaleuca stands and adjacent environ- Schultz, G. E. 1992. Colubrina asiatica.Ele- ments in southwestern Florida. Florida Sci. 48(1), ment Stewardship Abstract. The Nature Conser- 41-44. vancy, Arlington, VA. 7 pp. (Available from TNC office, Florida Museum of Natural History, Gaines- Stocker, R.K., A.P. Ferriter, D.D. Thayer, M. ville, 352-846-5949.) Rock and S. Smith, 1997. Old World Climbing Fern: Hitting South Florida Below the Belt. Wild- Scurlock, J.P., 1987. Native Trees and Shrubs land Weeds 1(1). of the Florida Keys. Laurel Press, Inc. Bethel Park, Pennsylvania. 220 pp. Stoddard, A.A. III, 1989. The phytogeography and paleofloristics of Pistia stratiotes L. Aquatics Sharma, B.M., 1984. Ecophysiological studies 11:21-23. on water lettuce in a polluted lake. J. Aquat. Plant Manage. 22:19-21. Stresau, F.B., 1986. Florida, My Eden. Florida Classics Library, Port Salerno, FL. 301 pp. Simberloff, D., 1994. Why is Florida being invaded? In Schmitz, D. C. and T. C. Brown (eds.). Stuckey, R. L., and D. H. Les, 1984. Pistia An Assessment of Invasive Non-indigenous Spe- stratiotes recorded from Florida in Bartram's trav- cies in Florida’s Public Lands. Tech. Report TSS- els, 1765-1774. Aquaphyte 4:6. 94-100. Fla. Dept. of Environmental Protection, Tallahassee. 303 pp. U.S. Congress, Office of Technology Assess- ment. 1993. Harmful Nonindigenous Species in the Simberloff, D., D.C. Schmitz, and T.C. Brown United States. Pub. OTA-F-565. U.S. Govt. Print- (eds.), 1997. Strangers in Paradise. Island Press, ing Office, Washington D.C. 391 pp. Washington DC. 467 pp. USDA, 1997. PLANTS National Database, Singh, S., and G. Panigrahi, 1984. Systematics U.S. Dept. of Agriculture, Natural Resources Cons. of genus Lygodium Sw. (Lygodiaceae) in India. Service. Web site: http://plants.usda.gov/plants Proc. Indian Acad. Sci. 93:119-133. Wagner, W.H. Jr., 1993. Problems with biotic Small, J.K., 1918a. Ferns of Royal Palm Ham- invasives: A biologist’s viewpoint. In McKnight, mock. Published by the author, New York. 39 pp. B. N. (ed.). Biological Pollution, The Control and Impact of Invasive Exotic Species. Indiana Acad- Small, J.K., 1918b. Ferns of Tropical Florida. emy of Science, Indianapolis. 261 pp. Published by the author, New York. 80 pp. Ward, D.B., 1968. Checklist of the Vascular Small, J.K., 1927. Among floral aborigines: A Flora of Florida, Part 1. Tech. Bull. 726. IFAS, record of exploration in Florida in the winter of Univ. of Fla., Gainesville. 72 pp. 1922. J. New York Bot. Gard. 28:1-20, 25-40. Watkins, J.V., 1970. Florida Landscape Plants, Small, J.K., 1933. Manual of the Southeastern Native and Exotic. University of Florida Press, Flora, Part One and Two. Univ. of North Carolina Gainesville. 368 pp.

14-47 Chapter 14: Exotic Plants in the Everglades Everglades Consolidated Report

Watkins, J.V., and T.J. Sheehan, 1975. Florida Woodall, S.L., 1981. Site requirements for Landscape Plants: Native and Exotic. Revised ed. melaleuca seedling establishment. In R.K. Geiger University Presses of Florida, Gainesville. 420 pp. (ed.). Proc. Melaleuca Symposium (Sept. 23-24, 1980). Div. of Forestry, Fla. Dept. of Agric. & Watkins, J.V., and H.S. Wolfe, 1956. Your Cons. Svcs., Tallahassee. 140 pp. Florida Garden. Univ. Presses of Florida. Univer- sity of Florida, Gainesville. 349 pp. Woodall, S.L., 1982. Herbicide tests for con- trol of Brazilian pepper and melaleuca in Florida. Westbrooks, R.G., and R.E. Eplee, 1989. Fed- Research Note SE-314. Forest Service, USDA, eral noxious weeds in Florida. Proc. So. Weed Sci. Washington DC. 10 pp. Soc. 42:316-321. Woodall, S.L., 1983. Establishment of Mela- Wherry, E.T., 1964. The Southern Fern Guide, leuca quinquenervia seedlings in the pine-cypress Southeastern and South Midland United States. ecotone of southwest Florida. Fla. Scientist 46:65- Doubleday and Co., Garden City, NY. 349 pp. 71.

Whistler, W.A., 1992. Flowers of the Pacific Woolfe, T., 1995. Water weed is latest menace. Island Seashore. Isle Botanica, Honolulu. 154 pp. Tallahassee Democrat, Aug. 3, 1995: 4C.

Wildin, J.H. 1988. Register of Australian plant Wunderlin, R.P., 1982. Guide to the Vascular cultivars. Tropical Grasslands J. 22:190. Plants of Central Florida. University Presses of Florida, Univ. of So. Fla., Tampa. 472 pp. Willis, J.C., 1973. A Dictionary of the Flower- ing Plants and Ferns. 8th ed. (rev. by H. K. A. Wunderlin, R.P., B.F. Hansen, and E.L. Shaw). Cambridge Univ. Press, Cambridge, Bridges, 1995 (updated May 1996). Atlas of Flor- England. 1245 pp. ida Vascular Plants. Web site: URL:http:// www.usf.edu/~isb/projects/hb-atlas.html Wilson, K. 1997. Casuarinaceae R. Brown. In Flora of North America North of Mexico, Vol. 3. Wunderlin, R.P., B.F. Hansen, and E.L. Oxford Univ. Press, New York. 590 pp. Bridges, 1996. Atlas of Florida Vascular Plants, CD-ROM. Institute for Systematic Botany, Dept. Wolverton, B.C., and R.C. McDonald, 1979. of Biology, Univ. of South Fla., Tampa, FL. Water hyacinth (Eichhornia crassipes) productiv- ity and harvesting studies. Econ. Botany 33:1-10.

14-48