You will take a stance on whether you think exotic-invasive plant and animal species should be controlled, removed and managed using the options provided in the book chapter Exotic Species.

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Chapter 8E: Exotic Species
in the Everglades Protection Area

Amy Ferriter, Kristina Serbesoff-King, Mike Bodle,
Carole Goodyear1, Bob Doren2 and Ken Langeland3

INTRODUCTION

Invasive exotic species have become one of the most serious global environmental problems
today (IUCN, 1999). A recent Cornell University study found that invasive species – plants,
mammals, birds, amphibians, reptiles, fish, arthropods, and mollusks – cost the United States
alone over $100 billion annually (Pimentel, 2000). Such losses and costs will inevitably continue
to increase, especially if efforts to control these invasions are scattered. Planning, resources, and
actions must be integrated effectively in order to turn back the overwhelming spread of numerous
invasive species.

Florida is listed with Hawaii and California, and now Louisiana, as one of the states with the
greatest number of nonindigenous species. South Florida contains more introduced animals than
any other region in the United States. With an estimated 26 percent of all resident mammals,
birds, reptiles, amphibians, and fish not native to the region, South Florida has one of the largest
nonindigenous faunal communities in the world (Gore, 1976; Ewel, 1986; OTA, 1993; McCann,
et al., 1996; Shafland, 1996a; Simberloff, 1996; Corn et al., 1999). More than thirty years ago, a
Smithsonian publication described tropical Florida as a “biological cesspool of introduced life”
(Lachner et al., 1970).

INVASIVE SPECIES AND EVERGLADES RESTORATION

Control of exotic invasive species is a far-reaching issue. The importance of this issue in the
Everglades Protection Area (EPA) is demonstrated by the great number of plans, reports,
statements, and papers that have been written by numerous committees, state and federal
agencies, public and private universities, state and federal task forces, and various other
organizations. Most of the plans, reports, statements, and papers support an “all-taxa” approach.

1 Retired from the National Oceanic and Atmospheric Administration
2 U.S. Department of the Interior
3 University of Florida Institute of Food and Agricultural Sciences, Everglades Research and Education Center

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The general consensus of these parties is that control and management of nonindigenous species
is a critical component of ecosystem restoration in South Florida.

The topic of invasive species has been identified as an issue since the beginning of the
Everglades restoration initiative. Several organized efforts and mandates have highlighted the
problems associated with exotic species in the Everglades region. Control and management of
invasive exotics are the priorities established by the South Florida Ecosystem Restoration Task
Force (SFERTF) in 1993. One of the tasks in the 1993 charter for the former Management
Subgroup (December 16, 1993) was to develop a restoration strategy that addressed the spread of
invasive exotic plants and animals. The U.S. Fish and Wildlife Service (USFWS) was designated
as the lead agency for this strategy and submitted a brief report (Carroll, 1994). This report
highlighted some of the following issues: (1) a limited number of species are designated as
“nuisance” species and can be prohibited by law, (2) current screening processes are deficient, (3)
responsibilities remain vague, (4) there is a general lack of awareness and knowledge of the
harmful impacts of invasive species, and (5) an urgent need exists for statewide coordination and
cooperation to eliminate exotics. The greatest obstacle to combating nonindigenous species, as
identified in this report, was the lack of sufficient funding, knowledge, and staffing to stay ahead
of problems.

The first Annual Report of the South Florida Ecosystem Restoration Working Group
(SFERWG) in 1994 addressed all nonindigenous species, plants, and animals. The overall
objectives stated were to (1) halt or reverse the spread of invasive species already widespread in
the environment, (2) eradicate invasive species that are still locally contained, and (3) prevent the
introduction of new invasive species to the South Florida environment. The Everglades Forever
Act of 1994 (EFA) requires the South Florida Water Management District (SFWMD or District)
to establish a program to monitor invasive species populations and to coordinate with other
federal, state, and local governmental agencies to manage exotic pest plants, with an emphasis in
the EPA.

The Scientific Information Needs Report (SSG, 1996) of the SFERTF contains a regionwide
chapter on harmful nonindigenous species. One of the overall regional science objectives for the
restoration is to develop control methods on exotic invasives at entry, distribution, and landscape
levels. The specific objectives for work on nonindigenous species are to (1) halt and reverse the
spread of invasive naturalized exotics, and (2) prevent invasions by new exotic species. The
major issues in South Florida are inadequate funding for scientific investigations to develop
effective controls, lack of funding to apply control methods to problem species, and delays and
lack of consistency in responses to new problems. Most resources on nonindigenous animals have
been focused on agricultural pests, with little investigation of species that threaten natural areas.
Particular information needs are as follows: (1) studies to develop control technology, (2) basic
biological and ecological studies to improve understanding of invasive exotic species (e.g., how
water management alterations will affect nonindigenous plants and animals), (3) what are the
principal controls on expansion of a species, (4) what are the impacts of invasive species on
native species and ecosystems, (5) what makes a natural area susceptible to invasion, and (6)
screening and risk assessment technology to help focus on the greatest potential problems.
Overall, the major issue is the lack of meaningful information concerning the effects of
nonindigenous species on South Florida.

The Comprehensive Review Study Final Feasibility Report and Programmatic Environmental
Impact Study (USACE and SFWMD, 1999) addresses the presence of exotic animals as one of
several factors that preclude any serious consideration of achieving true restoration of the natural
system, one in which exotic species are not present. It discusses how removal of canals and
levees, which act as deepwater refugia for exotic fish and as conduits into interior marshes for

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other species, is expected to help control exotic species by slowing further movement into
relatively pristine areas. On the other hand, restoration of lower salinity levels in Florida Bay
might result in increases of reproductively viable populations of exotic fishes, such as the Mayan
cichlid in the freshwater transition zone, and this must be addressed during detailed design.

The Fish and Wildlife Coordination Act Report for the Comprehensive Everglades
Restoration Plan (CERP) (FGFWFC, 1999) from the Florida Game and Fresh Water Fish
Commission (currently known as the Florida Fish and Wildlife Conservation Commission
[FWC]) also considers the control and management of nonindigenous species as a critical aspect
of ecosystem restoration in South Florida. The report discusses the effects of the present canal
and levee system and of the preferred alternative of this system on the distribution of
nonindigenous animals. Some CERP components involve the construction of canals and
reservoirs, which could provide additional conduits from points of introduction into the
Everglades for species such as fish, amphibians, and snails. Other components involve removal or
partial removal of canals, a process which should reduce the spread of exotic fishes. Removal of
levees, which act as artificial terrestrial corridors into the wetland landscape, should reduce the
spread of species such as the fire ant. The U.S. Department of the Interior (DOI) recommended
establishment of an Exotic Animal Task Team to work on the issue during detailed planning for
removal of existing structures or construction of new facilities as part of CERP. In relation to
planned Water Preserve Areas (WPAs) and flow-ways, it was recommended that an aggressive
plan be developed for the perpetual removal of invasive exotics, both plants and animals. It was
also recommended that existing control measures should be accelerated, more effective
techniques should be developed, and regulations should be revised and better enforced to prevent
additional introductions of exotic species (FGFWFC, 1999). The U.S. Army Corps of Engineers
and the District (USACE and SFWMD, 1999) responded that in CERP this recommendation (for
team establishment) should be presented to the SFERTF.

Several other plans and reports also address exotic invasive species. The Coordination Act
Reports (FGFWFC, 1999) emphasize that the extent of the canal system’s role in the spread of
exotic fishes into natural marshes – as opposed to the fish remaining primarily in the disturbed
areas – is debatable. The draft report, A New Look at Agriculture in Florida (Evans, 1999),
discusses the introduction of exotic pests and diseases as a serious obstacle to sustainable
agriculture and the importance of exclusion and control strategies. The South Florida
Multi-Species Recovery Plan (USFWS, 1999) identifies exotic animal control as a restoration
need for two-thirds of the ecological communities and the individual species covered in the plan.
In addition, the South Florida Regional Planning Council’s 1991 and 1995 regional plans for
South Florida list the removal of exotic plants and animals and the discouragement of their
introductions as regional policies (SFRPC 1991, 1995).

The Florida Department of Environmental Protection (FDEP) formed an Invasive Species
Working Group (ISWG) in July 2001. Representatives from 13 state agencies and/or divisions
and one state university comprise the ISWG. Jeb Bush, governor of the state of Florida, charged
this group with developing a comprehensive invasive species plan for state agencies. The plan is
complete, and the group will begin implementation after it is accepted by the governor. In a
separate but complimentary program, the FDEP also administers funding for invasive plant
control efforts in Florida through regional working groups.

In 2002, the USACE authorized a conceptual plan for a multimillion-dollar Invasive Species
Management and Control project to be implemented as part of CERP. The main components of
this project include cost-share agreements to improve quarantine facilities for biocontrol agents, a
cost-share project with the District for the release of biological-control agents, and preparation of

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a report to detail federal interest and potential federal involvement in invasive species projects
within South Florida.

On a national level, the U.S. President’s Executive Order on Invasive Species (Executive
Order 13112) recognized the threats posed by invasive species and authorized a national invasive
species council that would, among other duties, prepare a national management plan for invasive
species. This plan was finalized and released in 2001. Implementation of this plan is ongoing
through the National Invasive Species Council, which is chaired by the secretaries of agriculture,
commerce, and the interior.

NONINDIGENOUS PLANT SPECIES

The South Florida Ecosystem Restoration Task Force and Working Group identified
nonindigenous plants as a priority. As a result, the Noxious Exotic Weed Task Team (NEWTT)
was established in 1997. NEWTT is a direct working team of the South Florida Ecosystem
Restoration Task Force and Working Group. This task team has the following two main
directives: (1) the development of an assessment to characterize the current problems with
invasive exotic plants in southern Florida and to identify the highest priority invasive species for
control, and (2) the development of a comprehensive interagency strategy for elimination or
control of the highest priority species and for management to control and minimize the spread of
other pest plant species.

The task team is made up only of government agencies – federal, state, and local. To comply
with the Federal Advisory Committee Act and Florida’s Sunshine , all NEWTT meetings are
open to the public. While nongovernmental organizations are not an official part of the NEWTT,
the Florida Exotic Pest Plant Council (EPPC) provides advice and peer review to the task team.

NEWTT developed a comprehensive strategic plan covering the issues and problems of
exotic pest plants in Florida, with programmatic and management focus on the Everglades.
However, a statewide perspective was used in developing this strategic plan, because any plan
that addresses the issues of exotic pest plants cannot do so in a fragmented geographic or political
framework. Federal, state, and local governmental policies affect, interact, and sometimes
contradict one another, and therefore must be addressed synthetically. In addition, the issues and
experiences learned regionally (regarding control method development, research results, public
education, technology transfer, policy, regulation, and funding) affect all agencies and programs
throughout the state. Likewise, national-level issues related to exotic pest plants affect state and
local policies and programs. The USACE is entering into an agreement with NEWTT to develop
a report on federal invasive species interests in Florida.

NONINDIGENOUS ANIMAL SPECIES

The effort to address the issue of exotic animals in the Everglades has lagged behind that of
invasive plants. While it is relatively easy to determine the extent to which nonindigenous plants
invade natural areas, the impact of nonindigenous animals on native communities and on those
species with which they compete directly is often less obvious (Schmitz and Brown, 1994).
Several reports have highlighted this difficulty as follows:

• The Multi-Species Recovery Plan (USFWS, 1999) states the following: “It is probably safe to
say that the most severe exotic species threats to the South Florida Ecosystem come from plants,

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rather than animals. Therefore, the emphasis on exotics in Florida has been on flora, rather than
fauna.”

• The Scientific Information Needs Report (SSG, 1996) states the problem as follows: “The
role of nonindigenous animals in South Florida natural areas is so poorly documented that it is
difficult to design and mount an effective effort to control those that are harmful to native plant
and animal communities.”

• In the book Everglades, the Ecosystem and its Restoration, Robertson and Frederick (1994)
bluntly state the following:

Although biologists were quick to anticipate the developing problem, their concerns and
pleas for regulation have been thoroughly overrun by events…Any present attempt to
assess the overall threat posed by nonnative animals to the integrity of the Everglades
ecosystem seems futile…In addition, thought may tend to become paralyzed by the
obvious, perhaps insurmountable, difficulty of effective countermeasures.

In spite of these daunting conclusions, the South Florida Ecosystem Restoration Task Force
and Working Group has been gathering information that is available as a basis for an assessment
of the problem. In February 1998, the South Florida Ecosystem Restoration Task Force and
Working Group established an ad hoc interagency team to focus on South Florida and evaluate
the status of nonindigenous animals in all habitats (freshwater, marine, and terrestrial), describe
efforts underway to deal with them, and identify agency needs and problems (Goodyear, 2000).

Nonnative animal species of concern include insects, marine and freshwater fish,
invertebrates, reptiles, amphibians, mammals, and birds. Species currently identified as the
greatest concern include the feral pig (Sus scrofa), Norway and black rats (Rattus norvegicus and
R. rattus), nine-banded armadillo (Dasypus novemcinctus), European starling (Sturnus vulgaris),
brown caiman (Caiman crocodilus), Tokay gecko (Gecko gecko), spinytail iguana (Ctenosaura
pectinata, C. similis), Cuban knight anole (Anolis equestis), brown anole (A. sagrei), boa
constrictor (Boa constrictor), Burmese python (Python molurus), Cuban treefrog (Osteopilus
septentrionalis), Asian swamp eel (Monopterus albus), bromeliad weevil (Metamasius callizona),
Diaprepes weevil (Diaprepes abbreviatus), brown citrus aphid (Toxopotera citricida), red fire ant
(Solenopsis invicta), Pacific whiteleg shrimp (Liptopinaeus vannamei), zebra mussel (Dresseina
polymorpha), red-rimmed melania aquatic snail (Melanoides tuberculata), and banded tree snail
(Orthalicus floridensis).

The SFERTF established a Noxious Exotic Animal Task Team (NEATT) in 2003. This group
convened and is developing a nonnative animal report to provide a broad picture of the status of
nonindigenous animal species in South Florida. It will focus on the agencies, along with their
respective departments, that are represented on the South Florida Ecosystem Restoration Task
Force and Working Group. This report is to be used as a basis for the South Florida Ecosystem
Restoration Task Force and Working Group to evaluate its members’ priorities relative to
nonindigenous animals and to determine if and how it might assist the work of individual
agencies, enhance interagency collaboration, and integrate South Florida efforts into state,
regional, or national programs.

MANAGEMENT EFFORTS

The District has been closely coordinating all vegetation management efforts with other
agencies within the EPA since 1990. This close coordination has resulted in detailed,

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species-based management plans (Melaleuca Management Plan, Brazilian Pepper Management
Plan, and Lygodium Management Plan) and a maximization of all available management
resources. In addition, the District has been required since 1979 to get permits from the FDEP for
all vegetation management activities in public waters. The permit process has helped to bring
peer review as well as statewide consistency to management approaches. Within the EPA,
floating aquatic plant control in canals has been coordinated with the USFWS and the Everglades
National Park (ENP or Park) since the early 1970s. Specifically, this relates to water hyacinth
(Eichhornia crassipes) and water lettuce (Pistia statiotes) spraying and/or harvesting in and
around the S-10 and S-12 structures and within the L-7, L-39, L-40, and L-29 canals. Currently,
the District does not have dedicated staff or funding to coordinate efforts and control
nonindigenous animals within the EPA.

INVASIVE PLANT MANAGEMENT TOOLS

Many different techniques are used to control exotic invasive plants within the EPA.
Biological controls, chemical controls, manual and mechanical controls, and cultural practices
(such as prescribed burning and water level manipulation) are used separately or in conjunction to
slow the spread of exotics. More detailed descriptions of each of these methods are presented
below. Specific species-level controls are discussed in the “Priority Species” section of this
chapter.

Biological Control

Plants are often prevented from becoming serious weeds in their native range by a complex
assortment of insects and other herbivorous organisms. When a plant is brought into the United
States, the associated pests are thoroughly screened by government regulations on plant pest
importation. Favorable growing conditions and the absence of these associated pest species have
allowed some plants to become serious weeds outside their native range.

“Classical” biological control seeks to locate such insects and import host-specific species to
attack and control the plant in regions where it has become a weed. The classical approach has a
proven safety record (none of the approximately 300 insect species imported specifically for this
purpose have ever become pests themselves) and has been effective in controlling almost 50
species of weeds.

The following are the performance steps of a classical biological control investigation:

1. Identify the target pest and prepare a report outlining the problem conflicts, potential for a
successful program, etc.

2. Survey and identify the pest’s native range for a list of herbivores that attack the pest plant

3. Identify the best potential biocontrol agents based on field observations, preliminary lab tests,
and information from local scientists

4. Conduct preliminary host-range tests on the most promising candidate in the native country in
order to obtain permission to import to U.S. quarantine

5. Complete host-range tests in U.S. quarantine to ensure the safety of the organism relative to
local native plants, agricultural crops, and ornamentals

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6. Petition the Technical Advisory Group of the U.S. Department of Agriculture (USDA) for
permission to release into the United States, and obtain permission from necessary state
agencies

7. Culture agents that are approved to have sufficient numbers to release at field sites, and test
release strategies to determine the best method

8. Monitor field populations of pest plants to:

a) Determine if biocontrol agent establishes self-perpetuating field populations

b) Understand plant population dynamics to have a baseline to measure bioagent effects,
especially if they are sublethal and subtle, and to know what portions of life history to
watch

9. Study effectiveness of the agents for controlling the target plant, and monitor plant
populations with and without the agent to determine impacts of the agent

10. Study means of integrating biocontrol into overall management plans for the target plant

In Florida, classical biological control of invasive nonnative plants in nonagricultural areas
has focused on aquatic weeds. The first biocontrol agent introduced was the alligatorweed flea
beetle (Agasicles hygrophila) in 1964 for control of alligatorweed (Alternanthera philoxeroides).
Subsequently, the alligatorweed thrips (Aminothrips andersoni) was released in 1967 and the
alligatorweed stem borer (Vogtia malloi) in 1971. The flea beetle and stem borer proved to be
fairly effective for suppressing growth of alligatorweed, although harsh winters can reduce their
populations. Less effective have been introductions of the water hyacinth weevils (Neochotina
eichhorniae and N. bruchi), released in 1972 and 1974, and the water hyacinth borer, released in
1977 (Sameodes albigutalis) for water hyacinth control. Likewise, effectiveness of a weevil
(Neohydronomous affinis) and a moth (Namangama pectinicornis) released for control of water
lettuce has been unpredictable. Water hyacinth and water lettuce continue to require management
by other methods, such as herbicide and mechanical harvesting. Current biological control
research is focused on water hyacinth, hydrilla (Hydrilla verticillata), melaleuca (Melaleuca
quinquenervia), Brazilian pepper (Schinus terebinthifolious), and Old World climbing fern
(Lygodium microphyllum).

Melaleuca snout beetles (Oxyops vitiosa) are damaging melaleuca stands and are showing
signs of range expansion after initial releases in 1997. The second melaleuca agent (a psyllid) was
released in April 2002. The first Brazilian pepper and Lygodium insects and additional
melaleuca-damaging insects may be approved for release in Florida within a period of years.
Overseas surveys and host-specificity screening for additional agents is ongoing.

Introduction of animals such as cattle, sheep, goats, or weed-eating fish may also be used to
control certain invasive plants. However, environmental impacts of using such nonselective
herbivores in natural areas should be carefully considered before implementation.

Herbicides

Herbicides are pesticides designed to control plants. They are a vital component of most
control programs and are used extensively for exotic plant species management in South Florida.

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Herbicide Application Methods

Foliar applications. A herbicide is diluted in water and applied to the leaves with aerial or
ground equipment. Foliar applications can either be directed, to minimize damage to nontarget
vegetation, or broadcast. Broadcast applications are used where damage to nontarget vegetation is
not a concern or where a selective herbicide is used.

Basal bark applications. A herbicide is applied, commonly with a backpack sprayer, directly
to the bark around the circumference of each stem/tree up to 15 inches above the ground.

Frill or girdle (sometimes called hack-and-squirt) applications. Cuts into the cambium are
made completely around the circumference of the tree, with no more than 3-inch intervals
between cut edges. Continuous cuts (girdle) are sometimes used for difficult-to-control species
and for large trees. Herbicide (concentrated or diluted) is applied to each cut until the exposed
area is thoroughly wet. Frill or girdle treatments are slow and labor intensive, but they are
sometimes necessary in mixed communities to kill target vegetation and to minimize impact to
desirable vegetation.

Stump treatments. After cutting and removing large trees or brush, an herbicide
(concentrated or diluted) is sprayed or painted onto the cut surface. The herbicide is usually
concentrated on the cambium layer on large stumps, especially when using concentrated
herbicide solutions. The cambium is next to the bark around the entire circumference of the
stump. When using dilute solutions, the entire stump is sometimes flooded (depending on label
instructions) with herbicide solution.

Soil applications. Granular herbicide formulations are applied by handheld spreaders, by
specially designed blowers, or aerially.

Where Herbicides Can Be Used

A pesticide, or some of its uses, is classified as restricted if it could cause harm to humans or
to the environment unless it is applied by certified applicators that have the knowledge to use the
pesticide safely and effectively. Although none of the herbicides commonly used for invasive
plant control in the Everglades are classified as restricted-use, the basic knowledge of herbicide
technology and application techniques that are needed for safe handling and effective use of any
herbicides can be obtained from restricted-use pesticide certification training. All District
applicators and contractor supervisors are required to obtain and maintain this certification before
applying herbicides in the EPA.

No pesticide can be sold in the United States until the U.S. Environmental Protection Agency
(USEPA) has reviewed the manufacturer’s application for registration and has determined that the
use of the product will not present unreasonable risk to humans or to the environment.

The USEPA approves use of pesticides on specific sites, i.e., for use on individual crops,
terrestrial non-crop areas, or aquatic settings. Only those herbicides registered by the USEPA
specifically for use in aquatic sites can be applied to plants growing in lakes, rivers, canals, etc.
For terrestrial uses, the USEPA requires herbicide labels to have the following statement: “Do not
apply directly to water, to areas where surface water is present, or to intertidal areas below the
mean high-water mark.” Rodeo® is registered for aquatic use and can be applied directly to
water. Certain, but not all, products that contain 2,4-dichlorophenoxyacetic acid (2,4-D) can also
be applied directly to water. The state supplemental “special local need” (SLN) label for the

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imazapyr-containing product, Arsenal® (USEPA SLN NO. FL-940004) allows government
agencies and their contractors to use it to control melaleuca and Brazilian pepper growing in
water. An SLN label was also obtained for Escort® (Metsulfuron methyl) herbicide in 2003. This
herbicide will be used by government agencies to treat Old World climbing fern.

Herbicide Toxicity to Wildlife

Invasive plant management is often conducted in natural areas to maintain or restore wildlife
habitat. Therefore, it is essential that the herbicides are not toxic to wildlife. Herbicides used for
invasive plant control in the Everglades have shown very low toxicity to the wildlife they have
been tested on, with the exception of the relatively low LC50 of triclopyr ester (0.87 parts per
million [ppm]) and fluazifop (0.57 ppm) for fish, neither of which can be applied directly to
water. Ester formulations are toxic to fish because of irritation to fishes’ gill surfaces. However,
because triclopyr ester …