Part One of the Strategic Plan for Managing Florida's Invasive Exotic Plants  

Item 18 of the CROGEE Read-ahead | About this Document | Credits |

Exotic plants—those species not native to an area and found beyond their natural range—are being found more frequently throughout the world as people and their cultures are transported around the world. We derive numerous benefits from many of these plants.

Virtually every crop plant and most ornamental landscape or aquarium plants used in the United States originated outside the United States. Most of these species remain in cultivation and continue to provide benefits in their intended settings. However, some of these species are serious pests of agriculture and some are invading natural areas and replacing the native flora and fauna. Some of those in natural areas have spread to the extent that the plants and animals in the natural areas they invade are in danger of being replaced in their entirety by these invasive exotic plants. In some states, like Florida and Hawaii, exotic plants make up as much as 31% of the total plant species (Winderlin 1998) (See Figure 1). Globally around 1 - 4% of the plant species introduced become invasive pests (Westbrooks 1998). But it takes only a few species to cause environmental and economic havoc and as long as the numbers of species introduced continues to increase, the chance of introducing one that will become a serious pest remains very high. This is especially true since we are doing essentially nothing to prevent undesirable plant species introductions nor are we trying to assess which ones may become invasive before they are introduced.

These plants invade natural areas irrespective of geographic and political boundaries, agency authorities and legislative mandates. Only by tackling the problem—related to the consequences of invasive exotics—in an integrated crosscutting strategy can we hope to be effective in controlling and managing them. Without a comprehensive strategy we will probably only continue the current piecemeal method of managing small isolated patches of individual species or intermittently and inadequately funding the few comprehensive species control projects that do exist. The need for an integrated interagency program for controlling exotic pest plants has been raised in several venues. The National Association of Exotic Pest Plant Councils, and specifically in Florida, the Florida Exotic Pest Plant Council (FLEPPC) and recent reports by the Office of Technology Assessment (1993), The Florida Department of Environmental Protection (1994), Vice President Al Gore’s national strategy for controlling exotic pests, and President Clinton’s Executive Order on Invasive Species have brought the issues of Invasive Exotic Plants to the highest levels of federal, state and local governments’ attention.

President Clinton’s Executive Order on Invasive Species is the first clear and authoritative action taken at the National level to attempt to deal with the serious threats invasive species pose to our natural resources. In regard to invasive species it directs all Federal agencies to prevent, detect, control, monitor, restore natural areas, and conduct research. Agencies are also prohibited from funding or carrying out actions that may cause or promote the introduction or spread of invasive species. And it establishes an Invasive Species Council that agencies must consult with, and to develop a National Invasive Species Management Plan. Federal funding for invasive species will be available, but each state must develop a statewide strategic plan for invasive species in order to be considered for program funding.

There is a crucial lack of acknowledgement by both the public and policy makers of the serious threats that exotic invasive pests pose. Although Florida has generally recognized the seriousness of exotic pest plants, they were—and in most instances still are—viewed as problems in urban or human dominated environments and typically a human nuisance. Aquatic plants clogging water control canals or recreational water- bodies are prime examples. Only recently has the issue of exotics invading natural areas begun to receive the attention necessary to start addressing the magnitude of the problem, but the lack of acceptance of the seriousness of the threat still hampers management of these species.

Several developments helped to focus this issue in Florida. First, the Florida Legislature established the Bureau of Aquatic Plant Management in 1972 within the Florida Department of Environmental Protection (then the Florida Department of Natural Resources—DEP was established in 1993). This was the first statewide program that targeted specific invasive aquatic plants in Florida. DEP coordinates and centralizes the statewide control activities for three aquatic weeds, and provides significant funding for these activities. This centralization helps to maximize effectiveness of control work but still does not organize agencies into a coordinating body to deal with the broader invasive species issues and strategies. It also does not include a number of key federal agencies and NGO’s. Instead cooperating agencies operate as a tacit arm of the DEP aquatic plant program. Funding levels have supported control efforts in approximately 400 designated water-bodies (out of almost 8,000 water-bodies in the state) predominantly used for recreation or water management. While the 400 water-bodies managed represent better than 80% of the state’s water surface, thousands of small lakes and agricultural canals are not included in the state’s management program for aquatic weeds presenting a continuing long term management problem and source of reinvasion (Shafer et al. 1986, Florida Division of Water Resources and Conservation 1966). In 1998 DEP transformed the former Bureau of Aquatic Plant Management into the Bureau of Invasive Plant Management. The Bureau of Aquatic Plant Management developed and carried out many of the kinds of strategies necessary for successful exotic aquatic plant control and management and they are now expanding into the area of terrestrial invasive plants. Another program bringing attention to the issue of invasive species has been the recent emphasis on South Florida Ecosystem Restoration. The structure for this emphasis has been established through the Governor’s Commission for a Sustainable South Florida, and the US Congress’ establishment of the South Florida Ecosystem Restoration Task Force (SFERTF) to coordinate the restoration efforts. Both these forums have recognized exotic pest plant threats and the agencies are supporting and involved in strategic planning (through this process) and management (through individual agency programmatic action plans and projects) of invasive plants. Control and management of invasive exotics is one of the priorities established by the SFERTF in 1993. The Everglades Forever Act of 1994 requires the South Florida Water Management to establish a program to coordinate with other Federal, State, and local governmental entities to manage exotic pest plants with emphasis in the Everglades Protection Area. The Governor’s Commission for a Sustainable South Florida (1995) incorporated exotic plant management as one of their restoration objectives. Control of Melaleuca and other exotics programs were ranked as the third highest projects in the Critical Ecosystems Studies Initiative established by the SFERTF Working Group and Governor’s Commission and for funding by Congress through the Water Resources Development Act (WRDA) administered by the US Army Corps of Engineers. However, despite this designation as a high priority in WRDA the Corps has not funded WRDA exotic plant projects since the bill was approved by congress in 1996.

Any effective strategy for the southern Florida ecosystem must take into account issues that are not limited to geographic or programmatic considerations. Examples include invasive plants in central and northern Florida that pose threats to southern Florida and vice versa, legislation or policy aimed at prevention and prohibition, and development of broad policies and regulations. In addition assessment techniques and strategies for determining geographic distribution of species and success among control programs cannot be done if there is not some level of consistency among agencies and organizations throughout Florida. In the future, this will probably need to be expanded from states to bioregions. And last but not least coordination of local, state and federal agencies with non-government organizations to develop reasonably consistent goals and strategies clearly extends beyond the south Florida milieu. The difficulties of doing seemingly simple things, such as allowing employees of one agency to borrow equipment from another agency for mutual exotic control has so far proven an intractable problem. Another situation that illustrates the need for a comprehensive strategy and better coordination involves the Florida Department of Agriculture and Consumer Services (FDACS) and Florida Department of Environmental Protection. Two separate Florida Statutes authorize two separate lists of noxious weeds. FDACS maintains the Florida Noxious Weed List of parasitic and terrestrial agricultural weeds and DEP maintains the list of Prohibited Aquatic Plants. FDACS has review and approval authority over the DEP aquatic weed list but DEP has no review or approval over the FDACS list. Recently DEP tried to list torpedo grass (a serious aquatic weed that is frequently found in sod) on their Prohibited Aquatic Plant List. FDACS refused to allow this listing because of the potential economic impact on sod farmers. The result is that torpedo grass a serious invasive weed may be transported throughout Florida in sod (J. Schardt personal communication). The imported fire ant’s spread across the southeastern US is similar and has been largely due to transport via nursery plant containers (Tschinkel 1993).

An example of the kinds of successful coordination needed is the establishment by DEP of a statewide contract—available to all state and local governments—for the purchase of Fluridone herbicide at a significantly reduced price. So far all but one county has participated in the contract and DEP has been able to save $500,000.00, enough to treat one or two additional large lakes infested with hydrilla.

There are many such examples of inter and intra-agency consistencies and inconsistencies. What they clearly point out is the need for an integrated organization focused on invasive plants, and a comprehensive plan that incorporates broader and consistent strategies, reduces the inconsistencies, and takes into account differing agency mandates. This would result in an approach that is appropriate and applicable to and coordinated with the broader State and Federal efforts to manage invasive exotic plants, and supports each agency in carrying-out their role(s) in the broader program of invasive plant control.

As a result of the priorities established by the South Florida Everglades Restoration Task Force and Working Group in 1997, the Noxious Exotic Weed Task Team (NEWTT) was established. NEWTT was charged with developing a comprehensive strategy to cover the issues and the problems of exotic pest plants in Florida with programmatic and management focuses on southern Florida. This document (the Assessment and it’s Addendum) is Part One of that comprehensive strategic plan.

The Noxious Exotic Weed Task Team is a working team of the South Florida Ecosystem Restoration Working Group. The task team is made up of government agencies—federal, state and local. All NEWTT meetings are open to the public. While nongovernmental organizations (NGOs) are not an official part of NEWTT, the Florida Exotic Pest Plant Council provides advice and peer review. Task Team members are land-managers and scientists from key federal, state and local government agencies that in some way deal with exotic pest plant issues. Their responsibilities may range from managing lands or waters infested with exotics; importation, restriction or prohibition; development of biological controls; or conducting research on exotic pest plants.

The SFERWG directives charged NEWWT to produce an assessment and strategic plan that addressed southern Florida exotic plant problems. However, 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 must be addressed synthetically. In addition, the issues and experiences learned regionally with regard to control methods development, research results, public education, technology transfer, policy and regulation, and funding, are important to and affect all agencies and programs throughout the State. In turn, National level issues related to exotic pest plants affect State and local policies and programs. The directive for NEWTT, however, came primarily from the Everglades’ Restoration initiative. Therefore, while NEWTT is emphasizing south Florida, we are developing a statewide strategy to facilitate partnerships among the key agencies and organizations, and address all the elements required for a successful program incorporating these broader strategic concepts at each level of organization.

No new information has been specifically generated or new research conducted in the development of this assessment. It is an update and compilation, evaluation, review and summary of existing available information. It is also not intended to address issues better addressed in the Strategic Plan; like organization, goals, research needs, priorities and outcomes.

The information presented comes from many different sources and agencies. Each agency and source collects, stores and reports information in different ways. The lack of consistency in information between organizations admittedly compromised this and previous assessments. Each agency varies in how they track treatment and re-treatments, plant distribution, funds, and program success. In addition, each agency has different and sometimes inconsistent roles identified regarding how it addresses the issues of exotics. Some agencies have no specific roles identified regarding exotic plants. This is true at the International, national, state and local levels.

Not all agencies in Florida that have a role in invasive exotic species are represented on NEWTT. However, NEWTT has been successful in bringing representation of most of these additional groups and local government representation in through cooperation with institutions like the Institute for Food and Agricultural Sciences at the University of Florida, and the Florida Exotic Pest Plant Council, and local agencies that have been leaders in invasive plant management.

No assessment to date has achieved complete and direct involvement or integration of all concerned with invasive species issues. There are three basic reasons for this. First, a formal inter-agency partnership to manage invasive species has never been established. Second, some agencies and organizations (like many local governments and the military) are usually only involved with direct control of invasive species and therefore have limited or no involvement with other important aspects. Some may not yet recognize the seriousness of invasive species or perhaps the lack of a formal organization or role may limit agency interest or ability to participate more fully. Third, it is organizationally impossible to directly involve every agency or organization in a formalized structure. An all-inclusive group would literally embody hundreds of individual members, making such an organizing body impractical and non-functional.

NEWTT is the first agency level organization to bring agencies that have principal roles for invasive species in research, management, education, restoration, regulation and policy development together for the purpose of coordinating exotic invasive plant issues and developing an assessment and strategic plan.

Exotic invasive animals pose as serious a threat to our natural resources as do exotic invasive plants. Control activities and planning for exotic invasive plant management however is much farther advanced, and with the completion of this strategic plan and assessment there will be enough information in place to hopefully provide the impetus to implement a comprehensive and long-term program for managing invasive plants. The status of invasive animals is incomplete and in some cases virtually unknown and no strategic approaches have yet been considered. The first assessment of the status of invasive animals in Florida is being prepared by the USGS, Biological Resources Division (BRD).

Many organizations are concerned and involved in the issue of invasive species besides government agencies and conservation groups charged with their control or with protecting the environment. Organizations like the National Fisherman are showing their alarm at the loss of our natural resources to exotic invasive species (See Figure 2). Their excellent article in the March 1999 edition of National Fisherman magazine is a wonderful example of public concern and signs of awareness. This level of public involvement will be crucial to help inform and educate and move policy toward effective management of invasive species. This kind of public involvement and awareness should be encouraged and supported by agencies charged with exotic invasive species management.

We wish to note that discussions regarding exotic pests, both plant and animal, and their inclusion into one organizing body has been a topic in Florida for the past 10-15 years. FLEPPC first tackled the issue in 1988 during their international symposium on exotic pest plants. Each time the issue comes up for debate, the conclusion reached is, that while both exotic plant and animal pest problems are similar they require different scientific disciplines. The scientists who deal with the biology, control and management of animals do not have the same expertise and little common ground with those who deal with plants, except both disciplines can be characterized as ecological and biological sciences. In fact, many different animal experts will be required to effectively deal with this very complex problem.

The members of NEWTT strongly support work toward organizing the management of exotic animal pests. However, while the two groups should coordinate and communicate regarding issues of mutual interest such as broad strategic points, methods to integrate tactical procedures, and organizational approaches, an assessment of the status of invasive animals and subsequent tactical and strategic planning for the control and management of animals needs to be addressed by different specialists.

There are however, similarities to developing an assessment and strategies for managing invasive animals that have common themes and approaches inherent to invasive plant management, or any well considered planning effort. It is important that as planning for control and management of invasive animals progresses that common themes and strategic approaches are developed concomitant with the planning development for plant species. What we have learned regarding exotic plant management, both from past research, experience and assessments should be incorporated during the future development of any plans for the management of invasive animals.

This assessment is a compilation of previous and current information. It combines information from earlier, often wide-ranging efforts to assess the status of exotic pests in Florida. Some of those previous efforts also included animals as well as plants. While it contains much updated and recent information it is a synthesis of existing information and reports and a compilation of information gathered from agencies and non- governmental organizations. Information from earlier assessments is combined and summarized and presented in a more condensed and integrated manner (especially the species location data), and data gathered from participating agencies is updated.

1. THE MOST INVASIVE SPECIES

The 65 Category I species on the Florida Exotic Pest Plant Council (1999) list of Florida’s Most Invasive Exotic Plant Species make up this category, with one added species, giant salvinia (Salvinia molesta). The Category I list helps to provide a consistent and peer reviewed framework that includes most of the serious problem plants in Florida. However, the FLEPPC list does not include species that are not known to be invading natural areas in Florida or species known to be invasive in similar climates or ecotypes, but are not yet in Florida or the US. While developing an evolving program of species risk assessment will be essential, it is important to point out that research has yet to find clear commonalities in ecological traits of invading species and simply identifying aggressive species from similar climates or biomes does not account for environmental differences among regions nor ecological differences among species (Mack 1996, Vermeij 1996).

The FLEPPC Category II list includes 60 species that have shown a potential to invade natural areas but have not yet “disrupted” natural communities. However the Category II list does not take into account species still found only in cultivation, many of which are known to be invasive pests elsewhere or have characteristics of successful invaders (sensu Williamson and Fitter 1996). Weeds that have incipient populations in Florida or are known to be serious invasive pests in other similar environments need to be recognized and considered as part of any strategy (including research) for managing invasive species (see Williamson and Fitter 1996, and Vermeij 1996). Giant salvinia was added for this reason.

It is important to understand that of an estimated 3,834 vascular plant species known to occur in Florida, approximately 1,180 are exotic (Wunderlin 1997). The 3,834 “known” species described by Wunderlin (1997) do not include many additional species currently in cultivation, nor does it include species that are not represented in the state herbaria. It is impossible to determine how many other species there may be and how many of them may become pests here. However, included are species such as Miconia calvescens (living specimens of which exist at Fairchild Tropical Garden and at least one private collection in south Florida). M. calvascens, referred to as the “green cancer” is considered the most serious threat to island ecosystems throughout the indo-pacific and Hawaii (Coordinating Group on Alien Pest Species Report, undated). It has completely replaced over 70% of Tahiti’s native rain forest understory (Coordinating Group on Alien Pest Species Report, undated). An assessment of the risk Miconia poses to Florida has never been done.

The unimpeded flow of new plant introductions for agriculture is a major element of the invasive plant problem (See Figures 3 and 4). Without considering previously unknown introductions of possibly invasive plants—and a risk assessment of their potential for invasiveness and a means of preventing such species from being introduced—any programmatic strategy for managing invasive plants will be continually assaulted with new invasive species because of the virtually unlimited nature of new introductions and reintroduction’s of weedy species. The more often a weedy plant is introduced the greater the chance (a principal means is through propagule pressure, see Williamson 1996) it has of establishing reproducing populations in the wild (Bright 1998).

Because of the limited understanding of just how many and which exotic species may be present Chapter 2 includes an additional listing of those species that are pests in other similar environments or have weedy characteristics and have been observed in cultivation in south Florida. Where known, their invasiveness in other ecotypes similar to Florida is discussed. Their potential invasiveness in Florida has never been assessed.

2. DISTRIBUTION OF THE MOST INVASIVE SPECIES

The geographic distribution of exotic pest plant species was developed where we had reasonably comprehensive and quantitative data. Spatially explicit maps represent these data for four species, melaleuca, Brazilian pepper, Australian pine, and Old World climbing fern (See Chapter 2). Other data from less quantitative surveys that were not as comprehensive are represented by species sightings by county (See Chapter 2). County sighting data are developed as maps combined and compiled from three different surveys. They include surveys done by the Florida Department of Environmental Protection for aquatic plants (1997), the Florida Exotic Pest Plant Council (1999), and Richard Wunderlin (1998). The sighting data from the three surveys were also combined into an overall map showing the number of invasive species present by county (see Chapter 2).

There are several obvious limitations to the use and representation of these data. The maps show some counties to be free of a particular exotic while it is present in every surrounding county. It is probably reasonable to assume that the survey simply missed the species and that the exotic species is also present in that county. Additionally, a number of species have been observed in counties that do not indicate occurrence from the survey information. These observations were not included because consistency is important in reporting to reduce errors. While it is misleading to color an entire county when the survey may only have observed one plant or a few small populations of a particular species these data are generally not robust enough for more comprehensive use. These problems are methodological artifacts and provide good insight for improving future surveys. Each map also includes the scientific name, common name(s), origin, habit, and invasiveness for each of the Category I species and giant salvinia.

As noted earlier, all the spatial mapping data evaluated had inherent flaws that limited the use of the spatial information in determining the locations of exotics. Some problems were due to the way the data were collected (different agencies use different techniques and therefore we cannot combine the information for analysis). There were a number of other inherent limitations in the collection techniques that resulted either from the resolution (this affects the level of detail available from the data) or type of data collected. The levels of data collected are sometimes too different from one another or may be limited in areal coverage or inability to obtain sufficient accuracy. In other cases the data could not be interpreted more accurately or precisely to represent pest plant locations. Much of the existing data simply cannot be used in ways we might like. However, in spite of these drawbacks, these data are extremely valuable as a base to develop further information. It also provides a clear idea of the additional information needs and how to improve existing means of collecting, analyzing and reporting geospatial data across agencies. These concepts will be further developed in the Strategic Plan.

3. REGULATIONS AND POLICIES

Agency regulations and policies related to invasive species are reviewed and summarized in Chapter 4. The review discusses each agency’s regulatory role and how the regulations or policies affect an agency’s ability to carry out effective invasive exotic plant management. Regulations are cross-referenced to highlight consistencies, inconsistencies, and gaps. This review includes overall federal, and state regulations, and typical examples of local government regulations.

4. SUMMARY OF CURRENT MANAGEMENT PROGRAMS BY ORGANIZATION, ROLES, ACTIVITIES GAPS AND SUCCESSES

As part of this document, a summary of key program elements is provided giving an overview of program tactics, and conclusions regarding program successes and gaps. We also summarize the collective aspects of all programs, their important inter- and intra- program successes and gaps and offer a subjective evaluation of the success of the overall Florida effort. Because of the lack of objective (numerical), consistent criteria, an objective evaluation among agencies was not possible.

Key non-governmental organizations are also included. A number of NGO’s play an important role in managing invasive pest plants, directly, like The Nature Conservancy, or indirectly, such as the Florida Exotic Pest Plant Council. Some of the NGOs included here also contain some agency members but the groups are not agency oriented per se. Control programs on private lands and 298 districts are not included. It is important for the implementation of the strategic plan that private-land management programs and 298 districts are included. However, for the purposes of this assessment only agencies and key NGO’s could be included due to organizational and time constraints and the principal fact that Florida’s agencies and organizations are not coordinated or organized properly to deal with the issue of invasive exotic plants. Thus they are not well suited to provide the kinds of information needed for a more comprehensive regional or statewide, multi- agency assessment.

5. THE CURRENT MANAGEMENT PROGRAMS

Most of the key agencies involved in invasive exotic plant management in Florida, via NEWTT, have provided a review of their agency or individual programs. As noted above, most local governments, 298 districts, and private-landowners exotic plant management programs could not be included in this assessment but need to be taken into better account for future assessments. Results of two previous reviews covering state or local agency involvement in invasive plant control are summarized (Committee on Environmental Protection 1999, Gregg 1994).

Agency roles, activities, funding levels, policies, management function(s) and species managed are discussed. These reviews contain differing levels and detail of information that seem due to how well developed or oriented an agencies’ program on invasive plants is, and how well defined an agency’s role is in managing invasive plants. A few agencies also provide relatively detailed maps of individual species within their management area or park. Included is information as to how each agency manages, and more importantly some insight as to its role(s) in managing, exotic pest plants. Each agency also provides a general evaluation of the successes of their exotic pest plant management program. These reviews are provided in a separate appendix to this assessment.