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