IMPROVEMENT OF CORAL REEF CONDITIONS
|Dr. Michael P. Crosby (NOAA/NOS)|
The South Florida Ecosystem Restoration effort is an integrated activity among federal, tribal, state and non-governmental partners to halt the continued degradation of South Florida's ecosystems and restore the ecosystems' valuable functions and services from the Kissimmee Lakes through the Everglades, into Florida Bay and the Florida Keys coral reef habitats. The South Florida Ecosystem Restoration Task Force was established through an Interagency Agreement signed on September 23, 1993. The Task Force was established to "coordinate the development of consistent policies, strategies, plans, programs, and priorities for addressing the environmental concerns of the South Florida ecosystem."
The following draft ecological success indicators (ESIs) were developed from a review of various reports and literature, and through input from numerous coral reef experts via personal meetings, workshops [most notably - the Resource Working Team - Fish and Wildlife, Chaired by Craig Johnson (US FWS) and Dave Busch (DOI ENP), at the April 1996 "Workshop on South Florida Ecological Sustainability Criteria", and the January 1997 Florida Keys National Marine Sanctuary sponsored Coral Reef Monitoring Workshop in Marathon, FL;, and Internet exchanges in response to a January 1996 presentation of the initial suggested indicators of ecological success for coral reefs [most notably - Bill Arnold (Florida Department of Environmental Protection), Richard B. Aronson (Dauphin Island Sea Lab), Charles Birkeland (University of Guam), Christopher D'Elia (University of Maryland), Robert Ginsburg (University of Miami), Gregor Hodgson (Binnie Consultants LTD, Hong Kong), Walt Jaup (Florida Department of Environmental Protection), J. Landsberg (Florida Department of Environmental Protection), Steven Miller (University of North Carolina-Wilmington), Erich Mueller (Mote Marine Laboratory), Bob Steneck (University of Maine), and Hugh Sweatman (Australian Institute of Marine Science). The Internet discussions were initiated and conducted via the internationally distributed and acclaimed Coral ListServer operated by the NOAA AOML in Miami, Florida. The coral reef ESIs were endorsed by the 1996 workshop (although it recommended dropping fishes, shellfish, sponges and algae from the ESI) and by the participants of the January 1997 workshop in Marathon (it recommended inclusion of sponges and algae). While the above named individuals who participated in the Coral ListServer discussions had significant comments, input and advice that formed the basis of this document, it would be improper to suggest that they, by extension, endorse this final draft version. It is, therefore, strongly recommended that prior to final acceptance by the South Florida Intergovernmental Science Sub-Group, these criteria be subjected to additional discussion by the broader scientific and management community.
The importance of coral reef ecosystems may be seen in their numerous ecological, aesthetic, economic and cultural functions (Crosby and Maragos, 1995; Maragos et al., 1996). Coral reefs protect coastlines from shoreline erosion, while the cycle of reef accretion and erosion maintains beaches, and provides habitat for seagrasses and mangroves. Coral reef passes and channels provide safe navigation channels for boats, and natural protection for harbors from heavy wave action. Coral reefs have far greater productivity than other marine systems, surpassing 7,000 g C m-2 yr- 1 (Odum et al., 1959; Helfrich and Townsley, 1965). Biogeographic and environmental factors determine the density and diversity of the species on coral reefs (Jaap and Hallock, 1990). The Florida Keys' coral reef biological diversity makes the Keys' ecosystem ecologically, economically, aesthetically, and biogeographically unique within the U.S. The Keys' reefs are highly complex and diverse communities whose success is limited by the presence of suitable substrate and a narrow range of environmental and hydrographical parameters. Not only are coral reef structures themselves composed of and built by a diversity of organisms, but the reef structure serves as the basis for one of the highest diversity ecosystems in the world (Talbot, 1994). Corals are the principal builders of the reef community and form the main source of spatial complexity and shelter.
Healthy coral reefs, along with a healthy Florida Bay and clean coastal waters, are the foundation of a healthy South Florida economy. Large portions of South Florida's economy are dependent on healthy coral reefs in the Florida Keys. The Florida Keys coral reefs have become a major attraction for visitors to South Florida and are now recognized as an important resource for not only South Florida, but for the Nation and the World. Deterioration of South Florida's coral reef resources will significantly impact these industries, the people that depend on them, and the people who come to use them from all over the United States and the World. More than 3 million tourists yr-1 visited South Florida and the Florida Keys from all over the U.S. and spent an estimated $1.3 billion in 1991. Florida's coral reefs are the #1 diving destination in the world, attracting more than 1.2 million divers yr -1. Divers bring over $220 million yr -1 into the economy. The asset value of water related recreation in the Keys is estimated at $22 billion. Commercial fishing is an important part of South Florida's economy. In good seasons, for example, pink shrimp catches produced over $ 120 million yr-1. Spiny lobster catches produced $24 million yr -1 . Recreational fishing produces more than 23,500 jobs.
However, few aspects of anthropogenic activities, especially modern uses, are beneficial to reefs. On a global scale the most significant threats to reefs are associated with high density human population living near coral reefs. Human migration and population increase is the single most significant cause of reef degradation worldwide and is the basic cause for most at the impacts to coral reefs in urban centers (Maragos et al., 1996). The ability of coral reef ecosystems to exist in balanced harmony with other naturally occurring competing/limiting physico-chemical and biological agents has been severely challenged in the last several decades by the dramatically increased negative and synergistic impacts from poorly managed anthropogenic activities (Maragos et al., 1996). Managers, scientists and other reef users have begun to realize that Florida's coral reefs are fragile and are now threatened from chronic anthropogenic disturbance.
Like the Everglades grasslands, South Florida's coral reef habitats are in jeopardy. Coastal waters have changed: increased salinity, increased nutrient concentrations, increased pesticide concentrations, decreased clarity, and changes in water flow. Many scientists, managers and the general public seem to believe that the health, or condition, of the Florida Keys coral reef ecosystem is directly linked to the health of Florida Bay and the Everglades. Before 1900, freshwater flowed from the Kissimmee Lakes through the Everglades and into Florida Bay and coastal waters, where it mixed with seawater and moved onto the Florida Keys coral reefs. This created some of the world's most productive and diverse coastal habitats. From the Everglades grasslands to Florida Bay seagrass beds and Florida Keys coral reefs, the areas are an ecosystem linked together by the flow of freshwater. During the past century, the pattern and intensity of freshwater flows to the estuaries of south Florida have been significantly affected by the construction of the C&SF Project for Flood Control. Historically, freshwater input to the area was via rainfall. Canals, dikes and development for agriculture and a growing population changed the direction, quantity and quality of freshwater flow. These changes threaten South Florida's productive inland and coastal habitats, and the economies and people who depend on them.
The Florida Keys coral reef tract, which is the focus of this ESI report, and the organisms that compose its characteristic rich biodiversity require clear, naturally oligotrophic ocean water. The impacts of changing the quantity and timing of freshwater flow into Florida Bay on the circulation dynamics, ecosystem dynamics, and living marine resources of not only the Bay, but also to the waters of the Florida Keys coral reef tract are not known. Fishing, pollution and other human impacts have impacted portions of the reef, but many of the causes of reef degradation are unknown and in the past there has been little capacity to monitor reef status (or "health"). As previously noted by the Science Sub-Group Report, the criteria for success in restoration is met primarily by restoring the ecology of the focal area and measured by the abundance, diversity, and viability of living resources. This report recognized that degradation and changes in the various habitats that have been reported are likely the result of the continued development of South Florida. It also noted that the impact of the hydrological changes in the Everglades on the coral reef tract is not fully known.
There are many methods to monitor coral reefs and the associated biota. Each method has its strengths and weaknesses, benefits and costs. These must be considered carefully . Each method also varies in how much scientific training is necessary to successfully use it. In addition, the choice of a method depends on the question being asked, the resources available, and the training of the persons who will do the work (see Crosby and Reese, 1996; Crosby et al., 1996; and Rogers et al., 1994). The ecological success criteria presented here are aimed at answering the question: Is the overall condition of the principal, non-mobile benthic invertebrates of the Florida Keys coral reef tract changing?
The initial draft of the ESIs for the coral reef tract included all of the indicators listed below, as well as fishes, shellfish, and water quality parameters. The Coral ListServer discussions gave little support for the water quality parameters (due in part to widely fluctuating temporal and spatial dynamics), and the 1996 Workshop recommended only focusing on the coral itself (fishes and shellfish, sponges and algae not be included). The 1997 workshop, however, strongly endorsed the inclusion of sponges and algae as part of the indicator list, as presented below.
Sub region 8 of the South Florida region includes the Atlantic coast estuaries from Biscayne Bay to Barnes Sound, Florida Bay proper and its fringing mangrove habitat, as well as the Florida Keys and the associated coral reef tract. The Florida Keys are a limestone island archipelago extending southwest over 320 km from the southern tip of the Florida mainland to the Dry Tortugas (101 km west of Key West). They are bounded on the north and west by Biscayne Bay, Barnes and Blackwater sounds, Florida Bay, and the Gulf of Mexico.
Although the reef ecosystem has historically been one of the Keys' most widely examined marine communities (Smith, 1948; Voss and Voss, 1955), most scientific studies have focused primarily on the shallow bank reef habitat. In many cases, scientists have ignored the deeper and more expansive intermediate-to-deep reef habitats, and only recently have these areas been rigorously investigated (Jameson, 1981, Pomponi and Rutzler, 1984; Bohnsack et al., 1987; Miller, 1987; Wheaton and Jaap, 1988; Lidz et al., 1991; Kruer and Causey, 1992; Lapointe et al., 1992). Numerous scientists have identified and described the organisms comprising the Keys' coral reef ecosystem. Jaap (1984) and Jaap and Hallock (1992) thoroughly described the ecology of South Florida's coral reef ecosystems and provided a historical overview of coral reef research and the resulting published literature.
In a general survey at Looe Key, Littler et al. (1985) reported a diverse tropical flora among the hermatypic corals, gorgonians, and nonarticulated coralline algae that help form Looe Key Reef. Ninety algal taxa representing 28 families were identified, and similar communities are believed to exist along the Keys' reef tract. Wheaton and Jaap (1988) surveyed fire corals, octocorals, stony corals, zoanthids, and corallimorpharians (false corals ) and found two species of fire coral, 42 species of octocorals, and 63 taxa of stony corals. Pomponi and Rutzler (1984) reported 38 species of sponges, and Thomas (1984) identified 82 species of echinoderms. Bohnsack et al. (1987) reported 188 fish species within Looe Key, and Kruer and Causey (1992) surveyed three depths near Big Pine Shoals, reporting 104 fish species in shallow depths, 114 species in mid depths, and 109 species in the deep reef habitat. A much more thorough literature survey dealing with the habitat characterizations of the Florida Keys' coral reef tract may be found in the Florida Keys National Marine Sanctuary Final Management Plan/Environmental Impact Statement (1996).
Implicit in the restoration goal is the intention to modify or eliminate anthropogenic processes harmful to the coral reef. The science program needed to accomplish successful restoration must be long term and goal oriented and be committed to the integration of emerging results into the management decision-making process. Separating anthropogenically induced changes in the Florida Keys coral reef ecosystem from natural system variation requires a comprehensive, long-term effort. Both natural disturbances (e.g., hurricanes, freezes) and long-term climate processes (drought cycle, sea-level rise) have strongly influenced the structure and function of the coral reef. These same processes may mask or exacerbate the effects of anthropogenic forces on the ecosystem. The relatively high level of natural variation in the coral reef ecosystem, the expected relatively slow response of the flora and fauna of the reef tract to changed hydrologic conditions, and the time required to plan, fund, and construct canal structures for water deliveries, argue that system-wide restoration of Florida Bay and coral reef tract will be a long-term process. However, it is also reasonable to expect noticeable changes within a period of five year, and significant changes within ten years.
As already discussed here and elsewhere (D'Elia, et al., 1991; Maragos et al., 1996), there is compelling evidence that coral reef ecosystems around the world, as in Florida, are under increasing stress. Staghorn coral (Acropora cervicornis) and elkhorn coral (Acropora palmata) in Caribbean reef systems in general have declined significantly in recent years (Brown, 1987). There have also been significant changes in other species associated with coral reefs. Diadema antillarum (sea urchins) have died off in the wider Caribbean region and in the Florida coral reef tract (Lessios, et al., 1983; Lessios, 1988), and fish assemblages have been changing dramatically in the past few years as well (Bohnsack and Ault, pers. com.). Nutrients and toxic compounds, as well as high temperatures can negatively impact corals as well as the anthropogenic activities referred to earlier. All of these stressors and individually and through synergy exert significant influence on the individual coral physiology as well as the broader community dynamics. It is critical to the proper evaluation of the coral reef ESIs presented in this document, that all of these other potential stressors of coral reefs be documented as thoroughly as possible.
The information required to directly measure the coral reef ESIs, is fairly straightforward, and can be gather using standard techniques that require little "high tech" laboratory analyses (see Crosby and Reese, 1996; Crosby et al., 1996; and Rogers et al., 1994). In many cases, slight modification of ongoing and/or recently completed research and monitoring projects can provide a significant data resource. In addition, there is a growing volunteer monitoring effort in the Florida Keys that can provide a wealth of information to this effort with little additional resources. It is critically important that all of the data gathered for this effort meet minimum quality assurance and quality control (QA/QC), and be managed in a coordinated fashion. It is proposed here that this effort build on the existing C-MAN/SEAKEYS data management effort within NOAA and that NOAA's National Oceanographic Data Center be requested to assist with long-term data management and archival.
The Florida Keys coral reef tract ecosystem is not composed solely of coral reefs. It also included the seagrass community, mangroves and other biotic communities that, in combination, help make the system ecologically unique in the U.S. Few places have the environmental and geological setting that has made it possible for such an ecosystem to form, and when combined with the other biogeographic regions of the Key's, the entire ecosystem is unique to much of the Caribbean. All of the different components of the coral reef ecosystem are influenced by, and have influence on, each other. The ESI criterion presented here focus solely on the condition of the coral reef and the corals themselves. It is clear that variables related to fish, shellfish, other macro and micro invertebrates, seagrasses, mangroves, and physico-chemical water quality parameters that are gathered as part of other regional and subregional ESI efforts should be considered when interpreting changes in the coral reef ESIs in future years.
As part of the South Florida Ecosystem Restoration effort, NOAA is attempting to inventory, integrate and build on the existing, uncoordinated coral reef monitoring efforts. This initiative will seek to develop and implement the first integrated Florida Keys coral, reef monitoring program. [Initial efforts with the State of Florida have already inventoried, placed in a geographically-referenced computer information system and made Internet accessible more than 250 existing coastal monitoring programs.] This effort will enhance existing partnerships between NOAA, other agencies, universities, NGOs and the State of Florida. The establishment of an easily accessible and understood information transfer mechanism will also be providing an invaluable service to the broader management and scientific community.
A great many of the reports of coral reef degradation in the Florida Keys are anecdotal or based on limited scientific data. In general, there is a lack of long-term, spatially comprehensive data to determine the extent of degradation and whether the situation is improving or worsening. To adequately fulfill the restoration and management needs for this special reef tract, there must be an increased effort to monitor coral resources, manage human uses and determine the effectiveness of these efforts. Such a monitoring effort should ideally employ straightforward relatively easy to assess variables (such as the ESIs presented here) indicative of improving coral reef conditions. It should also seek to:
There are several state and federal agencies responsible for the management of the Florida Keys coral reef tract within Sub Region 8. Most recently, the Florida Keys National Marine Sanctuary (FKNMS) was created by the Florida Keys National Marine Sanctuary and Protection Act, on November 16, 1990. The FKNMS includes 9500 km2 of submerged lands and waters between the southern tip of Key Biscayne and the Dry Tortugas Back. North of Key Largo it includes Barnes and Card sounds, and to the east and south the oceanic boundary is the 300 m isobath. The FKNMS includes part of Florida Bay and the entire Florida Reef. The primary focus of the FKNMS is to comprehensively manage the ecosystem in order to restore and provide for long-term sustainable ecological and economic viability of the system.
With the creation of the FKNMS, there is now a focus point for a long-term comprehensive monitoring program that will provide information about the status and trends of coral reef water quality and biological resources, and the potential changes due to the larger South Florida restoration effort. Various governmental, academic and volunteer monitoring programs can provide information about the effectiveness of restoration actions to reduce perturbations and improve the overall condition of coral reefs in the Florida Keys. This document recommends specific ESIs that will be the end-point success measures of ecological restoration of the coral reef tract. The type of long-term integrated ecosystem monitoring program and information base on Florida Bay and Florida Keys that is being established under this intergovernmental effort, will enable managers and scientists to assess ecosystem conditions and the effectiveness of management actions throughout South Florida in restoring the coral reef ecosystem.
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