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Threats to the Parks: Biscayne National Park


Divers clean debris from reef at Biscayne National Park. Photo by tiswango via Flickr.

Situated a few miles south of Miami, where it encompasses all but the northernmost part of Biscayne Bay, Biscayne National Park is one of our largest marine national parks as well as the only place in the world where a living tropical coral reef lies adjacent to a large urban center.

The park’s fragile resources, heavy visitation, and location on the periphery of the big, rapidly growing Miami-Dade County metro complex make it one of our most vulnerable parks.

When Biscayne was established, it was clear that preserving the park’s ecological, scenic, and cultural resources would be very difficult. It therefore comes as no surprise that Biscayne’s resources are in constant jeopardy. the park has been heavily impacted by chronic overfishing, boating accidents, disruption of natural water flow, pollution, and adjacent land-use activities.

This sorry situation has drawn plenty of attention and a good deal of scientific research. In 2004 the National Parks Conservation Association placed Biscayne on its annual list of the Ten Most Endangered National Parks. At Biscayne, the NPCA pointed out, “Important fish and coral populations are threatened by overfishing, destructive use, and pollution [and] sensitive coastline slated for wetlands restoration is being developed, impeding the restoration of the fresh water flows necessary to restore the estuary.”

A more recent (2006) NPCA assessment of Biscayne gave the park a score of just 58 out of 100 (“poor”) for natural resources condition and only 48 for cultural resources. The full 44-page State of Biscayne National Park report can be seen at this site.

Struggling to Maintain Coral Reefs in Biscayne National Park

Although there are many resource management challenges at Biscayne, the central, monumentally difficult one is preserving and restoring Biscayne’s coral reef system. This reef complex, which covers about half of the park, consists primarily of small patch reefs – about 4,000 in all – that are part of the Florida Keys chain. There are some transitional barrier reefs on the Atlantic (eastern) margin of the park.

A reef system is based on the work of polyps -- tiny marine organisms with exterior skeletons consisting of little cups that they manufacture from calcium they excrete. Over very long periods of time the skeletons build up to form various kinds of coral, and the coral masses create reefs. A coral reef is a community of plants and animals interacting with each other and their environment in very complex ways. To remain healthy, this community requires clean flowing water as well as sunlight and nutrients.

Biscayne’s coral is growing very close to the northern limits of its range and on the fringe of one of America’s larger urban regions, Miami-Dade County. Under these barely adequate conditions the coral is easily sickened or killed by pollution and changes in sunlight, water temperature and salinity, nutrient loads, turbidity (sediment load and deposition), and related factors.

Coral can be injured in many ways. The park gets heavy use, is situated next to Miami, has the Intracoastal Waterway running through it, and is close to coastal shipping lanes. Recreational boats frequently bump into coral heads and damage them with their anchors. Some skin divers steal coral or accidentally damage it. Storms cause commercial ships to run aground on the reef, where they do extensive damage. Repairs are sometimes possible, but only when the physical damage is minimal.

There can be no doubt that Biscayne’s reef system is in deep trouble, and that this has serious implications for the future health of the various ecosystems the park was created to protect.

Here is what the NPCA said about this situation in its 2006 State of Biscayne National Park report:

Over the past several decades, coverage and species abundance on coral reefs within Biscayne National Park and the south Florida Reef Tract has … declined. Coral cover was measured in the early 1980s on transitional bank-barrier and patch reefs in the park at 29 percent and 26 percent, respectively. Nearly two decades later, coral cover was 11 percent on transitional bank-barrier reefs and 17 percent on patch reefs in the park. From 1989 to 1991, both bank-barrier and patch reefs in Biscayne National Park also experienced a decline in coral diversity (number of species) of between 13 and 29 percent. Loss of the coral reef ecosystem, or major components of the coral reef community, will have a cascading effect on mangrove, seagrass, and hardbottom ecosystems found in the park because they are all highly interconnected and interdependent.

This is ominous. Biscayne National Park not only protects numerous threatened or endangered species, but also preserves habitat and nursery grounds for most of the region's important commercial and recreational fish, shellfish, and crustaceans. Not surprisingly, all corals in Biscayne are included on state or federal protection lists.

Diversity is the hallmark feature of reefs. Among all of this planet’s major ecosystems, only the tropical rainforest is more biologically diversified. (To drive this point home, conservationists often refer to reefs as the “rainforests of the sea.”) Biscayne’s reef system supports more than 200 species, and the park is home to a total of at least 325 fish and macroinvertebrate species, 200 bird species, about 30 mammal and reptile species, and six amphibian species.

The reef system in Biscayne National Park belongs to the world’s third-largest barrier reef system, the Florida Reef Tract, which extends from Fowey Rocks on Biscayne’s northern boundary to Loggerhead Reef on the western boundary of Dry Tortugas National Park.

Reef preservation and other aspects of ecosystem management at Biscayne are tied in with the Florida Keys National Marine Sanctuary, a contiguous preserve that was created by presidential order in 1990. This managerial approach recognizes that ecosystem borders do not neatly coincide with park boundaries, and that protecting migratory species (such as sea turtles and manatees) and confronting outside threats requires integrated resource management efforts that extend over very large areas and involve many different public and private resource managers and stakeholders.

Working to Invigorate Biscayne's Coral Reefs

Protection may be the most important facet of reef management, but it is not the only one. Some of the most exciting developments are in the area of reef repair and restoration. In 1992, scientists began conducting research and experimentation on growing coral in a field nursery and rehabilitating reefs with coral taken from undamaged reefs. The park established four coral nurseries to cultivate up to 2,000 coral colonies for restoration projects. In addition, coral fragments taken from grounding sites are raised until they are large enough to be transplanted back to damaged reefs. Cables are used to secure transplanted coral. Researchers are able to electronically monitor coral fragment growth and survival rates using transponders imbedded in the transplants.

A Damage Recovery Program that the park inaugurated in 1995 focuses on the problem of seagrass and coral reef damaged by boats running aground. This program is designed to not only restore the damaged resources, but also prevent future incidents through education, law enforcement, and related means.

Alas, Biscayne Bay’s coral may be dying faster than it can be replaced. In a phenomenon called coral bleaching, vast areas of coral become diseased, turn white and die. Coral bleaching has reached such alarming proportions that two important species of Caribbean coral — elkhorn (acropora palmate) and staghorn (acropora cervicornis) -- were added to the list of threatened species in 2006. Scientists are speeding up efforts to identify precise causes, but it is already clear that ocean warming is a major underlying factor. Since the Biscayne patch reefs are living near their maximum temperature, only a few degrees of warming is needed to trigger diseases or initiate processes that seriously damage or kill Biscayne’s coral.

In addition to preserving the reefs at Biscayne, the National Park Service must confront serious hydrology issues and pollution problems, curb overfishing, protect seagrass and endangered species, minimize the impact of invasive species, cope with illegal immigrants and drug smugglers, and address homeland security issues. This is not to mention dealing with the ravages of hurricanes and the inundation threat of rising sea levels.

Hydrological Problems Also Confront The Park Service

Changes in regional hydrology have severely impacted Biscayne Bay and greatly contributed to the severity of the park’s pollution problems. Biscayne Bay (aided by Barnes and Card Sounds) serves as the outlet for water flowing out of the Everglades eastward toward the Florida Straits. Until about the mid-1900s, the water flowing into Biscayne Bay was clean and clear because it was filtered through freshwater marshes. By the time the park was established, however, the coastal wetlands had been extensively drained and filled for agricultural use and to control floods and mosquitoes. In addition, South Florida water diversion and canal projects had disrupted the natural hydrologic flows and changed Biscayne Bay from a naturally functioning estuary system to an artificial water disposal system receiving freshwater from canals. Subsurface flows of groundwater had decreased so much that saltwater intrusion was contaminating the Biscayne aquifer.

Combined with changes in the quantity, timing, and distribution of freshwater flows, dramatic changes in adjacent land use greatly increased the amount and severity of pollution entering Biscayne Bay. Agricultural activities, which account for about 8 percent of Miami-Dade County land use, border parts of the bay and contaminate its waters with pesticides, nutrients, and sediment. The huge urban-industrial complex adjoining the northern bay contributes chemicals and sewage, and also redirects some water to urban uses. The South Miami- Dade Landfill, which is situated close to the bay (at Black Point), is a known source of contaminants, and so is the adjacent South Miami-Dade sewage treatment plant.

The Park Service would love to have more water of better quality delivered to the park, and would also like to see the park buffered against the harmful spread of agricultural and urban-industrial land use. The Comprehensive Everglades Restoration Plan (CERP) currently under way in South Florida is supposed to address these and other problems affecting the bay and the park.

One of the nearly 70 CERP projects is the proposed Biscayne Bay Coastal Wetlands Project (BBCW). The BBCW, which will encompass 13,600 acres (including the park’s entire mainland), is designed to divert canal flow through coastal marshes and creeks so as to restore natural estuarine functions and improve habitat for the fish and wildlife in the bay. Reconnecting the estuarine wetlands with the adjacent freshwater wetlands should not only reestablish the oyster reef community, but also create a much more productive nursery habitat for the bay’s many fish, shellfish, and crustacean species. One huge benefit will be to reduce the abrupt freshwater discharges (like turning a faucet on) that are so stressful to fish and benthic invertebrates near canal outlets.

Overfishing is Depleting Fisheries in and Around Biscayne National Park

Overfishing is another serious concern in the park. In fact, it poses a major threat to the coral reefs, which depend on biodiversity for healthy functioning. In 2006 the NPCA reported that at least 27 of 35 fish species studied in the park were over-fished, largely because many species could be legally harvested before they reached the size of sexual maturity. Developing highly effective fisheries management plans is complicated because it requires the cooperation of the Florida Fish and Wildlife Conservation Commission and other state and federal regulatory agencies. The fact that commercial fishing was grandfathered in when the park was created adds an additional element of complexity.

Biscayne Bay’s lush beds of seagrass (five varieties in all) are a major part of the food chain and provide vital habitat for fish, spiny lobsters, shrimp, manatees, sea turtles, and many other species. Unfortunately, seagrass beds are easily damaged by boat propellers, boat groundings, anchor moorings, dredging, and other disturbances. Damaging seagrass is certainly not a laughing matter in the federal courts. A man who damaged seagrass beds in Biscayne Bay while boating under the influence of alcohol was fined $25,000, ordered to pay $106,000 in restitution, and given a four-month home detention sentence in addition to three years probation.

Protecting threatened and endangered species is an important part of the park’s mission. At least 16 federally listed threatened or endangered species find sanctuary in the park. The nearly one dozen endangered species, a very diverse assortment indeed, include the West Indian manatee (Trichechus manatus), American crocodile (Crocodylus acutus), hawksbill sea turtle (Eretmochelys imbricate), green sea turtle (Chelonia mydas), smalltooth sawfish (Pristis pectinata), wood stork (Mycteria americana), least tern (Sterna antillarum), beach jacquemontia (Jacquemontia reclinata), Schaus swallowtail butterfly (Heraclides aristodemus ponceanus), Johnson’s seagrass (Halophila johnsoni), and Key Largo cotton mouse (Peromyscus gossypinus allapaticola). A number of other species are threatened, and three more are candidates for listing.

Biscayne Bay and its environs provide critical habitat for more than 172 “species of concern” (species that are included on at least one state or federal protection list) and the park itself provides critical habitat for several federally listed endangered species. One small island in the park, Soldier Key, is the only place outside the Caribbean that provides nesting sites for the critically endangered hawksbill sea turtle. The park also has the world’s only viable population of the endangered Schaus swallowtail butterfly, which has an impressive wingspan of up to four inches.

Public education and strict law enforcement are key elements of endangered species protection at Biscayne. For example, boaters are less likely to injure manatees, sea turtles, or seagrass if they wear polarized sunglasses, obey the relevant rules and regulations, and exercise due caution in shallow water where the danger of damaging underwater resources and wildlife is greatest.

Exotic plant and animal species cause some serious problems at Biscayne. Of the more than 450 plant species that live in the park, at least 130 (29 percent) of them are nonnative. The Florida Exotic Pest Council has listed 14 of these on its list of most invasive species. Four of these highly invasive species -- Brazilian pepper (Schinus terebinthifolius), Australian pine, (Casuarina equisetifolia), sisal hemp (Agave sisalana) and seaside mahoe (Thespesia populnea) – have been targeted with special control programs operated by the Park Service in cooperation with the Florida Department of Environmental Protection.

How to Cope With Illegal Immigrants and Drug Runners?

South Florida is a magnet for illegal immigrants as well as one of the great crossroads of the international trade in illicit drugs. Biscayne Bay lies athwart the seaward approach to Miami, so the Park Service is continually involved in detecting, chasing, and apprehending smugglers. Many smugglers in “go fasts” try to slip through the park’s waters, usually speeding through at night without lights and at the risk of colliding with recreational and commercial fishing boats going after stone crabs and lobsters. In their haste to get ashore, smugglers run their “go fasts” aground in shallow water and kill fragile sea grass. When discovered and pursued, they sometimes leap from their boats and leave them to careen in tight circles until the engine fails or they run aground.

Security concerns in the aftermath of the September 11, 2001, terrorist attacks led to increased protection for America’s nuclear power plants as part of the Homeland Security program. Florida Power and Light has a nuclear power plant at Turkey Point, which is located only a mile and a half from the park headquarters. This facility is deemed a potential terrorist target, and most of the security zone established around it is in park waters. Park management is thus required to interact with many different agencies and organizations, including the Coast Guard, the FBI, the Miami-Dade Police Department, the Florida Dept. of Law Enforcement, the Florida Wildlife Conservation Commission, and the security operations for the Turkey Point plant.

Hurricanes and other tropical storms pose a serious threat to the park. National Hurricane Center data show that the greater Miami area has a 48 percent probability of being hit by at least one hurricane in any given year (only Cape Hatteras, NC, has a probability this high). This is no idle threat. In 1992 Hurricane Andrew ravaged Miami, wrecked nearby Homestead Air Base beyond repair, and damaged Biscayne National Park so badly it was closed for four months. As recently as 2005, Hurricane Wilma substantially damaged park structures and compelled a temporary closing.

Sea level rise associated with global warming is also a matter of concern. Park managers are keenly mindful of the fact that no part of the park lies more than eight feet above sea level.


this was really helpful!! It makes people inspired to help out.! You should make a page about how people have helped out.

Understanding what has gone wrong and why is a vital step in the process of repairing damage. In the case of Biscayne National Park, the National Park Service has a very good grasp of the basic facts -- that is, the agency understands the nature and severity of the problems besetting the park. The major obstacle is inadequate resources. There just isn't enough money, staffing, and other essentials, including political capital. Sadly, Biscayne is being so heavily used (and abused) that managers will be hard pressed to keep the park's natural resources situation from markedly worsening. It's very frustrating for resource managers, at Biscayne or anywhere else, to know that they must run faster and faster just to stay in place.

Traveler will continue to monitor and report on resource management issues and actions at Biscayne. As you've suggested, we'll try to find out more about individuals and organizations that are helping out so we can tell our readers about that too.

how many people depend on the biscayne aquifer

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