Everglades National Park

Everglades National Park

Everglades National Park is a U.S. National Park in Florida that protects the southern 20 percent of the original Everglades. In the United States, it is the largest tropical wilderness, the largest wilderness of any kind east of the Mississippi River, and is visited on average by one million people each year. It is the third-largest national park in the lower 48 states after Death Valley and Yellowstone. It has been declared an International Biosphere Reserve, a World Heritage Site, and a Wetland of International Importance, one of only three locations in the world to appear on all three lists.

Everglades National Park

Although most U.S. national parks preserve unique geographic features, Everglades National Park was the first created to protect a fragile ecosystem. The Everglades are a network of wetlands and forests fed by a river flowing .25 miles (0.40 km) per day out of Lake Okeechobee, southwest into Florida Bay. The Park is the most significant breeding ground for tropical wading birds in North America, contains the largest mangrove ecosystem in the western hemisphere, is home to 36 threatened or protected species including the Florida panther, the American crocodile, and the West Indian manatee, and supports 350 species of birds, 300 species of fresh and saltwater fish, 40 species of mammals, and 50 species of reptiles. The majority of South Florida's fresh water, which is stored in the Biscayne Aquifer, is recharged in the park.

Humans have lived for thousands of years in or around the Everglades, until plans arose in 1882 to drain the wetlands and develop the recovered land for agricultural and residential use. As the 20th century progressed, water flow from Lake Okeechobee was increasingly controlled and diverted to enable explosive growth of the South Florida metropolitan area. The park was established in 1934 to protect the quickly vanishing Everglades, and dedicated in 1947 as massive canal building projects were initiated across South Florida. The ecosystems in Everglades National Park have suffered significantly from human activity, and restoration of the Everglades is a politically charged issue in South Florida.

Climate

Everglades National Park has a tropical savanna climate and tropical monsoon climate, depending on location. Most of the central region has a savanna climate while regions closer to shore, especially the eastern quarter of the park has a monsoonal climate. Both climates are characterized by two seasons: wet and dry. The park's dry season lasts from December to April, when temperatures vary from 53 °F (12 °C) to 77 °F (25 °C) and humidity is low. Since water levels are low at that time, animals congregate at central water locations, providing popular opportunities for viewing the wildlife. During the wet season, from May to November, temperatures are consistently above 90 °F (33 °C) and humidity over 90 percent. Storms can drop 10 to 300 mm of rain at a time, providing half the year's average of 60 inches of rainfall in just two months.

Ecosystems

At the turn of the 20th century common concepts of what should be protected in national parks invariably included formidable geologic features like mountains, geysers, or canyons. As Florida's population began to grow significantly and urban areas near the Everglades were developed, proponents of the park's establishment faced difficulty in persuading the federal government and the people of Florida that the subtle and constantly shifting ecosystems in the Everglades were just as worthy of protection. When the park was established in 1947, it became the first area within the U.S. to protect flora and fauna native to a region as opposed to geologic scenery. The National Park Service recognizes nine distinct interdependent ecosystems within the park that constantly shift in size owing to the amount of water present and other environmental factors.

Freshwater sloughs and marl prairies

Freshwater marl prairies are similar to sloughs, but lack the slow movement of surface water; instead, water seeps through a calcitic mud called marl. Algae and other microscopic organisms form periphyton, which attaches to limestone. When it dries it turns into a gray mud. Sawgrass and other water plants grow shorter in freshwater marl than they do in peat, the other type of soil in the Everglades which is found where water remains present longer throughout the year. Marl prairies are usually under water from three to seven months of the year, whereas sloughs may remain submerged for longer than nine months and sometimes remain under water from one year to the next. Sawgrass may dominate sloughs, creating a monoculture. Other grasses, such as muhly grass (Muhlenbergia filipes) and broad-leafed water plants can be found in marl prairies. Animals living in the freshwater sloughs also inhabit in marl prairies. Marl prairies may go dry in some parts of the year; alligators play a vital role in maintaining life in remote parts of the Everglades by burrowing in the mud during the dry season, creating pools of water where fish and amphibians survive from one year to the next. Alligator holes also attract other animals who congregate to feed on smaller prey. When the region floods again during the wet season, the fish and amphibians who were sustained in the alligator holes then repopulate freshwater marl prairies.

Endangered and threatened animals

The American crocodile has notable differences from the alligator. Habitat destruction and vehicle collisions are some of the largest threats it experiences.

Thirty-six federally protected animals live in the park, some of which face grave threats to their survival.

In the United States, the American crocodile's only habitat is within South Florida. They were once overhunted for their hides. They are protected today from hunting, but are still threatened due to habitat destruction and injury from vehicle collisions when crossing roads to reach waterways. About 1,000 crocodiles live in Florida and there are roughly 50 nests in the Everglades and Biscayne National Parks. Crocodiles populations in South Florida have increased as has the number of alligators. Crocodiles were reclassified from "endangered" to "threatened" in the United States in 2007. The Florida panther is one of the most endangered mammals on earth. About 50 live in the wild, primarily in the Everglades and the Big Cypress Swamp. The biggest threats to the panther include habitat destruction from human development, vehicle collisions, inbreeding due to their limited gene pool, parasites, diseases, and mercury poisoning.

Four Everglade species of sea turtle including the Atlantic green sea turtle, the Atlantic hawksbill, the Atlantic loggerhead (Caretta caretta), and the Atlantic ridley (Lepidochelys kempii) are endangered. Also, the leatherback sea turtle (Dermochelys coriacea) is threatened. Numbers are difficult to determine, since males and juveniles do not return to their birthplace, although females lay eggs in the same location every year. Habitat loss and illegal poaching and destructive fishing practices are the biggest threats to these animals.

Two species of birds in the park are in danger of disappearing. The range of the Cape Sable seaside sparrow is restricted to Everglades National Park and the Big Cypress Swamp. In 1981 6,656 Cape Sable seaside sparrows were reported in park boundaries, but surveys over 10 years documented a decline to an estimated 2,624 birds by 2002. Attempts to return natural levels of water to the park have been controversial; Cape Sable seaside sparrows nest about a foot off the ground, and rising water levels may harm future populations, as well as threaten the endangered snail kite. The Everglades snail kite eats apple snails almost exclusively, and the Everglades is the only location in the United States where this bird of prey exists. There is some evidence that the population may be increasing, but loss of habitat and food sources keep the estimated number of these birds at several hundred.