Everglades

I

Introduction

Everglades, vast marsh covering much of southern Florida. Formed by thousands of years of overflow from Lake Okeechobee after heavy rains, the Everglades extends southwestward from the lake to the shores of Florida Bay and the Gulf of Mexico. The marsh lies in a shallow basin of limestone, tilted slightly to the southwest, that begins a few kilometers north of Cape Sable at the southernmost tip of the Florida peninsula and stretches northward to Lake Okeechobee. Several small streams, such as the Miami, Little, and New rivers on the east and the Shark and Harney on the southwest, drain the region, but none flows into it. The swampy Everglades constitutes a “River of Grass” (so named by its famous chronicler, 20th-century American author Marjory Stoneman Douglas), covering 13,000 sq km (5,000 sq mi) and averaging 80 km (50 mi) wide and 15 cm (6 in) deep.

II

Description

The Everglades is a unique wetland ecosystem on the margin of the tropics. Its slow flow of water supports grasslands, thick forests, and a diverse group of animal, fish, and bird life. The Everglades originated between 8,000 and 10,000 years ago at the end of the most recent of the Ice Ages, when the melting of the glaciers caused sea levels to rise, inundating the region’s outlets to the Atlantic Ocean and the Gulf of Mexico and converting the low-lying basin into a swamp.

Today, tidal bays, lakes, and connecting waterways, varying in depth from 0.3 to 2.0 m (1 to 7 ft), and sometimes considerably less in dry years, honeycomb the wilderness of swamp, savanna, and virgin forest that make up the surface of the Everglades. Most of the marsh, however, is covered with saw grass that rises 1 to 3 m (3 to 10 ft) above the surface of the water, and is often so dense that passage is effectively blocked except for the natural water lanes. The entire region lies less than 6 m (20 ft) above sea level, with elevations overall averaging between 2 and 3 m (7 and 10 ft).

The climate of the Everglades is tropical savanna, characterized by hot, wet summers and warm, dry winters, with no month exhibiting a mean temperature below 18°C (64°F). Average annual rainfall exceeds 130 mm (50 in), although this amount can vary widely when hurricanes cross the region or multiyear droughts strike (as happened during most of the 1980s). Cypress, mangrove thickets, palms, live oaks, pines, and lush vegetation cover the numerous islets (known as hammocks) that are found in the Everglades. The lower-lying floodplain that surrounds these hammocks becomes a swamp or is covered by water during the long summer rainy season, which is usually marked by heavy downpours associated with daily thunderstorms. Wildlife, although severely reduced in number and diversity over the past century, is still abundant and includes alligators, American crocodiles, deer, wading birds, fish, snakes, and the endangered Florida panther.

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III

Population and Economy

The Everglades have been inhabited by native peoples for several thousand years. During much of the 19th century, the marsh was a sanctuary for the Seminole people during their conflicts with United States troops. Today, the Miccosukee people constitute most of the region’s residents. They are concentrated in reservations near the center of the Everglades; much of their income is now derived from gambling profits in large bingo halls, which attract large numbers of retirees from the urbanized coastal areas to the east.

Agriculture, the leading economic activity in the region, is confined to the northern segment of the Everglades in the area south of Lake Okeechobee. Here, on rich, drained lands, farmers have raised sugarcane, fruit, and vegetables since the 1920s. In the wilderness to the south and west, tourism dominates, with most of the swamp’s visitors drawn to certain sites where the natural processes of the Everglades can be closely observed. Approximately 1 million people per year visit Everglades National Park, which covers 5,661 sq km (2,186 sq mi) in the southern Everglades.

A

Environmental Threats

During the 20th century, human interference altered the Everglades ecosystem. Shortly after 1900, large drainage projects were launched. Soon many canals were built, which lowered the level of Lake Okeechobee and inhibited its natural tendency to overflow into the Everglades. As urban growth along the Atlantic coastal strip accelerated after World War I (1914-1918), more and more water was diverted from the Everglades. Simultaneously, an agricultural zone was developed south of Lake Okeechobee, and farming soon consumed huge quantities of water. Meanwhile, the farms’ phosphorus-rich fertilizer wastes and pesticide residues were dumped into water that made its way southward across the swamp. At the same time, two major east-west highways were built across the region, enhancing the accessibility of wilderness areas.

In addition, the introduction of exotic vegetation with no natural local enemies, notably melaleuca trees and Brazilian pepper plants, has upset the traditional biological balance in the Everglades. Melaleuca trees were imported from Australia early in the 20th century in an attempt to launch a timber industry and to drain the region. The wood proved too difficult to harvest, but the new trees spread quickly, overwhelming many other plant communities and consuming much of the marsh’s dwindling water supply. Brazilian pepper was initially imported as an ornamental shrub for landscaping, but it, too, spread out of control.

The federal government tried to preserve the Everglades ecosystem by designating the southwestern segment of the swamp as the Everglades National Park in 1947. Although wildlife protection was thereby enhanced, the park was too small (covering only 20 percent of the Everglades) to counter the negative environmental forces plaguing the region. Later, during the 1960s, the United States Army Corps of Engineers thought it could help by converting the Kissimmee River, the source of Lake Okeechobee’s water, from a meandering subtropical stream into a straightened concrete-lined channel. However, this channel has wreaked further environmental havoc in the northern part of the Everglades watershed.

In the 1980s and 1990s the environmental problems of the Everglades received national attention, and a number of restoration efforts were initiated. In 1989 the federal government approved the expansion of the Everglades National Park in order to control more of the area’s water resources. The state of Florida also worked to attack the chemical pollution problems in the Lake Okeechobee farming sector. In 1996 the federal government passed an act to protect and restore the Everglades. The act allowed the federal government to acquire farmland in order to let it revert back to marsh. The act also appropriated money to help restore the Kissimmee River to its original channel. That same year Congress formally established the South Florida Ecosystem Restoration Task Force, which included federal and state agencies responsible for developing policies and plans to restore the ecosystem. In 2000 Congress passed the Everglades Restoration Act as part of the Water Resources Development Act. The 30-year plan was designed to return the natural flow of water to the Everglades by removing levees. It also included plans to restore the quality and quantity of water flowing into the Everglades.