Important Bird Areas

Lake Okeechobee

Florida

Glades, Hendry, Martin, Okeechobee, and Palm Beach counties
470,000 acres (90,209 hectares), including >28,250 acres (>11,432 hectares) of marshland

In south-central Florida, bordered by Glades County to the west, Okeechobee County to the north, Martin County to the northeast, Palm Beach County to the southeast and south, and Hendry County to the southwest. The Everglades Agricultural Area occupies a huge area between the lake?s southeastern boundary and the northern Everglades. Contiguous with the Kissimmee Lake and River IBA to the north and the Fisheating Creek Watershed IBA to the west, and near the Loxahatchee River and Slough IBA to the east.

At over 730 square miles (1880 square km), Lake Okeechobee is the second-largest freshwater lake entirely within the Lower 48 states (second only to Lake Michigan). Formed about 6000 years ago, it is quite shallow, with its deepest portions only 20 feet (6 m) deep. Much of the southern and western portions are composed of extensive marshes. Hurricanes in the 1920s swept over the lake, causing it to overflow its banks, which killed over 2000 people at Belle Glade, Okeechobee, and Moore Haven. To prevent this human tragedy from recurring, an earthen dike (the Herbert Hoover Dike) 35 feet (10.5 m) tall and 140 miles (224 km) long was built from the 1930s to the 1960s, nearly encircling the lake. This dike separated the lake from the Everglades, into which it previously drained, lowered water levels in the lake, and reduced its size Extensive marshes remain inside the dike, along the lake's western half and to a lesser degree in the south and southeast. There is even a development ? a campground a marina complex ? built on uplands inside the dike. For several decades, water levels in Lake Okeechobee have been manipulated for human uses and the lake now serves primarily as an artificial reservoir. Unnatural water levels, and unseasonable releases of wat

Ornithological Summary

Significant populations of Endangered, Threatened, FCREPA, and IBA species; significant numbers of aquatic birds, wading birds, and shorebirds; significant natural habitats; and long-term research.

Lake Okeechobee is (or was) one of the two most critical sites in Florida for Snail Kites in Florida, and when water levels are favorable, is used abundantly by wading birds, waterfowl, and shorebirds. In 1991, three Brown Pelican nests were discovered on a ?spoil? island in the southern portion of the lake, and at least 14 nests was observed the following year. These nests represent the first known inland breeding records in Florida +(Smith and Goguen 1993). Diversity is at least 109 native species.

Conservation Issues

*exotic plants, *altered hydrology, *runoff, human disturbance

?... Lake Okeechobee is managed under a multiple-use concept that includes competing objectives such as: flood control, water supply, protection against saltwater intrusion for wellfields, production of fish and [other] wildlife resources, recreation, and a water source for the Water Conservation Areas and Everglades National Park? +(David 1994a). See +David (1994b) for a comparison of wading bird use of Lake Okeechobee relative to water levels. ? Lake Okeechobee is used by the South Florida Water Management District primarily as a water storage reservoir. The optimal water depth is between 12?15 feet (3.6?4.5 m) above mean sea level (MSL), a level that was maintained through the 1970s. However, state agencies maintained extremely high water levels (above 15 feet [4.5 m] MSL) during the late 1990s, which drowned out more than 50,000 acres (20,000 hectares) of marshes and willow stands. This action virtually extirpated all wading birds, waterfowl, and Snail Kites +(see Smith et al. 1995). During the drought of 2001, when Snail Kites needed nesting and foraging habitats, the South Florida Water Management District pumped water out of the lake (dropping its level to a record low of 9 feet [2.7 m] MSL) to supply water for the Everglades Agricultural Area. The subsequent pumping of polluted irrigation water back into the lake contributed to its rapid refilling, and prevented drowned plant communities from becoming reestablished. ? Agricultural runoff from farms along the Kissimmee River and the lake's northern shore has resulted in large amounts of phosphorus (around 200 parts per billion) entering the lake, which has caused massive algae blooms, the spread of cattails over preferred vegetation, increased turbidity, changes from a sand-bottom community to a mud-based community, and other damaging impacts. A management plan has recommended a maximum phosphorus level of about 40 parts per billion. ? Invasive e

Habitat

*lacustrine, *freshwater marsh, cattail marsh, and sawgrass marsh, willow heads, mudflats

Land Use

*conservation, *water supply (up to 700 million gallons per day; 2.6 billion liters/day), *recreation, *fishing, hunting, commercial uses (frogs, alligators, turtles, lotus seeds)