9459 - Laserfiche WebLink

Home Browse Search

Williams and Dodd To illustrate the importance of wetlands to endangered and threatened species several examples are examined. The examples were selected to cover species and geographic areas which were not primary topics of discussion elsewhere in this symposium. We have re- stricted our discussion to species protected or being considered for protection under pro- visions of the Endangered Species Act of 1973 (16 USC 1531-1543). Definition of the terms endangered and threatened as we use them are included in the Act. WETLANDS AND CROCODILIANS The American alligator, Alligator mississippiensis, is -the best known reptile con- sidered either endangered or threatened within the United States and its territories. It has been feared, praised, and exploited since man first came to the southeast. Early naturalists, such as Bartram (1791), presented startling and unbelievable stories concern- ing the species and its behavioral patterns. Despite its suspected major role in wetlands ecosystems of the south, surprisingly little scientific work has been published on it and then often with conflicting results (McIlhenm~, 1935; Neill, 1971). The importance of the alligator as a top predator, modifier of its environment, and behaviorally sophisticated species is recognized universally by the scientific community (Craighead, 1968; Garrick and Lang, 1977). Hunting, poaching, and habitat degradation at one time seriously reduced the number of alligators throughout the species' range and led to its inclusion as endangered under provisions of the Endangered Species Conservation Act of 1966 (Laycock, 1972). Valen- tine, et al. (1972), estimated that illegal poaching probably equaled the legal take on the Sabine National Wildlife Refuge in Louisiana. This-would amount to almost 7500 illegally harvested alligators. Strict Federal protection, coupled with strong state laws pioneered by Louisiana and Florida, enabled alligator populations to recover dramatically in many parts of the species' former range. For example, the alligator population in Louisiana in- creased from an estimated 26,000 in 1957 to over 300,000 presently (Duffy, 1963; 3oanen, pers. comm.). Because of this, the alligator has been reclassified twice to reflect its improved status (Greenwalt, 1975, 1977). The improving status of the alligator is good news from both an ecological as well as an esthetic or commercial point of view. The ecological role of the alligator in shaping plant communities is especially important in southern Florida wetlands, and particularly in the Everglades (Craighead, 1968; Carr, :~ 973). In this area, the alligator builds "gater holes" by pulling plants loose and dragging them to the sides of a natural depression in limestone bedrock, and then pushing and carrying marl and organic muck to the sides of the depression. In this way, the alligator creates a pool with a raised perimeter above the surrounding wetland area. Often the areas form "islands" which provide the only high ground for many acres of sawgrass prairie. Trees, such as willow, red bay, pop-ash, maple, bottonbush, myrtle, acid other small species, become established and then provide cover, breeding sites, and food for in- sects and birds. The islands provide high ground which can be used by tl i 1 .~ an~lkes on which to lay eggs. Mammals such as rabbi,~.,,,ptt~~~,,,,~nd raccoon, use the islands for cover acrd as areas for feeding. Thus, a unique community of plants and animals can make use of the by-product of the alligator's building activities. Continued maintenance by the resident alligator, perhaps consisting of nothing more than its everyday movements 566