After three weeks in the Everglades, the East Aiken classes reluctantly decided to move on. As they headed west along the Tamiami Trail, a stop at Shark Valley on the north side of Everglades National Park offered a fantastic a day of viewing river otters and wood storks; then the classes continued their trek westward. On January 6, 2000, East Aiken arrived at Big Cypress National Preserve. Big Cypress is a very large area (more than 700,00 acres, or 280,000 hectares) that was established in 1974 to provide additional protection to the Everglades watershed. (More info on Big Cypress in available at http://www.nps.gov/bicy/.)
Indigo Snake (Drymarchon corais)
The Eastern Indigo Snake is the largest non-venomous snake in North America. The indigo is yet another herp species that illustrates the severity of the problems faced by numerous reptiles and amphibians. Of the six threats to the herpetofauna outlined by Partners in Amphibian and Reptile Conservation (PARC), populations of the indigo snake have been dramatically affected by two threats: habitat loss and unsustainable use. Population declines have been so substantial that the U.S. Fish and Wildlife Service listed indigo snakes as a "threatened species" in 1979—for a snake species to be federally listed, the problem has to be bad, as snakes are not typically high on the list of people’s favorite animals. Indigo snakes are protected at the state level in Alabama, and have full protection as a threatened species in Florida and Georgia, and as an endangered species in South Carolina and Mississippi.
Indigo snakes inhabit a variety of habitats. Although habitat destruction has been a major factor in the snake’s decline, habitat preservation will be one key to its survival. To some extent the "protection" of indigo snake habitat stems from efforts to protect two other species, the red-cockaded woodpecker and the gopher tortoise. All three species (indigo snakes, gopher tortoises, and red-cockaded woodpeckers) rely on a healthy longleaf pine forest ecosystem. By protecting and managing this habitat type for birds and tortoises, we are also creating conditions that will enhance indigo survival. It is likely that the management of red-cockaded woodpecker habitat, using periodic growing season burns, will have a positive effect on both gopher tortoise and indigo snake populations. Because approximately 95% of the longleaf pine habitat in the Southeast has already been destroyed, protection and management of the remaining habitat will be critical.
The ecology of indigo snakes makes protection of them more problematic than some species. For example, at many sites in winter indigo snakes are found almost exclusively in gopher tortoise burrows. Thus, any human activity that degrades this type of refuge (such as off-road vehicles, rattlesnake round-ups, or fire suppression) is likely to be bad for indigo snakes (as well as all other inhabitants of the burrows). Additional conservation challenges are presented by the fact that indigo snakes have very large home ranges, and therefore probably cannot persist in a fragmented habitat. At a minimum, habitat corridors must be maintained to link upland and lowland habitats, which are both used by snakes during different seasons. Some researchers believe that the minimum area of suitable habitat required to sustain an indigo population is 2500 acres (1000 hectares).
The original range of the eastern indigo snake once included southern Mississippi and Alabama, Florida, much of Georgia, and perhaps parts of southeastern South Carolina. Currently the distribution is restricted to Florida and the Coastal Plain of southern Georgia. In spite of reintroduction efforts at some locales, indigo snake populations continue to decline.