Published: Sep 07, 2010 5:31 PM EDT
Updated: Sep 07, 2010 2:30 PM EDT

BIG CYPRESS NATIONAL PRESERVE, Fla. (AP) - Wildlife officials are calling off this fall and winter deer hunting season on 100,000 acres in the Big Cypress National Preserve due to a dramatic decline in the size of the deer herd.

The National Park Service has been keeping a watchful eye on the decline in the preserve's southernmost region. The area is known as the Stairsteps Unit for its jagged shared boundary with Everglades National Park south of U.S. 41.

The Florida Fish and Wildlife Conservation Commission is responding by calling off the hunting seasons for certain parts of the park. Deer season is open, though, to other parts of the 729,000-acre preserve.

A task force will try to find out the reason for the decline. Theories include high water levels, disease and predators with an upper hand.