PARENT SESSION
Contributed Oral Session 7: Disturbance Ecology: Fire; Litter; Animal response
Monday, August 8, 8:00 AM - 11:30 AM, Meeting Room 518 A, Level 5, Palais des congrès de Montréal
Habitat manipulation to induce gopher tortoise usage of fire suppressed forest.
Balbach, Harold*,1, Hinderliter, Matthew2, Yager, Lisa2, Heise, Colleen2, Epperson, Deborah3, 1 US Army Engineer Research and Development Center, Champaign, IL, USA2 Camp Shelby Field Office, Camp Shelby, MS, USA3 US Department of the Interior, New Orleans, LA, USA
ABSTRACT- The Gopher Tortoise (Gopherus polyphemus) is a large, terrestrial turtle originally widespread in open, sunny pine forests of the Gulf Coast states where deep, sandy soils supported its borrows. As with many species associated with the longleaf pine system, populations have decreased dramatically as a result of 20th century forest management, urbanization, and highway construction. The Louisiana, Mississippi, and western Alabama populations are now federally listed as threatened. Camp Shelby Mississippi, within the DeSoto National Forest, has one of the larger tortoise populations within the listing area, and also supports Army National Guard mechanized training. While many sunny habitats remain, and are preferred tortoise habitat, fire has been suppressed to a great degree in the past 30 years. A dense understory of deciduous shrubs has therefore developed in much of the second-growth forest. Tortoises tend to utilize openings they are able to find, including roadsides and, especially, mowed openings maintained for military training. Within these openings, they face hazards from operation of tracked and wheeled military vehicles. To examine ways to decrease this direct hazard, a series of studies was initiated in 2001 to see if fire would be an effective means to improve the forest habitat, as measured by increase in tortoise usage of forested areas. Each study site utilized a mowed opening of 1 to 3 ha with a resident tortoise colony, and a 200m deep adjacent forested area. Four sites received two controlled burns, one dormant-season and one growing-season, and four sites were maintained as controls. Overall, results were modest, with no significant long-term change in any vegetation component or in tortoise activity patterns. Shrub cover, however, was initially reduced by the first burn treatment, though it was then re-established toward the end of the study in 2004. Also, the number of burrows found within the 200m forest buffer did increase by 90+% on the burned sites. A conclusion might be that while the premise of reduction in forest cover as a means to induce tortoises to utilize the forest areas was sound, this short term treatment regime was insufficient to create long-term behavioral changes, and that a more aggressive, continuing, cover reduction program is required.
Key words: gopher tortoise, military training, controlled burn, habitat change