BEAUMAN, R.L.*; MENDON�A, M.T.; Auburn University; Auburn University: Factors Affecting Degree of Burrow Collapse and Resulting Tortoise Self Excavation and Behavior

The gopher tortoise is a federally listed species in the western portion of its range, and a species of concern elsewhere. Their burrows are often collapsed during human activity associated with logging activity and land use. Little is known to what extent burrows collapse, what factors contribute to the degree of collapse, how this impacts the tortoises� ability to self excavate after the collapse, and what effect this has on movement behavior. As part of a larger study to determine how physiologically detrimental this disturbance is to tortoises, we documented the physical factors that impact the degree of the collapse and monitored pre collapse and post excavation movement behavior. In the spring of 2004, we experimentally collapsed active burrows with tortoises in them using a JD 648 logging skidder (n = 22). We measured the collapse zone and monitored the number of days until each tortoise self excavated. The collapsed zone ranged from 0.66 to 2.21m and the amount of time to self excavation ranged from hours to 85 days. The majority of tortoises excavated within 20 days. The distance from the original mouth to the point of exit on self excavation ranged from 0 to 3.05m. There was a significant positive correlation between the amount of burrow collapse and the exit distance from the original mouth. There was no significant difference between the number of burrows used, the number of times moved or the size of the home range pre and post collapse. Upon self excavation, tortoises stayed in the collapse burrow (50%), moved to a previously used burrow (4.5%), or moved to a new burrow (45.5%). A follow up study was conducted in 2005 to look at the long term effects of burrow collapse on tortoise movement and home range size. This and other aspects of movement behavior will be discussed.