Alva Mihalik

Alva Mihalik

Mapping Burrows of the Gopher Tortoise


Alva Mihalik, Dr. Daniel J. Johnson


Dr. Daniel J. Johnson


College of Agricultural and Life Sciences


<p>The gopher tortoise, <em>Gopherus polyphemus</em>, is a burrowing tortoise whose range covers most of the southeastern US. The tortoises dig deep burrows which maintain regular temperature even during exceptionally hot or cold days, providing hundreds of different species refuge from extreme temperatures and fires.  Gopher tortoises are a keystone species in sandhill habitats, but have experienced population declines leading to categorization as vulnerable and threatened in portions of its range. Longleaf pine forests in the sandhills have low tree densities allowing sunlight to reach the ground, creating a rich understory and basking spots providing preferred habitat for tortoises. Deepening the understanding of burrow site selection would help in the recovery and conservation of tortoise populations through guidance of habitat restoration. We conducted research on the factors which relate to gopher tortoise burrow placement at the Ordway-Swisher Biological Station. We censused gopher tortoise burrows in a 23 ha forest where all the trees had been mapped. We found 191 burrows total: 73 active, and 118 inactive or abandoned. Active burrows were less dense than random chance at the 10 m scale according to spatial point pattern analysis. We hypothesized that there will be a negative relationship between the tortoise burrows location and the tree species abundance and a positive correlation with the slope of the land. We found that burrow location was significantly correlated with the openness of the tree canopy, but had no relation with slope.</p>


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