Forecasting Gopher Tortoise (Gopherus polyphemus) Distribution and Long-Term Viability at Fort Benning, Georgia

Abstract

The gopher tortoise (Gopherus polyphemus), once thrived in the southeastern USA, is now at risk due to habitat destruction and fragmentation throughout its native range. The US Army installation at Fort Benning, GA, provides a significant amount of habitat for the gopher tortoise. However, both installation operations and natural processes such as forest canopy growth may disrupt the highly specialized habitat that the gopher tortoise needs to survive. This chapter presents a spatially explicit agent-based simulation model of gopher tortoise population distribution and viability on Fort Benning lands. The model, developed in NetLogo (http://ccl.northwestern.edu/netlogo/), incorporates geospatial data for Fort Benning, ecological characteristics of the land, and data on the gopher tortoise life cycle. Because there is little published data on gopher tortoise population dynamics, the model is based on published studies of species individuals. The purpose of this model was to investigate whether useful simulations of tortoise population dynamics and movement may be produced by a model based on robust data on individuals of the species. The authors conclude that the model can produce valid science-based simulations that provide valuable insights on how alternate land-management policies may affect gopher tortoise distribution on Fort Benning.