The U.S. Fish and Wildlife Service’s 12-month finding for listing the gopher tortoise as Threatened under the Endangered Species Act (ESA) has stimulated additional interest in conservation of the species. A Candidate Conservation Agreement and a comprehensive strategy have been developed for the gopher tortoise. It will be necessary to define a minimum viable population size, the number of viable populations needed, and the ideal geographic distribution of these populations in order to successfully conserve this species.
The scientific literature provides mixed guidance about what constitutes a minimum viable gopher tortoise population. Results from existing population viability models vary from 25 to 250 individuals under ideal habitat conditions. In addition, there is no consistency in the scientific literature regarding how large a parcel of habitat must be to support a viable population. Therefore, there was a clear need to convene experts in gopher tortoise biology, ecology, management, and demographic modeling to reach consensus regarding the following objectives:
The first workshop was held on 13-14 March 2013, to define the minimum viable population (MVP) and minimum reserve size for the gopher tortoise (Gopherus polyphemus) using the best available scientific information. In this case, the purpose of establishing MVP parameters is to provide acceptable benchmarks for conservation and recovery efforts and is not to determine absolute minimum thresholds that if not met will result in certain population demise. Gopher Tortoise Minimum Viable Population and Minimum Reserve Size Working Group Report 1
The second workshop was held 4-5 March 2014 at the Solon Dixon Forestry Education Center in Andalusia, Alabama. The objectives for the second workshop were to: 1) Establish consensus on the number and distribution of viable gopher tortoise (Gopherus polyphemus) populations necessary to ensure the long-term viability of the species; 2) Discuss desired population structure based on existing data from long-term monitoring, tortoise surveys, and translocation events, and; 3) Address stakeholder concerns regarding the role of small gopher tortoise populations (those fewer than 250 adults) and small tracts of intact habitat. Gopher Tortoise Minimum Viable Population and Minimum Reserve Size Working Group Report 2