Timucuan partners with Jacksonville University to protect gopher tortoises
By Shauna Ray Allen and Ken Hoover

NPS

Several mature gopher tortoises have colonized the sand hill habitat within the headquarters complex of the Timucuan Preserve. Prescribed fire, which would help maintain an open canopy, is excluded in this area because of the densely populated human neighborhoods nearby.

The gopher tortoise (Gopherus polyphemus) is a species of special concern in Florida, where its status will be elevated to “threatened” if a recent proposal is accepted. It is a keystone species, providing refuge through its burrows to a variety of other organisms, and is thus an indicator species of ecosystem health. Existing tortoise populations in the Timucuan Ecological and Historic Preserve are small and widely separated. Ideal gopher tortoise habitat is a pine savannah of widely spaced trees with an understory dominated by wiregrass, legumes, shrubs, and other herbaceous vegetation on which the tortoises feed. This habitat requires sunlight for the growth of these food species. In the past this landscape would be burned naturally on an average cycle of 7 to 10 years by lightning strikes brought by summer thunderstorms, preserving the open canopy. However, the Timucuan Preserve is near areas of human residential development where fire is controlled and prescribed burning cannot be practiced.

To protect gopher tortoises within the constraints of a landscape shared with humans, the preserve undertook a project to identify and classify areas suitable for gopher tortoise habitat and to recommend management practices in these areas that will promote viability of existing tortoise populations. The project was conducted from September 2002 through May 2004 with Dr. Ken Hoover, professor of biology at Jacksonville University, under a cooperative agreement with the Southern Appalachian Cooperative Ecosystem Studies Unit. The fieldwork began in April 2003 and was completed in September of that year.

The project findings were based on field surveys of known and potential habitat, which were classified based on established criteria. The survey also included vegetation sampling and statistical analysis to determine the most important vegetation species in occupied habitat. Preserve resource management staff provided GIS and GPS training and technical assistance for the fieldwork. In the course of its research, the project created a bibliography of 178 references on gopher tortoises.

The project determined that under current conditions, the longleaf pine sand hills are succeeding to oak-hickory hardwood forests or scrub oak–dominated communities. Sunlight penetration through these heavily canopied areas is greatly reduced, affecting herbaceous species needed by gopher tortoises.

Recommendations for good management of the gopher tortoise include mechanically removing trees, selectively planting food species, and creating corridors to link isolated populations and help promote genetic variability. Other suggestions are relocating isolated tortoises from weedy, disturbed habitats to populations in areas that are being managed, and protecting gophers and burrows from human and domestic animal intrusion. The project recognizes the possibility of increasing Jacksonville community involvement; volunteers might provide labor necessary to implement each of the management steps to preserve habitat areas. Recommended management actions will be incorporated into the preserve’s resource management plan in the hope that the gopher tortoises will thrive.