An experimental habitat restoration in Pumpkin Hill Creek Preserve State Park for the management of Gopherus polyphemus

Background/Question/Methods

The gopher tortoise (Gopherus polyphemus) was recently elevated to threatened status in Florida.  However, many protected lands in Florida are not managed for gopher tortoises, even in state parks such as Pumpkin Hill Creek Preserve State Park (PHC) in Duval County.  Controlled burns are frequently used to manage tortoise habitat, however there are many logistical constraints that limit their use on public lands.  A potential alternative is the mechanical removal of overgrown vegetation.  The objective of this study is to determine the order of succession in plots that have had vegetation mechanically removed and to determine if tortoises are more likely to immigrate into the treated plots over control plots or burned plots.  Sixteen 100 m transects running through 10 x 10 m treatment plots were marked off with ten 1 x 1 m sample plots evenly spaced along each transect.  Six of the treatment plots were mechanically cleared, four are located in recently burned areas, and the remaining six received no treatments.  At each sampling plot every two months following the treatments the canopy, shrub, and herbaceous cover were visually estimated; all species of plants identified; and soil samples were taken and analyzed.

Results/Conclusions

In the four burn plots no saw palmetto (Serenoa repens) was removed, wiregrass (Aristida stricta) and oak (Quercus sp.) returned within days, and other herbaceous species appeared within a month following the burn.  In the six mechanically cleared plots palmettos were effectively removed (a maximum of four returned within any individual plot), seedlings were present in four months, and common species (including wiregrass) returned within six months.  Saw palmetto was found in over 2/3 of the sample plots and was ubiquitous throughout the study area.  Shiny blueberry (Vaccinium myrsinites) was also found throughout the study area and was commonly seen in burrow aprons.  Elliott’s milk pea (Galactia elliotti) was found in half of all sample plots and was seen throughout the study area.  Other common species that were found in restricted sites of the study area include shiny lyonia (Lyonia lucida), dangleberry (Gaylussacia tomentosa), sandweed (Hypericum reductum), dwarf huckleberry (Gaylussacia dumosa), tarflower (Befaria racemosa), and multiple Quercus species.  Statistical analyses are currently being conducted and will be discussed.