Vegetation Structure and Plant Flammability Traits Surrounding Gopher Tortoise Mounds Suggests Localized Fuel Limitation, Central Florida, 2022

While large herbivore effects on fire are well-described, effects of small ecosystem engineers are often overlooked. To test the hypothesis that gopher tortoises (Gopherus polyphemus) are limiting fire intensity around their burrows by promoting a nonflammable plant community, we characterized the vegetation structure surrounding 30 gopher tortoise mounds of varying activity regimes and 25 control points in Archbold Biological Stations’ southern-ridge sandhill in the summer of 2022. Plant cover by species, plant height, and litter cover were measured around the burrows and control points, and these data are published in this package. This data package also includes 11 flammability traits that were measured in 23 of the most common plant species found in our vegetation survey, to observe how community-weighted flammability varies among burrows and control points. We found no evidence that community-weighted flammability did not co-vary substantially with burrowing activity. Data collected show that vegetation (between 71 and 74%) and litter (between 35 and 46%) cover were strongly reduced immediately surrounding the burrows of active and recently inactive mounds, relative to the surrounding vegetation matrix. We found no comparable trend in mounds that were abandoned, suggesting that burrowing activity is limiting fuels and potentially contributing to the localized reduction in burn severity during prescribed burns we also characterized. Our results emphasize the potential for small ecosystem engineers to alter fire behavior and a novel mechanism through which gopher tortoises create fire refugia for hundreds of other small animals throughout its range.