Divergent Size-Class Distributions of Gopher Tortoise Burrows in Scrub and Flatwoods Habitats of Peninsular Florida

Abstract. In the southern half of peninsular Florida, where longleaf pine (Pinus palustris) sandhill communities are scarce, gopher tortoises (Gopherus polyphemus) primarily occupy mesic flatwoods and Florida scrub habitats that appear suboptimal due to poorly drained soils in flatwoods and low forage abundance in scrub. Tortoise populations persist in these habitats, but their demography is poorly understood. We used burrow size-class distributions to assess population age structure in flatwoods and scrub habitats. In addition, we monitored tortoise nests and burrows with automated cameras to assess nest fate and visitation by predators. Burrows in flatwoods were strongly skewed toward adult size classes, suggesting low juvenile recruitment, which may be due to poor nest success caused by surface flooding or saturated soils. Size class distributions in scrub were also skewed but were closer to the expected range for a long-lived species with slowed growth following maturity. Rates of predator visitation did not differ between habitats but nests in flatwoods were inundated by heavy rains. More research is needed to clarify the demographics of gopher tortoises in the southernmost extent of their range. However, we suspect that some negative demographic consequences of suboptimal conditions may be offset by the warm climate in southern Florida, which may lengthen the growing season, promoting faster growth and earlier age at first reproduction that could boost population growth.