Fire Ecology of the Florida Box Turtle (Terrapene Carolina bauri Taylor) in Pine Rockland Forests of the Lower Florida Keys

摘要

Eastern box turtles (Terrapene Carolina) inhabit many fire-prone habitats in eastern North America and frequently succumb to natural and anthropogenic fires. However, little is known about the fire ecology of box turtles, and population-level effects of burning have yet to be quantified. We studied the effect of prescribed burns on a population of Florida box turtles (T. Carolina bauri) inhabiting National Key Deer Wildlife Refuge, Big Pine Key, Florida. A total of 27.4 ha were burned during seven prescribed fires (1998 to 2000). We found 14 fire-killed box turtles after four wet season burns (1.04 turtles/ha); no mortality was observed following three dry season burns. Multiple regression analysis indicated that season of burning had a significant effect on the occurrence of box turtle mortality. The effect of char height (used as a surrogate measure of fire intensity in our model) was only marginally significant. Our results suggested that between 10.2% and 21.6% of box turtles per ha perished during wet season fires. Fires appeared to affect male and female turtles equally. No juvenile mortality was observed, perhaps due to their apparent rarity in the study population. If fire mortality is a concern to land managers, we recommend restricting prescribed burns to periods of the year when box turtles are dormant (dry season in south Florida; late fall, winter, and early spring in temperate regions of North America). If prescribed burns must be conducted when turtles are active, survival might be enhanced by using slower moving, less intense backfires, and burning small areas. More frequent burning might reduce fuel loads and thus fire intensity, reducing the likelihood of turtle mortality.