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Box turtles Terrapene carolina are long-lived vertebrates found in many habitats throughout eastern North America. Because they routinely live >30-70 years, individuals and populations likely face periodic catastrophic effects from habitat alteration, such as hurricanes and other violent storms, flooding, and climatic perturbations such as cold or drought. We used a dataset based on a 16-year mark-recapture study of a Florida box turtle population inhabiting an isolated island to model the effects of rare and chronic removal of individuals from the population. 'Removing' individuals based on actual sampling records allowed us to compare the resulting effects on population structure and persistence with the known demographic characteristics of the population. For the increasing population, removal had no effect on population size over a projected 50-year time span. However, only the increasing population could sustain an annual loss of up to 56 individuals (3.8% of our initial model population) per year. Beyond this level of annual removal, the population would eventually go extinct. Both the stable and declining populations were projected to become extinct by year 50, regardless of removal intensity. Irrespective of frequency, a pre-reproductive season loss leads to a smaller population than a post-reproductive season loss. These results have implications for understanding the effect of individual removal on population persistence of declining box turtle populations. [ABSTRACT FROM AUTHOR]

We investigated the ecology, distribution, and density of Florida Box Turtle ( Terrapene carolina bauri Taylor, 1895) populations in the Ten Thousand Islands (TTI), an estuarine mangrove ecosystem in southwestern Florida. The distribution and ecology of Box Turtles in this region and this habitat type have not been previously investigated. The study area encompassed 18 islands and included five natural islands, 13 man-made shell islands, and adjacent mangrove environments. Two hundred and twenty-nine live Box Turtles and 95 Box Turtle shells were detected a total of 409 times on seven of the 18 islands. The seven islands where Box Turtles were detected ranged in size from 7.3 to 31.0 ha and were ancient shell work sites, apparently constructed by the Calusa or other Prehistoric Indians approximately 1,900 to 900 years before present (ybp). Box Turtles were not detected on natural islands. We detected Box Turtles primarily in subtropical hardwood hammock forests, but we detected 10% of turtles in mangrove or mangrove ecotones. Males were larger than females across all sites. We detected a significant difference in body size between living and dead adults. We estimated population size on four shell work islands to range from 43 (SE = 3.5) turtles to 270 (SE = 244) turtles and estimated densities ranging from 2.7-12.2 turtles/ha. Box Turtles on the shell work islands of the TTI are a unique example of populations living on ancient, manmade islands. However, known populations are small and isolated and may be susceptible to increased human recreational use, mechanized vegetation management, or predation by raccoons. [ABSTRACT FROM AUTHOR]

Disturbances can affect the structure of ecological communities, and their impacts may have consequences for individual species' population dynamics and long-term persistence. Even without catastrophic mortality, survivorship could be reduced following a disturbance, thus leading to population decline. We used a 16-year mark-recapture dataset to determine the effects of catastrophic storms and the cutting of nonindigenous vegetation on the survivorship and abundance of a population of long-lived terrestrial turtles (Terrapene bauri). Our results indicate that these habitat disturbances had little long-term effect on abundance. Indeed, the population continued to grow despite severe changes to its habitat, although recapture probabilities decreased. through time. Tertiary (adult) sex ratios became more highly skewed temporarily but eventually approached their predisturbance levels. In long-lived box turtles, short-term disturbances may alter growth rates and dispersal tendencies, but they appear to have little long-term effect on abundance. as long as initial mortality is not severe and food resources remain available. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Disturbances often help structure ecological communities, and their impacts may have consequences on population dynamics and long-term species persistence. Should disturbances affect resources, a trade-off may result between reproduction and individual growth, which in turn could affect the timing of sexual maturity in animals dependent on reaching a requisite size for the onset of maturation. We used a 14-year mark–recapture dataset to determine the effects of catastrophic storms and the removal of nonindigenous vegetation on individual growth rates of a long-lived turtle Terrapene carolina bauri. Adult male growth rates increased 19% after the disturbances, whereas female growth rates decreased by a similar percentage. Juvenile growth rates briefly increased, but as these animals became subadults, their growth rates slowed after disturbance, a change more pronounced in females than males. After the disturbances, the onset of male sexual maturity decreased by c. 1 years (from 10.8 to 9.5 years), female maturity was delayed by 2.5 years (from 8.5 to 11.0 years), and the subadult life stage was extended from 2 to 3.5 years. With resources and habitats similarly available to adults, we hypothesize that adult females diverted resources from growth to reproduction, whereas males allocated available resources to growth. Subadult growth rates decreased regardless of sex, implying that fewer or lower quality prey were available to smaller sized turtles in the years following disturbance. The results of this study suggest that habitat disturbances affected individual growth rates differently according to sex and life stage, which in turn affected the timing of maturation. In long-lived vertebrates, such perturbations on life-history traits such as growth rates likely affect population recovery, and may help to explain why turtle populations recover slowly following catastrophic disturbance, even when adult survivability is high. [ABSTRACT FROM AUTHOR]