Seed dispersal by reptiles has received little attention from researchers. Liu et al. (2004) studied seed dispersal by the Florida Box Turtle (Terrapene carolina bauri) in pine rockland forests in Key Deer National Wildlife Refuge (KDNWR) on Big Pine Key in the lower Florida Keys (U.S.A.). Examining the feces of 145 box turtles from KDNWR in 1999 and 2000, they found that the bulk of the diet consisted of fleshy fruits and terrestrial snails. The seeds of fleshy-fruited plants and snail remains were present in the feces of 138 (95.1%) and 128 (88.2%) turtles, respectively. Leafy vegetation occurred in the feces of 33 (22.7%) turtles, while insects, fungi, and vertebrate remains (most likely consumed as carrion) were each found in the feces of 10 (6.8%) or fewer turtles.
In their study, Liu et al. found that box turtles consumed and probably dispersed at least a third of the species with fleshy fruits that occur in pine rockland forests of KDNWR, including dominant components of the shrub layer (Byrsonima lucida, Thrinax morrissii, Serenoa repens, Coccothrinax argentata) and herbaceous (Morinda royoc) layer (in addition to seeds from 11 fleshy-fruited plant species, seeds were found in turtle feces from a grass, Paspalum, and a legume. The researchers planted the seeds of nine species and found that germination percentage (percentage of seeds that germinated during the experiment) varied from 10% to 80%. Comparative germination experiments were conducted with Thrinax morrissii, Serenoa repens, and Byrsonima lucida. The authors compared the germination percentage and germination rate (number of days from planting to seedling emergence) of seeds from three treatments (seeds recovered from feces, control seeds with pulp, and control seeds without pulp) and continued these experiments for up to 2 years. Passage through the box turtle digestive tract greatly enhanced the germination percentage and germination rate of S. repens, but decreased the germination percentage of B. lucida and T. morrissii and decreased the germination rate for T. morrissii. Subsequent destructive seed viability tests revealed that many ungerminated T. morrissii seeds remained viable, suggesting long-term seed dormancy may occur, even after passage through the turtle digestive system. In addition, the proportion of ungerminated seeds which remained viable was greater for seeds recovered from turtle feces than from control seeds with pulp. Removal of fleshy pulp either manually or by the turtle digestive system may allow T. morrissii to escape insect predation. (Liu et al. 2004)
Box turtles may be significant seed dispersal agents in the pine rockland forests of the Florida Keys as they occur at high densities (up to 14.9 turtles per hectare on other islands in south Florida) and the pool of potential bird and mammal seed dispersers is less diverse relative to the Florida mainland. Furthermore, seeds require from 2 to 20 days to pass through the digestive tract, during which time turtles can move several hundred meters within a home range as large as 5 hectares. (Liu et al. 1994 and references therein)
The Florida Box Turtle (Terrapene carolina bauri) is a subspecies of the Eastern Box Turtle. It occurs in both the Florida Peninsula and the Florida Keys (U.S.A.) and intergrades with (blends into) other subspecies of Eastern Box Tutle where they come into contact in the northernmost part of the Florida Box Turtle's range. (Conant and Collins 1991)
Ernst et al. (1998) studied growth rates in Florida Box Turtles (Terrapene carolina bauri). They found that male Florida box turtles grow proportionally longer (relative to their height and width) than do females, resulting in a longer, flatter carapace, whereas females develop shorter, higher, and slightly narrower carapaces, possibly as an adaptation to accommodate hard-shelled eggs before oviposition. The subspecies has a typical growth pattern for a North American emydine turtle. Growth is rapid in juveniles, but starts to slow once maturity is reached at an age of 12 to 13 years. Growth rates approach an asymptote at about age 17 years in males and 16 years in females; very little growth occurs after 20 years. Florida Box Turtles (T. c. bauri) from Florida apparently grow at a slower annual rate than do Eastern Box Turtles (T. c. carolina) from Maryland despite having a longer annual activity and growth period. The cervical scute and all vertebral scutes have a greater width:length ratio in juveniles, but this ratio declines as the scutes lengthen with elongation of the carapace; however, the rare of increase in length varies among the scutes. (Ernst et al. 1998)
The Florida Box Turtle (Terrapene carolina bauri) is found throughout most of the Florida Peninsula and the Florida Keys (Verdon and Donnelly 2005 and references therein).
Box turtles are relatively sedentary, with low fecundity and high adult survivorship, delayed sexual maturity (in Florida, males reach maturity at 5-6 years and females at 7-8 years), low nest and hatchling survival, and a long life span (Dodd et al. 2006 and references therein).
The Florida Box Turtle (Terrapene carolina bauri) is 12.5 to 16.5 cm long (record 17.9 cm). The shell is arched, highest toward the rear. The light radiating lines on the shell may be broken or irregular, at least on some scutes (shell segments). There are two yellow stripes on the head, which also may be interrupted or incomplete. There are usually 3 toes on each hind foot. The plastron (lower shell) of males is deeply concave. Young Florida Box Turtles have a yellow mid-dorsal stripe and a mottled pattern, yellowish or greenish on dark brown. (Conant and Collins 1991)
Verdon and Donnelly (2005) studied Florida Box Turtles on Big Pine Key in the National Key Deer Wildlife Refuge in the lower Florida Keys (U.S.A.). The population was estimated to be 7.5% juveniles, 58.75% females, and 33.75% males, resulting in a female-biased sex ratio (1 male:1.74 females). Population size was estimated to be between about 40 and 114 individuals per 6 hectares in a pine rockland forest, with an estimated density of 4.8 to 10.2 turtles per hectare.
In a study in the Florida Keys, modal clutch size (i.e., most frequent clutch size) was 2, with turtles producing between 0 and 3 clutches per year (Dodd 1997, cited in Dodd et al. 2006).
