Endangered Box Turtles
Belzer explains that box turtles aren't the best at reproduction and that in some years there is no success at all. One result of this reproductive dilemma, he says is that it is important for box turtles to remain in their habitat so that over many years reproduction can cumulatively be successful. He writes that "Just slightly diminished egg production, caused by loss of a few adults, can be critical for populations . . .. Seeing adults around is no gauge of whether the population is managing to sustain itself."
Patton and Messinger quote James H. Harding in a 1993 journal article as saying: "Compared to almost all other species of hunted wildlife, turtles are slow maturing animals with very high egg and hatchling mortality balanced in nature by the longevity of the small percentage of animals reaching adulthood. Studies show that box turtles must have a comparatively high annual survivorship to compensate for the normally low annual recruitment of new breeding animals into the population. It is thus unlikely that box turtles anywhere have harvestable population surpluses."
Collecting not only reduces the adult population, Belzer explains, but it also affects the long-term reproductive potential of the remaining population. For reproductive success, the population density has to be good or the turtles can't find each other and males can't find females old enough to reproduce. Those eggs that are produced are under greater pressure from predators than would a larger egg population, so the odds against eggs and hatchlings surviving are greater than with a larger population.
Fragmentation of habitat is another serious threat to turtles as it is to hundreds of other species world wide. Fragmentation is the process in which habitats are divided by roads, trails, dams, canals, fences, housing and anything else that divides a habitat into smaller sections. Fragmentation prevents species from moving from one section of habitat to another, reduces the size of the habitat, reduces the size of the population within the given habitat, reduces genetic diversity, reduces the number of turtles available for reproduction and the number of choices among those that remain. The smaller population is affected more by collection and predation. Several studies show that predation, particularly by raccoons, can be a major factor, up to 100 percent, in extirpation of box turtles. If the cause of fragmentation is a highway, the likelihood of road kill increases dramatically.
Belzer concludes: "With its habitat increasingly fragmented
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