Jon Atwood, PhD
Department of Environmental Studies
The Sulawesi forest turtle, Leucocephalon yuwonoi and the forstens tortoise, Indotestudo forsteniirepresent the only two endemic chelonians from Sulawesi Indonesia. Both are poorly understood and rapidly declining in numbers throughout their ranges due to overexploitation for pet, live food, and medicial purposes. I conducted a preliminary in-situ investigation of the current distribution and trade of the two species, investigated population dynamics and phenotypic differences in I.forstenii, and analyzed baseline levels of the stress hormone corticosterone in a large group of captive L. yuwonoi. My in-situ investigation provided evidence for previously undocumented populations for both species in Sulawesi and the surrounding islands that, if confirmed, significantly increase the species’ known distribution. Trade of L yuwonoi over the last three years appears to have changed little. Anecdotal information obtained from interviews with hunters suggests that there have not been significant changes in yield per hunt over the last 3 years. Similarly, large exporters are not finding it necessary to pay higher prices for individuals caught, as would be expected with a decline in supply. Comparisons of I. forstenii populations from the north of Sulawesi with those from the south revealed differences in mass, MCL and the presence of a nuchal scute. To determine if these phenotypic differences are diagnostic for mtDNA lineages in the species, an examination of cytb Mitochondrial DNA (mtDNA) sequences in two groups of wild caught captive I. forstenii, one group with and one without the nuchal scute was performed. Results showed that the nuchal differences do not correspond to mtDNA lineages. I therefore suggest that the differences in size are the result of environmental factors. Corticosterone (CORT) levels in a long term captive group of L. yuwonoi were high relative to other reptiles, showed no detectable increase during the first 5 ½ minutes after capture, were higher in males than in females, and were lower in females housed in groups of 3 than in females housed alone. Future research is required to better understand the cause and biological significance of the high CORT levels detected in both sexes of this collection. L. yuwonoi collections experiencing reproductive success, as well as those experiencing reproductive failure should have CORT assays conducted in order to determine if stress is a contributing factor to the lack of reproductive success in captivity. This work provides much needed baseline information for future studies involving range and distribution of the two species, population studies of I. forstenii, and reproductive biology of L. yuwonoi.