GENETIC DIVERSITY OF SPOTTED TURTLE (CLEMMYS GUTTATA) POPULATIONS IN A FRAGMENTED LANDSCAPE

2019-10-16T17:18:47Z (GMT) by Tyler J Scoville

Turtle species are facing losses to genetic variation caused by habitat fragmentation and large-scale landscape changes caused by humans. These losses to genetic variation disproportionally effect species that have become rare due to human interaction. Spotted Turtle (Clemmys guttata) is one such species that has become rare across a large portion of its natural geographic range including the Midwest. I examined genetic variation in spotted turtles in Indiana and Ohio to delineate populations and assess levels of genetic variation within populations. Eight microsatellite loci were used to genotype 94 individuals, which originated from four sites in Indiana and two sites in Ohio. Bayesian and ordination based cluster analyses identified three genetic clusters within the sample. Individuals from one Ohio locality were largely clustered alone and had a significant degree of differentiation from all of the Indiana sites. A majority of the Indiana sites had individuals that were clustered into both of the two remaining clusters with the exception of IN-1 which only had individuals grouped into the first inferred cluster. The two sites geographically closest to one another IN-2 and IN-4, both had individuals grouped into the first and third inferred clusters. Differentiation statistics disagreed on the level of structure between these two populations. Two of the six sites had detectable bottlenecks, even though levels of genetic allelic diversity and heterozygosity were relatively high and comparable to populations investigated in other studies. Overall, population structure was identified among localities in Indiana and Ohio that may warrant independent management. Populations where the bottlenecks were detected may be of special concern in the future as they continue to be subjected to isolation.