The community ecology of a riverine turtle assemblage in the Tennessee River Gorge

In attempting to characterize a community, it is necessary to measure ecological attributes to quantitatively describe the unique aspects of that community and to make comparisons. This thesis reports on a long-term investigation of the community ecology of a turtle assemblage in the Tennessee River Gorge relative to the following hypotheses: 1) ecologically generalized species will be the most numerically abundant forms present in the TRG, 2) adult sex ratios of turtle populations in the TRG will be biased in favor of males, and 3) mean adult body size measurements and size dimorphism index (SDI) values of turtle populations in the TRG will be consistent with those reported from other populations. To examine these hypotheses, a balanced trapping regime was carried out during May through August, from 2000 to 2006, in the Tennessee River Gorge. Trapping methods included baited traps (hoop nets and fyke nets) and unbaited traps (fyke nets, basking traps, hand capture, and trammel nets). The relative abundance of generalist turtle species was consistently greater than that of more sensitive species during each study year and for the entire study period. Habitat specialist were detected in relatively low numbers and were absent during some years of the study. Accordingly, species diversity and evenness measurements were low and reflected the numerical dominance of a few species. Adult sex ratios for all turtle species in the TRG were biased in favor of males, indicating differential survival rates for adult female turtles. Multiple limiting factors may be responsible for this finding as the ecology of each species is unique. Observed adult body measurements for TRG turtle populations were generally larger than those reported from other studies within their respective ranges. One species in particular, Sternotherus odoratus, was observed to display a carapace length that was significantly greater than those reported from southern or northern climes. This finding appears contrary to the theory that body sizes for turtles increase with latitude, or Bergmann's rule. The SDI values from the TRG turtles were not as substantial as those reported from other localities, primarily due to the relatively greater body sizes achieved by male turtles in the TRG. Generally, larger body sizes and observed dimorphism index values for some species could be the end result of individual processes acting simultaneously, such as: 1) variable maturation rates for the sexes, 2) genetic variability, and 3) a productive ecosystem.

Grantor dc:publisher

University of Tennessee at Chattanooga

Author dc:creator

• Manis, Christopher Bob

Contributors dc:contributor

• Wilson, Thomas P.
• Schorr, Mark; Aborn, David
• College of Arts and Sciences

• Turtles -- Southern States
• Turtles

Licence

• https://rightsstatements.org/page/InC/1.0/?language=en

Language dc:language

English, eng

Identifier

LB2369.2 .M365 2008

OAI identifier oai:identifier

oai:scholar.utc.edu:theses-1322