Literaturdatenbank
Literaturdatenbank |
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Pitt, A. L. (2008). Freshwater river turtle populations influenced by a naturally generated thermal gradient. Unpublished thesis , University of Florida, Gainesville.
Added by: Sarina Wunderlich (30 Jun 2012 22:01:45 UTC) |
| Resource type: Thesis/Dissertation BibTeX citation key: Pitt2008 View all bibliographic details  |
Categories: General Keywords: Emydidae, Graptemys, Graptemys geographica, Habitat = habitat, Nordamerika = North America, Schildkröten = turtles + tortoises Creators: Pitt Publisher: University of Florida (Gainesville) |
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| URLs http://purl.fcla.edu/fcla/etd/UFE0022630 |
| Abstract |
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The North Fork of White River (NFWR), Ozark County, Missouri, receives a large volume of water from several major springs. These springs create a temperature gradient along the stream’s length. Historical studies dating back to 1969 of a 4.6 km section of NFWR reveal that the North Fork supports a diverse turtle community, predominated by the northern map turtle (Graptemys geographica). The 4.6 km research section from which historical data are available is located downstream of the major spring-flows and thus represents a relatively cooler portion of the stream for much of the year, but especially during the summer months. Because rivers, especially those that are spring-fed, such as NFWR, are spatially and temporally dynamic, it was hypothesized that turtle communities may differ within various sections of the same river. Additionally, because temperature can influence turtles’ physiology, it was hypothesized that turtles in the upstream, and therefore relatively warmer, sections of NFWR, may grow faster than those in areas downstream of the major spring-flows. Assessment of turtle populations and communities located in thermally distinct areas of NFWR indicated that community composition differed within relatively close sections of the same river. Furthermore, the turtle community located in a less impacted (by humans) section of NFWR more closely resembled the community described in 1969 surveys in an area that is now degraded. These results indicated that thermal regimes, habitat quality, and microhabitat availability influence chelonian community composition. Significant temperature differences within NFWR did not appear to influence turtle growth rate, though body temperature and behavior of G. geographica varied with thermal habitat. Growth rate did vary with time and length of growing season. These patterns indicate that global climate change may influence turtle growth rate. Von Bertalanffy growth curves were generated for male and female G. geographica inhabiting NFWR, thus providing information relevant to life history characteristics that can be compared with data from other populations or taxa.
Added by: Sarina Wunderlich |