Literaturdatenbank
Literaturdatenbank |
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Bandas, S. J. (2003). Geographical distribution and morphometrics of south dakota turtles. Unpublished thesis Master of Science, South Dakota State University.
Added by: Admin (15 Mar 2009 13:31:27 UTC) |
| Resource type: Thesis/Dissertation BibTeX citation key: Bandas2003 View all bibliographic details  |
Categories: General Keywords: Apalone, Apalone mutica, Apalone spinifera, Chelydra, Chelydra serpentina, Chelydridae, Chrysemys, Chrysemys picta, Emydidae, Emydoidea, Emydoidea blandingii, Graptemys, Graptemys geographica, Graptemys pseudogeographica, Habitat = habitat, Morphologie = morphology, Nordamerika = North America, Schildkröten = turtles + tortoises, Terrapene, Terrapene ornata, Trionychidae Creators: Bandas Publisher: South Dakota State University |
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| Abstract |
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Relatively little information has been published on South Dakota turtles compared to the neighboring Midwest states. This study was conducted to compile literature relevant to the species of turtles that occur in the state; develop proper protocols for field collection, morphological measurement, live animal handling and voucher specimen preservation; and update species distribution maps. Seven species of turtles are thought to occur in South Dakota including the western painted (Chrysemys picta bellii), snapping (Chelydra serpentina), spiny softshell (Apalone spinifera), smooth softshell (Apalone mutica), false map (Graptemys pseudogeographica), ornate box (Terrapene ornata ornata) and Blanding’s (Emydoidea blandingii) turtle. Relevant historic and more recent literature was synthesized to determine the former status of these turtles. A variety of wetlands and deepwater habitats were sampled for turtles during 2002 and 2003 in every county in South Dakota. Turtles were captured more efficiently and effectively by hand or with baited hoop nets than with crab traps or basking traps. Eight hundred and one turtles representing six species were captured or positively sighted during this study. Blanding’s turtles were neither captured nor sighted during this study. Male:female ratios were nearly equal for all six turtle species. Based on 405 trap nights, turtles were captured in 45% of the sets. Based on capture and sightings data, five species of turtles captured were found more widely distributed than previously reported. Spiny softshell distribution was extended by 241 km (150 mi) north and 386 km (240 mi) west. In contrast, the range of smooth softshells was decreased by 193 km (120 mi). Male western painted, spiny softshell, smooth softshell and false map turtles averaged smaller across all morphological measurements than females of the same species. In contrast, female snapping turtles averaged smaller across all measurements than male snapping turtles. Carapace length was the best measurement overall for predicting weight of western painted, snapping, spiny softshell and smooth softshell turtles. Reticulate melanism had not been reported in South Dakota prior to this study, but it was found on carapaces of 31% (99 of 321) of male western painted turtles captured during 2002-2003. Weight and carapace length of male western painted turtles were significantly greater (p<0.0001) for turtles with reticulate melanism compared to males without it. Further investigations are needed on alternative trapping methods to more accurately determine the distribution of false map, ornate box and Blanding’s turtles in South Dakota. The environmental and geographical limits that affect each turtle species range need to be investigated. Future studies consisting of population estimates for each turtle species, including their sustainable harvest and age structure, would be beneficial to determine the future of turtles in South Dakota.
Added by: Admin |