Literaturdatenbank
Literaturdatenbank |
|
 |
|
Johansen, E. P. (2011). Survey of the freshwater turtles of eastern oklahoma. Unpublished thesis , Oklahoma State University.
Added by: Admin (06 Jan 2014 18:22:53 UTC) |
| Resource type: Thesis/Dissertation BibTeX citation key: anon2011e View all bibliographic details  |
Categories: General Keywords: Apalone mutica, Apalone spinifera, Chelydra serpentina, Chelydridae, Chrysemys picta, Deirochelys reticularia, Emydidae, Graptemys geographica, Graptemys ouachitensis, Graptemys pseudogeographica, Habitat - habitat, Kinosternidae, Kinosternon subrubrum, Macrochelys temminckii, Nordamerika - North America, Pseudemys concinna, Schildkröten - turtles + tortoises, Sternotherus carinatus, Sternotherus odoratus, Trachemys scripta, Trionychidae Creators: Johansen Publisher: Oklahoma State University |
Views: 4/553
Views index: 14% Popularity index: 3.5% |
| Abstract |
|
The purpose of this study was to assess the effects of commercial harvesting on turtle populations across eastern Oklahoma. I also analyzed differences between harvest and no-harvest sites. Lastly, I temporarily removed turtles from selected sites to understand the short-term impacts of harvest on populations. For all objectives, I captured turtles using baited, three-ring, hoop traps. Objective 1: Commercial harvest has likely played a role in the decline of turtle populations in both northeastern and southeastern Oklahoma. Significant declines in catch per unit effort were found since surveys in 1997-1999. Species richness and species diversity also were significantly lower, but only in northeastern Oklahoma. The northeast appeared to have more severe declines since 1997-1999, indicating that heavier or more recent harvesting occurred there. Objective 2: I did not find significant decreases in number of turtles, species richness, or species diversity one year after turtles were temporarily removed. Turtles at all sites (treatment and control) showed non-significant decreases in numbers, species richness, and species diversity in the second year of the study, confounding comparisons of paired treatment and control sites. Likewise, I did not find significant changes in size distributions of three common species one year after removal when I compared paired treatment and control sites. More replications would likely yield stronger results. Objective 3: No-harvest sites compared to harvest sites had more turtles, larger turtles, and slightly higher species richness and species diversity, but these differences were not statistically significant. It is likely that my sites identified as no-harvest and harvest sites in fact did not differ much in harvest intensity. Nevertheless, species of Oklahoma turtles were in decline in 1997-1999 and have continued to decline since, especially in the northeast. Although I did not demonstrate experimentally or by strategic comparison of sites that commercial harvest has played a role, numbers of turtles harvested from Oklahoma waters reported by the Oklahoma Department of Wildlife Conservation 1994-2010 are staggering. Almost certainly, commercial harvest has had a negative impact on Oklahoma turtles and should be regulated or prohibited. Chelydra serpentina Macrochelys temminckii Kinosternon subrubrum Sternotherus carinatus odoratus Chrysemys picta Deirochelys reticularia Graptemys geographica ouachitensis pseudogeographica kohnii Pseudemys concinna Trachemys scripta Trionychidae Apalone spinifera mutica
Added by: Admin |