Literaturdatenbank
Literaturdatenbank |
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Richards-Dimitrie, T. M., & Seigel, R. A. , Spatial ecology of northern map turtles (graptemys geographica) in an altered river system: Implications for state endangered species management and mitigation.
Added by: Admin (06 Jan 2014 18:23:07 UTC) |
| Resource type: Conference Paper BibTeX citation key: RichardsDimitrie2011 View all bibliographic details  |
Categories: General Keywords: Emydidae, Graptemys geographica, Habitat - habitat, Nordamerika - North America, Schildkröten - turtles + tortoises Creators: Richards-Dimitrie, Seigel |
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| Abstract |
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Riverine turtle species are declining worldwide and many populations have been extirpated due to anthropogenic stressors. Last officially recorded in Maryland in the early-1990’s, the Northern Map Turtle (Graptemys geographica) is listed as state endangered and is currently only known from the lower Susquehanna River in northern Maryland with a few records from nearby waterways (Elk and Bush Rivers). The Susquehanna River is divided by a hydroelectric dam, is heavily used for recreational activities, and has increasing shoreline development, all of which may negatively impact this population. Given the absence of basic ecological data of map turtles in Maryland, we used visual encounter surveys, trapping, and radio-telemetry to examine the habitat utilization of this population and further our understanding of these impacts. Our data suggest that impacts of dam operations on river water levels are dramatic and that high flows from the dam hinder basking activity and movements of turtles. Basking sites are submerged during high flows, drastically reducing the availability of suitable basking habitat. Dam activities have also hindered the natural deposition of sand, impacting the number of available nesting beaches. The remaining beaches are heavily inundated with human activity and force map turtles to nest in sub-optimal conditions (e.g. heavy canopy cover). We suggest the turtle’s reaction to sudden changes in river flow and depth and the management of public lands for optimal nesting conditions is crucial in mitigating impacts on this population.
Added by: Admin |