Black Bear Connectivity

May 20, 2014 (Last modified Aug 22, 2017)
Uploaded by SouthAtlantic LCC
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For more information about how these data were developed, please see the final report.

Expert opinion was used to define a resistance surface for each of the target animals, with higher resistance representing map units expected to be more difficult and more dangerous for species to move through. A set of nodes for each species, with node points indicating center locations for potential source populations for the species, are also defined. Note actual species population data to define the nodes is not used, as that data was often unavailable, and the focus is on the potential spread of the species across the SALCC region and not limited to models to known populations. Therefore, node locations were determined by using an innovative approach to search for local minima in the resistance surfaces, as such areas likely represent some of the most favorable habitat for each species in terms of the # of dispersing animals that might be produced.The Circuitscape program was then used to calculate expected flow of animals between each pair of nodes within a species-specific threshold of each other. Circuitscape works in similar fashion to ordinary least cost path analysis, but instead of returning a single least cost path or corridor, it calculates the expected flow of the target species across all of the different pathways from one node to the other, treating the nodes as electrodes and the landscape as a circuitboard matrix with varying levels of resistance. Pathways that are expected to receive lots of dispersing animals are scored with high current density values, whereas cities, major roads, and out-of-the-way routes between the nodes tend to get low current density values. Once all the pairwise runs were done, they were summed together to create a cumulative current map for each species. The current sums were calculated using an innovative weighted average approach, with pairwise current layers that included a larger node counting more than layers that only included smaller nodes.

Circuitscape models were run on a study region that was defined by a 100km buffer of the SALCC region. This helped models avoid the edge effects that can be prevalent in connectivity studies of this variety. After results were obtained for the entire study region, they were clipped to the SALCC region. Results beyond the SALCC are available, but due to aforementioned edge effects, their use is not highly recommended.
Data Provided By:
Sutherland, R.W., Leonard, P., Carnes, R., Fedak, D., and Baldwin, R. Terrestrial habitat connectivity models for the South Atlantic Landscape Conservation Cooperative. 2014. Wildlands Network.
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ScienceBase (USGS) View Record
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2014 (Publication Date)
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not specified
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not specified
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Sutherland, R.W., Leonard, P., Carnes, R., Fedak, D., and Baldwin, R. Terrestrial habitat connectivity models for the South Atlantic Landscape Conservation Cooperative. 2014. Wildlands Network.
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SouthAtlantic LCC
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The South Atlantic LCC encompasses and ecologically diverse 89 million acres across portions of six states, from southern Virginia to northern Florida. The geography also includes the marine environment within the federal Exclusive Economic Zone The South Atlantic region is a place where major urban...