When hybridizing species come into contact, understanding the processes that regulate their interactions can help predict the future outcome of the system. This is especially relevant in conservation situations where human activities can influence hybridization dynamics. We investigated a developing hybrid zone between red wolves and coyotes in North Carolina, USA to elucidate patterns of hybridization in a system heavily managed for preservation of the red wolf genome. Using noninvasive genetic sampling of scat, we surveyed a 2880 km2 region adjacent to the Red Wolf Experimental Population Area (RWEPA). We combined microsatellite genotypes collected from this survey with those from companion studies conducted both within and outside the RWEPA to describe the gradient of red wolf ancestry. A total of 311 individuals were genotyped at 17 loci and red wolf ancestry decreased along an east–west gradient across the RWEPA. No red wolves were found outside the RWEPA, yet half of individuals found within this area were coyotes. Hybrids composed only 4% of individuals within this landscape despite co‐occurrence of the two species throughout the RWEPA. The low proportion of hybrids suggests that a combination of active management and natural isolating mechanisms may be limiting intermixing within this hybrid system.
Differentiation between scats of sympatric canid species is important for determining speciesspecific presence and movements, but distinction in the field is difficult. We calculated upper and lower thresholds of scat diameters to distinguish between scats of red wolves (Canis rufus) and scats of coyotes (C. latrans) and coyote-wolf hybrids in the field, in North Carolina, USA, from February 2009 to March 2010. We used DNA genotyping to identify scats collected in the field and took diameter measurements of those scats. Based on normal-distribution probability functions of scat diameters, scats !29 mm in diameter were !95% certain to be of red wolf origin. Conversely, scats 14 mm in diameter were 95% certain to be of coyote or hybrid origin. Scats >14 mm and <29 mm in diameter could not be identified by diameter alone. We suggest these upper and lower thresholds of scat diameters be used in concert with other methods (e.g., DNA genotyping) to monitor for red wolf, coyote, and hybrid activity to help conserve a lone, freeranging population of wild red wolves. ß 2011 The Wildlife Society.
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