Describing a developing hybrid zone between red wolves and coyotes in eastern North Carolina, USA.

Justin H Bohling,Lisette P Waits,Christopher E Moorman,David T Cobb,Justin Dellinger,Justin M Mcvey

doi:10.1111/eva.12388

Abstract

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.

Highlights

Fluctuations in environmental conditions can alter patterns of contact between reproductively compatible species
Scat samples were transported to the Laboratory for Ecological, Evolutionary, and Conservation Genetics at the University of Idaho and extracted in a laboratory dedicated to low-quality DNA samples using the QiAmp Stool Kit (Qiagen, Valencia, CA, USA)
Two hundred sixty-four scats were identified as Canis using the mitochondrial fragment test: 201 possessed a red wolf/coyote fragment and 63 a gray wolf/dog fragment

Summary

Introduction

Fluctuations in environmental conditions can alter patterns of contact between reproductively compatible species. As ranges shift and individuals interact potential outcomes can range from genetic homogenization to reproductive isolation (Jiggins and Mallet 2000; Crispo et al 2011; Robbins et al 2014). Human alterations to the environment can increase the rate at which previously isolated species come into contact and hybridize (Rhymer and Simberloff 1996; Seehausen et al 2008; Crispo et al 2011). While some human activities may promote hybridization, active management for conservation purposes could limit the degree of interbreeding and genetic introgression. The interaction between natural processes, anthropogenic disturbance, and conservation management is poorly understood but potentially drive the fate of emerging hybrid systems

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Results

Conclusion