Exploring patterns and mechanisms of red wolf (Canis rufus) hybridization in North Carolina

Hybridization poses the greatest threat to the recovery of the critically endangered red wolf (Canis rufus) in eastern North Carolina. Mitigating the impacts of hybridization requires understanding the scale at which this process occurs across the landscape. Such descriptions of hybridization also require an evaluation of the methods used to assess hybridization and mechanisms regulating this process. The goal of this dissertation was to discern landscape-level patterns of hybridization between red wolves and coyotes ( C. latrans) and elucidate mechanisms governing interbreeding between these species. To describe the patterns of hybridization between these species, we used non-invasive genetic sampling to characterize the genetic profile of canids across the landscape. In 2008, we collected scat across a 22 000 km2 region surrounding the Red Wolf Experimental Population Area (RWEPA) and used mitochondrial and nuclear microsatellite DNA data to identify individual canids and determine their ancestry (Chapter 1). From this survey we identified no pure red wolves and found little evidence of red wolf introgression into the coyote population. A similar follow-up survey conducted in 2010 confirmed that red wolves were restricted the RWEPA (Chapter 2). Coyotes were found to be widely distributed across the entire landscape; hybrids, however, were rare compared to the abundance of the parental species. For both surveys we utilized Bayesian clustering methods to estimate genetic ancestry for individuals identified through molecular genotyping. We tested the ability of these methods to detect genetic introgression under different scenarios using data from the red wolf pedigree (Chapter 3). We also examined characteristics of red wolves involved in known hybridization events within the RWEPA to illuminate potential mechanisms governing this process. Our review found that most of the red wolves that hybridized with coyotes did so following the disruption of a stable breeding pair of red wolves, often due to human-caused mortality (Chapter 4). Most hybrid litters occurred in the furthest west portion of the RWEPA and were produced by young, first-time breeding red wolves with mixed ancestry. Our findings provide valuable information regarding the patterns, process and detection of hybridization that can guide future management of this system.