Ecology, genetics, and morphology of North American wolf-like canids of the Southern Great Plains

Human persecution of North American wolf-like canids (Canidae: Canis) had a notable impact on canid population sizes and distributions. Prior to the end of the 20th century, the geographic ranges of multiple Canis taxa once overlapped in the Southern Great Plains region spanning the states of Oklahoma, Texas, and New Mexico, USA. This former diversity hotspot historically supported the red wolf (Canis rufus), two gray wolf (Canis lupus) subspecies the Great Plains wolf (Canis lupus nubilus) and Mexican wolf (Canis lupus baileyi), the coyote (Canis latrans), in addition to the domestic dog (Canis lupus familiaris). Current diversity has been reduced to the coyote, domestic dog, and Mexican wolf that is largely restricted to recovery program area in Arizona and New Mexico. Historical ecological, morphological, and genetic conditions within this region have been underexplored using recent methodological approaches. Understanding past dynamics is crucial for anticipating future interactions as Canis distributions continue to change with recolonizations and recovery program development. This dissertation uses an interdisciplinary approach to characterize the taxonomy and historical interactions among Canis taxa in the Southern Great Plains. Radiocarbon dating and stable isotope analysis were used to establish a temporal baseline, explore niche overlap among taxa, and investigate changes in dietary trends among coyotes following wolf extirpation. Stable isotope analysis suggests competition may have been significant among taxa, and differing mitigation strategies may have facilitated their co-occurrence. Comparisons between coyote groups before and after wolf extirpation suggests relative dietary stability. 3D geometric morphometrics was used to characterize contributions to skull morphological variation among wolf taxa and coyotes. Results supported size and taxonomic membership as significant variables contributing to shape variation, with taxonomic differentiation related to ecology and hybridization. Within-individual asymmetry was also a significant source of shape variation and was highest among red wolves. Genetic sequencing of morphologically identified “gray wolves” revealed gray wolves with ancestral ties to Alaskan and Canadian gray wolf populations, and domestic dogs of probable Paleoindian origins, suggesting potential historical wolf x dog hybridization in Oklahoma. Overall, these results will inform future directions of wolf recovery and wolf-like canid dynamics.