Gulf coast canids: A wetland coyote ecotype shaped by red wolf introgression

Morphology and behavior are fundamental components of ecology because
phenotypic variation influences the distribution and abundance of species,
interspecific interactions, and community assemblages. Hybridization and
introgression can increase phenotypic variation when novel traits
accompany new genetic variants. Assessing the adaptive role of
introgression requires linking increased phenotypic variation to
ecologically relevant population processes such as reproduction, survival,
emigration, and immigration. Recent research confirmed significant red
wolf (Canis rufus) ancestry in coyote (Canis latrans) populations along
the coastal region of the Texas-Louisiana border, USA, where the last
known red wolves existed prior to their extirpation from the wild. Coyotes
in this region are referred to as ‘Gulf Coast canids’ by some because the
magnitude and impact of the observed introgression is not well understood
yet. We conducted a phenotypic assessment of Gulf Coast canids to explore
whether these canids are red wolf-coyote hybrids, or a wetland ecotype of
the coyote formed during the coyote’s initial colonization of the
southeastern United States. We concluded that Gulf Coast canids are a
wetland ecotype of the coyote derived from a mid-20th century red
wolf-coyote hybrid swarm. Our assessment indicates that Gulf Coast canids
are tall, lanky coyotes with post-cranial traits similar to red
wolf-coyote hybrids. However, their head sizes are coyote-like. Gulf Coast
canids exhibited strong selection for wetland land cover such as large
river floodplains and coastal saltwater wetlands limiting their potential
distribution to the coastal wetlands of the Gulf of Mexico. We observed
little use of white-tailed deer (Odocoileus virginianus) and significant
use of nutria (Myocastor coypus) by Gulf Coast canids, food habits that
differ significantly from those of the surrounding coyote populations.
Finally, high annual survival rates indicate that Gulf Coast canids could
potentially be a source population and responsible for the persistence of
red wolf ancestry in coyotes along coastal Texas and Louisiana.