Rooting out genetic structure of invasive wild pigs in Texas

Invasive wild pigs (Sus scrofa), also called feral swine or wild hogs, are
recognized as among the most destructive invasive species in the world.
Throughout the United States, invasive wild pigs have expanded rapidly
over the past 30 years with populations now established in 38 states. Of
the estimated 6.9 million wild pigs distributed throughout the United
States, Texas supports approximately 40% of the population and similarly
bears disproportionate ecological and economic costs. Genetic analyses are
an effective tool for understanding invasion pathways and tracking
dispersal of invasive species such as wild pigs and have been used
recently in California and Florida, USA, which have similarly
long-established populations and high densities of wild pigs. Our goals
were to use molecular approaches to elucidate invasion and migration
processes shaping wild pig populations throughout Texas, compare our
results with patterns of genetic structure observed in California and
Florida, and provide insights for effective management of this invasive
species. We used a high-density single nucleotide polymorphism (SNP) array
to evaluate population genetic structure. Genetic clusters of wild pigs
throughout Texas demonstrate 2 distinct patterns: weakly resolved,
spatially dispersed clusters and well-resolved, spatially localized
clusters. The disparity in patterns of genetic structure suggests
disparate processes are differentially shaping wild pig populations in
various localities throughout the state. Our results differed from the
patterns of genetic structure observed in California and Florida, which
were characterized by localized genetic clusters. These differences
suggest distinct biological and perhaps anthropogenic processes are
shaping genetic structure in Texas. Further, these disparities demonstrate
the need for location-specific management strategies for controlling wild
pig populations and mitigating associated ecological and economic costs.