Feral pigs (Sus scrofa) in Texas: Population genetics, movements, and management

Background/Question/Methods Feral pigs represent a threat to the sustainability of multiple agriculture products, to the health of ecosystems, to other wildlife, and humans. Population reduction is the best current alternative for controlling pig damage.

However, reduction is crude and inefficient in terms of human-power and resources because pigs from neighboring areas quickly re-colonize managed areas. We used a panel of 12 microsatellite loci to study broad-scale population structure in feral pigs from south Texas. We also estimated cost-weighted distance among a subset of sampling sites to model movements of individuals along the landscape. At a broad scale, pig populations displayed a moderate degree of genetic structure (Fst = 0.16), suggesting that at broad geographic scales, populations are differentiated enough to be functionally independent. Preliminary analysis suggests that we can identify 7 discrete populations in the region. However, genetic similarity was not a simple function of geographic distance, implying that movement and dispersal are not equal among populations. At a local scale, animal samples taken before and after a removal event were genetically different (Fst = 0.08), indicating rapid re-colonization into the controlled area.

Results/Conclusions Overall, our results indicate that knowledge of population structure in Texas could be used to improve pig control efforts.