Modeling and mapping the probability of occurrence of invasive wild pigs across the contiguous United States.
Wild pigs (Sus scrofa), also known as wild swine, feral pigs, or feral hogs, are one of the most widespread and successful invasive species around the world. Wild pigs have been linked to extensive and costly agricultural damage and present a serious threat to plant and animal communities due to their rooting behavior and omnivorous diet. We modeled the current distribution of wild pigs in the United States to better understand the physiological and ecological factors that may determine their invasive potential and to guide future study and eradication efforts. Using national-scale wild pig occurrence data reported between 1982 and 2012 by wildlife management professionals, we estimated the probability of wild pig occurrence across the United States using a logistic discrimination function and environmental covariates hypothesized to influence the distribution of the species. Our results suggest the distribution of wild pigs in the U.S. was most strongly limited by cold temperatures and availability of water, and that they were most likely to occur where potential home ranges had higher habitat heterogeneity, providing access to multiple key resources including water, forage, and cover. High probability of occurrence was also associated with frequent high temperatures, up to a high threshold. However, this pattern is driven by pigs' historic distribution in warm climates of the southern U.S. Further study of pigs' ability to persist in cold northern climates is needed to better understand whether low temperatures actually limit their distribution. Our model highlights areas at risk of invasion as those with habitat conditions similar to those found in pigs' current range that are also near current populations. This study provides a macro-scale approach to generalist species distribution modeling that is applicable to other generalist and invasive species.
Conservation Science Partners, Truckee, California, United States of America.
Meredith L
ML
McClure
Department of Biology, Colorado State University, Fort Collins, Colorado, United States of America.
Christopher L
CL
Burdett
Conservation Science Partners, Truckee, California, United States of America.
Matthew L
ML
Farnsworth
National Wildlife Disease Program, Animal and Plant Health Inspection Service, United States Department of Agriculture, Fort Collins, Colorado, United States of America.
Mark W
MW
Lutman
Conservation Science Partners, Truckee, California, United States of America.
David M
DM
Theobald
Center for Epidemiology and Animal Health, Animal and Plant Health Inspection Service, United States Department of Agriculture, Fort Collins, Colorado, United States of America.
Philip D
PD
Riggs
Center for Epidemiology and Animal Health, Animal and Plant Health Inspection Service, United States Department of Agriculture, Fort Collins, Colorado, United States of America.
Daniel A
DA
Grear
Center for Epidemiology and Animal Health, Animal and Plant Health Inspection Service, United States Department of Agriculture, Fort Collins, Colorado, United States of America.
Ryan S
RS
Miller
D000818:Animals; D000835:Animals, Wild; D004463:Ecology; D017753:Ecosystem; D058865:Introduced Species; D013552:Swine; D014481:United States