An Interdisciplinary Approach to Mapping and Modelling Resource Selection and the Rapid Spread of Invasive Wild Pigs (Sus scrofa) at the Northern Extent of their Introduced Range
Date
2022-09-08
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
0000-0002-3803-3268
Type
Thesis
Degree Level
Doctoral
Abstract
This research provided the first-ever peer-reviewed and publicly available baseline of invasive wild pig (Sus scrofa) distribution in Canada. The results of this thesis quantified some of the serious ecological, economic, and animal health risks posed by wild pigs at the northern extent of their introduced range in North America. An interdisciplinary approach that integrated a diverse array of stakeholders and multiple, independent data collection methods was applied throughout the research. Wild pigs have exhibited an exponential range increase from initial introductions onto the landscape in the early 1990s. The cumulative distribution of wild pig occurrences has expanded to encompass 777,000 km2 across Canada from British Columbia to Quebec as of 2017, with 92% of the spread occurring in the Prairie Provinces. Resource selection function (RSF) models that incorporated propagule pressure were developed to quantify the factors influencing wild pig distribution and resource selection on the Canadian prairies. Wild pigs selected for deciduous forest (β [95% CI] = 1.32 [ 1.00, 1.64]), annual crop (β [95% CI] = 0.65 [ 0.32, 1.00]), and water (β [95% CI] = 0.32 [ 0.06, 0.58]). The distance to domestic wild boar farms was a primary driver of wild pig distribution (β [95% CI] = -1.19 [-1.41, -0.97]). This research used spatial overlap as a proxy measure to estimate the relative risk of disease transmission at the wildlife-livestock interface, predation of species at risk (SAR), and degradation of protected habitats. The relative likelihood of the risk of spatial overlap was predicted using RSFs and multivariate analyses. The results of this research established that wild pigs posed a significant risk to native species and natural habitats as well as the potential for disease transmission risk to livestock at the northern extent of their introduced range. This study identified the high relative likelihood of spatial overlap at the wildlife-livestock interface and with protected areas and SAR. Heterogenous landscapes with a mix of forest cover, annual crop, and water within the agro-ecosystem in close proximity to current or historical domestic wild boar farms were at greatest risk for wild pig presence. The results from this study may be used to guide effective wild pig management across Canada and may be adapted and applied to a wide range of invasive species management and control strategies.
Description
Keywords
Wild Pigs, Invasive Species, Resource Selection
Citation
Degree
Doctor of Philosophy (Ph.D.)
Department
Animal and Poultry Science
Program
Animal Science