Understanding contingency in wolf-mediated livestock predation across a mosaic of land uses: An agent-based modelling approach

Abstract

The return of grey wolves to multi-use landscapes in North America and Europe raises concerns over accompanying risks of livestock predation. While local-level risk factors have received attention, it is difficult to explore the role that landscape-scale variables, such as landscape connectivity, play in driving livestock losses. Furthermore, it is unclear how changes in landscape structure might interact with livestock management practices. As wolf populations continue to grow, it is critical to understand how management of both land and livestock might be approached to reduce instances of livestock loss. We developed a spatially explicit, agent-based model designed to emulate hunting by a wolf pack within an agricultural-wildland landscape matrix. We investigated the effects of three different livestock grazing practices—free-roaming, pasture-limited and seasonal grazing—on interactions between livestock, wolves and wild ungulates. For each grazing practice, we explored how varying connectivity and availability of managed wildlands affected these interactions. Livestock predation rates were influenced by the size of wildlands and the degree to which these parcels were connected: increased wildland availability and connectivity led to reduced livestock losses, primarily due to greater wolf access to wild ungulates. Trends in livestock losses in relation to herd management and landscape composition were consistent and predictable on highly connected landscapes but broke down on landscapes experiencing a high degree of fragmentation. The different grazing practices employed in our model had minimal impact on overall levels of livestock loss, but did shape where livestock predation occurred. In particular, most livestock deaths occurring under the seasonal grazing treatment occurred on wildlands, indicating the heightened risk involved in seasonal use of these spaces. Synthesis and applications: Reducing risks of livestock predation on multi-use landscapes is crucial to the economic persistence of livestock producers and continued grey wolf recovery across Europe and North America. Our analysis shows that livestock loss to wolf predation is influenced more by the size and connectivity of wildland habitat than by grazing practice, suggesting that landscape restoration and preservation may benefit livestock producers and recovering large predator populations alike by ensuring continued access to wild prey. Read the free Plain Language Summary for this article on the Journal blog.