Potential fence density in central and Western North America and implications for Bison (Bison bison) restoration

Abstract

Fences serve multiple purposes, including livestock management, agriculture, property delineation, and conservation. However, fences often act as ecological barriers, limiting wildlife movement and access to resources, particularly for species like bison (Bison bison) in North America. Despite the substantial impacts of fencing, large-scale datasets on fence densities are lacking. Our goal was to create potential fence density maps for the western and central U.S. and Canada using GIS modelling and freely accessible data. Specifically, we aimed to: (1) map potential fence density and identify high density of fence, (2) contrast the potential fence density map with the patterns of high human influences, and (3) identify areas with high bison habitat suitability and low density of potential fences. Using GIS modelling, we generated potential fence density maps by integrating data on land parcels, croplands, roads, and railroads. Subsequently, we identified regions with high and low potential fence density and compared them with patterns of human influence and bison habitat suitability. We found high total potential fence density in central regions of Canada and the U.S., mainly due to agriculture and transportation corridors. Interestingly, areas with high potential density of fence in the western U.S., often had low other human influence, suggesting that human influence maps may underestimate impacts if they miss fences. We also identified large areas with high bison habitat suitability and low fence density, which are promising for bison restoration. Our findings highlight the importance of assessing fences for wildlife conservation and supporting bison restoration in the Great Plains.