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Spring 2024 |
Newsletter Archive |
Do fences impact pronghorn movement? |  |
Pronghorn interactions with fences can disrupt movement patterns, fragment and reduce access to important habitats, and indirectly reduce an animal's reproductive fitness. Roadways, and additional linear infrastructure such as fences, have been identified as the most significant threat to ungulate migrations. The Northern Sage Brush Steppe Ecosystem (southeastern Alberta, southwestern Saskatchewan and northern Montana) is a landscape dominated by fence infrastructure. The highest fence densities in this region are to the north of Suffield in Alberta and along Highway 2 in Montana. To assist government agencies, ranching and farming organizations, and conservation groups to identify the best opportunities for fence modification projects, we analyzed individual behavioural responses of pronghorn to fences. We used software developed by Dr. Xu called 'Barrier Behaviour Analysis' to examine individual pronghorn response to fences. We accessed pronghorn GPS data from 157 individuals and fencing datasets for Alberta, Saskatchewan, and Montana. Pronghorn fence encounters were classified into normal, altered, and trapped animal movement types. In a year on average a pronghorn had to navigate a fence 244 times with 66% of fence interactions classified as normal, 30% classified as altered movement and 2% trapped. Our results suggest that pronghorn have likely learned where they can move under fences, but that there are opportunities for improving movement through mitigation measures (installing a smooth bottom wire 18-28 inches off the ground) to enhance fence crossings. Fence interactions within 500 m of a paved road had a greater percentage of altered and trapped movements (44%) indicating paved roads may be further inhibiting pronghorn movement. We identified key areas on the landscape where fence mitigation could best improve pronghorn movement opportunities. To learn more see 'Pronghorn Fencing Permeability in the NSS.' Thanks to Alberta Conservation Association and Environment and Climate Change Canda for supporting our conservation work. Photo credit: John Wilmshurst. | |