Pronghorn Study Finds Migration Trends

Wildlife must move to thrive and survive, however the habitat connectivity they rely on for spring and fall seasonal migrations continues to be fragmented by housing, roads, fences, energy facilities and other human-made barriers. An article focused on migration routes of pronghorn, recently published in the scientific journal PLOS ONE, shed new light on the important factors and the cumulative effects from habitat conversion and fragmentation of migratory routes.

“Novel applications of wildlife tracking technology have given us insights of the determinants of pronghorn migration routes across vast landscapes and seasons,” said Andrew Jakes, wildlife biologist for the National Wildlife Federation. “Our findings affirmed the importance of open grassland and sagebrush habitats as important migration habitat. We could also document the extent to which natural changing conditions such as foraging quality, and human-created features, such as road density and fossil fuel infrastructure (i.e., oil and gas wells) shape pronghorn migration routes. Integrating these multi-scale predictions into one spatial map will be highly valuable to wildlife managers and habitat managers.”

The 6-year study followed 185 GPS-collared pronghorn as they moved across international borders, from Saskatchewan and Alberta, Canada to Montana in the United States. Key study findings also revealed:

• Large landscapes, such as grasslands, and the quality of forage (NDVI) is a critical determinant of pronghorn migration
• At large scales, pronghorn avoided areas with high road density and areas with high fossil fuel infrastructure from oil and gas development.
•  During fall migration, herds tend to follow river systems, so that they can arrive at winter range quickly, however this is not important during spring as pronghorn recover from the previous winter and prepare for fawning.

Paul Jones, senior wildlife biologist for Alberta Conservation Association asserted “When we stand on a small piece of native prairie here in Alberta, Canada looking towards our neighbors to the south we loose perspective of the bigger picture and what is happening on the big stage.  What this research has highlighted is how pronghorn are indicative of how wildlife try to edge out a living on a highly fragmented landscape and that jurisdictional boundaries are just lines on a piece of paper. It also shows that pronghorn at the northern periphery of their range are sitting on the edge of a precipice ready to fall off if we lose these migration routes and they are no longer able to move in response to fluctuating conditions.”

The mapping of migration habitat for ungulates, such as pronghorn, is a topic of high conservation relevance, yet their migration routes, and what determines them in an everchanging landscape, are still not fully understood. “We see this approach as a holistic view of identifying important migration habitat across entire landscapes and can help conservation planning and management decisions for a wide-ranging species like pronghorn. Agencies around the West have shown their commitment to addressing migration needs, especially for ungulates,” said Jakes.

Mark Hebblewhite, wildlife biology professor at University of Montana concurs. “Our paper is a great example of the need for Montana Fish, Wildlife and Parks’ recently released wildlife movement and migration strategy to help conserve migratory species, like pronghorn, here in Montana.”