BLM Las Cruces District and partners improve pronghorn habitat connectivity in New Mexico bootheel

Story by Rachel Burke, Wildlife Biologist, BLM Las Cruces District Office. Photos courtesy of New Mexico Department of Game and Fish.

Pronghorn (Antilocapra americana) are a native ungulate found throughout the grasslands of western North America. Although they are often referred to as antelope, they are the only living member of the family Antilocapridae and their closest living relative is the giraffe. Pronghorn are endemic to North America, meaning they do not occur anywhere else in the world. Throughout the West, pronghorn conduct long-distance migrations following food availability and seasonal habitat conditions. To undertake these migrations, pronghorn require expansive grasslands that are free of barriers such as highways, sprawl, and fencing that is not wildlife-friendly.

In southern New Mexico, pronghorn have adapted to undertake shorter movements following ephemeral (lasting a very short time) grassland conditions. However, habitat connectivity is no less important down here. In fact, the compounding impacts of climate change, grassland degradation, and inconsistent rainfall patterns in southern New Mexico make the pronghorn’s ability to move freely across the landscape to more favorable conditions even more important; the inability to do so can increase the risk of extirpation.

Over the past several decades, habitat fragmentation, climate change, and grassland degradation have likely had negative impacts on pronghorn populations in the bootheel of New Mexico, the far southwestern part of the state comprised of Hidalgo and southern Grant counties. However, pronghorn in this area have not been well studied.

To better understand pronghorn movements, habitat selection, and barriers to movement in this understudied region, the Bureau of Land Management (BLM) New Mexico Las Cruces District Office (LCDO), New Mexico Department of Game and Fish (NMDGF), the U.S. Geological Survey, and the New Mexico Cooperative Fish and Wildlife Research Unit at New Mexico State University are partnering on a project that involves tracking pronghorn movement with GPS collars. In December 2022, NMDGF biologists worked with BLM LCDO wildlife biologists and Dr. James Cain III, the principal investigator on the project, to deploy 50 GPS collars in areas north and south of I-10. The collars will collect pronghorn location data for two plus years, after which analyses will begin.

As pronghorn location data is obtained, biologists will analyze the data to identify barriers to movement, which will help land managers plan future connectivity projects such as fence modification, fence removal, and grassland restoration projects. Fence modification projects can include updating old barbed wire fences to meet wildlife-friendly specifications, with a smooth bottom wire that is at least 16 inches from the ground. Fence removal could include the removal of old net-wire fencing that was originally put up for domestic sheep in areas that no longer have active sheep grazing allotments. 

The BLM LCDO also hopes to use a biologically-informed dataset to evaluate the condition of grasslands being used by pronghorn and determine if pronghorn are using grasslands that have undergone previous restoration treatments. Then the BLM will determine how future treatments and vegetation management can better meet the needs of pronghorn populations.

Ultimately, this project will help BLM LCDO better evaluate the impacts of management activities on pronghorn and their habitat, prioritize where vegetation treatments will have the greatest benefit for grassland obligate species, and prioritize habitat connectivity projects that will allow pronghorn herds to more effectively respond to changing habitat conditions due to climate change. The BLM hopes to build on this project and associated partnerships to help improve wildlife habitat connectivity across the lands managed by the LCDO.