Pronghorn Habitat Fragmentation and Genetics

Habitat fragmentation is a growing concern across Texas.  Habitats become fragmented when obstacles or barriers inhibit free movement of wildlife from one habitat patch to another. Struggling pronghorn populations in the Trans-Pecos may be susceptible to the effects of habitat fragmentation.  Barriers can potentially inhibit pronghorn from finding adequate food and water, reduce gene flow which can cause inbreeding, and reduce genetic diversity and health of populations.

In other western states, natural (e.g., mountains and canyons) and manmade obstacles (e.g., fences, railroads, and roads) have been shown to reduce pronghorn movements and isolate populations. 

We evaluated the effects of fences, highways, and other barriers on pronghorn movements and genetic variability.  Using hunter-harvested pronghorn during the 2007 and 2008 hunting seasons, we obtained 344 tissue samples from across the Trans-Pecos, Panhandle, and western Edwards Plateau.  We then extracted DNA from the tissue and analyzed it for genetic variation and compared our genetic data across management units and delineated barriers.

Our data suggests that few barriers currently exist in the Trans-Pecos to curtail genetic flow of pronghorn.  Additionally, our findings revealed moderate levels of genetic diversity for Trans-Pecos and Panhandle pronghorn herds.  However, the northwestern portion of the Trans-Pecos (Culberson and Hudspeth counties) did show genetic differences.  These herd units are separated from most of the Trans-Pecos pronghorn herds by several mountain ranges and Interstate 10.  We also discovered that Trans-Pecos and Panhandle had similar genetic diversity.

The levels of genetic diversity may be a result of adequate movements of pronghorn across herd units in the Trans-Pecos or from previous translocation efforts.

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Barriers such as roads, railroads, and fences may reduce genetic flow for pronghorn in the Trans-Pecos.

 

Pronghorn are reluctant to jump over or maneuver through fences, making them susceptible to habitat fragmentation and genetic isolation.