Biodiversity Relative to Habitat Suitability for Black Bears and Mountain Lions in the Trans-Pecos Region of Texas

Concern for loss of biodiversity, or the variety of life in a particular area, has caused an increase in studies reviewing methods used to conserve and protect biodiversity in different ecosystems.  In the past, management plans have applied only to small reserves or one specific species, such as an endangered species. More recently, greater importance has been placed on developing management plans that apply to multiple species or ecosystems.  One multi-species approach includes using one or two species, typically large mammals, as umbrella species for conservation and management of all other species that fall within its distribution. 

The Chihuahuan desert is recognized as one of the most biodiverse and unique deserts in the world, but changes to the land, including habitat loss and habitat fragmentation can lead to a decline in diversity.  We conducted a study to assess the usefulness of using large carnivores, such as black bear and mountain lions, as umbrella species for conservation in the Chihuahuan Desert ecosystem of the Trans-Pecos region of Texas.  To do this, we performed surveys in order to quantify the diversity of mammals, avifauna, and herpetofauna along areas of suitable habitat for black bear and mountain lions in the Trans-Pecos region of Texas. 

The Rapid Ecological Assessment method, which is a fast, efficient, and inexpensive method used to conduct diversity surveys of both flora and fauna, was used to survey species richness and biodiversity at Big Bend National Park, Elephant Mountain Wildlife Management Area, and the Davis Mountains Preserve.  To determine biodiversity we conducted small mammal trapping, bird surveys, herpetofauna, and large mammal surveys.  Contrary to what we expected to see, the strata of lowest suitability for black bears and mountain lions had the highest species richness when study sites were combined.  However, species diversity was significantly higher in high black bear habitat at Big Bend National Park and Elephant Mountain Wildlife Management Area.  Species diversity was also higher in high mountain lion habitat at Big Bend National Park.  The results of this study could help establish a long-term monitoring program of biodiversity in each of the study sites.


small mammal

418 small mammals representing over 11 species were captured across the 3 study areas.

burned area

Map showing habitat suitability strata at Big Bend National Park, Brewster County, Texas, defined as: GBGL) good suitability for black bears and mountain lions; GBPL) good suitability for black bears, poor suitability for mountain lions; PBGL) poor suitability for black bears, good suitability for mountain lions; and PBPL) poor suitability for black bears and mountain lions.