Ecological Diversity in the Big Bend Region: How Sky Islands, Water Resources and Grasslands Make This Region Unique

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Photo courtesy of Dana Karelus.

If there is one term that best describes the topography and biology of the greater Big Bend region, it is diverse. High mountain ranges erupt from sparse desert floors, with grasslands interspersed in the low to mid elevations, and water sources scattered throughout.

The high desert ecosystem found in the Big Bend region is not only unique and beautiful, it is also essential for the wildlife and people who live here.

Sky Islands, Water Resources and Grasslands is one of the shared conservation values of the Respect Big Bend coalition, identified by the Trans-Pecos Stakeholder Advisory Group. Members of this group include landowners, conservation partners and community members from the Big Bend region counties of Brewster, Jeff Davis and Presidio.

What do the tallest peaks in the Big Bend region have in common? The tallest peaks in the region have some of the most diverse ecosystems and are commonly referred to as sky islands! Sky islands are isolated mountain ranges that are surrounded by desert “seas” below. These Chihuahuan Desert islands consist of montane, or mountainous, habitats characterized by more precipitation and cooler temperatures than the surrounding desert floor, which means a wide diversity of plants and animals can be found (or seen) in just a short hike.

But where can you find these sky islands in Big Bend region? Sky islands can be found throughout the Big Bend and includes Emory Peak, in the Chisos Mountains, sits around 7,800 feet above sea level while Mount Livermore, in the Davis Mountains, sits at over 8,300 feet, and is the highest point in the Big Bend region. These peaks are great places to experience sky islands in the Big Bend region.

There is nothing more precious in the desert than water. The once mighty Rio Grande forms the true bend of the Big Bend region. However, today, because of overexploitation and severe drought, the flow of the Rio Grande is seasonal at best.

Rainfall in the Chihuahuan Desert forms vital ephemeral, or short-lived, streams and creeks such as Limpia, Alamito, Terlingua, and Calamity. The Chihuahuan Desert additionally has some groundwater, or water that is found in the spaces between soil, sand, and rocks. Groundwater is the main source of water for any perennial, or year-round, surface water present. The ecological sanctuaries (e.g., wetlands of cienegas) that are formed by these areas of surface water are crucial for many species of wildlife.

Why is water so important in this area? Water is crucial to all walks of life, but especially so in the desert. The Chihuahuan Desert is limited in rainfall, and receives only 6-18 inches of rain per year. Rain also does not typically occur throughout the year, and instead follows the monsoon season, bringing heavy rains from July to September. The conservation of water resources is critical for plants, wildlife and humans of the Big Bend.

Chihuahuan Desert grasslands make up a large portion of the Trans-Pecos, providing important habitat for species such as pronghorn and kit fox. Additionally, around 90% of grassland bird species that breed in the northern Great Plains of the United States winter in the Chihuahuan Desert grasslands. Almost all of these species have experienced cataclysmic population declines over the past several decades.

Not only are these grasslands fundamental for numerous wildlife species, they are also important for the people of the area. Grasslands of the greater Big Bend region support numerous cattle ranches and have done so for more than a century. Private landowners rely on these grasslands to feed their cattle to earn their livelihood, and the grasslands are dependent on the landowners for proper stewardship.

It is imperative, now more than ever, to conserve and restore these native grasslands for wildlife, livestock, and the people of the Big Bend region.

Many organizations across West Texas offer resources for landowners and managers to help support the conservation of the sky islands, water resources and grasslands, including:

Audubon Texas
Big Bend National Park
Big Bend Ranch State Park
Bird Conservancy of the Rockies
Chihuahuan Desert Research Institute
Davis Mountains State Park
Dixon Water Foundation
Groundwater Conservation Districts of Brewster, Jeff Davis and Presidio Counties
National Fish and Wildlife Foundation
Natural Resources Conservation Service
Partners for Fish and Wildlife
Rio Grande Joint Venture
Rio Grande Research Center at Sul Ross State University
Texas Agricultural Land Trust
Texas Parks and Wildlife Department
Texas Parks and Wildlife Department Inland Fisheries Division
Texas Parks and Wildlife Department Wildlife Management Areas
Tierra Grande Master Naturalists
The Nature Conservancy in Texas
Soil and Water Conservation Districts of Big Bend, Highland, Toyah-Limpia
United States Department of Agriculture – Farm Service Agency

Read more about the latest Respect Big Bend report here, https://respectbigbend.org/final-report

The Respect Big Bend coalition was launched by the Cynthia and George Mitchell Foundation, and is sponsored in part by the Permian Basin Area Foundation, The Meadows Foundation, and the Still Water Foundation. Find out more about the project at RespectBigBend.org.


A view from the sky islands on the South Rim trail in Big Bend National Park, one of the tallest peaks in the region.


Limpia Creek in the Davis Mountains State Park just after a late June 2021 monsoon. Photo courtesy of Price Rumbelow, Texas Parks and Wildlife Department Region 1 Habitat Conservation Specialist.

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Many species of birds use the Chihuahuan Desert grasslands during the winter months.