Endangered golden-cheeked warbler photo by Melody Lytle
Endangered golden-cheeked warbler photo by Melody Lytle

 

The Balcones Canyonlands on the eastern edge of the Texas Hill Country have historically been home to a broad range of wildlife; many of the native plants and animals that live here are found nowhere else on earth.

The Balcones Canyonlands Preserve was created to protect eight endangered species and 27 species of concern. By protecting the most vulnerable species—the first ones to become endangered or threatened—we can help maintain the entire ecosystem.

Endangered Species

Golden-Cheeked Warbler

golden cheeked warbler by tom hausler
Photo by Tom Hausler

The golden-cheeked warbler (Setophaga chrysoparia) is a small, colorful songbird that nests exclusively in Central Texas. It spends the winter in Mexico and Central America, returning each spring to breed in the Hill Country’s mature oak-juniper forests. Ashe juniper trees (often referred to as ‘cedar’) are essential to the warbler’s survival. The golden-cheeked warbler makes its nest from the bark of mature Ashe junipers, binding strips of it together with spider webs. The main threat to the golden-cheeked warbler is habitat loss.

Karst Invertebrates

Six cave-dwelling endangered species are protected in the Balcones Canyonlands Preserve. They spend their entire lives underground in limestone caves and sinkholes. A number of adaptations allow them to live in this unique environment, such as elongated legs and a slower metabolism. These six endangered invertebrates are only found in Travis and Williamson Counties, and in many cases their ranges are much smaller. They are threatened by pollution, changes in drainage patterns, invasive species like the red-imported fire ant and tawny crazy ant, and loss of habitat due to development.

tooth cave pseudoscorpion by piers hendrie
Photo by Piers Hendrie

The Tooth Cave pseudoscorpion (Tartarocreagris texana) resembles a tiny scorpion with no tail. Reaching only about 4 millimeters, the size of a single grain of rice, this tiny eyeless predator catches small invertebrates by seizing them with its pincers.

tooth cave spider by robert and linda mitchell
Photo by Robert and Linda Mitchell

The Tooth Cave spider (Tayshaneta myopica) is the smallest of the six species, with a body only 1/16th-inch of an inch long. This pale, sedentary spider with rudimentary eyes has adapted to cave life by slowing its metabolism so it can live longer with less prey. They are usually found hanging from small webs on cave walls and ceilings, waiting to catch tiny invertebrates.

tooth cave ground beetle by dr. jean krejca
Photo by Dr. Jean Krejca, Zara Environmental, LLC.

The Tooth Cave ground beetle (Rhadine persephone) is the largest and most active of the six cave-dwelling endangered species on the preserve. It moves quickly, patrolling the cave floor and digging holes in the loose silt to find cave cricket eggs to eat.

kretschmarr cave mold beetle by robert and linda mitchell
Photo by Robert and Linda Mitchell

The Kretschmarr Cave mold beetle (Texamaurops reddelli) is an eyeless predatory beetle with short wings and long legs. It is usually found under rocks and organic debris.

bee creek cave harvestman by piers hendrie
Photo by Piers Hendrie

The Bee Creek Cave harvestman (Texella reddelli) is orange with eight legs. Harvestmen are often confused with spiders; while both have eight legs, these two groups are actually quite different. Most harvestmen have only two eyes (instead of eight) and unlike spiders, they have no fangs or silk glands to make webs.

bone cave harvestman by piers hendrie
Photo by Piers Hendrie

The Bone Cave harvestman (Texella reyesi) appears nearly identical to the Bee Creek Cave harvestman and is only found north of the Colorado River. It preys upon tiny invertebrates and is especially sensitive to dry conditions.

Jollyville Plateau Salamander

jollyville plateau salamander by nathan bendik
Jollyville Plateau Salamander photo by Nathan Bendik

The Jollyville Plateau salamander (Eurycea tonkawae) is a relative of the better-known Barton Springs salamander that lives in Barton Springs Pool in Austin’s Zilker Park. Though found on the BCP, the Jollyville Plateau salamander is not one of the species the preserve was created to protect. Developers cannot mitigate for destruction of its habitat through the BCCP - see Development in Endangered Species Habitat for more information. But the Jollyville Plateau salamander benefits from the preserve nonetheless. Much of the salamander’s remaining natural-spring habitat is found within the BCP. The most significant cause of decline for this species is increased impervious cover (like roads and parking lots), which leads to poor water quality and the alteration of natural flows.

Species of Concern

Protecting these 27 species on the BCP helps keep them from becoming threatened or endangered.

texabama croton
texabama croton

Texabama croton (Croton Alabamensis var. texensis) is an unusual woody shrub usually found in canyon woodlands. The central Texas population of this species is isolated—the nearest population is over 600 miles away in Alabama.

mock orange in bloom

The canyon mock orange (Philadelphus ernestii) is a small shrub with showy white flowers that is found in limited areas on the Edwards Plateau, and nowhere else on earth. It prefers rocky cliffs and other well-drained sites near wet areas.

See the list of the 25 cave-dwelling species of concern found on the BCP.

Black-Capped Vireo

lack capped vireo by bret whitney
Photo by Bret Whitney

The Black-Capped Vireo (Vireo atricapilla) is a migratory songbird that spends the winter in Mexico and breeds in parts of Texas, Oklahoma, and northern Mexico. It builds its nests in low, bushy trees and shrubs just a few feet off the ground.

The black-capped vireo was one of the eight endangered species that the Balcones Canyonlands Preserve (BCP) was created to protect. In May 2018, the black-capped vireo was removed from the federal list of Endangered and Threatened Wildlife. The delisting does not affect the preserve, however; the land will continue to be preserved in perpetuity. The U.S. Fish & Wildlife Service's (USFWS) decision to delist the vireo was made with the assumption that protected habitat would remain intact and continue to be managed for the species. They continue to be threatened by habitat loss and cowbird parasitism.

Landscape-Scale Conservation

drone shot of balcones canyonlands preserve by heather valey
Preserve photo by Heather Valey

Landscape-scale conservation, like the Balcones Canyonlands Preserve, is the most effective way to preserve a viable ecosystem. Large natural areas are more resilient compared to smaller tracts. They also provide resources to a larger number of species, many of which rely on each other for food and shelter. Larger preserve tracts connected to each other also create important wildlife corridors for animal populations to freely move between protected areas and maintain genetic diversity.

Many species, including the golden-cheeked warbler, do best in the interior of larger tracts, where they are buffered from “edge effects”. Non-native vegetation can invade from preserve edges, and urban predators such as blue jays, foxes, squirrels and feral cats can more easily threaten nesting warblers. There’s usually more noise and other disturbances along the edge that the warblers tend to avoid as well. Preserving larger areas provides more of the interior habitat that the warblers and other animals prefer.

The BCP also protects large expanses of karst terrain (limestone areas that contain a network of caves, fractures, fissures and sinkholes), which provides habitat for rare karst invertebrates. Protecting the surface above this underground world is extremely important for providing necessary habitat components to cave-dwelling species. These include nutrient input, infiltration of water, and stable temperature and humidity. Preserving karst terrain also provides a buffer to edge effects and ensures gene flow among karst invertebrate populations by sustaining the interconnection between caves. Protecting these special ecosystems also allows rainwater to infiltrate the ground, recharging the aquifers many people rely on for clean drinking water.