Endangered Species in the Texas Hill Country
The Texas Hill Country is well known for its unique ecosystems supporting several endangered species (e.g., Texas blind salamander, San Marcos salamander, black-capped vireo, golden-cheeked warbler, and Tobusch fishhook cactus). Managing the Hill Country to provide the variety of natural habitats on which each of these species depends is quite challenging. Golden-cheeked warblers prefer stands of old-growth cedar, while black-capped vireos prefer more open areas of early-succession plant communities (e.g., shrubby growth forms of shin oak, evergreen sumac, flameleaf sumac, skunkbush sumac, etc.).
Habitat loss is often the primary factor threatening a species' existence. In the Hill Country we have a situation where loss of a particular habitat type will detrimentally affect one species, while other endangered species may benefit. The golden-cheeked warbler depends on stands of mature Ashe juniper (blueberry cedar) mixed with deciduous trees including Lacey oak, Spanish oak, shin oak, post oak, cedar elm, and escarpment black cherry. Suitable habitat will contain both(1) mature Ashe juniper, and (2) adequate mix of deciduous trees. Mature Ashe juniper is a major factor resulting in decreased water supply to the Edwards Aquifer. Two other endangered species depend on an adequate supply of water. The San Marcos salamander is threatened by reduced spring flow, and the Texas blind salamander depends on a constant supply of clean water from the Edwards Aquifer. Research indicates that removal of Ashe juniper results in a tremendous increase in groundwater. One such study reported an increase of 100,000 gal/acre/year with 100% cedar removal. Conflicting needs between two (or more) endangered species can make for a sticky situation.
Historically, golden-cheeked warblers were more confined to areas protected from wildfires (e.g., canyons and steep draws). Those areas contained stands of Ashe juniper and deciduous trees, providing suitable warbler habitat. Historical reports explain that cedar was not found on upland sites, simply because periodic fires effectively controlled cedar. In the absence of fire (for the past 100+ years), Ashe juniper has encroached on the upland sites, forming dense woodlands containing only cedar, bare soil, and rock. In addition to other obvious ecological concerns (e.g., soil erosion), dense stands of cedar (also known as cedar brakes) have played a major role in the depletion of the Edwards Aquifer. Furthermore, cedar brakes do not provide suitable habitat for golden-cheeked warblers, as the deciduous tree component is absent and overall plant diversity is nil. Other sections of this web site elaborates on these issues. Just click to get a historical perspective on Hill Country management, or to learn more about sound ecosystem management. To learn more about golden-cheeked warbler requirements, read Life History(PDF 565.4 KB) of the Golden-cheeked Warbler, or to learn how to effectively manage your land to promote these warblers, download Management Guidelines(PDF 192.6 KB).
Black-capped vireos are a great indicator of overall ecosystem health. If your ranch contains this little bird, you likely have great habitat for white-tailed deer, bobwhite quail, Rio Grande turkey, and various species of songbirds. You can learn all about the Management Guidelines(PDF 224.7 KB).
The Tobusch fishhook cactus is an endangered plant found in the Hill Country. While some fear that fire (i.e., prescribed burning) may be detrimental to this plant, this is another species that evolved with fire. Sites under intensive management programs, where prescribed burning is used regularly, have shown increases in the number of Tobusch fishhook cactus. The decline of this cactus across the Hill Country has occurred in the absence of fire.