In 1970, due to threats primarily from habitat loss, the Houston toad was listed as endangered under the Endangered Species Conservation Act of 1969 (which was replaced by the
Endangered Species Act in 1973). Critical habitat (areas that are considered essential to the conservation of the species) was designated in 1978 in Bastrop and Burleson counties, in areas
supporting the largest populations known at that time. The population within critical habitat in Burleson County has not been seen since 1983.
Urban Development - Habitat conversion poses the most serious threat to the Houston toad. Several populations were eliminated with the expansion of Houston, and the largest remaining
population in Bastrop County is also under intense and immediate threat from urban development. Recent trend analyses suggest that Houston toads are declining in Bastrop State Park, which
lies near the center of its critical habitat in Bastrop County. The Park is the only public land that supports large numbers of this species.
The U.S. Fish and Wildlife Service is working with community leaders, private landowners, and conservation organizations to develop and implement a regional Habitat Conservation Plan for
Bastrop County, which would provide for the issuance of endangered species permits that allow development to proceed while ensuring permanent habitat protection. The Service also has established
a fund with the National Fish and Wildlife Foundation to assist in local habitat protection efforts for the Houston toad.
Road Mortality - Many Houston toads are killed each year by automobiles. Roadway mortality will increase as human populations continue to increase within the species’ habitat and as the
habitat continues to be dissected by more roads. Road construction further isolates populations and disrupts or prevents the movement of individual toads between populations. This movement of
toads is necessary to maintain gene flow, and thus genetic diversity, and to supplement small or declining local populations. It is possible to build roads with underpasses or other structures
that allow toads and other wildlife to pass safely beneath the roads.
Agriculture - While converting woodlands to pastures or plowed fields destroys Houston toad habitat and favors the proliferation of other toad species, certain agricultural practices
can be beneficial to Houston toads. These include maintaining low to moderate numbers of livestock to avoid overgrazing, protecting pond habitat from livestock and predatory fish, planting
native bunchgrasses instead of sod-forming grasses, such as Bermuda grass, which are difficult for the toads to move through, and conserving large blocks of woodlands. The
Texas Parks and Wildlife Department and Service have jointly prepared a brochure for private landowners who wish to implement their agricultural
practices in ways that are compatible with the needs of the Houston toad.
Forestry Practices - Certain forestry practices may benefit the Houston toad, while others, such as clearcutting, are harmful. Thinning and burning have been shown to benefit some species
of amphibians and reptiles by opening up the forest canopy and allowing more sunlight to reach the forest floor. This practice encourages the growth of vegetation and, in turn, increases insect
numbers. This may be beneficial to the Houston toad. The Texas Forest Service has formed a committee to develop management practices that protect the Houston toad and its habitat.
Other Factors - Other threats that often appear in conjunction with the factors outlined above include drought and the presence of fire ants, an unwelcome species from Brazil. Fire ants
have been observed preying on toadlets as they leave their breeding pond. Fire ants thrive in open, sunny areas where the soil has been disturbed and woody vegetation uprooted, as in agricultural
fields and urban areas. Protecting large forested areas is one of the most effective deterrents to fire ants. Where fire ant control with pesticides is necessary, mounds should be treated
individually, rather than broadcasting the chemicals, to avoid impacting other invertebrates that the Houston toad eats.
Research is urgently needed to determine the status of Houston toad populations outside of Bastrop County and promote conservation efforts in these areas. Research is also
critical to determine which management practices are most conducive to the Houston toad and the ecosystem on which it depends.