Houston Toad Scientific Name: Bufo Houstonensis Federal Status: Endangered, 10/13/70 • State Status: Endangered
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Houston Toad Scientific Name: Bufo houstonensis Federal Status: Endangered, 10/13/70 • State Status: Endangered Description include ephemeral (temporary) rain toadlets) between 15 and 100 days, The Houston Toad is 2 to 3.5 inches pools, flooded fields, blocked depending on the water temperature. long and similar in appearance drainages of upper creek reaches, wet Young toadlets are about the size of to Woodhouse’s Toad (Bufo woodhou- areas associated with seeps or one’s pinkie fingernail when they sei), but smaller. General coloration springs, or more permanent ponds complete metamorphosis. They then varies from tan to brownish-black. containing shallow water. Shallow leave the pond and spend their time The pale ventral surfaces often have areas of deep water, such as the feeding and growing in preparation small, dark spots. Males have a dark coves and inflow to Bastrop State for the next breeding season. Males throat, which appears bluish when Park Lake, are also used. The source generally breed when they are a year distended. of ephemeral or permanent water old, but females may not breed until should be located within one-half to they are two years old. three-quarters mile of the toad’s hibernation/foraging habitat (deep sands supporting woodland or savan- nah). Recent research indicates that mortality in toadlets is 100% if their ponds are in open pastures more than 55 yards from woodland habitat. The toads do best in ponds without predatory fish. Life History The Houston Toad is a year- round resident where found, although its presence can Houston Toad © Bruce G. Stewart most easily be detected during the breeding season, when males may be Habitat heard calling. Males usually call in The Houston Toad is a terrestrial or near shallow water, from small amphibian associated with deep sandy mounds of soil or grass surrounded soils within the Post Oak Savannah by water, or from floating objects vegetational area of east central such as logs or algae mats. Males Houston Toads, especially first- Texas. Since Houston Toads are poor occasionally call from wooded habitat year toadlets and juveniles, are active burrowers, loose friable soils are located within about a 100-yard year round under suitable tempera- required for burrowing. The toads radius of breeding ponds. The call is ture and moisture conditions. Their burrow into the sand for protection a high clear trill that lasts an average diet consists mainly of insects and from cold weather in the winter of 14 seconds. The call is much like other invertebrates. (hibernation) and hot, dry conditions that of the American Toad (Bufo in the summer (aestivation). Large americanus), but usually slightly Threats and areas of predominantly sandy soils higher in pitch. The American Toad greater than 40 inches deep are char- occurs in Texas, but north of the Reasons for Decline acteristic of habitat. The vegetation range of the Houston Toad. Habitat loss and alteration are the type of currently known Houston Houston Toads may call from most serious threats facing the Hous- Toad sites can typically be described December through June. Most breed- ton Toad. Alteration of ephemeral as pine or oak woodland or savannah, ing activity takes place in February and permanent natural wetlands for with native bunchgrasses and forbs and March, and is stimulated by urban and agricultural uses elimi- (flowering plants) present in open warm evenings and high humidity. nates breeding sites. Draining a wet- areas. Plants that are often present Toads emerge from hibernation to land, or converting an ephemeral in Houston Toad habitat include breed only if moisture and tempera- wetland to a permanent pond, can loblolly pine, post oak, bluejack or ture conditions are favorable. eventually cause the Houston toad to sandjack oak, yaupon, curly threeawn Females, responding to calling males, decline or be eliminated entirely. and little bluestem. move toward the water to mate. The Conversion to permanent water not For breeding, including egg and female lays her eggs as long strings only makes them more vulnerable to tadpole development, Houston Toads in the water, where they are fertilized predation by snakes, fish, and other also require still or slow-flowing bod- by the male as they are laid. The ies of water that persist for at least eggs hatch within seven days and tad- 30 days. These water sources may poles metamorphose (turn into Houston Toad 1 predators; but also increases competi- determine the effects of various pre- tion and hybridization with closely scribed burning programs. related species of toads. The invasion of the Red Periodic drought is also a threat, Imported Fire Ant makes it harder to particularly long-term drought such ensure the long-term survival of the as that experienced during the 1950s. Houston Toad. These toads occur in Drought may result in the loss or small, scattered populations, and may reduction of breeding sites as well as be more seriously affected by fire enhanced mortality of toadlets and ants than species that are more com- adults. mon and widespread. Fire ants kill Extensive clearing of native young toadlets (less than 7-10 days vegetation near breeding ponds and old) moving out of the breeding pond on the uplands adjacent to these into the surrounding land habitat. ponds reduces the quality of breed- Current research shows that fire ants ing, foraging, and resting habitat, and have a devastating impact on local increases the chances of predation arthropod communities, and thus and hybridization. Conversion of may also limit the toad’s food supply. native grassland and woodland savan- There is no specific information Calling male nah to sod-forming introduced on the effects of various chemicals on © Bruce G. Stewart grasses, such as bermudagrass and the Houston Toad, but it is known bahiagrass, eliminates habitat because that amphibians in general are very grass growth is generally too dense sensitive to many pollutants, includ- for the toad to move freely. Dense ing pesticides and other organic com- sod also inhibits burrowing. pounds. These chemicals may affect High traffic roads are a barrier the toad directly, particularly in the to Houston Toad movement, and tadpole stage, or indirectly by lower- toads are sometimes killed on roads. ing the abundance and diversity of its Other linear features such as food supply. Widespread use of pesti- pipelines and transmission lines can cides and herbicides from about 1950 create barriers between foraging, to 1975 may also have contributed to hibernating, and breeding sites, espe- declining populations. During this cially if native vegetation has been period, DDT and similar non-specific removed. chemicals accumulated in the environ- Continuous grazing (not rotating ment, affecting a wide variety of ani- cattle), heavy stocking rates, and long mal life. Although threats from Toads in amplexus term fire suppression have caused persistent, non-specific chemicals are © Jim Godwin loss of habitat in a significant part of not as serious today as in the past, and landowners regarding life history the toad’s range. Historically, peri- the use of pesticides and herbicides and habitat requirements of the toad odic fire played an important role in for agricultural and residential pur- are a vital part of the recovery maintaining native bunchgrass com- poses may still pose a danger for the process. munities in loblolly pine and post oak Houston Toad. savannah. Due to poor grazing man- Although Houston Toad popula- Where To See agement practices and fire suppres- tions are inherently separated The Houston Toad sion since the arrival of European because they exist only in areas of The best place to visit if you want to man, much of the former savannah deep sandy soil, further fragmenta- see and learn about the Houston grasslands of the Post Oak region tion of habitat due to human activity Toad is Bastrop State Park near Bas- have grown into brush thickets can be a problem. Widely scattered trop, Texas. The largest known popu- devoid of herbaceous vegetation. parcels of habitat may not easily be lation of the toad exists in the park Houston Toads need the herbaceous re-colonized by toads from nearby and surrounding areas. For more layer of bunchgrasses for cover and populations if extensive areas of information, contact Bastrop State foraging habitat. unsuitable habitat exist between Park at (512) 321-2101. Although the toad is believed to them, or human impacts eliminate a be adapted to fire regimes, prescribed population. How You Can Help burning may result in toad mortality. You can help by protecting pond Frequent and/or severe burns may be Recovery Efforts habitat. Conservation and wise man- detrimental to the toad, particularly Research is continuing into the life agement of native vegetation is for small, fragmented populations. history, habitat requirements, and important in preserving Houston However, increased fuel loads due to land management practices affecting Toad habitat. You can also help by prolonged periods of fire prevention the Houston Toad. Population sur- landscaping with native plants to may result in very hot wildfires. veys are being conducted in areas reduce water and pesticide use, and Additional research is needed to where toads have been found and in by proper storage and disposal of potential habitat areas. Efforts to household, gardening, and agricul- provide information and educational tural chemicals. Hopefully, thought- 2 Houston Toad opportunities to the general public ful and effective compromises For More Information Contact Texas Parks and Wildlife Department Wildlife Diversity Branch 4200 Smith School Road Austin, Texas 78744 (512) 912-7011 or (800) 792-1112 or U.S. Fish and Wildlife Service Ecological Services Field Office 10711 Burnet Road, Suite 200 Austin, Texas 78758 Breeding pond in Milam County (512) 490-0057 © TPWD Andrew Price Management guidelines are available from the Texas Parks and Wildlife Department and U.S.