Coachella Valley Fringe-toed Lizard
Coachella Valley Fringe-toed Lizard
|Listed||September 25, 1980|
|Description||Medium-sized, gray lizard with a wedge-shaped head and a fringe of scales on toes.|
|Habitat||Windblown sand dunes.|
|Reproduction||Breeds from April through mid August.|
|Threats||Residential development, habitat degradation.|
The Coachella Valley fringe-toed lizard, Uma inornata, has a wedge-shaped snout and a flattened body that can reach 10 in (25.4 cm) in length, including the long tail. This lizard is pale above and covered with a regular pattern of darker eye-shaped markings. The underside is white, sometimes with several black dots on each side of the abdomen and dusky lines on the throat. The body scales are smooth and overlap evenly, giving the skin a velvety texture. A sensor on the top of the head monitors solar radiation, stimulating the lizard to seek shelter if it gets too hot. The lizard's most distinctive characteristic is a row of elongated scales on the edge of the toes. This fringe of scales, which helps the lizard maintain traction in loose sands, is the source of the common name for lizards in the genus Uma.
The Coachella Valley fringe-toed lizard seeks shelter underground to avoid heat and predators, often using abandoned rodent burrows. It literally dives into the sand to escape predators. It retracts its front legs, closes flexible flaps to protect its ears, and uses its strong hind legs to push beneath the surface. The lizard can stay submerged for an indefinite time, breathing air trapped in the spaces between the grains of sand. This lizard is active when the air temperature ranges from 71.6-102.2°F (22-39°C) and can bear much higher ground temperatures. Dormant in winter, lizards emerge in the spring and enter a prolonged breeding season, lasting from April to mid August. Lizards reach sexual maturity in their second year. The Coachella Valley fringe-toed lizard is an insectivore but occasionally rounds out its diet with plant matter. In years when rainfall is below normal, lizard reproduction is correspondingly low.
The Coachella Valley fringe-toed lizard is superbly adapted to the harsh extremes of desert climate and to windblown sand dunes. Loose sands are essential for its burrowing nature. The sand that forms dunes in the Coachella Valley washes down from the mountains in storm runoff. The valley is located east of the resort city of Palm Springs and west of the Joshua Tree National Monument.
This lizard is endemic to the Coachella Valley (north central Riverside County) in California, and occupied an original range of nearly 270 sq mi (700 sq km).
By 1980 more than half of the original range had been lost to agricultural and residential development. The remaining dunes have been fragmented by roads and railroad cuts. Large tracts of dune have been stabilized by planted windbreaks. Once dunes are stabilized, the fringe-toed lizard is forced to seek out other sites. In the 1990s, however, a series of new dunes was constructed to serve as habitat for the species; the first series was completed in 1993, and the second batch in the summer of 1994. By the beginning of 1996, no Coachella Valley fringe-toed lizards had yet been observed in either rehabilitated area.
Conservation and Recovery
Three Coachella Valley cities—Desert Hot Springs, Palm Desert, and Rancho Mirage—have experienced annual growth rates of 13-19%. Construction of luxury homes and related commercial development continued at breakneck speed through the 1980s and threatened to engulf the entire valley. Preservation groups, such as the Coachella Valley Fringe-Toed Lizard Advisory Committee and the Coachella Valley Ecological Reserve Foundation, formed as early as 1977 to prevent lizard habitat from disappearing. By 1983 with help from The Nature Conservancy, these foundations had acquired 425 acres (170 hectares) of lizard habitat to establish an ecological reserve—a good beginning, but not enough to ensure the lizard's survival.
In 1989 developers, conservationists, local, state, and federal agencies forged a compromise agreement to preserve a large part of remaining habitat, while allowing development in the rest of the valley to continue. The compromise plan, described as a model for resolving many of the divisive issues that surround the preservation of endangered wildlife, included an agreement from developers to pay a "lizard surcharge" for each acre that is developed, with funds going to support the preserve. The agreement set aside 13,000 acres (5,200 hectares) as the Coachella Valley Preserve, with a goal of maintaining about 10% of the valley's area in its natural state. The preserve is designed to keep an open corridor for the windblown dunes, which will allow the habitat to replenish itself with new sand washing down from the mountains. As the human population in the valley grows, the preserve becomes increasingly important in protecting an array of desert ecosystems. Within the portion of the preserve owned by the U.S. Fish and Wildlife Service (FWS) are sand dune ecosystems that receive their sediment from the Little San Bernardino Mountains. These natural and increasingly rare dune areas on the refuge are some of the last homes for Coachella Valley fringe-toed lizards, which rely on the presence of windblown sand for survival. Tiny projections on the lizard's toes allow it to run easily over the sand and into the loose surfacet to evade predators. The perpetuation of this highly specialized species depends upon the continuing renewal of windblown sand from the surrounding hills to create and maintain sand dunes. In the early 1990s, the FWS began an experimental program to restore dune ecosystems. Vineyards and other agricultural lands purchased for the refuge are being rehabilitated so that they can revert back to natural desert habitat. Refuge staff have also begun creating artificial dunes in some of this reclaimed area in hopes of trapping windblown sand for the fringetoed lizards. By early 1996, five dunes had been created by using earth moving equipment to push existing sediment. The dunes are oriented so that free-moving sand (known as blow sand) from the mountains will hit the long edge of the dune to catch moving sediments. After all the vineyards are removed, more artificial dunes will be constructed. Non-native trees (such as salt cedar and eucalyptus) in the reclaimed area then will be removed to allow blow sand to accumulate on the dunes rather than near the trees. Removal of exotic trees also is essential to eliminate potential perch sites for raptors that would feed on lizards in the area. Though they had no model for this unique construction project, the recovery team hope that the newly created dunes will eventually become the specialized habitat needed by the Coachella Valley fringe-toed lizard.
U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
Eastside Federal Complex
911 N. E. 11th Ave.
Portland, Oregon 97232-4181
Telephone: (503) 231-6121
Adest, G. A. 1977. "Genetic Relationships in the Genus Uma (Iguanidae)." Copeia 1977: 47-52.
Mayhew, W. W. 1964. "Taxonomic Status of California Populations of the Lizard Genus Uma. " Herpetologica 20: 170-183.
U.S. Fish and Wildlife Service. 1984. "Coachella Valley Fringe-Toed Lizard Recovery Plan." U.S. Fish and Wildlife Service, Portland.