Oi(r Liviiifi Resources — Reptiles anil Amphibians 



I.U 



Jacohson. E.R. 199.V Implications of infectious diseases for 

 captive propagation and introduction progratiis of threat- 

 ened/endangered reptiles. Journal of Zoo and Wildlite 

 Medicine 24(3):245-255. 



Lamb. T., J. Avise, and J.W. Gibbons. 1984. Phylogeo- 

 graphic patterns in mitochondrial DNA of the desert tor- 

 toise {Xerohcites iigassizi) and evolutionary relationships 



among the North American gopher tortoises. Evolution 

 43(11:76-87. 

 USFWS. 1994. Desert Tortoise (Mojave Population) 

 Recovery Plan. U.S. Fish and Wildlife Service. Portland. 

 OR. 77 pp. + appendices. 



For further information: 



Kristin H. Berry 



National Biological Service 



Riverside Field Station 



6221 Bo.x Springs Blvd. 



Riverside. CA 92507 



Fringe-toed lizards (Unia spp.l inhabit many 

 of the scattered windblown sand deposits of 

 southeastern California, southwestern Arizona, 

 and northwestern Mexico. These lizards have 

 several specialized adaptations: elongated 

 scales on their hind feet ("fringes") for added 

 traction in loose sand, a shovel-shaped head and 

 a lower jaw adapted to aid diving into and mov- 

 ing short distances beneath the sand, elongated 

 scales covering their ears to keep sand out, and 

 unique morphology (form or structure) of inter- 

 nal nostrils that allows them to breathe below 

 the sand without inhaling sand particles. 



While these adaptations enable fringe-toed 

 lizards to successfully occupy sand dune habi- 

 tats, the same characteristics have restricted 

 them to isolated sand "islands." Three fringe- 

 toed lizard species live in the United States: the 

 Mojave {U. scopaiiu). the Colorado Desert (U. 

 nokitii), and the Coachella Valley {U. inonniki}- 

 Of the three, the Coachella Valley fringe-toed 

 lizard has the most restricted range and has been 

 most affected by human activities. In 1980 this 

 lizard was listed as a threatened species by the 

 federal government. 



In 1986 the Coachella Valley Preserve sys- 

 tem was established to protect habitat for the 

 Coachella Valley fringe-toed lizard. This action 

 set several precedents: it was the first Habitat 

 Conservation Plan established under the 

 revised (1982) Endangered Species Act and the 

 newly adopted Section 10 of the act, it estab- 

 lished perhaps the only protected area in the 

 world set aside for a lizard, and its design was 

 based on a model of sand dune ecosystem 

 processes, the sole habitat for this lizard. Three 

 disjunct sites in California, each with a discrete 

 source of windblown sand, were set aside to 

 protect fringe-toed lizard populations: 

 Thousand Palms, Willow Hole, and Whitewater 

 River. Collectively, the preserves protect about 

 2% of the lizards' original range. 



Eight years after the establishment of the 

 preserve system, few Coachella Valley fringe- 

 toed lizards exist outside the boundaries of the 

 three protected sites. Barrows (author, unpub- 

 lished data) recently identified scattered pockets 

 of windblown sand occupied by fringe-toed 

 lizards in the hills along the northern fringe of 

 the valley, but only at low densities. Fringe-toed 

 lizard populations within the protected sites 

 have been monitored yearly since 1986. During 



this period, California experienced one of its 

 most severe droughts, which ended in spring 

 1991. Numbers of fringe-toed lizards within the 

 Thousand Palms and Willow Hole sites 

 declined during the drought, but rebounded 

 after 1991 (Fig. 1). By 1993. after three wet 

 springs, lizard numbers had increased substan- 

 fially, 



Lizards at the Whitewater River site were 

 intensively monitored since 1985 by using 

 mark-recapture methods to count the population 

 on a 2.25-ha (5.56-acre) plot. In 1986 this site 



^ 

 85 



93 



Year 



had the highest population density of the three 

 protected sites. As with the other two sites, the 

 Whitewater River population declined through- 

 out the drought, but only increased slightly after 

 the drought broke in 1991 (Fig. 2). 

 Compounding the drought effect, much of the 

 fine sand preferred by fringe-toed lizards was 

 blown off the site during the dry years. This 

 condition was unique to the Whitewater River 



Coachella 

 Valley Fringe- 

 toed Lizards 



by 



Cameron Barrows 



The Nature Conservancy 



Allan Muth 



Mark Fisher 



University of California, Boyd 



Deep Canyon Desert 



Research Center 



Jeffrey Lovich 

 National Biological Service 



Fig. 1. The mean number of 

 lizards per transect at the 

 Thousand Palms and Willow Hole 

 sites, 1986-93. Data were pooled 

 from five 10 x 1.000 ni( 32.8 x 

 3.281 ft) transects. All transects 

 were sampled six times each year, 

 and all sampling was conducted 

 within a 6-week span in the late 

 spring of each year. 



Coachella Valley fringe-toed lizard 

 ( Uma inornata). 



