ISH 



Rt'pnlis iiiul Aniphibuins — Otir Liviiii^ Rt's(mrci'S 



Fig. 2. The known population size 

 of a Coacheila Valley fnnge-loed 

 lizard population on a 2.25-ha 

 (5.56-aere) study plot on the 

 Whitewater River preserve. 



For further information: 



Cameron Barrows 



The Nature Conservaney 



53277 Avenida Diaz 



La Quinta, CA 92253 



S 250 



= 200 



86 



90 



92 



Year 



site: the other two piotected sites have much 

 deeper sand deposits and are less susceptible to 

 wind erosion. New windblown sand was 

 deposited on the Whitewater River site in 1993 

 after a period of high rainfalf The population 

 appears to be increasing in response to these 

 favorable conditions. 



The decline in fringe-toed lizards during the 

 monitoring period appears to be the result of 

 responses to natural fluctuations in habitat. The 

 dynamic nature of sand dune systems, coupled 

 with the lizards" apparent sensitivity to drought, 

 underlines the importance of preserve design. 

 Appropriate designs anticipate the effect of nat- 

 ural habitat fluctuation. 



The ecological model that governed the 

 design of the Coacheila Valley Preserve system 

 was reevaluated in 1993 with one disturbing 

 result. A primary sand source was identified that 

 supplies the sand dunes at the Thousand Palms 

 site, but was not emphasized sufficiently in the 

 original model and design. Fortunately, the sand 

 source and its path to the existing preserve have 

 not been affected severely by human develop- 

 ment at this time, so options for correcting the 

 design's shortcomings are still available. The 

 fringe-toed lizard population sustained by this 

 sand source has been the largest of the three 

 sites for the past few years. Monitoring the 

 lizards without investigating ecosystem 

 processes would not have identified the design 

 error until it was too late to correct. 



Disappearance 

 of the 



Tarahumara 

 Frog 



by 

 S.F. Hale 



Herpelologist 



C.R. Schwalbe 



National Biological Senice 



J.L. Jarchow 



Soiiora Pel Hospital, 



Tucson, AZ 



C.J. May 



Pima Community College 



C.H. Lowe 



University of Arizona 



T.B. Johnson 



Arizona Game and Fish 



Department 



In the spring of 1983 the last known 

 Tarahumara frog in the United States was 

 found dead. Overall, the species seems to be 

 doing well in Mexico, although the decline of 

 more northern populations are of concern. The 

 Tarahumara frog {Rami tarahuinanw) inhabits 

 seasonal and permanent bedrock and bouldery 

 streams in the foothills and main mountain mass 

 of the Sierra Madre Occidental of northwestern 

 Mexico. It ranges from northern Sinaloa, 

 through western Chihuahua and eastern and 

 northern Sonora. and until recently into extreme 

 south-central Arizona (Fig. 1). Arizona locali- 

 ties, all in Santa Cruz County, include three 

 drainages in the Atascosa-Pajarito Mountains 

 (Campliell 1931: Little 1940: Williams 1960) 

 and three in the Santa Rita Mountains (Hale et 

 al. 1977). 



Population Estimates, 1975-93 



We have drawn our review from museum 

 records, the published literature, and reports, 

 journal entries, and personal observations by 

 the authors, other biologists, and knowledge- 

 able persons. From May 1975 through June 

 1977, we conducted an ecological, demograph- 

 ic, and life-history study of the population at 

 Big Casa Blanca Canyon (Santa Rita 

 Mountains). 



Between 1980 and 1993, we visited 22 of 30 

 historical Tarahumara frog localities. We sur- 



veyed 43 additional streams with potential habi- 

 tat and found Tarahumara frogs at 25 new local- 

 ities in Mexico. Localities were extensively 

 searched, often both day and night, sometimes 

 repeatedly. Frogs and tadpoles were counted, 

 size-classed, and sexed when possible. Time, 

 streamwater pH, air, substrate and water tem- 

 peratures, habitat description and condition, and 

 relative abundances of other aquatic vertebrates 

 were noted. 



During the summers of 1982-83. rain sam- 

 ples were collected at The Nature 

 Conservancy's Sonoita Creek and Canelo Hills 

 preserves for pH determination and heavy metal 

 analysis. Both sites are within 22-56 km (14-35 

 mi) of declining frog populations and 64-129 

 km (40-80 mi) north and northwest of copper 

 smelters. Streamwater samples from sites of 

 declining populations in Sycamore and Big 

 Casa Blanca canyons in Arizona and Carabinas 

 Canyon in northeastern Sonora were also col- 

 lected for pH and heavy metal analyses. 



Decline of Populations 



In April 1974, 27 dead and dying 

 Tarahumara and leopard frogs were observed at 

 Sycamore Canyon, Atascosa-Pajarito 

 Mountains, the best-known and most frequently 

 visited Tarahumara frog population. The last 

 sightings of Tarahumara frogs in that range 

 were in the summer of 1974. 



