Urosaurus auriculatus 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Reptilia Squamata Phrynosomatidae

Scientific Name: Urosaurus auriculatus (Cope, 1871)

Assessment Information [top]

Red List Category & Criteria: Endangered B1ab(ii) ver 3.1
Year Published: 2007
Date Assessed: 2007-03-01
Assessor(s): Ponce-Campos, P. & García Aguayo, A.
Reviewer(s): Cox, N., Chanson, J.S. & Stuart, S.N. (Global Reptile Assessment Coordinating Team)
Listed as Endangered because its extent of occurrence is less than 5,000 km², all individuals are in fewer than five locations, and there is continuing decline in the extent and quality of its habitat.

Geographic Range [top]

Range Description:This species is endemic to the Pacific island of Isla Socorro (132 km²), in the Archipielago Revillagigedo of Colima State, Mexico. The species is generally distributed throughout Socorro, being absent from areas of erosion that have resulted from overgrazing by sheep (Arnaud et al. 1993). Animals range from sea level to the top of the Everman volcano at around 1,040 m asl (Arnaud et al. 1993).
Countries occurrence:
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Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:It was reported by Slevin (1926) and Brattstrom (1955) to be a common, but not abundant species. It is less abundant in areas with very dense vegetation and few open areas (Brattstrom 1955). Arnaud et al. (1993), reported that the species was found at high densities in the remnants of natural ecosystems of the island, but was absent in deforested areas.
Current Population Trend:Decreasing
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Habitat and Ecology [top]

Habitat and Ecology:The species is found in many vegetation types, including dry forest and scrubland, throughout the island (Brattstrom, 1955; Arnaud et al. 1993). Animals were recorded by Brattstrom (1955) 'in cracks in rocks, under debris on sandy beaches, in piles of lava boulders, under rocks on the ground, and, higher in the island, crawling about in trees'. It is presumably an oviparous species.

Threats [top]

Major Threat(s): Suitable habitat for this species is rapidly disappearing. The effects of feral sheep on Socorro have been severe, causing erosion damage, shifts in abundance of plant species and impaired forest regeneration (Ortega et al. 1992; Arnaud et al. 1993). Over 30% of the natural vegetation and soil have been destroyed through overgrazing by the sheep (Ortega et al. 1992, Arnaud et al. 1993). Arnaud et al. (1993) reports that lizards are absent from the areas of erosion. Feral cats are a significant predator of lizards, with the occurrence of lizard in scats varying from 33.3% in February to 66.7% in November (Arnaud et al. 1993). It is anticipated that the impact of predation by cats on the lizard will increase directly as the cat population grows (Arnaud et al. 1993). A species of house gecko (Hemidactylus frenatus) has recently established a population on the buildings of the island Navy Garrison (Galina-Tessaro, et al. 1999). Further studies are needed into the impact of this introduction on Urosaurus auriculatus.

Conservation Actions [top]

Conservation Actions: The Revillagigedo Islands were declared a biosphere reserve in 1994 (Rodríguez-Estrella et al. 1996). There is an ongoing eradication programme in the region, and there are plans to eradicate cats and sheep from Socorro (BirdLife International 2007). There is a need to implement a vegetation and soil restoration plan after sheep have been removed (Martínez-Gómez et al. 2001). Establish a research monitoring station on Socorro (Rodríguez-Estrella et al. 1996). Monitor the population, especially before and after the proposed eradication process (BirdLife 2007). Additional studies are needed into the impact of the introduced gecko Hemidactylus frenatus (Galina-Tessaro et al. 1999) on populations of U. auriculatus.

Citation: Ponce-Campos, P. & García Aguayo, A. 2007. Urosaurus auriculatus. The IUCN Red List of Threatened Species 2007: e.T64167A12750339. . Downloaded on 23 April 2018.
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