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Ameiva polops 

Scope: Global
Language: English
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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Reptilia Squamata Teiidae

Scientific Name: Ameiva polops
Species Authority: Cope, 1862
Common Name(s):
English St. Croix Ameiva, Saint Croix Ground Lizard, St. Croix Ground Lizard
Taxonomic Source(s): Harvey, M.B., Ugueto, G.N. and Gutberlet Jr., R.L. 2012. Review of Teiid morphology with a revised taxonomy and phylogeny of the Teiidae (Lepidosauria: Squamata). Zootaxa 3459: 1-156.

Assessment Information [top]

Red List Category & Criteria: Endangered B2ab(iii) ver 3.1
Year Published: 2016
Date Assessed: 2015-07-23
Assessor(s): Platenberg, R.
Reviewer(s): Bowles, P.
Contributor(s): Hedges, B. & Hanson, S.
Facilitator/Compiler(s): NatureServe
Justification:
This species is listed as Endangered due to its small area of occupancy (16 km2), occurrence in four locations, and an ongoing decline in the extent and quality of its habitat to various natural and anthropogenic processes on three of the four islands where it occurs. Population estimates suggest that fewer than 1,000 mature individuals remain globally; past population estimates have varied by up to an order of magnitude, and while it is not clear whether this reflects the true magnitude of population fluctuations there may be extreme fluctuations in its population numbers. The persistence of this species is entirely dependent on the continuation of conservation efforts, especially the eradication and continued exclusion of introduced mammals, and habitat protection.
Previously published Red List assessments:

Geographic Range [top]

Range Description:This lizard currently occurs naturally on Protestant Cay and Green Cay near St. Croix in the U.S. Virgin Islands. The species has been extirpated from St. Croix and introduced on Buck Island (in 2008) and Ruth Cay (in 1990) (Henderson and Powell 2009, Hurtado et al. 2014). The elevation range is sea level to approximately 50 m.
Countries occurrence:
Native:
Virgin Islands, U.S.
Additional data:
Estimated area of occupancy (AOO) - km2:16Continuing decline in area of occupancy (AOO):No
Estimated extent of occurrence (EOO) - km2:
Number of Locations:4
Upper elevation limit (metres):50
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Several estimates have been made of population sizes on the small cays over the past several years. The total population size of the species is estimated at less than 1,000 individuals (Henderson and Powell 2009, J. Valiulis unpubl. data 2011). The population fluctuates due to management actions and vegetation response to precipitation events (rains cause the open sun spots favored by the lizards to be covered by vegetation); historical population estimates have ranged from around 20 to several hundred (R. Platenberg pers. comm. 2016, J. Valiulis unpubl. data) but it it is not clear whether this accurately reflects the genuine magnitude of population fluctuation. The species' population is increasing on Buck Island due to the conservation introduction and management of this island, which is a US National Monument (Fitzgerald et al. 2015); conversely reductions in habitat quality elsewhere (R. Platenberg pers. comm. 2016) may result in declines.
Current Population Trend:Unknown
Additional data:
Extreme fluctuations:Unknown

Habitat and Ecology [top]

Habitat and Ecology:This species occurs in xeric environments such as dry forest, open woodland, coastal scrub, and beaches that are dominated by Coccoloba uvifera. It is associated with leaf litter and artificial debris. Individuals forage on invertebrates associated with beach wrack. They seek refuge in crab burrows and under logs during the night and the hot part of the day. The species is somewhat adaptable judging by their persistence in a resort area on Protestant Cay (R. Platenberg pers. comm. 2015). It is an egg laying species (Henderson and Powell 2009).
Systems:Terrestrial
Continuing decline in area, extent and/or quality of habitat:Yes

Use and Trade [top]

Use and Trade: There is no known use of or trade in this species.

Threats [top]

Major Threat(s): Mongoose (Herpestes auropunctatus) and rats (Rattus rattus) represent a major threat (Henderson and Powell 2009); the former are not present on any island within its range but there is a risk that they may be introduced, which would likely result in the immediate loss of this species from invaded islands (R. Platenberg pers. comm. 2016). Rats are periodically eradicated and reintroduced to these islands (R. Platenberg pers. comm. 2016). The subpopulations on Protestant Cay, Green Cay, and Ruth Island are extremely small in size, and vulnerable to hurricanes, sea level rise, introduction of exotic species and landscape transformation (Hurtado et al. 2014). The latter is the result of both natural succession (on Green and Ruth Cays), with open shrubby areas invaded by grass and dense shrubland that offer fewer opportunities for basking, and artificial landscaping. Protestant Cay is entirely converted for a hotel and its grounds (McNair and Coles 2013), and current landscaping practices involve the removal of leaf litter and other shelter sites (R. Platenberg pers. comm. 2016). This exposes the lizards, which avoid the resulting open areas, to predatory birds. Although one major roosting site for cattle egrets has been removed as a conservation measure to help the lizards, land clearance nevertheless reduces the availability of suitable habitat for the lizard (R. Platenberg pers. comm. 2016).

Conservation Actions [top]

Conservation Actions: This species is entirely dependent on conservation efforts by the U.S. Fish and Wildlife Service, the U.S. Park Service, and the U.S. Virgin Islands government. It is listed Endangered under the U.S. Endangered Species Act. There is a species recovery plan for this species. Conservation actions include rat eradication and monitoring, population monitoring of the lizards, habitat management (Green Cay), and conservation introductions (Ruth and Buck Islands). The species occurs in Green Cay National Wildlife Refuge and Buck Island National Monument.

Citation: Platenberg, R. 2016. Ameiva polops. The IUCN Red List of Threatened Species 2016: e.T1118A71739354. . Downloaded on 07 December 2016.
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