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Alsophis rijgersmaei 

Scope: Global
Language: English
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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Reptilia Squamata Dipsadidae

Scientific Name: Alsophis rijgersmaei
Species Authority: Cope, 1869
Common Name(s):
English Anguilla Racer, Leeward Island Racer
Synonym(s):
Alsophis rijersmai Cope, 1869 [orth. error]

Assessment Information [top]

Red List Category & Criteria: Endangered B1ab(iii) ver 3.1
Year Published: 2016
Date Assessed: 2015-07-20
Assessor(s): Daltry, J.C.
Reviewer(s): Bowles, P.
Contributor(s): Hedges, B. & Hanson, S.
Facilitator/Compiler(s): NatureServe
Justification:
Listed as Endangered on the basis that this species has an extent of occurrence little over 1,000 km2 and is known to survive on only five islands, each of which is considered a single location based on widespread threats from development, including the likely eradication of the population from Scrub Island following planned development. The population on St. Barts is however presently viable and probably subject to at most localized threats, and while threats to Anguilla are severe it is not yet clear how severe declines have been.
Previously published Red List assessments:

Geographic Range [top]

Range Description:This species occurs on several islands of the Lesser Antilles (Henderson and Powell 2009). The species is extant on Anguilla, Scrub Island and St. Barthélemy, as well as La Tortue (Questel 2011). It may have been lost from Sint Maarten/St. Martin, from where it was last reported in 1996; the last confirmed collection was in 1991 (Breuil 2002). It was reported from Le Fourche and l'Ille Bonhomme in the 1980s; no recent sightings exist, but it is possible that it survives on these two islands (Questel 2012).
Countries occurrence:
Native:
Anguilla; Saint Barthélemy
Possibly extinct:
Saint Martin (French part); Sint Maarten (Dutch part)
Additional data:
Number of Locations:5
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:The frequency with which this species has been recorded has been dropping rapidly on Anguilla (J. Daltry, unpubl. data) in tandem with increased levels of development and an associated increase in rat and cat numbers. In 2014 the Anguilla National Trust interviewed 100 randomly-selected residents, 70% of whom indicated that they considered this species had declined over the past 15 years (taken to represent three generations) (J. Daltry pers. comm. 2016). A survey by J. Daltry, R. Williams and D. Lay in August 2015 found racers on Anguilla to be highly localized, and animals recorded were underweight (unpubl. data). The most recent confirmed record from St. Martin/Sint Maarten was taken in 1991 (a report that it was recorded in 1996 is not supported by a citation and may be a typo); prior to this it had not been recorded from the island since the 1950s. The species has probably been in decline since the introduction of mongoose, and may now have been lost from the island. Populations on the smaller islands appear stable, and the species is widespread on St. Barts, however it is probably under pressure (Questel 2012). Only the St. Barts population may be viable, as the two small French islands might be too small to retain a viable population and the one on Anguilla is sufficient cause for conservation concern that captive breeding is underway. The species might consequently qualify as a severely fragmented population; as it may not survive as a viable subpopulation on St. Maarten, it is considered to occur at, at most, five locations.
Current Population Trend:Decreasing
Additional data:

Habitat and Ecology [top]

Habitat and Ecology:This species occurs in xeric and mesic habitats, found in open areas, thorn forest and residential gardens, always associated with rocks. It can be found in dry stone walls. It feeds on lizards and frogs (Henderson and Powell 2009). Little published information exists about its reproduction, but Questel (2012) reports two observations of gravid females containing four eggs, and one dead specimen containing a single egg.
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 or trade in this species.

Threats [top]

Major Threat(s): The introduction of mongooses to Sint Maarten/St Martin resulted in only a tiny remnant population remaining there, and this may now be extinct. Feral and pet cats on both Anguilla and St Bathelemy are believed to be significant predators; mongoose are presently absent from these islands, but there is always a risk that the species will become established due to heavy traffic between these islands and Sint. Maarten/St. Martin. Habitat loss, degradation and fragmentation is still occurring in all three islands due to development; this has been particularly extensive in Anguilla in recent years, in particular with the loss of dry stone walls on which the snakes rely. Despite widespread recognition among residents that snake numbers have declined on Anguilla, 80% of residents interviewed by the Anguilla National Trust in 2014 said they would kill the animals on sight (J. Daltry pers. comm. 2016), suggesting that persecution is likely to be a problem on this island. On St. Barts, the species has been reported to suffer direct mortality from the use of pesticides in gardens and from human persecution, as it frequently occurs in residential areas (Questel 2012), Scrub Island has been sold to developers.

Conservation Actions [top]

Conservation Actions: Traffic between Sint Maarten/St. Martin and the other islands is high, and monitoring is needed to ensure that mongoose from this (or other) islands do not become established on the islands where the Anguilla racer survives (Questel 2012). This author also proposes the feasibility of rat eradication from the satellite islands (La Tortue and Scrub Island) be investigated, that protected areas be established to limit the impacts of development, and that on St. Barts specifically an education campaign is undertaken to raise awareness that this snake is not venomous in an effort to reduce persecution. In 2015 a breeding colony was established at Durrell Wildlife Park in Jersey, and presently appears to be doing well (J. Daltry pers. comm. 2016).

Citation: Daltry, J.C. 2016. Alsophis rijgersmaei. The IUCN Red List of Threatened Species 2016: e.T941A71739256. . Downloaded on 08 December 2016.
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