Establishment of Anolis sagrei on Bermuda represents a novel ecological threat to Critically Endangered Bermuda skinks (Plestiodon longirostris)
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Bermuda is an isolated, oceanic island with only one endemic terrestrial vertebrate, the Critically Endangered Bermuda skink (Plestiodon longirostris; Squamata, Scincidae). Major declines in P. longirostris populations have been caused primarily by habitat loss and mortality via invasive species (e.g., predation from birds and cats) and human waste products (e.g., trapped in discarded bottles). However, biotic interactions and interspecific competition with invasive lizards have also been identified as potentially detrimental to P. longisrostris populations. Here, we provide the first occurrence records of a highly invasive lizard, the Cuban brown anole (Anolis sagrei), on Bermuda. We assess the brown anole’s diet, habitat use, morphology, and island-wide distribution for comparison to the native skink, P. longirostris. Results of this study indicate that A. sagrei in Bermuda are highly terrestrial (>60% of all lizards observed on the ground vs. in trees) and forage primarily on terrestrial invertebrates. These data indicate substantial ecological overlap with the exclusively-terrestrial P. longirostris. This is in contrast to the other established non-native lizards on Bermuda, which are principally arboreal and have successfully coexisted with P. longirostris for >60 years. At present, the geographic distributions of A. sagrei and P. longirostris do not overlap. However, all extant skink populations are within several kilometers of brown anole populations (with the nearest being <0.5 km). The extensive overlap in ecological niche between the Bermuda skink and the invasive brown anole will likely present a serious conservation threat if contact is made. This study is exceptional in providing clear in situ ecological data which predict a conservation threat of an established invasive species to a Critically Endangered island endemic prior to coexistence. Continued monitoring of this situation as P. longirostris and A. sagrei inevitably come into contact will allow these a priori hypotheses of conservation risk via ecological overlap to be tested.
KeywordsAnolis Invasive species Oceanic island Endemic Endangered Competition Niche
This is contribution #246, Bermuda Biodiversity Project (BBP), Bermuda Aquarium, Natural History Museum and Zoo, Department of Environment and Natural Resources. We thank the Bermuda Zoological Society (Eric Clee Fund) for financial research support, as well as to Thad and Evan Outerbridge for providing accommodation. We thank Kenneth Feeley, Evan Rehm, Rachel Hillyer, Catherine Bravo-Avila, Jason Kolbe, Joe Macedonia, and one anonymous reviewer for providing important and insightful comments on previous versions of this manuscript. JS was supported by the FIU Judith Evans Parker Travel Fund and an FIU Dissertation Evidence Acquisition Fellowship. STG was supported by NSF DEB #1406399.
- Edgar P, Kitson L, Glasspool AF, Sarkis S (2010) Recovery plan for the Bermuda skink, Eumeces longirostris. Department of Conservation Services, Government of Bermuda, CrawlGoogle Scholar
- IUCN (2015) The IUCN red list of threatened species. Version 2015-4. http://www.iucnredlist.org. Downloaded on 17 Mar 2016
- Norval G, Hsiao WF, Huang SC, Chen CK (2010) The diet of an introduced lizard species, the brown anole (Anolis sagrei), in Chiayi County, Taiwan. Russ J Herpetol 17(2):131–138Google Scholar
- Powell R, Henderson RW, Farmer MC, Breuil M, Echternacht AC, van Buurt G, Romagosa CM, Perry G (2011) Introduced amphibians and reptiles in the greater Caribbean: patterns and conservation implications. In: Hailey A, Wilson BS, Horrocks JA (eds) Conservation of Caribbean Island Herpetofaunas. Volume 1: conservation biology and the wider Caribbean. Brill, Leiden, pp 63–143CrossRefGoogle Scholar
- Raine A (1998) A study of the morphological differentiation, fluctuating asymmetry and the threats facing isolated populations of the Critically Endangered Bermuda Rock Lizard (Eumeces longirostris). Dissertation, University College London, England, UKGoogle Scholar
- Simberloff D (1995) Why do introduced species appear to devastate islands more than mainland areas? Pac Sci 49(1):87–97Google Scholar
- Sodhi NS, Brook BW, Bradshaw CJ (2009) Causes and consequences of species extinctions. In: Levin SA (ed) Princeton guide to ecology. Princeton University Press, Princeton, pp 514–520Google Scholar
- Stroud JT, Outerbridge ME, Giery ST (2016) First specimen of an American green anole (Anolis carolinensis) on the oceanic island of Bermuda, with a review of the species' current global distribution. IRCF Reptiles Amphib 23(3):188–190Google Scholar
- Verill AE (1902) The Bermuda Islands: their scenery, climate, productions, physiography, natural history and geology: with sketches of their early history and the changes due to man, vol 11. Connecticut Academy of Arts and Sciences, New HavenGoogle Scholar
- Wingate DB (1965) Terrestrial herpetofauna of Bermuda. Herpetologica 21:202–218Google Scholar
- Wingate R (1998) A comparison of demography and morphological variation in two insular populations of the Bermuda rock lizard (Eumeces longirostris). Dissertation, University of Swansea, Wales, UKGoogle Scholar