Habitat use and ecological interactions of an introduced and a native species of Anolis lizard on Grand Cayman, with a review of the outcomes of anole introductions.

Since its introduction ten years ago, Anolis sagrei has spread over much of Grand Cayman and is now more common in some habitats than the native anole, A. conspersus. Interspecific differences in body size, perch height, and microclimatic preference may have facilitated the colonization. Nonetheless, competition may be occurring between the species; comparisons with studies of habitat use prior to the arrival of A. sagrei indicate that in open habitats, where A. sagrei is now abundant, A. conspersus perches higher, but in closed habitats, where A. sagrei is absent, no change in perch height is evident. Review of data concerning 23 Anolis introductions indicates that the presence or absence of an ecologically similar native species may be an important determinant of colonization success or failure.