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The lizard fauna of Guam's fringing islets: Island biogeography, phylogenetic history, and conservation implications

Global Ecology and Biogeography Letters

By:
, , , and
DOI: 10.1046/j.1466-822X.1998.00307.x

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Abstract

We sampled the lizard fauna of twenty-two small islets fringing the Pacific island of Guam and used these data to shed light on the processes responsible for present-day diversity. Habitat diversity, measured by islet area and vegetation complexity, was significantly correlated with the number of species found on an islet. However, islet distance and elevation were not significant predictors of diversity. Distribution patterns were slightly different for the two major families in our sample, Scincidae and Gekkonidae: skinks needed larger islets to maintain a population than did geckos. Presence/absence patterns were highly and significantly nested, and population density was correlated with the number of islets on which a species was found. An area cladogram was poorly supported and showed no faunal similarity between nearby islands. These patterns indicate that extinctions on most islets were due mostly to non-catastrophic, long-acting biological causes. The presence on the islets of species extirpated on Guam and the lack of significant nestedness on islands with greater maximum elevation highlight the impact that predators (primarily brown treesnakes) can have. Our findings also show that small reserves will not suffice to protect endangered lizard faunas, and that the islets may serve as a short-term repository of such species until snake-free areas can be established on Guam.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
The lizard fauna of Guam's fringing islets: Island biogeography, phylogenetic history, and conservation implications
Series title:
Global Ecology and Biogeography Letters
DOI:
10.1046/j.1466-822X.1998.00307.x
Volume
7
Issue:
5
Year Published:
1998
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Global Ecology and Biogeography Letters
First page:
353
Last page:
365
Number of Pages:
13