ESR 17:193-200 (2012)  -  DOI: https://doi.org/10.3354/esr00424

Using non-conspicuous metrics to examine selected impacts of disturbance on a long-lived reptile

Charles R. Knapp1,3,*, Caro Perez-Heydrich2

1San Diego Zoo Institute for Conservation Research, 15600 San Pasqual Valley Road, Escondido, California 92027, USA
2Carolina Population Center, University of North Carolina at Chapel Hill, CB 8120, University Square, 123 West Franklin Street, Chapel Hill, North Carolina 27516, USA
3Present address: Daniel P. Haerther Center for Conservation and Research, John G. Shedd Aquarium, 1200 South Lake Shore Drive, Chicago, Illinois 60605, USA

ABSTRACT: Loss or disturbance of habitat often results in landscapes being fragmented into a series of isolated remnants varying in size, quality, and conservation value. Habitat disturbance has deleterious consequences for ecosystem processes, but can have varying effects on species persistence. Many deleterious effects on species post-disturbance are obvious, yet some are more subtle and can elude detection in long-lived species. We used more subtle metrics to evaluate populations of endangered iguanas Iguana delicatissima inhabiting disturbed (i.e. low- to moderate-density villages and towns) and non-disturbed areas on the island of Dominica, West Indies. We investigated differences in iguana sex ratios, asymptotic size, characteristic growth rate, body condition, abundance, and densities between our defined disturbed and non-disturbed habitats. Contrary to expectations, there were no statistical effects of disturbed areas on density, sex ratio, body condition, or characteristic growth rates, yet there was a slight positive effect on asymptotic body size for iguanas on Dominica. Despite these results, I. delicatissima is still affected adversely by manifold threats, as evidenced by the continued precipitous declines and local extirpations of the species across its range. Our results do, however, suggest that if factors such as degraded nest sites and killing by non-native mammalian predators are mitigated, then moderately disturbed, human-occupied areas can be managed as corridors or buffer zones for I. delicatissima in an increasingly fragmented landscape.


KEY WORDS: Caribbean · Conservation · Dominica · Buffer · Fragmentation · Body size · Iguana delicatissima


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Cite this article as: Knapp CR, Perez-Heydrich C (2012) Using non-conspicuous metrics to examine selected impacts of disturbance on a long-lived reptile. Endang Species Res 17:193-200. https://doi.org/10.3354/esr00424

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