Predation of Jamaican rock iguana (Cyclura collei) nests by the invasive small Asian mongoose (Herpestes auropunctatus) and the conservation value of predator control

摘要

The introduced small Asian mongoose (Herpestes auropunctatus) has been widely implicated in extirpations and extinctions of island taxa. Recent studies and anecdotal observations suggest that the nests of terrestrial island species are particularly vulnerable to mongoose predation, yet quantitative data have remained scarce, even for species long assumed to be at risk from the mongoose. We monitored nests of the Critically Endangered Jamaican Rock Iguana (Cyclura collei) to determine nest fate, and augmented these observations with motion-activated camera trap images to document the predatory behaviour of the mongoose. Our data provide direct, quantitative evidence of high nest predation pressure attributable to the mongoose, and together with reported high rates of predation on hatchling and juvenile iguanas (also by the mongoose), support the original conclusion that the mongoose was responsible for the apparent lack of recruitment and the aging structure of the small population that was 're-discovered' in 1990. Encouragingly however, our data also demonstrate a significant reduction in nest predation pressure within an experimental mongoose-removal area. Thus, our results indicate that otherwise catastrophic levels of nest loss (at or near 100%) can be ameliorated or even eliminated by removal trapping of the mongoose. We suggest that such targeted control efforts could also prove useful in safeguarding other threatened insular species with reproductive strategies that are notably vulnerable to mongoose predation (e.g., the incubation of eggs on or underground).