Assessing threats and conservation action using population viability analysis for the Critically Endangered Grenada Dove Leptotila wellsi

Accurate estimation of extinction risk is crucial to preventing further declines of wild populations and identifying appropriate management actions. The Critically Endangered Grenada Dove Leptotila wellsi (approx. 136–182 mature individuals) is at risk from habitat loss, invasive species and disease along with the threat of further population reductions due to hurricane activity. The 2008 Species Recovery Plan for the Grenada Dove recommends establishing a new population, predator control, a captive breeding programme, and management strategies to safeguard this species. This study used original data, along with published long-term population count data, and data from closely related species to conduct a population viability analysis (PVA) for the two extant populations of Grenada Dove to quantify extinction risk and compare the relative impacts of proposed management actions. Probability of extinction of the Grenada Dove in the West population (PE: 100 %) had a mean time to extinction of 19.2 years which was substantially sooner than the probability of extinction in the Southwest (PE: 91.3 %) which has a mean time of extinction of 50 years. Extinction probability was increased under scenarios simulating tourist developments, increased disease transmission and unbalanced sex-ratios. Loss of forest habitat to commercial development is likely to have a big impact on extant Grenada Dove populations and of the potential management approaches, population supplementation is likely be the most effective conservation strategy. This PVA demonstrates the potential to reduce extinction risk for Grenada Dove and highlights the importance of demographic and genetic monitoring which is urgently needed for conserving this Critically Endangered species.