PUPPING HABITAT USE IN THE MEDITERRANEAN MONK SEAL: A LONG-TERM STUDY

摘要

The Mediterranean monk seal gives birth almost exclusively in coastal caves. Given its critical conservation status, the identification and protection of such sites is important for the survival of the species. From 1990 to 2004 we collected data on physical and environmental variables and monitored pupping events in thirty-four coastal caves in Greece. We modeled the probability of cave occupancy as a function of the properties of each cave. Model selection and model averaging enabled us to rank thevariables that influenced use of potential pupping sites. Environmental variables related to cave seclusion, substrate, and degree of protection from wind and wave action were the most important among them. The relative importance and directions of these relationships confirm the long-standing assumption that Mediterranean monk seals require sheltered pupping sites, far from sources of human disturbance and thus are progressively limited to isolated parts of the country's coastline. We used cross-validation to examine the predictive ability of our analysis and quantified the sensitivity of our predictions to the degree of extrapolation. We conclude that, although more data are required, the model is capable of predicting occupancy for caves close to the middle of the environmental space examined in this study.