Bats and other vertebrates form large colonies concentrating key populations of multiple endangered species. Their foraging ranges are of critical importance for the colony but can be too vast to preserve in full extent. We evaluated an approach to prioritize areas within this range that conciliates the distinct needs of various species.
Our model colony was a large cave-bat nursery harboring Rhinolophus mehelyi, Myotis myotis and Miniopterus schreibersii located in Southern Portugal. With radio-tracking data of foraging bats and spatially explicit modeling, we generated habitat suitability maps for each species. Models incorporated both habitat variables and distance to the roost. The resulting maps were then used separately or in combinations to identify the areas with greatest multispecies conservation value.
The best results were obtained by combining individual suitabilities in a single value, weighting each species by its threat risk. Although the overall range of the colony was very extensive, this approach identified the areas that had most multispecies value; more than half of the foraging sites are included in the best 13% of the range, and adding the next best 12% includes almost all sites of the most threatened study species, R. mehelyi. The efficiency of the prioritization can be evaluated not only for the species ensemble, but also for individual species.
The concentration of most multispecies conservation value in a small area is partly due to the importance of distance to roost as a determinant of foraging habitat selection in all species, so this factor is essential in suitability models used for prioritization. This prioritization process successfully minimizes the amount of land required for protection, while maximizing the quality of the habitat to protect. Such prioritizations should spur the preservation of foraging areas of large multispecies colonies, thus improving the chances of survival of populations of great conservation value.