Identifying conservation priorities when data are scanty: A case study with small mammals in Italy

Species prioritisation is an important component of conservation strategies. However, identifying species that are threatened is not easy for many taxa that lack detailed information on distribution and population trends. We propose a ranking system for small mammals, based on their degree of vulnerability and their conservation value. Scores were derived from data on life history traits and ecological requirements of individual species, with respect to their sensitivity to changes in landscape and the composition and qualities of ecosystems. Twelve variables were considered, related to the distribution, demography, ecological adaptability, and their endemism and taxonomic diversification. Rodents with the highest score values were either characteristic of mountain habitats (Apodemus alpicola, Chionomys nivalis and Marmota marmota), typical of lowlands (Micromys minutus) or forest species (dormice), and they were also short living, with few reproduction events. Top ranking Soricomorpha were endemic (Crocidura sicula, C. pachyura), range restricted (Sorex alpinus, Talpa caeca) and habitat specialists (Neomys fodiens, N. anomalus), and were further characterised by low reproduction, low dispersal ability, and restricted elevation range. The factors used in the score system were able to emphasise localised endemisms that could be recognised in the future whenever subspecies should be promoted to the rank of species. Soricomorpha, highlighted in the IUCN national red list as nearly threatened or for the absence of information, ranked at the top of our list. The methodological framework proposed here could be used when a pool of species needs to be evaluated for further investigation or conservation actions, helping by focusing on species that are more sensitive to habitat changes or have an intrinsic conservation value.