Ricerc@Sapienza

Broad-scale destruction of natural habitats, in particular tropical forest, overexploitation of natural resources, and competition with/predation by introduced species are the primary sources of terrestrial biodiversity loss. Since the 1970s the human population has doubled, leading to increased anthropogenic pressures that have caused the size of animal populations to fall by almost half. However, the relationship between human activities and species distribution and abundance is complex. Every species has a climatic niche, which is the set of large-scale precipitation and temperature conditions where that species occurs. The niche can reflect physiological tolerances to these climatic conditions (fundamental niche), but can also be influenced by other factors, such as biotic interactions or human activities (realized niche). The latter is usually measured through models that relate the geographical distribution of species with climate in a given time. This implies that, according to the factors limiting the distribution of species in the time interval considered, the modelled realized niche of a species can vary.
In this project I plan to collect historic (1970s) and current distributions of terrestrial mammals and use them as a basis for building the climatic niche of species. I will compare the two niches of each species to identify changes in their breadth. I will then identify the climatic areas lost to understand niche breadth change, and will use anthropogenic factors (e.g. land use change, change in human population density) as correlates of this change. This will enable me to understand which variables have been more important in shaping the climatic niche of species, thus allowing more accurate predictions of their future potential distribution. I will focus my analyses on mammals because they have greater availability of historical distribution data and show also the largest contractions in their distribution compared to other taxonomic groups.