Conservation Biogeography of the Terrestrial Mammals in Iran: Diversity Patterns, and Vulnerability to Climate Change and Extinction

Abstract

Under the framework of a “conservation biogeography” approach, initially, I reviewed and updated the taxonomy and distribution of the rich but understudied mammalian diversity of Iran. This data then formed the basis for the biogeographical regionalization of this complex transitional area using hierarchical clustering and infomap network methods. I used linear models to explore the correlates of extinction risk for this threatened mammalian fauna. Functional grouping of target species was used to assess their vulnerability to the magnitude and velocity of climate change impacts. Both clustering and network methods successfully illuminated the intricate biogeographic patterns, while the network detected many more small bioregions, including two transition zones. The extinction risk analyses revealed that direct human impacts through hunting and persecution played a major role in the decline of these taxa, as opposed to the minor effect of indirect and intrinsic and extrinsic factors. The magnitude and velocity of climate change impacts varied significantly between functional groups, with the highest risk of exposure to extreme climates in large and threatened species occurring in lowlands. This study provides a foundation for future biogeographic, systematics and ecological studies of Iranian mammals while simultaneously adding to the limited available information on the bioregionalization at regional scales. It also highlights the importance of incorporating threats in extinction risk models and functional trait information in climate change impact assessments.