Phylogenetic beta diversity of Odonata assemblages in the extreme condition of Central Iran

Freshwater ecosystems are of the most diverse ecosystems in the world, but anthropogenic disturbance and climate change are threatening the biodiversity of these habitats, particularly in the highly vulnerable arid regions. Understanding the compositional patterns in aquatic biota and discovering factors responsible for these patterns enable researchers to predict the impacts of environmental changes and reduce their destructive effects. As a first step for evaluating the conservation value of freshwater ecosystems in the arid areas of Central Iran, we investigated the phylogenetic beta diversity of Odonata assemblages and their response to climate, landscape, and local predictors. A total of 41 water bodies were surveyed and 42 species of Odonata were recorded. The distance matrices related to the total phylogenetic beta diversity of Odonata and the replacement and richness difference components were computed. Each of the three dissimilarity matrices were modelled by generalized dissimilarity modelling (GDM). The average phylogenetic beta diversity was high, and the replacement component had a higher contribution rather than the richness difference component. GDMs results showed that total phylogenetic beta diversity was strongly associated with climate and local predictors. The most influential variables observed were climate variables. Our findings indicated that even in extreme conditions, the freshwater ecosystems could support species with various phylogenetic histories. We emphasize the importance of man-made water bodies in supporting freshwater biodiversity in arid areas. Given the growing threat of habitat degradation and climate change, with no conservation plan, many vulnerable species may be in danger of localized extinction within the region.