Optimization of conservation network based on phylogenetic diversity–A case of some vascular plants on the Qinghai - Tibet Plateau

The Qinghai–Tibet Plateau (QTP) is a biodiversity hotspot of national and global significance. Prerequisites for the effective conservation of biodiversity on the QTP are the identification of biodiversity conservation hotspots and gaps in the region and the subsequent optimization of the spatial planning of conservation networks. However, there is a lack of understanding and assessment of phylogenetic diversity in the QTP conservation network. In this study, 136 species of vascular plants included in the Red List of China’s Biodiversity - Higher Plants on the QTP were selected. The maximum entropy model (MaxEnt) and the zonation model were used to identify conservation priority areas and analyze gaps on the QTP using 17%, 30%, 36% and 50% of the area as the conservation targets. In contrast to existing protected area planning based only on species richness (SR), this study also considered evolutionary distinctiveness (ED), which is a measure of the contribution of species to the overall evolutionary history, to determine the priority areas for biodiversity conservation on the QTP; thus, this study takes into account both taxonomic and evolutionary dimensions. The results showed the following: (1) The current conservation network protects an average of only 18.9% of the habitats of the 136 vascular plant species. (2) Under different conservation targets, the coverage percentages of the conservation network for the conservation priority areas identified based on the superposition of SR and ED were approximately 24.7%, 26.1%, 25.5%, and 25.3%, which accounted for approximately 4.6%, 8.5%, 9.7%, and 12.5%, respectively, of the QTP area. (3) Under different conservation targets, the priority areas were concentrated in the southeastern part of the QTP, and as the target area expanded, these priority areas gradually extended into the central and northwestern parts of the QTP. Conservation gaps are mainly concentrated in the eastern Yarlung Zangbo River, the Three Parallel Rivers region, the Southern Hengduan Mountains, the Songpan Plateau–Qionglai Mountains region, and the Yellow River Headwater Region. Phylogenetic diversity reveals evolutionary information about species, and its spatial pattern of divergence from taxonomic diversity emphasizes the significance of incorporating it into conservation, with the aim of promoting multidimensional biodiversity conservation for future conservation planning.