Geographical patterns in phylogenetic diversity of Chinese woody plants and its application for conservation planning

Aim Biodiversity hotspots are widely used as conservation priorities to preserve the tree of life. However, many conservation practices identify biodiversity hotspots without considering phylogenetic diversity (PD), which reflects total evolutionary history and feature diversity of a region. Moreover, conservation planning rarely distinguishes between neo- and palaeo-biodiversity hotspots despite their differences. Here, we (a) estimated large-scale patterns in PD of woody plants, (b) identified neo- and palaeo-biodiversity hotspots and (c) demonstrated their implication in conservation planning, with special focus on Hengduan Mountains and southern China. Location China. Methods Distributions of 11,405 woody species from the Atlas of Woody Plants in China were updated and were transformed into a grid of 50 x 50 km(2). By integrating distribution maps with a genus-level phylogeny of angiosperms, we estimated Faith's PD of each grid cell and evaluated the contribution of species relatedness to PD at given levels of species diversity (i.e. standardized PD, sPD) using regressions and three null models. Then, we identified areas with significantly lower or higher sPD than expected as neo- and palaeo-hotspots and estimated the coverage of protected areas in these regions. Results Species diversity and PD decreased towards the north. Southern China had high species diversity, PD and sPD, while Hengduan Mountains had high species diversity and PD but low sPD. The coverage of protected areas in southern China was less than half of that in Hengduan Mountains and entire China. Main conclusions Our results identified Hengduan Mountains as a neo-hotspot and southern China as a palaeo-hotspot, highlighting their importance for biodiversity conservation. Compared to Hengduan Mountains, southern China has low coverage of protected areas, which calls for more conservation attention. Our study demonstrates a way of incorporating the phylogenetic component in the identification of neo- and palaeo-hotspots, and hence of achieving a more complete perception of biodiversity patterns for conserving the tree of life.

Automated summary

This study identified the Hengduan Mountains as a neo-hotspot and southern China as a palaeo-hotspot in terms of phylogenetic diversity of woody plants. Southern China had high species diversity and PD, but relatively low coverage of protected areas, indicating a need for more conservation efforts. Incorporating phylogenetic components in identifying biodiversity hotspots can provide a more comprehensive understanding of biodiversity patterns and aid in conserving the tree of life.