Complexity responses of Rhododendron species to climate change in China reveal their urgent need for protection

Abstract

Global climate change has been widely recognized as important factors that threaten biodiversity. Rhododendron species are not only famous woody ornamental plants worldwide but are also indispensable components in alpine and subalpine vegetation in southwest China. However, the geographical distribution ranges response of this broad taxonomic group to future climate change remains not be fully understood. Herein, we studied the impact of climate change on the distribution of Rhododendron species in China by predicting the changes in their suitable habitats, centroid, and species richness under three climate change scenarios (SSP1-2.6, SSP2-4.5 and SSP5-8.5) in the 2090s. The species richness changes of Rhododendrons along altitude were also evaluated. In addition, we calculated the phylogenetic signals of distribution response to climate change. We found that the distribution responses of Rhododendron to climate change have weak phylogenetic signals. In the 2090s, the suitable habitats of about 87% of Rhododendron species will be reduced, 77% of Rhododendron species are manifested as northward migration. The high species richness of Rhododendrons tends to migrate to transboundary areas with high altitudes in China. Some Rhododendron species with no concern previously should be taken seriously for their high risk of habitat loss under climate change. Thus, the urgent protection of Rhododendron species under climate change need to be paid more attention than previous acknowledged. We recommend carrying out the reintroduction of endangered species in future suitable habitat, strengthening the protection of transboundary areas with high species richness, and focusing on species with few concerns previously.