Transitional areas of vegetation as biodiversity hotspots evidenced by multifaceted biodiversity analysis of a dominant group in Chinese evergreen broad-leaved forests

Species in transitional areas often display adaptive responses to climate change and such areas may be crucial for long-term biodiversity conservation. Evaluation of spatial multidimensional biodiversity patterns and the identification of biodiversity hotspots and priority conservation areas may help mitigate the effects of climate change. Here, we examine the spatial distribution patterns, evolutionary and functional levels of Lauraceae from Chinese evergreen broad-leaved forests. The results show species richness (SR), corrected weighted endemism (CWE), phylogenetic diversity (PD), and phylogenetic endemism (PE) for Chinese Lauraceae are congruent, whereas evolutionarily distinct and globally endangered (EDGE) and function diversity (FD) are incongruent. Areas of paleo-endemism are present in the border region of Yunnan and Guangxi, whereas neo-endemic regions are distributed mainly along the Yarlung Zangbo River and the Himalayas in southern Tibet. Priority conser-vation areas are located in southern Tibet, the northern Hengduan Mountains, the north-south boundary of Qinling and Huaihe River, southern and south-eastern Yunnan, and south China. Biodiversity hotspots for Chi-nese Lauraceae overlap with transitional zones for several other vegetation types in adjacent areas. Climate factors are estimated to account for 82.72% of the SR and 86.86% of the PD for Lauraceae spatial distribution patterns, reflecting higher diversity under warmer and wetter conditions. This study confirms the conservation value of transitional areas and the significance of using multiple diversity facets as part of integrative approaches to maximize biodiversity protection in Chinese broad-leaved forests, especially under climate change.