Li Qin, Sun Hang, Boufford David E, Bartholomew Bruce, Fritsch Peter W, Chen Jiahui, Deng Tao, Ree Richard H
Department of Science and Education, Field Museum, Chicago, IL, 60605, USA.
Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, 650201, China.
New Phytol. 2021 Nov;232(3):1424-1435. doi: 10.1111/nph.17443. Epub 2021 Jun 5.
Identifying the contours and correlates of species turnover is central to understanding the nature of biogeographical regions. The Hengduan Mountains region of south-central China (HMR) is well known for its high diversity of plants, but its boundaries and internal floristic structure are poorly understood, especially in relation to geographical and environmental factors. With data on occurrences and elevational ranges of seed plants across the HMR and adjacent areas of the greater Qinghai-Tibet Plateau, we identified motifs (distinct species assemblages) by Grade of Membership models, and characterized relative contributions of geography, elevation, and climate to their spatial patterns. Motifs segregate primarily by latitude, elevation, and correlated environmental variables, most sharply across the tropical-temperate divide. Secondarily, they segregate by longitude and geographical features, and reveal a novel divide across the Jinsha River. A core set of motifs corresponds to previous delineations of the HMR. The HMR biodiversity hotspot is more a mosaic of floristic elements than a cohesive entity. Grade of Membership models effectively reveal the geographical contours of biotic structure, and are a valuable new tool for biogeographical analysis.
识别物种更替的轮廓和相关因素是理解生物地理区域本质的核心。中国中南部的横断山脉地区（HMR）以其丰富的植物多样性而闻名，但人们对其边界和内部植物区系结构了解甚少，尤其是与地理和环境因素相关的方面。利用横断山脉地区及青藏高原相邻区域种子植物的分布和海拔范围数据，我们通过隶属度模型识别出了植物群落模式（不同的物种组合），并描述了地理、海拔和气候对其空间格局的相对贡献。植物群落模式主要按纬度、海拔和相关环境变量划分，在热带与温带分界处最为明显。其次，它们按经度和地理特征划分，并揭示了金沙江沿线的一个新分界。一组核心的植物群落模式与之前对横断山脉地区的划分相对应。横断山脉地区生物多样性热点更多是植物区系元素的镶嵌体，而非一个紧密的整体。隶属度模型有效地揭示了生物结构的地理轮廓，是生物地理分析的一个有价值的新工具。
