Effects of the Qinling-Daba Mountains as Ecological Corridor on Patterns of Plant Distribution

The Qinling-Daba Mountains (QDM), extending east-west in central China, span warm temperate and subtropical zones and are characterized by complex geographical transitions and high biodiversity. They actually also act as a significant ecological corridor between the Tibetan Plateau and East China plains, but this almost has not been addressed. This study uses plant species data of 40 national nature reserves within QDM and 18 in adjacent area, performs consensus clustering at the levels of species, genus, and areal type, traces the origins and dispersal routes of 89 Chinese endemic genera, and, finally, assesses the importance and areal differentiation of environmental factors on species distribution. The results show: (1) The QDM as a corridor contribute greatly to the high biodiversity in the study areas, particularly in the easternmost and westernmost sections. (2) The QDM promote species interactions and exchanges between west China and east China. The genera involved are classified into four main types of geographic origins: Central-East China components (41 genera) and North China components (8 genera) spread southwestward; Southwest components (24 genera) spread eastward and northeastward; while Northwest components (6 genera) show limited eastward spread. (3) Multi-year average precipitation, elevation, and coldest quarter temperature significantly influence plant distribution. (4) Elevation differences (peak, base, and average) under 1000 m among reserves enhance plant dispersal, resulting in obvious corridor effect. This study provides theoretical support for understanding the corridor effect in the study area and its contribution to biodiversity pattern of China.