Local community assembly processes shape β‐diversity of soil phoD‐harbouring communities in the Northern Hemisphere steppes

Abstract Aim The contemporary coexistence theory suggests that species pool, environmental filtering, dispersal assembly processes, ecological drift and biotic interactions collectively determine the β‐diversity of communities. However, we know little about the biogeographical patterns of the β‐diversity of microbial communities harbouring the alkaline phosphatase phoD gene ( phoD communities, hereafter) and whether these mechanisms are all‐important in shaping phoD communities’ β‐diversity in natural steppe ecosystems. Location Northern Hemisphere steppes. Time period July to August 2018. Major taxa studied Alkaline phosphatase ( phoD gene) encoding community. Methods Using the high throughput amplicon sequencing method, soil phoD communities were comparatively studied along three representative regions of the Northern Hemisphere steppes, namely the Qinghai‐Tibetan Plateau, Inner Mongolian Plateau and the Loess Plateau. Each region harbours three types of steppes (habitats): meadow, typical and desert steppes. Results We observed significantly higher phoD β‐diversity in the Qinghai‐Tibetan than in the Loess and Inner Mongolian Plateaus and significantly lower β‐diversity in the typical steppes than in other steppe types. The decay rates of phoD β‐diversity with geographical distance varied in different steppe regions and types. The phoD β‐diversity was not significantly influenced by species pool; instead, environmental filtering, dispersal assembly processes, ecological drift and biotic interactions jointly shaped the β‐diversity patterns. The β‐deviation variations (β‐diversity excluding the effects of species pool) were influenced by spatial and environmental factors and biotic interactions, among which soil pH was the key environmental determinant. The soil pH driving β‐diversity mechanism was steppe region and habitat specific. Main conclusions The biogeographical patterns of phoD β‐diversity were mainly driven by local community assembly processes in the Northern Hemisphere steppes.