Microbes, especially bacteria and fungi, are of profound importance in sustaining multiple ecosystem functions on Earth. Anthropogenic activities, such as deforestation, industrialization, urbanization and pollution are currently not only affecting the microbial diversity and community structure, but also shaping the microbial evolutionary history that occurs in polluted sites. However, the effects of these activities on the distribution of microbial evolutionary history have been overlooked by current conservation efforts. Here, we analyzed a total of 472 soil samples from forest nature reserves across eastern China and characterized the bacterial and fungal communities by high-throughput sequencing. Faith’s phylogenetic diversity (PD) and the average evolutionary distinctiveness (ED) of taxa in each sample were calculated to quantify microbial evolutionary history. We partitioned the relative importance of anthropogenic activities, soil properties, climate variables and spatial factors on the spatial distribution of ED and PD of bacterial and fungal communities. We then explored that whether these factors influence the ED and PD of microbial communities through shifting the species richness or species phylogenetic relatedness.
Results/Conclusions
We found distinct spatial distribution patterns in bacterial and fungal evolutionary history, which were associated with different driving factors. Soil variables, especially soil calcium content, were the major determinant of the spatial distribution of ED and PD of bacterial communities and PD of fungal communities. However, anthropogenic activities accounted for the largest variation in the spatial distribution of ED of fungal communities. Nearest distance to large cities was the best individual predictor of fungal ED, and their negative relationships suggest that fungal communities in forests exposed to greater anthropogenic pressures are more likely to exhibit higher ED. Furthermore, we found that soil properties determining the ED and PD of bacterial communities and PD of fungal communities do so through impacting species richness, while anthropogenic activities associated with the spatial distribution of ED of fungal communities alter the phylogenetic relatedness of community members. Our results indicate that anthropogenic activities may have little effect on the evolutionary history of bacterial communities and PD of fungal communities, but might increase the ED of fungal communities by altering the phylogenetic structure.