Environmental Effects on Taxonomic Turnover in Soil Fauna across Multiple Forest Ecosystems in East Asia

SIMPLE SUMMARY: The mechanisms determining biotic turnover across geographic gradients are poorly understood. We obtained the catalogues of soil fauna orders across forest ecosystems in East Asia as well as the temperature, moisture and soil physical and chemical properties of the corresponding sites. We then studied the composition of soil fauna orders in different climatic regions and analyzed the effect of environmental factors on the composition of the soil fauna community in East Asia. Finally, we calculated the total variation in environmental and spatial factors in the orders’ composition of overall, phytophagous, predatory and saprophagous fauna and explored the large-scale patterns of soil meso-macrofauna turnover and the driving factors based on fourteen sampling sites in East Asia. The results showed that the patterns of soil fauna order turnover increased significantly with increasing latitude differences. The total variance in the environment was higher than the spatial factors in the orders’ composition. Meanwhile, the effects of climate factors on environmental processes were stronger than those of soil factors on phytophage, predacity and saprophage faunas. The results help us better understand, maintain and promote soil biodiversity conservation and ecosystem services at large scales. ABSTRACT: The large-scale spatial variation in and causes of biotic turnover of soil fauna remain poorly understood. Analyses were conducted based on published data from 14 independent sampling sites across five forest ecosystems in East Asia. Jaccard and Sørensen’s indices were used to measure turnover rates in soil fauna orders. A redundancy analysis was used to investigate multiple environmental controls of the composition of soil fauna communities. The results showed that both Jaccard’s and Sørensen’s index increased significantly with increasing latitude difference. The environment explained 54.1%, 50.6%, 57.3% and 50.9% of the total variance, and spatial factors explained 13.8%, 15.9%, 21.0% and 12.6% of the total variance in the orders’ composition regarding overall, phytophagous, predatory and saprophagous fauna, respectively. In addition, climate factors in environmental processes were observed to have a stronger effect than soil factors on the orders’ turnover rates. Our results support the hypothesis that the effect of environment factors on soil animal taxa turnover is more important than the effect of spatial factors. Climatic factors explained more variation in the turnover of phytophagic fauna, but soil and environment factors equally explained the variation in the turnover of predatory fauna. This study provides evidence to support both environmental filtering and dispersal limitation hypotheses at the regional and population scales.