Distribution of Soil Microbes in Urban Parks: An Effect of Under-Tree Crown and Hillside Position on Testate Amoeba Assemblages in Subtropics (Shenzhen, China)

Testate amoebae (TA) are important components of soil ecosystems, where they play an essential role in belowground food webs. In this study, we examined species composition, diversity, and structure of TA assemblages in soils beneath tree crowns (microscale) at three slope positions (mesoscale) in subtropical urban parks in Shenzhen, China. Forty-two species of TA belonging to 18 genera were identified in 81 samples. TA assemblages were the most diverse and abundant in the center of the tree crown comparing with other under-tree habitats. Foot of the hills harbored higher TA abundance and diversity comparing with upper locations along the hillslopes. The distribution of TA was mostly driven by under-crown and hillside positions but not by elementary environmental conditions such as pH, moisture content and thickness of leaf litter layer. None of later factors were sufficient in shaping TA assemblage composition. The findings of our study suggest that in regional studies of soil microbial eukaryotes both micro- (i.e., under-crown) and mesoscale (i.e., the slope position) heterogeneity should be considered.