Urban greenspaces shape soil nematode community across soil depth gradients: Belowground life at The Ohio State University

Abstract

Urban greenspaces face significant anthropogenic transformation, impacting soil ecosystems, multifunctionality, and global biodiversity. With increasing population and urbanization, understanding the drivers influencing soil nematode communities in urban greenspaces is crucial for sustainable urban ecosystem management. We chose the campus of The Ohio State University (OSU) due to its unique urban settings with minimally disturbed both turf and non-turf ecosystems. This study focuses on nematodes, the often-overlooked ecological engineers which play diverse roles in ecosystem functions. Nematodes were collected from 99 sampling locations across three soil depths to represent two ecosystem types (i.e., turf and non-turf) of the OSU campus. Among plant parasitic nematodes (PPN), Helicotylenchus and Pratylenchus populations were above damage threshold limits. No specific pattern of community composition was observed in the spatial variation map. The presence of rare PPN genera in the lower soil layers had a significant impact on beta diversity. Trophic group abundances displayed distinct patterns, with turf ecosystems exhibiting higher PPN as well as total nematode abundance decreasing with soil depths. In the subsurface layer (10–30 cm), both bacterivores and fungivores were higher in the non-turf than turf ecosystem. Fungal-dominated decomposition of organic matter was observed in both ecosystem types. Soil physiochemical properties, specifically, total organic carbon and soil texture, had a significant impact on PPN community composition. However, nematode trophic group composition was more altered by ecosystem type than edaphic factors followed by soil depths. Together these three explanatory variables explained 27.5 % of the total variance in trophic group composition. Overall, this study provides insights into the complex interactions between PPN, trophic groups, soil properties, and urban ecosystem characteristics, contributing valuable knowledge for sustainable urban greenspace management.