Litter decomposition driven by soil fauna, plant diversity and soil management in urban gardens

Simon Tresch, David Frey, Renée-Claire Le Bayon, Andrea Zanetta, Frank Rasche, Andreas Fliessbach & Marco Moretti

Résumé In the face of growing urban densification, green spaces in cities, such as gardens, are increasingly important for biodiversity and ecosystem services. However, the influences of urban green space management on biodiversity and ecosystem functioning (BEF) relationships is poorly understood. We investigated the relationship between soil fauna and litter decomposition in 170 urban garden sites along a gradient of urbanisation intensity in the city of Zurich, CH. We used litter bags of 1 and 4 mm mesh size to evaluate the contribution of soil meso- and macrofauna on litter decomposition. By using multilevel structural equation models (SEM), we investigated direct and indirect environmental effects and management practices on litter decomposition and litter residue quality. We evaluated the role of taxonomic, functional and phylogenetic diversity of soil fauna species on litter decomposition, based on a sample of 120 species (81007 individuals; 39 collembola, 18 earthworm, 16 isopod, 47 gastropod species). We found highest litter decomposition rates using 4 mm mesh size litter bags, highlighting the importance of soil macrofauna. Urban warming, a proxy for urbanisation intensity, covaried positively, whereas soil disturbances, such as intensive soil and crop management, were negatively correlated with decomposition rates. Interestingly, soil fauna species richness decreased, with the exception of gastropods, and soil fauna abundance increased with urban warming. Our data also show that plant species richness positively affected litter decomposition by increasing soil fauna species richness and microbial activity. A multivariate analysis of organic compounds in litter residues confirmed the importance of soil fauna species richness and garden management on litter decomposition processes. Overall, we showed, that also in intensively managed urban green spaces, such as gardens, biodiversity of plants and soil fauna drives key ecosystem processes. Urban planning strategies that integrate soil protecting management practices may help to maintain important ecosystem services in this heavily used urban environment.
Mots-clés Urban gardening
Litter bag decomposition
Biodiversity ecosystem functioning (BEF)
Urban ecosystem services
Urban soil biodiversity
MidDRIFTS analysis
Urban warming
Citation Tresch, S., Frey, D., Le Bayon, R. C., Zanetta, A., Rasche, F., Fliessbach, A., & Moretti, M. (2019). Litter decomposition driven by soil fauna, plant diversity and soil management in urban gardens. Science of the Total Environment, 658, 1614-1629.
Type Article de périodique (Anglais)
Date de publication 1-3-2019
Nom du périodique Science of the Total Environment
Volume 658
Pages 1614-1629
URL https://doi.org/10.1016/j.scitotenv.2018.12.235
Liée au projet Better Gardens - Soil quality, Biodiversity and Social Va...