Differential effects of soil trophic networks on microbial decomposition activity in mountain ecosystems

• Published in: Soil biology & biochemistry 2022-09, Vol.172, p.108771, Article 108771
• Main Authors: Martinez-Almoyna, Camille, Saillard, Amélie, Zinger, Lucie, Lionnet, Clément, Arnoldi, Cindy, Foulquier, Arnaud, Gielly, Ludovic, Piton, Gabin, Münkemüller, Tamara, Thuiller, Wilfried
• Format: Article
• Language: English
• Subjects: Biodiversity and Ecology; Ecosystem functioning; Environmental Sciences; Mountain ecosystems; Multitrophic communities; Soil food web; Structural equation models; Trophic regulation
• ISSN: 0038-0717; 1879-3428
• DOI: 10.1016/j.soilbio.2022.108771

Soil trophic networks are key to biogeochemical cycles, in particular decomposition. However, few studies have yet quantified how microbial decomposition activity along environmental gradients is jointly driven by bacteria, fungi, and their respective consumers. Here, we quantified these direct and indirect effects on decomposition and contrasted them between forests and open habitats using multiple elevational gradients in the French Alps. While environmental control on microbial decomposition activity was comparable in the two habitats, the pathways and strengths of biotic predictors strongly differed. The fungal channel composition played a moderate role in forests, while the bacterial channel composition was critical in open habitats. Importantly, we found trophic regulation by consumers to be a key modulator of the direct environmental effects on decomposition in open habitats. These results highlight the need to integrate trophic regulation when predicting future ecosystem functioning. •Comparable environmental effects on microbial decomposition in different habitats.•Fungal channel composition weakly influences microbial decomposition in forests.•Bacterial channel composition influences microbial decomposition in open-habitats.•Top-down regulation via the soil trophic network can affect microbial decomposition.