Risk-Management Ecology Lab, Department of Ecology, Evolution & Behavior The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel; Theoretical Ecology and Evolution Lab, Centre for Ecological Sciences, Indian Institute of Science, Bengaluru, India
Risk-Management Ecology Lab, Department of Ecology, Evolution & Behavior The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
J Alfred Daniel
The National Natural History Collections, The Hebrew University of Jerusalem, Jerusalem, Israel
Yael Hawlena
Risk-Management Ecology Lab, Department of Ecology, Evolution & Behavior The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
Efrat Gavish-Regev
The National Natural History Collections, The Hebrew University of Jerusalem, Jerusalem, Israel
Risk-Management Ecology Lab, Department of Ecology, Evolution & Behavior The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel; The National Natural History Collections, The Hebrew University of Jerusalem, Jerusalem, Israel
Litter decomposition is expected to be positively associated with precipitation despite evidence that decomposers of varying sizes have different moisture dependencies. We hypothesized that higher tolerance of macro-decomposers to aridity may counterbalance the effect of smaller decomposers, leading to similar decomposition rates across climatic gradients. We tested this hypothesis by placing plant litter baskets of different mesh sizes in seven sites along a sharp precipitation gradient, and by characterizing the macro-decomposer assemblages using pitfall trapping. We found that decomposers responded differently to precipitation levels based on their size. Microbial decomposition increased with precipitation in the winter while macro-decomposition peaked in arid sites during the summer. This led to similar overall decomposition rates across the gradient except in hyper-arid sites. Macro-decomposer richness, abundance, and biomass peaked in arid environments. Our findings highlight the importance of macro-decomposition in arid-lands, possibly resolving the dryland decomposition conundrum, and emphasizing the need to contemplate decomposer size when investigating zoogeochemical processes.
