Drying Halves Decomposition Rates in River Networks by Decreasing Decomposer Diversity
Rubén Del Campo1,2, Thibault Datry3, Arnaud Foulquier4
1Department of Ecology and Hydrology, University of Murcia, Murcia, Spain.
Global Change Biology
|July 20, 2026
Summary
River drying significantly reduces leaf litter decomposition by altering decomposer communities. These shifts persist, impacting ecosystem function, but hydrological connectivity can aid recovery in some river networks.
Area of Science:
- Ecology
- Environmental Science
- Hydrology
Background:
- River drying, driven by climate change and water abstraction, threatens biodiversity and ecosystem functions globally.
- Drying disrupts river network connectivity, affecting organism and resource movement.
- Leaf litter decomposition, a crucial freshwater ecosystem function, is sensitive to changes in decomposer communities.
Purpose of the Study:
- To investigate how spatiotemporal drying patterns influence decomposition rates by altering the diversity and composition of detritivorous macroinvertebrates, bacteria, and fungi.
- To assess the mediating role of local drying intensity and regional hydrological connectivity on decomposition processes.
- To understand the long-term effects of drying on decomposer communities and ecosystem functioning.
Main Methods:
- Analysis of data from six European river networks across a latitudinal gradient.
- Assessment of local drying intensity and regional hydrological connectivity.
- Evaluation of changes in the diversity and composition of macroinvertebrates, bacteria, and fungi as decomposers.
Main Results:
- Short drying events (≤6 days) reduced decomposition rates by up to 50%, primarily due to altered decomposer community structure and diversity.
- Drying shifted decomposition control from a balanced mix of fungi, bacteria, and detritivores to a dominance of less efficient, dry-tolerant bacteria.
- These community shifts and reduced decomposition persisted for months post-drying, even after flow resumed.
- Regional hydrological connectivity mitigated drying's negative impacts by facilitating decomposer recovery, though this effect varied by network aridness and fragmentation.
Conclusions:
- Spatiotemporal drying patterns significantly regulate the relationship between community structure and ecosystem functioning in river networks.
- Increasingly frequent and prolonged drying events will likely alter freshwater carbon cycling and energy fluxes due to shifts in decomposer diversity.
- Understanding these dynamics is crucial for predicting and managing freshwater ecosystems under global change.
Keywords:
bacteriabiodiversityclimate changedecompositiondryingecosystem functioningfungiintermittent riversmacroinvertebratesMore Related Videos
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