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, shifting function from diverse groups to less efficient bacteria. These impacts persist long after flow returns, affecting freshwater ecosystems.
Area of Science:
- Ecology
- Environmental Science
- Hydrology
Background:
- River drying is increasing globally due to climate change and water abstraction.
- Drying impacts riverine biodiversity, ecosystem functioning, and hydrological connectivity.
- Leaf litter decomposition, a crucial freshwater ecosystem function, is sensitive to decomposer community structure.
Purpose of the Study:
- To investigate how spatiotemporal drying patterns influence decomposition rates.
- To determine the role of detritivorous macroinvertebrates, bacteria, and fungi in mediating drying effects on decomposition.
- To assess the impact of local drying intensity and regional hydrological connectivity on decomposer communities and ecosystem function.
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.
Main Results:
- Short drying events (≤6 days) reduced decomposition rates by up to 50%, primarily due to shifts in decomposer communities.
- Drying decreased decomposer diversity, favoring dry-tolerant bacteria over fungi and macroinvertebrates, leading to reduced decomposition efficiency.
- These community shifts and reduced decomposition persisted for months after flow resumed.
- Regional hydrological connectivity mitigated drying impacts by aiding decomposer recovery, but this effect was network-dependent, with arid networks showing hindered recovery.
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 carbon cycling and energy flow in freshwater ecosystems.
- Conservation and management strategies must consider the complex interplay between drying, decomposer communities, and ecosystem functions.
Keywords:
bacteriabiodiversityclimate changedecompositiondryingecosystem functioningfungiintermittent riversmacroinvertebratesMore Related Videos
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