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Broad-Scale Meta-Analysis of Drivers Mediating Adverse Impacts of Flow Regulation on Riparian Vegetation
Xiaolei Su1, María Dolores Bejarano2, Roland Jansson3
1Key Laboratory of Eco-Environments in Three Gorges Reservoir Region (Ministry of Education), Chongqing Key Laboratory of Plant Ecology and Resources in Three Gorges Reservoir Region, School of Life Sciences, Southwest University, Chongqing, China.
Global Change Biology
|February 5, 2025
Summary
River flow regulation significantly reduces native riparian vegetation richness and abundance while increasing non-native species. Impacts are worse in arid climates and downstream of dams, with recovery slowed by regulation intensity.
Area of Science:
- Ecology
- Environmental Science
- Hydrology
Background:
- Over two-thirds of global rivers experience flow regulation.
- Flow regulation's adverse effects on riparian vegetation are known but poorly understood.
- Riparian vegetation is a critical component of river ecosystems.
Purpose of the Study:
- To elucidate how different factors mediate the adverse impacts of flow regulation on riparian vegetation.
- To quantify the effects of flow regulation on riparian species richness and abundance.
- To assess the influence of climate, dam position, and regulation intensity on riparian vegetation.
Main Methods:
- Broad-scale meta-analysis of 59 papers.
- Included data from 278 dams on 146 rivers.
- Compared riparian vegetation indices between regulated and free-flowing rivers.
Main Results:
- Moderate, significant reduction in native riparian species richness and abundance.
- Strong increase in non-native riparian species abundance.
- Greater negative impacts in arid/continental climates and downstream of dams.
Conclusions:
- Years since flow regulation is key for species richness recovery, but intensity slows it.
- Larger rivers and areas downstream of dams require prioritized protection.
- Management should focus on limiting regulation intensity and monitoring non-native species.
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