Floodplain reconnection usually helps biodiversity—but the test designs lag
WHAT THE EVIDENCE SAYS
A systematic review of 100 evaluations from 22 countries found predominantly positive biodiversity responses to reconnecting floodplains and restoring river structure, but effect size varied with taxon and project design. Temperate European sites dominated, and fewer than 20% used full before–after-control–impact comparisons. Soil microbes and terrestrial vertebrates were sparsely sampled.
WHY IT MATTERS / OUR READ
Floodplain projects can recreate a physical process while biological response still varies. Credible ecological assessment needs reference sites, repeated monitoring and target taxa from the outset, not just post-construction photographs.
CAVEATS / UNCERTAINTY
The evidence base is geographically uneven, and positive published responses are not a globally randomized treatment effect. Tropical floodplains remain poorly represented.
SOURCE
Journal of Applied Ecology — Parajuli et al., 7 July 2026
View original evidence ↗
A 100-study review across 22 countries finds promising responses and a shortage of strong counterfactuals.
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