Wetlands are amongst the richest, yet most threatened types of habitats on Earth.
One major threat is the modification of water regime for human activities, which disrupts
normal ecosystem equilibrium. In lacustrine wetlands, reduced flooding allows shrubs to
take over, ultimately leading to a shift towards woody communities. To counter this,
wetland managers have initiated a variety of measures, including mowing, burning, and
pasturing. Because of the short time frames of previous studies on the subject, little is
known on their potential negative side effects on the ecosystem. Here, we evaluate the
long-term effect of mowing on breeding populations of the five most abundant species in
our central European study area (the reed warbler Acrocephalus scirpaceus, the common
reed bunting Emberiza schoeniclus, Savi’s warbler Locustella luscinioides, the water rail
Rallus aquaticus, and the bearded reedling Panurus biarmicus). This study, of an
unprecedented time scale (30 years), shows that rotational mowing has no long-term
detrimental effects on birds. However, optimal mowing regime for the birds might often be
less frequent than what is usually applied. We recommend that mowing be spaced every
3 years at least, and ideally every 6 years or more. We discuss additional measures that
could be implemented to complement mowing. Because of the widespread distribution of
the target habitat and species, our study provides readily applicable information for wetland
managers in Europe and worldwide.