Regulating microclimatic conditions and vegetation succession in European wet meadows through mowing regime

Wet meadows are semi-natural habitats that represent hotspots of biodiversity across Europe. Historically, they were maintained by humans via mowing and grazing, but in modern times many meadows have been abandoned and become overgrown. A contributing factor is the rapid expansion of reeds (Phragmites spp.), and invasive plants such as goldenrods (Solidago spp.) and milkweeds (Asclepias spp.). Another recent threat to these habitats is climate change. Rising global temperatures lead to warmer microclimatic conditions, which could push them outside the optimal temperature range for meadow organisms. To design meadow management plans to mitigate these threats, we investigated the effect of meadow turf height on topsoil temperature, and the impacts of mowing frequency on turf height as well as on the presence of reeds, goldenrods, and milkweeds across six European regions. Mowing at least once every two years reduced turf height and limited the presence of goldenrods, milkweeds, and reeds. Greater turf height led to lower topsoil temperature across all regions. Considering these results and previous research, regular mowing, with the frequency of about every second year, of small meadow fragments to create a mosaic of different turf heights is a workable compromise for controlling habitat succession and invasive plant species. Preventing the negative effects of climate change in the future may require adopting less intensive management so that meadow microclimate remains within a favorable temperature range. Our results demonstrate that proper meadow management can strongly influence topsoil temperature, turf height, and the presence of invasive plants.