Habitat loss of floodplain meadows in north Germany since the 1950s

Abstract

Floodplain meadows are severely threatened by land use change and intensification in Central Europe. This study investigates quantitative and qualitative changes in the vegetation of wet and species-rich mesic meadows in the floodplains of north Germany since the 1950s, considering their spatial extent, fragmentation, and replacement by other land use types. Historical high-resolution vegetation maps were compared with recent vegetation surveys in seven study regions (six unprotected areas, one protected reference area) in former West and East Germany. The unprotected sites showed alarming losses in wet and species-rich mesic meadows in the past 50 years (>80%). Wet meadows were substituted by species-poor, intensively managed grasslands (26–60% of the former area), arable fields (0–47%) or set-asides (2–33%). Species-rich mesic meadows were transformed to arable fields (42–72%) or species-poor, intensively managed meadows (14–72%). Decreases in effective mesh size and patch size indicated increasing fragmentation of wet meadows, whilst changes in landscape structure were less consistent in mesic meadows. Only slight changes in the protected floodplain study area indicate that landscape change is mostly caused by local effects such as fertilisation and drainage, but not by general trends such as atmospheric N deposition or climate warming. Despite the contrasting political systems in West and East Germany with different agroeconomic frames, all unprotected study areas showed similar losses and increasing fragmentation of floodplain meadows, which may negatively influence the natural dynamics of, and the gene flow between, meadow plant populations. We conclude that floodplain meadows in north Germany urgently call for high-priority conservation measures.