Ground-Dwelling Spider Fauna of Flooded Meadows in Matsalu, Estonia
The River Shannon, Ireland, among the last unregulated rivers in western Europe, has extensive floodplains and supports rare and endangered species and habitats, of ecological and cultural importance. Unregulated floodplains result in community composition responding directly to natural fluctuations in water level. This study assesses how hydrological factors and farming practices effect flood meadow plant communities. Three main plant communities were identified, forming an uninterrupted ecotone, along a gradient of dry to wet. Habitats of European conservation interest (Lowland Hay Meadows and Molinia Meadows) were well represented. Hydroperiod, calculated using microtopographical measurements, was the primary factor determining community composition and was negatively correlated with elevation and plant species richness. The botanical continuum comprised a range of insect-pollinated species, demonstrating the role of floodplains in providing pollinator services. Climate change projections indicate more prolonged winter flooding in the future, signifying potential range shifts for these plant species and communities; highlighting the need for appropriate conservation measures in the surrounding landscape. Low-intensity farming practices, with minimal fertiliser use and regular hay-mowing, played an essential, secondary role in maintaining plant species diversity. Retaining the floodplain topography, its associated hydrological regime and low-intensity farming practices, are necessary to maintain species diversity and ecosystem services.