Impacts of hydrological restoration on lowland river floodplain plant communities

Many lowland floodplain habitats have been disconnected from their rivers by flood defence banks. Removing or lowering these banks can reinstate regular flooding and thus restore these important wetland plant communities. In this study we analyse changes in wetland hydrology and plant community composition following the lowering of flood defence banks at a floodplain of the River Don in the United Kingdom (UK). The aim of the restoration project was to improve the quality of “floodplain grazing marsh” habitat, which is a group of wetland communities that are of conservation interest in the UK. We analyse changes in species richness and community composition over a period of 6 years, and compare the presence of indicator species from the target floodplain grazing marsh plant communities. The lowering of the flood banks increased the frequency of flood events, from an estimated average of 1.7 floods per year to 571 floods per year. The increased flooding significantly increased the proportion of time that the wetland was submerged, and the heterogeneity in hydrological conditions within the floodplain. There were significant differences in composition between the pre-restoration and restored plant communities. Plants with traits for moisture tolerance became more abundant, although the communities did not contain significantly more ‘target’ floodplain grazing marsh species at the end of the study period than prior to restoration. Colonisation by floodplain grazing marsh species may have been limited because environmental conditions were not yet suitable, or because of a shortage of colonising propagules. While the desired target plant community has not been achieved after 5 years, it is encouraging that the community has changed dynamically as a result of hydrological changes, and that moisture-tolerant species have increased in occurrence. Over the next few decades, the restored flood regime may cause further environmental change or colonisation events, thus helping increase the occurrence of desired floodplain grazing marsh indicator species

Awareness of greater numbers of ecosystem services affects preferences for floodplain management

People's preferences for different habitat management scenarios determine the way that floodplain habitats are managed, and the ecosystem services that they provide. Making people aware of a greater number of ecosystem services may encourage them to design habitat management that better balances the provision of conflicting services. To investigate the impacts of ecosystem service information on people's preferences for floodplain habitat management options, we manipulated the number of ecosystem services that participants knew about, and the level of detail of the information they were provided with. The preferences of participants differed depending on the number of services that were described. Providing people with ecosystem service information had a quantifiable effect on their preferences among different habitat management options, and increased the variability in preferences between people. These findings are consistent with the theory that ecosystem service information should encourage people to consider a wider range of benefits that nature provides, and this in turn may enable habitat management that better balances trade-offs between different services. Simply describing more ecosystem services to people had no effect on their preferences for management options, suggesting that detailed, empirical data on ecosystem services are required to affect decision making