Potential impacts of groundwater conservation measures on catchment-wide vegetation patterns in a future climate

Abstract

In temperate Europe, warming, summer droughts, and increased winter precipitation are predicted to have profound effects on vegetation performance and composition. Especially groundwater dependent vegetation will be affected. These impacts within the landscape may negatively affect the connectivity within ecological networks. Objectives With an integrated surface- and groundwater model and a climate robust traits-based vegetation model, we simulated the implementation of water conservation measures in a stream valley catchment in the Netherlands. Methods We assessed the impacts of conservation measures on groundwater levels, seepage flux, and vegetation composition for the current climate and two climate scenarios, with a global temperature increase of 2 °C and an increase (+6 %) or decrease (−2 %) in annual precipitation. Results Our model showed that water conservation measures on average increased groundwater levels, although there were large spatial differences. At the same time, water conservation decreased the seepage flux in the stream valley, thereby decreasing the supply of nutrient-poor groundwater. These negative impacts on seepage flux will be amplified in a future climate. Semi-terrestrial vegetation along the streams will benefit from water conservation measures and increasingly so in a future climate. Other vegetation types showed a wide array of responses depending on spatially-differentiated changes in groundwater level and seepage fluxes. Conclusion Our results highlight the importance of integrating spatially-explicit hydrology-vegetation interactions into models that evaluate climate adaptation measures. Customized water conservation measures can contribute to minimize negative effects of climate change on groundwater dependent vegetation and ensure the robustness of ecological networks. Keywords