Effects of climate and land-use change on lowland stream ecosystems

Abstract

During the past decades human interference in regional hydrologic systems had intensified. These systems act as an integrating medium. They link climate, human activities and ecological processes through groundwater and surface water interactions. In this study we have examined the potential impacts of climate change on the streams Beerze and Reusel in the Netherlands, and also the possible interactions with other influences like agricultural drainage. For examining the potential impacts of climate change we have followed a scheme involving predictions for: - indirect effects of climate change, that are transferred to ecological subsystems through the regional hydrologic system. - direct effects of climate change, through the direct influence of temperature on the germination, flowering and fruiting of plant species. The results indicate for the study region a heigh sensitivity of the peak discharges for the precipitation: an increase of 17% in the winter precipitation caused a more than 50% increase of the peak discharges. The upward seepage of groundwater to the rootzone of natural vegetation is especially sensitive for the evapotranspiration, and hardly not for the precipitation. Under all scenarios the climate change had a significantly negative effect on the stream community of the aquatic ecosystem. Compared with the impact of other antropogenic influences like agricultural drainage, the effecs of climate change on the area of wet and moist reverine grasslands are moderate, and mostly they are positive.