Integrated modelling of aquatic ecosystems in China: Distribution of benthic macroinvertebrates at catchment scale

The distribution of freshwater benthic macroinvertebrates can be quantified by means of species distribution models (SDMs). For this purpose, the occurrence of a taxon is linked to environmental variables the occurrence sites to calculate the presence probability in the study area. The application of SDMs in freshwater ecosystems is relatively recent, as such models deliver limited information on potential species distribution at the catchment scale. Furthermore, the use of extensive environmental variables such as hydrological and hydraulic data is desirable in order to take into account relevant terrestrial and limnic processes and their interactions. Such information is rarely available. In the upper Changjiang catchment (approx. 1,717 km(2)) in China's south-east, an ecohydrological SWAT-model and a biological BIOMOD/R SDM were integrated for the first time, based on the examples of two taxa (Corbicula sp. and Hydropsyche sp.). The occurrence probability of the two taxa was calculated through hydrologic, climatic and topographic variables at a high resolution of 90 m. The hydrology-related variables (e.g. mean temperature during dry season) had the greatest impact on the modelled occurrence of the taxa. Their application and improvement point to a better understanding of the interactions between terrestrial and limnic processes, which is of great importance considering current environmental changes such as landuse and climate change.