Landscape - pressure – fish - cascades (LANPREF)

Environmental conditions across whole landscapes clearly impact instream habitats and biological communities; however, these linkages are not well understood and have not been synthesized for European streams and rivers. For many years, aquatic research has focused on the response of biota to the local instream environment. Investigators now recognize that land-use patterns at the landscape scale are a principal threat to the ecological integrity of river ecosystems, impacting habitat, water quality, and the biota via numerous and complex pathways. This innovative and efficient project, LANPREF, will apply recent advances in landscape ecology to the assessment of aquatic ecosystems. The LANPREF project contains four unique innovations. First, it will utilize new spatial databases that contain standardised and consistent spatial data on land use/cover, rivers, and catchments at the European scale. The LANPREF project will also take advantage of an enormous data set, containing more than ten thousand fish sampling sites from 16 European countries with profound information on hydromorphologic and water quality pressures compiled as part of the EU project EFI+. Using these existing resources and the combined expertise of the project collaborators, we will provide the first insights into the effects of land use patterns on aquatic organisms across the European continent. We use Burcher`s concept of "land cover cascades" (Burcher et al. 2007) and extend it to other pressures. In this way, we consider spatially-nested relationships through which land-cover change and other disturbances are propagated from larger to smaller spatial scales. Novel statistical tools and a dataset large enough to enable stratification across environmental characteristics will help us to identify and interpret covariation between pressures and the natural environment, providing a better understanding of mechanistic processes underlying the landscape - pressure - fish relationship. We will quantify the degree to which current relationships are influenced by the legacies of past land use and other pressures. The project`s second innovation will be to work simultaneously over multiple spatial scales. We will apply our unique expertise in GIS and spatial technologies to identify those spatial scales at which land-use and/or other pressures and fish communities are most tightly coupled. Our third innovation will be to work not only with compositional metrics (e.g., quantities of land-use within a catchment) but to develop and analyze metrics describing landscape and pressure configuration (e.g. distribution of patches, connectivity of vegetated areas) and to quantify their impacts on fish communities. Finally, LANPREF will build on cooperative international partnerships with colleagues in the Pacific Northwest, USA, to enable novel comparative analyses and a synthesis of landscape impacts on fish communities across continents and across extremely different land-use histories.

Environmental conditions across whole landscapes impact instream habitats and biological communities. However, these linkages are often not well understood and have not been synthesized for European running waters. For many years, aquatic research has focused on the response of biota to the local instream environment and was examined in related case studies. Investigators now recognize that human pressures and land-use patterns at the landscape scale are a principal threat to the ecological integrity and status of aquatic ecosystems, impacting habitat, water quality, and the biota via numerous and complex pathways. Such an approach needs analyses on a large scale. LANPREF builds on this understanding, i.e. how human pressures and different land-use patterns affect running waters, by using fish assemblages as indicators. Based on a large dataset, different pressures types (i.e. hydrological-, morphological-, water quality- and connectivity pressures) and land-use categories (as e.g. agriculture, urban, forest and shrub land) were compared with a large number of fish assemblage metrics to show the response of the fish fauna to pressures on the European and Austrian scale. As European running waters differ in their biogeographic characteristics, homogeneous fish assemblage types were identified and described by various environmental variables, i.e. altitude, river channel slope etc. The results show that the degradation of European rivers is widespread. Water quality degradation as single pressure is not very common; whereas many sites are affected by hydromorphological pressures or a combination of pressures, i.e. water quality pressures interacting with hydromorphological pressures. Moreover, the analysed fish metrics responded specifically to water quality pressures and hydromorphological pressures in three river types and to multiple pressures in all river types. The fact that many metrics reacted exclusively within one river type supports the hypothesis of a type-specific approach.Results of research questions concerning relationship between land use composition and fish assemblages could proof the findings of several studies and reveal new insight to functional fish guild response upon land use. We could find a cumulative effect of several land use categories and quantify thresholds that clearly impact fish assemblages. Agriculture and urbanisation were the best predictors and indicated significant effects at levels of >23.3% and >2% of upstream catchment, respectively. Effects of agriculture and urbanisation accumulated when both categories occur above the threshold in the catchment. Headwater river types showed stronger responses to land use than river types of lower gradient and turned out to be more sensitive to urbanisation than agriculture.Our results constitute a baseline from which future trends can be evaluated. Especially in the context of river restoration and aquatic ecosystem management, LANPREF helped to better identify processes and effects that are relevant for river protection and restoration.