title: Cumulative effects of land use on fish metrics in different types of running waters in Austria.
abstract: The catchment land-use composition of 249 fish sampling sites in Austrian running waters revealed effects on the biological integrity. Beyond correlative analysis, we investigated (1) which land-use category had the strongest effect on fish, (2) whether metrics of functional fish guilds reacted differently, (3) whether there were cumulative effects of land-use categories, and (4) whether effects varied in strength across river types. We fed 5 land-use categories into regression trees to predict the European Fish Index or fish metric of intolerant species (mainlySalmo trutta fario).Agriculture and urbanisation were the best predictors and indicated significant effects at levels of >23.3 and >2%, respectively. Model performance wasR2= 0.15 with the Fish Index andR2= 0.46 with intolerant species. The tree structure showed a cumulative effect from agriculture and urbanisation. For the intolerant species metric, a combination of high percentages for agriculture and urbanisation was related to moderate status, whereas <7.3% agriculture were related to good status, although urbanisation was higher than 1.8%. 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.
authors.affiliation: Department of Water, Atmosphere and Environment, Institute of Hydrobiology and Aquatic Ecosystem Management, BOKU, University of Natural Resources and Life Sciences, Max Emanuel-Strasse 17, 1180 Vienna, Austria.
authors.forename: Clemens
authors.initials: C
authors.lastname: Trautwein
authors.affiliation: Department of Water, Atmosphere and Environment, Institute of Hydrobiology and Aquatic Ecosystem Management, BOKU, University of Natural Resources and Life Sciences, Max Emanuel-Strasse 17, 1180 Vienna, Austria.
authors.forename: Rafaela
authors.initials: R
authors.lastname: Schinegger
authors.affiliation: Department of Water, Atmosphere and Environment, Institute of Hydrobiology and Aquatic Ecosystem Management, BOKU, University of Natural Resources and Life Sciences, Max Emanuel-Strasse 17, 1180 Vienna, Austria.
authors.forename: Stefan
authors.initials: S
authors.lastname: Schmutz
keywords: Cumulative effect; Fish; Fish metrics; IBI; Land use; Landscape composition; Moran’s I; Stream integrity