title: Linking land use variables and invertebrate taxon richness in small and medium-sized agricultural streams on a landscape level.
abstract: In this study the average numbers of invertebrate species across an arable landscape in central Germany (surveys from 15 years in 90 streams at 202 sites) were assessed for their correlation with environmental factors such as stream width, land use (arable land, forest, pasture, settlement), soil type, and agriculture-derived stressors. The stress originating from arable land was estimated by the factor "risk of runoff," which was derived from a runoff model (rainfall-induced surface runoff). Multivariate analysis explained 39.9% of the variance in species number, revealing stream width as the most important factor (25.3%), followed by risk of runoff (9.7%). The results showed that wider streams--with or without agricultural stressors--contained significantly higher species numbers than narrower streams. This can be explained by potentially more diverse in-stream structures leading to more habitats and niches. However, negative effects on species number owing to runoff from arable land could be distinguished from the effect of stream width: the number of species within each stream width class significantly decreased with increasing risk of runoff. Therefore the factor "risk of runoff" is considered to express a significant proportion of the variability in macroinvertebrate communities caused by stressors of agricultural origin.
authors.affiliation: Department of Limnology and Ecotoxicology, Zoological Institute of the Technical University Braunschweig, Fasanenstr. 3, Braunschweig 38092, Germany. m.probst@tu-braunschweig.de
authors.forename: Michael
authors.initials: M
authors.lastname: Probst
authors.forename: Norbert
authors.initials: N
authors.lastname: Berenzen
authors.forename: Annette
authors.initials: A
authors.lastname: Lentzen-Godding
authors.forename: Ralf
authors.initials: R
authors.lastname: Schulz
authors.forename: Matthias
authors.initials: M
authors.lastname: Liess
mesh_terms: D000383:Agriculture; D000818:Animals; D002965:Classification; D004784:Environmental Monitoring; D007448:Invertebrates / Q000254:growth & development*; D011891:Rain; D014872:Water Movements; D014873:Water Pollutants / Q000506:poisoning*
chemical_list: D014873:Water Pollutants