Tuexenia 36: 97–119. Göttingen 2016. doi: 10.14471/2016.36.006, available online at www.tuexenia.de Influence of grassland management on the biodiversity of plants and butterflies on organic suckler cow farms Einfluss des Grünlandmanagements auf Phytodiversität und Tagfalter auf ökologisch bewirtschafteten Mutterkuhbetrieben Michaela Kruse1, *, Karin Stein-Bachinger2, Frank Gottwald2, Elisabeth Schmidt3 & Thilo Heinken4 1Erich-Weinert-Straße 15, 14478 Potsdam, Germany,
[email protected]; 2Leibniz-Centre for Agricultural Landscape Research (ZALF) e.V., 15374 Müncheberg, Germany,
[email protected];
[email protected]; 3Mündener Str. 40, 37213 Witzenhausen,
[email protected]; 4General Botany, University of Potsdam, Maulbeerallee 3, 14469 Potsdam, Germany,
[email protected] *Corresponding author Abstract The intensification of agricultural practices has led to a severe decrease in grassland biodiversity. Although there is strong evidence that organic farming can reduce the negative impacts of land use, knowledge regarding the most beneficial management system for species richness on organic grass- lands is still scarce. This study examines differences in the biodiversity of plants and butterflies on rotationally and continuously grazed pastures as well as on meadows cut twice per year on two large organic suckler cow farms in NE Germany. Vegetation and flower abundance, as factors likely to influence butterfly abundance and diversity, were compared and used to explain the differences. The data attained by vegetation assessments and monthly transect inspections from May to August were analyzed using descriptive statistics and nonparametric methods. The abiotic site conditions of the studied plots had more influence on plant species numbers than the management method. Dry and nutrient-poor areas (mainly poor types of Cynosurion) and undrained wet fens (Calthion) were im- portant for phytodiversity, measured by the absolute number of species, indicator species for ecologi- cally valuable grasslands and the Shannon Index.