title: Effects of habitat structure and land-use intensity on the genetic structure of the grasshopper species Chorthippus parallelus.
abstract: Land-use intensity (LUI) is assumed to impact the genetic structure of organisms. While effects of landscape structure on the genetics of local populations have frequently been analysed, potential effects of variation in LUI on the genetic diversity of local populations have mostly been neglected. In this study, we used six polymorphic microsatellites to analyse the genetic effects of variation in land use in the highly abundant grasshopper Chorthippus parallelus. We sampled a total of 610 individuals at 22 heterogeneous grassland sites in the Hainich-Dün region of Central Germany. For each of these grassland sites we assessed habitat size, LUI (combined index of mowing, grazing and fertilization), and the proportion of grassland adjoining the sampling site and the landscape heterogeneity (the latter two factors within a 500 m buffer zone surrounding each focal site). We found only marginal genetic differentiation among all local populations and no correlation between geographical and genetic distance. Habitat size, LUI and landscape characteristics had only weak effects on most of the parameters of genetic diversity of C. parallelus; only expected heterozygosity and the grasshopper abundances were affected by interacting effects of LUI, habitat size and landscape characteristics. The lack of any strong relationships between LUI, abundance and the genetic structure might be due to large local populations of the species in the landscape, counteracting local differentiation and potential genetic drift effects.
authors.affiliation: Institute of Ecology, Friedrich-Schiller-University , 07742 Jena, Germany ; Terrestrial Ecology Research Group, Department of Ecology and Ecosystem Management , School of Life Sciences Weihenstephan, Technische Universität München , 85354 Freising, Germany.
authors.forename: Kerstin R
authors.initials: KR
authors.lastname: Wiesner
authors.affiliation: Terrestrial Ecology Research Group, Department of Ecology and Ecosystem Management , School of Life Sciences Weihenstephan, Technische Universität München , 85354 Freising, Germany.
authors.forename: Jan Christian
authors.initials: JC
authors.lastname: Habel
authors.affiliation: Terrestrial Ecology Research Group, Department of Ecology and Ecosystem Management , School of Life Sciences Weihenstephan, Technische Universität München , 85354 Freising, Germany.
authors.forename: Martin M
authors.initials: MM
authors.lastname: Gossner
authors.affiliation: Institute of Ecology, Friedrich-Schiller-University , 07742 Jena, Germany.
authors.forename: Hugh D
authors.initials: HD
authors.lastname: Loxdale
authors.affiliation: Institute of Ecology, Friedrich-Schiller-University , 07742 Jena, Germany.
authors.forename: Günter
authors.initials: G
authors.lastname: Köhler
authors.affiliation: Unit of Evolutionary Biology/Systematic Zoology , Institute of Biochemistry and Biology , University of Potsdam, 14476 Potsdam, Germany.
authors.forename: Anja R R
authors.initials: AR
authors.lastname: Schneider
authors.affiliation: Unit of Evolutionary Biology/Systematic Zoology , Institute of Biochemistry and Biology , University of Potsdam, 14476 Potsdam, Germany.
authors.forename: Ralph
authors.initials: R
authors.lastname: Tiedemann
authors.affiliation: Terrestrial Ecology Research Group, Department of Ecology and Ecosystem Management , School of Life Sciences Weihenstephan, Technische Universität München , 85354 Freising, Germany.
authors.forename: Wolfgang W
authors.initials: WW
authors.lastname: Weisser
keywords: agricultural intensification; edge effects; genetic differentiation; genetic diversity; land-use index