Chisté Melanie N, Mody Karsten, Kunz Gernot, Gunczy Johanna, Blüthgen Nico
Ecological Networks Research Group, Department of Biology, Technische Universität Darmstadt, Schnittspahnstr. 3, 64287, Darmstadt, Germany.
Institut für Zoologie, Karl-Franzens-Universität Graz, Universitätsplatz 2, 8010, Graz, Austria.
Oecologia. 2018 Feb;186(2):529-540. doi: 10.1007/s00442-017-4031-0. Epub 2017 Dec 4.
The current biodiversity decline through anthropogenic land-use not only involves local species losses, but also homogenization of communities, with a few generalist species benefitting most from human activities. Most studies assessed community heterogeneity (β-diversity) on larger scales by comparing different sites, but little is known about impacts on β-diversity within each site, which is relevant for understanding variation in the level of α-diversity, the small-scale distribution of species and associated habitat heterogeneity. To obtain our dataset with 36,899 individuals out of 117 different plant- and leafhopper (Auchenorrhyncha) species, we sampled communities of 140 managed grassland sites across Germany by quantitative vacuum suction of five 1 m plots on each site. Sites differed in land-use intensity as characterized by intensity of fertilization, mowing and grazing. Our results demonstrate a significant within-site homogenization of plant- and leafhopper communities with increasing land-use intensity. Correspondingly, density (- 78%) and γ-diversity (- 35%) declined, particularly with fertilization and mowing intensity. More than 34% of plant- and leafhopper species were significant losers and only 6% were winners of high land-use intensity, with abundant and widespread species being less affected. Increasing land-use intensity adversely affected dietary specialists and promoted generalist species. Our study emphasizes considerable, multifaceted effects of land-use intensification on species loss, with a few dominant generalists winning, and an emerging trend towards more homogenized assemblages. By demonstrating homogenization for the first time within sites, our study highlights that anthropogenic influences on biodiversity even occur on small scales.
当前因人为土地利用导致的生物多样性下降不仅涉及当地物种丧失，还包括群落同质化，少数广适性物种从人类活动中受益最多。大多数研究通过比较不同地点，在较大尺度上评估群落异质性（β多样性），但对于每个地点内β多样性的影响知之甚少，而这对于理解α多样性水平的变化、物种的小尺度分布以及相关栖息地异质性至关重要。为了获得包含117种不同植物和叶蝉（半翅目头喙亚目）物种的36,899个个体的数据集，我们通过对德国140个管理草地地点的每个地点定量真空抽吸五个1米样方，对这些地点的群落进行了采样。各地点在施肥、割草和放牧强度所表征的土地利用强度方面存在差异。我们的结果表明，随着土地利用强度增加，植物和叶蝉群落出现了显著的地点内同质化。相应地，密度（-78%）和γ多样性（-35%）下降，特别是随着施肥和割草强度的增加。超过34%的植物和叶蝉物种是高土地利用强度的显著受害者，只有6%是受益者，丰富且分布广泛的物种受影响较小。土地利用强度增加对食性特化物种产生不利影响，并促进了广适性物种。我们的研究强调了土地利用集约化对物种丧失具有多方面的重大影响，少数占主导地位的广适性物种胜出，且出现了群落更加同质化的新趋势。通过首次证明地点内的同质化，我们的研究突出了人为因素对生物多样性的影响甚至在小尺度上也会发生。
