Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland.
Department of Geography, University of Zurich, Zurich, Switzerland.
PLoS One. 2020 May 14;15(5):e0233104. doi: 10.1371/journal.pone.0233104. eCollection 2020.
Research of the past decades has shown that biodiversity is a fundamental driver of ecosystem functioning. However, most of this biodiversity-ecosystem functioning (BEF) research focused on experimental communities on small areas where environmental context was held constant. Whether the established BEF relationships also apply to natural or managed ecosystems that are embedded in variable landscape contexts remains unclear. In this study, we therefore investigated biodiversity effects on ecosystem functions in 36 forest stands that were located across a vast range of environmental conditions in managed landscapes of Central Europe (Switzerland). Specifically, we approximated forest productivity by leaf area index and forest phenology by growing-season length and tested effects of tree species richness and land-cover richness on these variables. We then examined the correlation and the confounding of these local and landscape-level diversity effects with environmental context variables related to forest stand structure (number of trees), landscape structure (land-cover edge density), climate (annual precipitation) and topography (mean altitude). We found that of all tested variables tree species richness was among the most important determinants of forest leaf area index and growing-season length. The positive effects of tree species richness on these two ecosystem variables were remarkably consistent across the different environmental conditions we investigated and we found little evidence of a context-dependent change in these biodiversity effects. Land-cover richness was not directly related to local forest functions but could nevertheless play a role via a positive effect on tree species richness.
过去几十年的研究表明，生物多样性是生态系统功能的基本驱动因素。然而，大多数关于生物多样性-生态系统功能（BEF）的研究都集中在小面积的实验群落上，这些群落的环境背景保持不变。已建立的 BEF 关系是否也适用于自然或管理的生态系统，这些生态系统嵌入在变化的景观背景中，目前尚不清楚。在这项研究中，我们因此调查了生物多样性对欧洲中部管理景观中 36 个森林林分的生态系统功能的影响（瑞士）。具体来说，我们通过叶面积指数来近似森林生产力，通过生长季节长度来近似森林物候，并测试了树种丰富度和土地覆盖丰富度对这些变量的影响。然后，我们检查了这些局部和景观多样性效应与与森林林分结构（树木数量）、景观结构（土地覆盖边缘密度）、气候（年降水量）和地形（平均海拔）相关的环境背景变量之间的相关性和混淆。我们发现，在所测试的所有变量中，树种丰富度是森林叶面积指数和生长季节长度的最重要决定因素之一。树种丰富度对这两个生态系统变量的积极影响在我们研究的不同环境条件下非常一致，我们几乎没有证据表明这些生物多样性效应存在依赖于环境的变化。土地覆盖丰富度与当地森林功能没有直接关系，但通过对树种丰富度的积极影响，它仍然可以发挥作用。
