Programa de Pós-Graduação em Ecologia, Instituto de Biologia (IB), Universidade Estadual de Campinas (UNICAMP), Campinas, Brazil.
Laboratory of Multitrophic Interactions and Biodiversity, Institute of Biology, University of Campinas, Campinas, SP, Brazil.
Glob Chang Biol. 2018 Aug;24(8):3715-3728. doi: 10.1111/gcb.14314. Epub 2018 Jun 3.
Global biodiversity is eroding due to anthropogenic causes, such as climate change, habitat loss, and trophic simplification of biological communities. Most studies address only isolated causes within a single group of organisms; however, biological groups of different trophic levels may respond in particular ways to different environmental impacts. Our study used natural microcosms to investigate the predicted individual and interactive effects of warming, changes in top predator diversity, and habitat size on the alpha and beta diversity of macrofauna, microfauna, and bacteria. Alpha diversity (i.e., richness within each bromeliad) generally explained a larger proportion of the gamma diversity (partitioned in alpha and beta diversity). Overall, dissimilarity between communities occurred due to species turnover and not species loss (nestedness). Nevertheless, the three biological groups responded differently to each environmental stressor. Microfauna were the most sensitive group, with alpha and beta diversity being affected by environmental changes (warming and habitat size) and trophic structure (diversity of top predators). Macrofauna alpha and beta diversity was sensitive to changes in predator diversity and habitat size, but not warming. In contrast, the bacterial community was not influenced by the treatments. The community of each biological group was not mutually concordant with the environmental and trophic changes. Our results demonstrate that distinct anthropogenic impacts differentially affect the components of macro and microorganism diversity through direct and indirect effects (i.e., bottom-up and top-down effects). Therefore, a multitrophic and multispecies approach is necessary to assess the effects of different anthropogenic impacts on biodiversity.
由于人为原因，如气候变化、生境丧失和生物群落的营养简化，全球生物多样性正在受到侵蚀。大多数研究只关注单一生物群体内的孤立原因；然而，不同营养层次的生物群体可能会以特定的方式对不同的环境影响做出反应。我们的研究使用自然微宇宙来调查变暖、顶级捕食者多样性变化和生境大小对大型动物、小型动物和细菌的α多样性和β多样性的预测的单独和交互影响。α多样性（即在每个凤梨科植物内的丰富度）通常解释了更大比例的γ多样性（分为α和β多样性）。总的来说，群落之间的差异是由于物种更替而不是物种丧失（嵌套性）。然而，三个生物群体对每个环境胁迫因子的反应不同。小型动物是最敏感的群体，α和β多样性受到环境变化（变暖、生境大小）和营养结构（顶级捕食者多样性）的影响。大型动物的α和β多样性对捕食者多样性和生境大小的变化敏感，但对变暖不敏感。相比之下，细菌群落不受处理的影响。每个生物群体的群落与环境和营养变化并不相互一致。我们的结果表明，不同的人为影响通过直接和间接影响（即自上而下和自下而上的影响），对宏观和微生物多样性的组成部分产生不同的影响。因此，需要采用多营养层次和多物种方法来评估不同人为影响对生物多样性的影响。
