Institute of Marine Biological Resources and Inland Waters, Hellenic Centre for Marine Research (HCMR), 46.7 km Athens-Sounio Ave., Anavyssos, 19013 Athens, Greece.
Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Bilbao, Spain.
Sci Total Environ. 2019 Jan 10;647:1179-1187. doi: 10.1016/j.scitotenv.2018.08.105. Epub 2018 Aug 8.
The hydrological and biological complexity of temporary rivers as well as their importance in providing goods and services is increasingly recognized, as much as it is the vulnerability of the biotic communities in view of climate change and increased anthropogenic pressures. However, the effects of flow intermittency (resulting from both seasonal variations and rising hydrological pressure) and pollution on biodiversity and ecosystem functioning have been overlooked in these ecosystems. We explore the way multiple stressors affect biodiversity and ecosystem functioning, as well as the biodiversity-ecosystem functioning (B-EF) relationship in a Mediterranean temporary river. We measured diversity of benthic communities (i.e. diatoms and macroinvertebrates) and related ecosystem processes (i.e. resource use efficiency-RUE and organic matter breakdown-OMB) across a pollution and flow intermittency gradient. Our results showed decreases in macroinvertebrate diversity and the opposite trend in diatom assemblages, whereas ecosystem functioning was negatively affected by both pollution and flow intermittency. The explored B-EF relationships showed contrasting results: RUE decreased with higher diatom diversity, whereas OMB increased with increased macroinvertebrate diversity. The different responses suggest contrasting operating mechanisms, selection effects possibly driving the B-EF relationship in diatoms and complementarity effects driving the B-EF relationship in macroinvertebrates. The understanding of multiple stressor effects on diversity and ecosystem functioning, as well as the B-EF relationship in temporary rivers could provide insights on the risks affecting ecosystem functioning under global change.
临时河流的水文和生物复杂性及其在提供货物和服务方面的重要性正日益得到认识，就像气候变化和人为压力增加导致生物群落的脆弱性一样。然而，在这些生态系统中，人们忽视了水流间歇性（由季节性变化和水文压力增加造成）和污染对生物多样性和生态系统功能的影响。我们探讨了多种胁迫因子对生物多样性和生态系统功能的影响，以及在一个地中海临时河流中生物多样性-生态系统功能（B-EF）关系。我们在污染和水流间歇性梯度上测量了底栖生物群落（即硅藻和大型无脊椎动物）的多样性及其相关生态系统过程（即资源利用效率-RUE 和有机物分解-OMB）。我们的研究结果表明，大型无脊椎动物多样性减少，而硅藻组合则呈现相反的趋势，而生态系统功能则受到污染和水流间歇性的负面影响。所探索的 B-EF 关系显示出相反的结果：RUE 随着硅藻多样性的增加而降低，而 OMB 随着大型无脊椎动物多样性的增加而增加。不同的反应表明存在不同的作用机制，选择效应可能驱动了硅藻的 B-EF 关系，而互补效应则驱动了大型无脊椎动物的 B-EF 关系。了解多种胁迫因子对多样性和生态系统功能的影响，以及临时河流中的 B-EF 关系，可以为了解全球变化下影响生态系统功能的风险提供见解。
