Chevillot Xavier, Drouineau Hilaire, Lambert Patrick, Carassou Laure, Sautour Benoit, Lobry Jérémy
Irstea, UR EABX, Cestas, FRANCE.
Université de Bordeaux, UMR CNRS 5805 EPOC-OASU, Station Marine d'Arcachon, Arcachon, France.
PLoS One. 2017 Mar 29;12(3):e0173752. doi: 10.1371/journal.pone.0173752. eCollection 2017.
Alterations of species phenology in response to climate change are now unquestionable. Until now, most studies have reported precocious occurrence of life cycle events as a major phenological response. Desynchronizations of biotic interactions, in particular predator-prey relationships, are however assumed to strongly impact ecosystems' functioning, as formalized by the Match-Mismatch Hypothesis (MMH). Temporal synchronicity between juvenile fish and zooplankton in estuaries is therefore of essential interest since estuaries are major nursery grounds for many commercial fish species. The Gironde estuary (SW France) has suffered significant alterations over the last three decades, including two Abrupt Ecosystem Shifts (AES), and three contrasted intershift periods. The main objective of this study was to depict modifications in fish and zooplankton phenology among inter-shift periods and discuss the potential effects of the resulting mismatches at a community scale. A flexible Bayesian method was used to estimate and compare yearly patterns of species abundance in the estuary among the three pre-defined periods. Results highlighted (1) an earlier peak of zooplankton production and entrance of fish species in the estuary and (2) a decrease in residence time of both groups in the estuary. Such species-specific phenological changes led to changes in temporal overlap between juvenile fish and their zooplanktonic prey. This situation questions the efficiency and potentially the viability of nursery function of the Gironde estuary, with potential implications for coastal marine fisheries of the Bay of Biscay.
物种物候对气候变化的响应变化现已确凿无疑。到目前为止，大多数研究报告称生命周期事件提前出现是主要的物候响应。然而，生物相互作用的不同步，特别是捕食者与猎物的关系，被认为会强烈影响生态系统的功能，正如匹配 - 不匹配假说（MMH）所阐述的那样。因此，河口幼鱼与浮游动物之间的时间同步性至关重要，因为河口是许多商业鱼类的主要育苗场。在过去三十年里，吉伦特河口（法国西南部）发生了重大变化，包括两次生态系统突变（AES）以及三个截然不同的突变间期。本研究的主要目的是描述不同突变间期鱼类和浮游动物物候的变化，并讨论由此产生的不匹配在群落尺度上的潜在影响。我们使用一种灵活的贝叶斯方法来估计和比较河口在三个预定义时期内物种丰度的年度模式。结果表明：（1）浮游动物产量峰值提前以及鱼类物种进入河口的时间提前；（2）这两个群体在河口的停留时间减少。这种特定物种的物候变化导致幼鱼与其浮游动物猎物之间的时间重叠发生变化。这种情况对吉伦特河口育苗功能的效率以及潜在的生存能力提出了质疑，可能会对比斯开湾的沿海海洋渔业产生影响。
