The increase in frequency and intensity of extreme climate events over the last few decades has been leading to profound changes in estuarine and marine ecosystems worldwide, with strong implications for the species inhabiting these ecosystems as well as for the services provided by them. In this study, we analysed the effects of climate variability on the temporal and spatial variations in population dynamics of the green crab Carcinus maenas in the Mondego estuary (Portugal), between 2003 and 2018. In this 15-year period, a greater recruitment of C. maenas was observed during drought periods, periods which was matched by an increase in secondary production. Ontogenic stage segregation was also observed, with juveniles being found mainly in the further upriver areas of the estuary. The estuarine population was mainly composed of the green morphotype, with the orange and red morphotypes present in more downstream areas of the estuary. Redundancy analysis (RDA) showed high spatial and temporal variability of C. maenas in the estuary which was related with environmental changes over the 15-year period. A correlation between C. maenas biological features and several local-scale (salinity and river runoff) and large-scale (North Atlantic Oscillation index and Eastern Atlantic pattern) environmental variables was identified through cumulative sums analysis (CUSUM), indicating a strong environmental control on C. maenas population dynamics. This paper shows the importance of relatively long-term datasets to unravel the effects of extreme weather events due to climate change on key epibenthic estuarine species, and also how they might cope with a changing marine environment.

过去几十年极端气候事件的频率和强度增加，导致全球河口和海洋生态系统发生深刻变化，对栖息在这些生态系统中的物种及其提供的服务产生重大影响。在这项研究中，我们分析了2003 年至 2018 年间气候变异对Mondego 河口（葡萄牙）绿蟹Carcinus maenas种群动态时空变化的影响。 在这 15 年期间，更多的C. maenas在干旱时期观察到，这与二次生产的增加相匹配。还观察到个体发育阶段的分离，幼鱼主要在河口的上游地区发现。河口种群主要由绿色形态型组成，橙色和红色形态型存在于河口下游地区。冗余分析 (RDA) 显示河口C. maenas 的高时空变异性与 15 年期间的环境变化有关。C. maenas之间的相关性通过累积总和分析 (CUSUM) 确定了生物特征和几个局部尺度（盐度和河流径流）和大尺度（北大西洋涛动指数和东大西洋模式）环境变量，表明对C. maenas种群动态的强大环境控制. 本文展示了相对长期数据集对于揭示气候变化导致的极端天气事件对主要底栖河口物种的影响的重要性，以及它们如何应对不断变化的海洋环境。