Evidence of large‐scale biodiversity degradation in marine ecosystems has been reported worldwide, yet most research has focused on few species of interest or on limited spatiotemporal scales. Here we assessed the spatial and temporal changes in the taxonomic and functional composition of fish communities in European seas over the last 25 years (1994–2019). We then explored how these community changes were linked to environmental gradients and fishing pressure. We show that the spatial variation in fish species composition is more than two times higher than the temporal variation, with a marked spatial continuum in taxonomic composition and a more homogenous pattern in functional composition. The regions warming the fastest are experiencing an increasing dominance and total abundance of r‐strategy fish species (lower age of maturity). Conversely, regions warming more slowly show an increasing dominance and total abundance of K‐strategy species (high trophic level and late reproduction). Among the considered environmental variables, sea surface temperature, surface salinity and chlorophyll‐a most consistently influenced communities' spatial patterns, while bottom temperature and oxygen had the most consistent influence on temporal patterns. Changes in communities' functional composition were more closely related to environmental conditions than taxonomic changes. Our study demonstrates the importance of integrating community‐level species traits across multi‐decadal scales and across a large region to better capture and understand ecosystem‐wide responses and provides a different lens on community dynamics that could be used to support sustainable fisheries management.

中文翻译：

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欧洲海洋鱼类群落分类和功能组成的长期变化


世界各地都报道了海洋生态系统大规模生物多样性退化的证据，但大多数研究都集中在少数感兴趣的物种或有限的时空尺度上。在这里，我们评估了过去 25 年（1994-2019）欧洲海域鱼类群落分类和功能组成的时空变化。然后我们探讨了这些群落变化如何与环境梯度和捕捞压力相关。我们表明，鱼类物种组成的空间变化比时间变化高两倍以上，分类组成具有明显的空间连续性，功能组成的模式更加均匀。变暖最快的地区的 r 策略鱼类（成熟年龄较低）的优势和总丰度正在增加。相反，变暖较慢的地区显示出 K 策略物种的优势和总丰度不断增加（高营养级和较晚的繁殖）。在考虑的环境变量中，海面温度、表面盐度和叶绿素-a对群落的空间模式的影响最一致，而底部温度和氧气对时间模式的影响最一致。群落功能组成的变化与环境条件的关系比与分类变化的关系更为密切。我们的研究证明了在多个十年尺度和一个大区域内整合群落层面物种特征的重要性，以更好地捕获和理解整个生态系统的反应，并为群落动态提供不同的视角，可用于支持可持续渔业管理。