Species in the brackish and estuarine ecosystems will experience multiple changes in hydrographic variables due to ongoing climate change and nutrient loads. Here, we investigate how a glacial relict species (Saduria entomon), having relatively cold, low salinity biogeographic origin, could be affected by the combined scenarios of climate change and eutrophication. It is an important prey for higher trophic-level species such as cod, and a predator of other benthic animals. We constructed habitat distribution models based occurrence and density of this species across the entire Baltic and estimated the relative importance of different driving variables. We then used two regional coupled ocean-biogeochemical models to investigate the combined impacts of two future climate change and nutrient loads scenarios on its spatial distribution in 2070–2100. According to the scenarios, the Baltic Sea will become warmer and fresher. Our results show that expected changes in salinity and temperature outrank those due to two nutrient-load scenarios (Baltic Sea Action Plan and business as usual) in their effect on S. entomon distribution. The results are relatively similar when using different models with the same scenarios, thereby increasing the confidence of projections. Overall, our models predict a net increase (and local declines) of suitable habitat area, total abundance and biomass for this species, which is probably facilitated by strong osmoregulation ability and tolerance to temperature changes. We emphasize the necessity of considering multiple hydrographic variables when estimating climate change impacts on species living in brackish and estuarine systems.

中文翻译：

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物种分布和海洋生物地球化学模型的结合表明，气候变化将富营养化视为波罗的海河口生态系统中主要底栖甲壳类动物未来分布的驱动因素

由于持续的气候变化和养分负荷，咸淡和河口生态系统中的物种将经历水文变量的多种变化。在这里，我们调查了一个冰川遗迹物种（Saduria entomon），具有相对较低的盐度和较低的生物地理起源，可能会受到气候变化和富营养化的综合影响。它是较高营养级别物种（例如鳕鱼）和其他底栖动物捕食者的重要猎物。我们基于整个波罗的海地区该物种的发生和密度构建了栖息地分布模型，并估算了不同驱动变量的相对重要性。然后，我们使用了两个区域耦合的海洋生物地球化学模型，研究了2070-2100年两个未来气候变化和养分负荷情景对其空间分布的综合影响。根据方案，波罗的海将变得越来越热。S. entomon分布。当在相同场景下使用不同模型时，结果相对相似，从而增加了预测的置信度。总体而言，我们的模型预测，该物种的适宜栖息地面积，总丰度和生物量将净增加（和局部减少），这可能是由于强大的渗透调节能力和对温度变化的耐受性所致。我们强调在估算气候变化对咸淡水和河口系统中物种的影响时必须考虑多个水文变量。