In the current scenario of climate change characterized by a generalized warming, many species are facing local extinctions in areas with conditions near their thermal tolerance threshold. At present, the southern limit of the geographical distribution of several habitat-forming algae of cold-temperate affinities is located in the Northwest Iberian Peninsula, and the Rías Baixas may be acting as contemporary refugia at the range edge. Therefore, it is necessary to analyze future changes induced by ocean warming in this area that may induce changes in macroalgae populations. The Delft3D-Flow model forced with climatic data was used to calculate July–August sea surface temperature (SST) for the present (1999–2018) and for the far future (2080–2099). Mean daily SST was used to develop and calibrate a mechanistic geographical distribution model based on the thermal survival threshold of two intertidal habitat-forming macroalgae, namely Himanthalia elongata (L.) S.F.Gray and Bifurcaria bifurcata R. Ross. Results show that H. elongata will become extinct in the Rías Baixas by the end of the century, while B. bifurcata will persist and may occupy potential free space left by the decline in H. elongata.

在当前以普遍变暖为特征的气候变化背景下，许多物种在条件接近其耐热阈值的地区面临局部灭绝。目前，几种冷温带亲缘性栖息地藻类地理分布的最南端位于伊比利亚半岛西北部，而拜萨斯河口可能是该范围边缘的当代避难所。因此，有必要分析该地区海洋变暖引起的未来变化可能引起大型藻类种群的变化。 Delft3D-Flow 模型结合气候数据用于计算当前（1999-2018 年）和遥远的未来（2080-2099 年）7 月至 8 月的海面温度（SST）。利用日平均海表温度来开发和校准基于两种潮间带生境形成大型藻类（即Himanthalia elongata (L.) SFGray 和Bifurcaria bifurcata R. Ross）的热生存阈值的机械地理分布模型。结果表明，到本世纪末， H. elongata将在下海湾地区灭绝，而B. bifurcata将继续存在，并可能占据H. elongata减少后留下的潜在自由空间。