Quantifying changes in functional community structure driven by disturbance is critical to anticipate potential shifts in ecosystem functioning. However, how marine heatwaves (MHWs) affect the functional structure of temperate coral‐dominated communities is poorly understood. Here, we used five long‐term (> 10 years) records of Mediterranean coralligenous assemblages in a multi‐taxa, trait‐based analysis to investigate MHW‐driven changes in functional structure. We show that, despite stability in functional richness (i.e. the range of species functional traits), MHW‐impacted assemblages experienced long‐term directional changes in functional identity (i.e. their dominant trait values). Declining traits included large sizes, long lifespans, arborescent morphologies, filter‐feeding strategies or calcified skeletons. These traits, which were mostly supported by few sensitive and irreplaceable species from a single functional group (habitat‐forming octocorals), disproportionally influence certain ecosystem functions (e.g. 3D‐habitat provision). Hence, MHWs are leading to assemblages that are deficient in key functional traits, with likely consequences for the ecosystem functioning.

中文翻译：

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气候变化改变了地中海珊瑚群落的功能特征

量化由干扰驱动的功能性群落结构的变化对于预测生态系统功能的潜在变化至关重要。但是，人们对海洋热波（MHW）如何影响以温带珊瑚为主的社区的功能结构知之甚少。在这里，我们在基于特征的多分类单元中使用了五个地中海珊瑚组合的长期（> 10年）记录，以调查MHW驱动的功能结构变化。我们表明，尽管功能丰富性（即物种功能性状的范围）稳定，但受MHW影响的组合在功能性状状（即其主要性状值）方面经历了长期的方向性变化。性状下降包括大尺寸，长寿命，树状形态，滤食策略或钙化骨骼。这些特质 它们主要由单个功能组（形成栖息地的八齿动物）中的少数敏感且不可替代的物种提供支持，它们不成比例地影响某些生态系统功能（例如3D栖息地的提供）。因此，MHW导致缺乏关键功能特征的组合，从而可能对生态系统的功能造成影响。