Macroalgae constitute an important habitat for several marine invertebrates, and their biomass and structural complexity modulates the abundance and diversity of species that live on them. Overall, fluctuations in algae biomass inflict fluctuations in the abundance of the associated mobile macrofauna, but the structure of the community may vary according to how each group/species uses the resources provided by the algal habitat. Here, we evaluated how temporal variations in the biomass of Sargassum algal bed (increase, decrease, or maintenance) can affect the abundance, density, and assemblage structure of distinct associated faunistic groups. The collections were performed in three rocky shores located on the north coast of São Paulo, southeastern Brazil, during Fall and Spring. We observed different patterns of algal substrate variation between sampling events, and this reflected on variable effects on the associated fauna. The algal substrate reduction was accompanied by the reduction in the abundance and density of all associated faunal groups. However, the increase or maintenance of the algal substrate was accompanied by an increase in the abundance of peracarids, due to the dominance of herbivorous species, while other taxonomic groups like mollusks and polychaetes decreased or maintained their abundance, although with higher species evenness of gastropods when alga increases. Seasonal biomass variations in macroalgae beds are relevant for the dynamics of its associated fauna, and our results indicate that some taxonomic groups may preferentially use the available extra resources originated from biomass increment when compared to other groups.

中文翻译：

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生境形成藻类马尾藻变化对巴西圣保罗海岸不同相关移动动物群的不对称影响

大型藻类构成了几种海洋无脊椎动物的重要栖息地，它们的生物量和结构复杂性调节了生活在其上的物种的丰度和多样性。总体而言，藻类生物量的波动会导致相关移动大型动物群的丰度波动，但群落的结构可能会根据每个群体/物种如何使用藻类栖息地提供的资源而有所不同。在这里，我们评估了马尾藻生物量的时间变化藻床（增加、减少或维持）会影响不同相关动物群的丰度、密度和组合结构。这些系列于秋季和春季在巴西东南部圣保罗北海岸的三个岩石海岸进行。我们观察到采样事件之间藻类底物变化的不同模式，这反映了对相关动物群的可变影响。藻类底物的减少伴随着所有相关动物群的丰度和密度的减少。然而，由于草食性物种的优势，藻类基质的增加或维持伴随着棘皮动物丰度的增加，而其他分类群如软体动物和多毛类动物则减少或保持其丰度，尽管当藻类增加时，腹足动物的物种均匀度更高。大型藻床中的季节性生物量变化与其相关动物群的动态相关，我们的结果表明，与其他群体相比，某些分类群体可能会优先使用源自生物量增量的可用额外资源。