Perennial streams and rivers are now largely subjected to fragmentation and lentification processes due to flow reduction, which creates a number of lateral habitats with different degrees of hydrological connectivity. These habitats have environmental conditions and biotic interactions that can be far divergent than those of main channel habitats. However, they remain largely unexplored, especially in temperate regions. We here focused on studying algal dynamics and their interactions with aquatic invertebrates across mesohabitats (i.e., main channel, secondary channel, pools) in streambeds under both normal and low flow conditions. We selected four watercourses in the Po Plain (northern Italy), where we detected the main dynamics and drivers of algal and invertebrate communities by applying mixed effect modelling. A clear algal growth trend was detected in summer, and was similar for all mesohabitats, but with temporal decoupling and doubled values in pools. Mesohabitat and time were central factors in driving benthic algae dynamics that, in turn, negatively affected aquatic invertebrates. Hydrology and algae seemed to have a mutually reinforcing effect on macroinvertebrates by reducing almost all the investigated metrics. By considering future projections on further regime shifts in lotic systems, loss of biodiversity driven by algal blooms could become a major concern, and also for potential cascade impacts on other biotic compartments of river networks.

中文翻译：

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间歇性辫状河中的藻类生物量和大型无脊椎动物动力学：河床池的新观点

由于流量减少，多年生的溪流和河流现在主要受到破碎和隆起作用的影响，这造成了许多具有不同程度水文连通性的横向生境。这些栖息地的环境条件和生物相互作用可能比主要河道栖息地大不相同。但是，它们仍未开发，尤其是在温带地区。在这里，我们专注于研究正常和低流量条件下河床中生境中藻类的动力学及其与水生无脊椎动物的相互作用（即主要河道，次要河道，水池）。我们在意大利北部的波平原（Po Plain）选择了四个水道，在这里我们通过应用混合效应模型检测了藻类和无脊椎动物群落的主要动态和驱动因素。夏季检测到明显的藻类生长趋势，并且对所有中生境都相似，但是池中的时间解耦且值增加了一倍。中生境和时间是驱动底栖藻类动力学的主要因素，而底栖藻类反过来又对水生无脊椎动物产生负面影响。水文和藻类似乎通过减少几乎所有研究指标而对大型无脊椎动物具有相互促进的作用。通过考虑未来对乐透系统进一步政权转变的预测，藻华引发的生物多样性丧失可能成为人们的主要关切，同时也可能对河网的其他生物区系产生潜在的级联影响。负面影响的水生无脊椎动物。水文和藻类似乎通过减少几乎所有研究指标而对大型无脊椎动物具有相互促进的作用。通过考虑未来对抽水系统进一步政权转移的预测，藻华引发的生物多样性丧失可能成为一个主要问题，同时也可能对河网的其他生物区系产生潜在的级联影响。负面影响的水生无脊椎动物。水文和藻类似乎通过减少几乎所有研究指标而对大型无脊椎动物具有相互促进的作用。通过考虑未来对抽水系统进一步政权转移的预测，藻华引发的生物多样性丧失可能成为一个主要问题，同时也可能对河网的其他生物区系产生潜在的级联影响。