Overcoming challenges of water scarcity necessitates creative flow management approaches that account for multiple, potentially competing water needs of plants and animals in river ecosystems. Mechanistic multispecies models can guide decision making by evaluating trade-offs associated with flow regimes designed for specific ecosystem outcomes before implementation. We investigated the cross-ecosystem effects of environmental flow regimes designed to benefit focal groups of riparian vegetation, fishes, and invertebrates. The models revealed trade-offs among different designer flow regimes with narrow taxonomic targets, which in some cases caused non-target taxa to become locally extirpated within short (decadal) timespans. By incorporating multiple flow frequencies – from intra-annual-scale pulses to large decadal-scale floods – the simulated natural flow regime enabled balanced, albeit smaller, population sizes across the three ecosystem components: 72% of that achieved by designer flow regimes, on average. Although returning to a natural flow regime may not be possible in highly flow-modified rivers, novel flow regimes must incorporate diverse flood and drought frequencies to accommodate the occasionally conflicting requirements of different taxa at different times.

中文翻译：

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设计流态以支持整个河流生态系统

克服水资源短缺的挑战需要创造性的流量管理方法，以解决河流生态系统中植物和动物的多种潜在竞争性用水需求。机械多物种模型可以通过在实施前评估与为特定生态系统结果设计的流态相关的权衡来指导决策。我们调查了旨在使河岸植被、鱼类和无脊椎动物等重点群体受益的环境流态的跨生态系统效应。这些模型揭示了具有狭窄分类目标的不同设计者流动机制之间的权衡，这在某些情况下导致非目标分类群在短（十年）时间跨度内局部消失。通过结合多个流量频率——从年内尺度脉冲到大型十年级洪水——模拟的自然流态实现了三个生态系统组成部分的平衡，尽管人口规模较小：设计者流态实现的 72%，在平均。尽管在高度流量改变的河流中可能无法恢复自然流态，但新的流态必须包含不同的洪水和干旱频率，以适应不同时间段不同分类群偶尔发生的冲突需求。