Aquatic predation alters a terrestrial prey subsidy.
Aquatic predation alters a terrestrial prey subsidy.
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水生捕食改变了陆地猎物补贴。
DOI：
10.1890/09-1532.1
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发表时间：
2010
期刊：
影响因子：
4.8
通讯作者：
Jeff S. Wesner
中科院分区：
文献类型：
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作者：
Jeff S. Wesner
具有复杂生活史（CLH）的生物在从幼虫到成虫的发育过程中经常跨越栖息地或生态系统边界，在生态系统之间耦合能量流，既是猎物（自下而上），也是消费者（自上而下）。因此，在这个生命周期的一个阶段，捕食的影响可能会在整个生态系统中发生连锁反应，从而放大局部捕食的影响。大多数捕食研究只评估了局部水平上的影响，在捕食者的栖息地内。我使用大型户外溪流生态系统来验证一个假设，即水生栖息地的捕食会改变陆地栖息地猎物组合的大小和营养结构。我还测试了陆地栖息地的捕食者（织网蜘蛛）对猎物输出的这些变化的反应。在三种处理的实验中，两种鱼类是捕食者（红鲑，绿鲑和红鲑，Etheostoma spectabile）：两种鱼类单一养殖加无鱼对照。与无鱼对照相比，鱼类捕食使水生昆虫羽化生物量减少了50%，改变了新兴群落的营养结构，使新兴昆虫捕食者生物量减少了50%，但对其他昆虫营养类群没有影响。蜘蛛只捕获不受鱼类捕食影响的昆虫（主要是摇尾虫），因此对昆虫丰度或生物量的总体变化没有数字上的反应。昆虫出现的模式主要是由鱼类和掠食性蜻蜓（Pantala flavescens）之间的强烈负相关关系驱动的。本实验结果表明，一个栖息地的捕食对进入邻近栖息地的补贴的生物量和营养结构有很强的影响，从而导致对这些补贴在受援食物网中的作用的不同预测。在没有鱼类的情况下，水生生境产生的陆生昆虫群落的生物量（自下而上的潜力）和捕食者的比例（自上而下的潜力）都高于有鱼类时。
Organisms with complex life histories (CLH) often cross habitat or ecosystem boundaries as they develop from larvae to adults, coupling energy flow between ecosystems as both prey (bottom-up) and consumers (top-down). Predation effects on one stage of this life cycle can therefore cascade across ecosystems, magnifying the impact of local predation. The majority of predation studies have assessed effects only on a local level, within the habitat of the predator. I used large outdoor stream mesocosms to test the hypothesis that predation in an aquatic habitat alters the magnitude and trophic structure of a prey assemblage in a terrestrial habitat. I also tested how a consumer in the terrestrial habitat (web-weaving spiders) responded to these changes in prey export. Two fish species were the predators (red shiner, Cyprinella lutrensis and orangethroat darter, Etheostoma spectabile) in an experiment with three treatments: both fish species monocultures plus a fishless control. Fish predation reduced aquatic insect emergence biomass by 50% compared to the fishless control and altered the trophic structure of the emergent community, reducing emerging insect predator biomass by 50%, but had no effect on other insect trophic groups. Spiders captured only insects that were unaffected by fish predation (mostly chironomids) and therefore did not respond numerically to overall changes in insect abundance or biomass. Patterns of insect emergence were largely driven by a strong negative relationship between fish and a predatory dragonfly (Pantala flavescens). The results of this experiment show that predation in one habitat can have strong effects on the biomass and trophic structure of subsidies entering adjacent habitats, resulting in contrasting predictions for the role of these subsidies in recipient food webs. In the absence of fish, aquatic habitats produced terrestrial insect communities with higher biomass (bottom-up potential) and a higher proportion of predators (top-down potential) than when fish were present.