Water temperature determines strength of top-down control in a stream food web
Water temperature determines strength of top-down control in a stream food web
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DOI：
10.1111/j.1365-2427.2005.01404.x
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发表时间：
2005-08-01
影响因子：
2.7
通讯作者：
Maekawa, K
中科院分区：
文献类型：
--
作者：
Kishi, D;Murakami, M;Maekawa, K
1.研究了水温对北方河流中三个营养级食物链（捕食性鱼类、草食性石蛾幼虫和附着生物）群落结构的影响。本研究采用室内实验的方法，研究了（1）水温对鱼类和石蛾幼虫摄食活动和附着生物生产力的影响，并评估了温度对各营养级的影响（种水平实验），（ii）水温对鱼类捕食压力的影响对丰富的低营养级，评估温度如何影响鱼类自上而下的控制（社区级实验）。2.在物种水平的实验中，鱼的摄食活动在12摄氏度时很高，这与日本北海道森林溪流的夏季平均温度相一致，但在3摄氏度时很低，这与冬季平均温度相一致，也高于18摄氏度，这与夏季最高温度相一致。在水温范围内，附着生物生产力增加.在群落水平的实验中，在12摄氏度下，鱼类对石蛾幼虫和附着生物丰度的自上而下的影响很明显。在3和21摄氏度下没有观察到这种效果，因为在这些温度下鱼类的捕食压力较低。这些实验表明，营养级联效应可能会随着温度的变化，即使在丰富的捕食者的存在。温度胁迫对捕食者的生理抑制可以改变自上而下的控制，导致群落结构的变化.我们认为，热生境改变可以改变食物网结构，通过直接和间接的营养相互作用的组合。
1. We examined effects of water temperature on the community structure of a three trophic level food chain (predatory fish, herbivorous caddisfly larvae and periphyton) in boreal streams. We used laboratory experiments to examine (i) the effects of water temperature on feeding activities of fish and caddisfly larvae and on periphyton productivity, to evaluate the thermal effects on each trophic level (species-level experiment), and (ii) the effects of water temperature on predation pressure of fish on abundance of the lower trophic levels, to evaluate how temperature affects top-down control by fish (community-level experiment).2. In the species-level experiment, feeding activity of fish was high at 12 degrees C, which coincides with the mean summer temperature in forested streams of Hokkaido, Japan, but was depressed at 3 degrees C, which coincides with the mean winter temperature, and also above 18 degrees C, which coincides with the near maximum summer temperatures. Periphyton productivity increased over the range of water temperatures.3. In the community-level experiments, a top-down effect of fish on the abundance of caddisfly larvae and periphyton was clear at 12 degrees C. This effect was not observed at 3 and 21 degrees C because of low predation pressure of fish at these temperatures.4. These experiments revealed that trophic cascading effects may vary with temperature even in the presence of abundant predators. Physiological depression of predators because of thermal stress can alter top-down control and lead to changes in community structure.5. We suggest that thermal habitat alteration can change food web structure via combinations of direct and indirect trophic interactions.