Effect of predatory fish presence on habitat use and diel movement of the stream amphipod, Gammarus minus
Effect of predatory fish presence on habitat use and diel movement of the stream amphipod, Gammarus minus
复制标题
掠食性鱼类的存在对溪流片脚类 Gammarus minus 栖息地利用和昼夜运动的影响
DOI：
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发表时间：
1990
期刊：
影响因子：
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通讯作者：
J. Hoyle
中科院分区：
文献类型：
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作者：
J. Holomuzki;J. Hoyle
概括。
1 我们研究了掠食性鱼类的存在如何影响二阶溪流中片脚类（Gammarus minus Say）的宏观和微观生境利用以及运动模式。
2 在大型栖息地中，片脚类动物在奔跑中的数量始终多于在水池中的数量。无论鱼的存在与否，水池中的密度都很低，而流道中的低密度与鱼的存在相关。淤积和缺乏粗基质颗粒可能是池中 G. minus 稀缺的原因。在微生境中，G. minus 在落叶层和砾石中比在淤泥/沙基质中更丰富。鱼类的存在并不影响田间微生境的利用。然而，实验室操作表明，与其他微生境相比，绿色翻车鱼（Lepomis cyanellus Rafinesque）对落叶层中片脚类的捕食率明显较低。
3 G. minus 的大部分运动发生在夜间，并指向下游。在实验室中，片脚类动物因受到绿色翻车鱼调节的水的影响而显着减少了夜间的游泳活动。然而，在野外，当暴露于封闭的绿色翻车鱼的化学信号中时，片脚类动物在夜间奔跑时的活跃程度仅略有下降。溪流中端足类动物的分布受到鱼类存在的影响，但化学信号本身对于触发自然界中的捕食者回避行为可能并不重要。
SUMMARY.
1 We examined how the presence of predatory fish affected macro—and microhabitat use and movement patterns of the amphipod, Gammarus minus Say, in a second order stream.
2 Among macrohabitats, amphipods were consistently more abundant in runs than in pools. Densities in pools were low regardless of fish presence, whereas low densities in runs were correlated with fish presence. Siltation and the lack of coarse substrate particles probably accounted for the scarcity of G. minus in pools. Among microhabitats, G. minus was more abundant in leaf litter and gravel than in silt/sand substrates. Fish presence did not affect microhabitat use in the field. Laboratory manipulations showed, however, that predation rates by green sunfish (Lepomis cyanellus Rafinesque) were significantly lower on amphipods in leaf litter than in other microhabitats.
3 Most movement by G. minus in runs occurred at night and was directed downstream. In the laboratory, amphipods significantly reduced swimming activity at night in response to water conditioned with green sunfish. In the field, however, amphipods were only slightly less active in runs at night when exposed to chemical cues of confined green sunfish. The distribution of amphipods in streams is influenced by the presence of fish, but chemical cues alone may not be important in triggering predator avoidance behaviours in nature.