Influence of an exotic and a native crayfish species on a littoral benthic community
Influence of an exotic and a native crayfish species on a littoral benthic community
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外来和本土小龙虾物种对滨海底栖群落的影响
DOI：
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发表时间：
1999
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影响因子：
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通讯作者：
W. Granéli
中科院分区：
文献类型：
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作者：
Per Nyström;C. Brönmark;W. Granéli
本研究的目的是比较引进的信号小龙虾（小龙虾）和本地贵族小龙虾（Astacus astacus）对底栖食物网的影响。我们模仿的栖息地的池塘沿岸的在4.5米2的塑料池放养的自然密度的大型植物，无脊椎动物和信号小龙虾，高贵的小龙虾，或保持小龙虾自由控制。经过两个夏季的几个月，所有的无脊椎动物和大型植物，从每个游泳池，和附着生物进行采样的一个substratum暴露和两个substratum不暴露于小龙虾放牧。在养殖淡水螯虾的池塘中采集底栖生物稳定同位素分析样品。15 N比率表明，小龙虾是最大的消费者，13 C比率表明，它们从无脊椎动物获得大部分碳，但从初级生产者那里获得的碳较少。小龙虾并没有影响捕食性无脊椎动物的生物量，占主导地位的Heteroptera和鞘翅目之间的积极游泳者，但有很强的影响，以薄壳蜗牛为主的食草动物。硬壳Bithynia蜗牛的数量也减少了，但这些蜗牛中最大的蜗牛比薄壳的Eschermaea蜗牛消耗得少。蜗牛的生物量减少了间接的正面影响，所有三个基质上的附着生物量。克氏原螯虾选择性取食水生植物，减少轮藻的生物量，伊乐藻的影响较小。总体而言，外来信号螯虾对水生植物和食草动物生物量的影响比本地贵族螯虾更大。结果表明，螯虾可能通过从多个食物层次的消费来构建食物网。小龙虾对其他营养水平的短期影响取决于小龙虾的摄食效率、食物偏好和特定物种的消费率。
The aim of this study was to compare the effects of the introduced signal crayfish (Pacifastacus leniusculus) and the native noble crayfish (Astacus astacus) on a benthic food web. We mimicked the habitat of a pond littoral in 4.5-m 2 plastic pools stocked with natural densities of macrophytes, invertebrates and either signal crayfish, noble crayfish, or kept as crayfish free controls. After two summer months, all invertebrates and macrophytes were collected from each pool, and periphyton was sampled on one substratum exposed and two substrata not exposed to crayfish grazing. Samples for stabile isotope analysis of benthos were collected in pools with noble crayfish. 15 N ratios showed that crayfish were top consumers, and 13 C ratios indicated that they received most of their carbon from invertebrates, but less from primary producers. Crayfish did not affect the biomass of predatory invertebrates, dominated by active swimmers among Heteroptera and Coleoptera, but had a strong impact on grazers dominated by thin-shelled Lymmaea snails. Hard-shelled Bithynia snails were also reduced in numbers, but the largest of these snails were consumed less than thin-shelled Lymmaea snails. The reduced biomass of snails had an indirect positive effect on periphyton biomass on all three substrata. Crayfish grazed selectively on macrophytes and reduced the biomass of Chara, whereas Elodea was less affected. The exotic signal crayfish had, overall, a stronger impact on the biomass of macrophytes and grazers than the native noble crayfish. The results indicate that crayfish may structure food webs through consumption from many food levels. The short-term influence of crayfish on other trophic levels depends on crayfish feeding efficiency, food preferences and species-specific consumption rates.