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作 者 ：李宽意,张雷燕,刘正文*

期 刊 ：生态学报 2009年 29卷 12期 页码：6414~6418

关键词：螺类牧食；伊乐藻；苦草；种间竞争；

Keywords:snail herbivory, Elodea nuttallii, Vallisneria spiralis, interspecific relationship,

摘 要 ：动物牧食可以调节植物种间的相对竞争能力，从而改变物种在群落中的竞争地位。外来植物伊乐藻生长迅速、具有较强的光竞争能力，土著种苦草根系发达、具有较强的地下资源竞争能力。选择这两种各具竞争特色的沉水植物为模式生物，通过室外受控实验研究了螺类牧食对两种沉水植物种间关系的影响。结果表明：不管有无螺类牧食，伊乐藻的相对生长率为苦草的2~5倍，伊乐藻具有明显的竞争优势。苦草低密度种植时，螺类牧食与种间竞争对其生长没有显著影响；高密度种植时，螺类牧食活动促进了苦草的生长，种间竞争则使苦草的生长率明显降低。无论伊乐藻种植密度如何，螺类牧食均使其生长率明显降低，混栽高密度的苦草也能抑制伊乐藻生长。探讨了螺类牧食对沉水植物的种间竞争关系的作用机理。

Abstract:Grazing damage has been recognized as one of the most important factors determining species distribution and community structure in aquatic plants. The effects of snail hervivory on interspecific relationship between two aquatic macrophytes, Elodea nuttallii and Vallisneria spiralis were investigated using a 2×2 factorial experiment design. Results showed that Elodea has a competitive advantage over Vallisneria at various densities. When the macrophyte density was low, plant competition and snail herbivory had not significantly affected the growth of Vallisneria. At a high density, grazing activity of snail stimulated the growth of Vallisneria, and plant competition suppressed the plant growth. Intensive plant competition and grazing damage suppressed the growth of Elodea at various densities. The regulation mechanisms of snail grazing activity on interspecific relationship between the two macrophytes were discussed.

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