Abstract：
Biological invasions cause biodiversity erosion on a global scale. Invasive species spreading beyond their natural range compete with native fauna for food and space, push native species to suboptimal habitats, impairing their behaviour and thus limiting their occurrence. Freshwater ecosystems are especially vulnerable to biological invasions and their ecological and economic impacts. The invasive Asian clams (Corbicula spp.), due to their opportunistic life style, can occur at densities of thousands ind. m-2. They act as ecosystem engineers transforming bottom substrata through accumulation of shells. Our goal was to determine the effect of substratum modification by living Corbicula and their shells on substratum choice and behaviour of Unio tumidus and Anodonta anatina, two European freshwater mussel species of the highly imperilled Unionidae family. We assessed their substratum selection in pairwise choice tests (pure sand vs. sand modified by living Corbicula or their shells, sand modified by shells vs. living Corbicula). Next, we tested locomotion and burrowing of unionids on pure substratum and substrata modified by Corbicula. Unionids avoided sand modified by living Corbicula and their empty shells, not distinguishing between these two types of substratum modification. In the presence of Corbicula, their burrowing was shallower or it took them longer to obtain the same depth as in the pure sand. Additionally, on sand modified by Corbicula shells, we observed a locomotion increase (U. tumidus) or slowing down (A. anatina). Our research showed a novel mechanism of negative impact of Corbicula on unionids, consisting in pushing them away from their optimal habitats. This may contribute to their habitat loss and future declines in invaded ecosystems.
摘要：
生物入侵导致全球范围内的生物多样性侵蚀。超出其自然范围的入侵物种与本地动物争夺食物和空间，将本地物种推向次优的栖息地，损害他们的行为，从而限制他们的发生。淡水生态系统特别容易受到生物入侵及其生态和经济影响。侵入性亚洲蛤仔（Corbiculaspp。),由于他们的机会主义生活方式，可以发生在成千上万的密度。m-2.他们充当生态系统工程师，通过贝壳的积累来改变底层基质。我们的目标是确定通过活体Corbicula及其贝壳对基质选择和Uniotumidus和Anodontaanatina的行为进行基质修饰的影响，高度危险的Unionidae家族的两种欧洲淡水贻贝。我们在成对选择测试中评估了他们的基质选择(纯砂与用活的Corbicula或它们的贝壳改性的沙子，贝壳改良砂vs.活着的Corbicula）。接下来,我们在纯基质和Corbicula修饰的基质上测试了unionids的运动和挖洞。工会避免了被活着的Corbicula及其空壳修饰的沙子，不区分这两种类型的基质修饰。在Corbicula面前,他们的洞穴较浅，或者花了更长的时间才能获得与纯沙相同的深度。此外,在用Corbicula贝壳改性的沙子上，我们观察到运动能力增加(U.tumidus）或减速（A.anatina）。我们的研究显示了Corbicula对unionids的负面影响的新机制，包括将它们从最佳栖息地推开。这可能会导致它们的栖息地丧失和入侵生态系统的未来下降。
