The invasive freshwater bivalve Limnoperna fortunei in South America: multiannual changes in its predation and effects on associated benthic invertebrates
The invasive freshwater bivalve Limnoperna fortunei in South America: multiannual changes in its predation and effects on associated benthic invertebrates
复制标题
南美洲的入侵淡水双壳类动物 Limnoperna Fortunei：其捕食情况的多年变化及其对相关底栖无脊椎动物的影响
作者：
Daniela Duchini;D. Boltovskoy;F. Sylvester
众所周知，入侵的金贻贝（Limnoperna fortunei）会强烈影响南美洲淡水中的底栖生物群落，但这些影响在早期入侵阶段后的演变却鲜为人知。采用捕食者排除法（15和40毫米网）和包涵法（无保护）研究了帕拉那<e:1>河三角洲不同捕食者暴露水平下金贻贝与底栖无脊椎动物群落之间的相互作用。底物的定殖主要以贻贝为主。少毛纲、线虫纲和水蛭纲是最丰富的伴生类群，轮虫纲、缓步纲、桡足纲、枝足纲、手足纲、腹足纲、水螅纲、片足纲和无足纲零星出现。无论它们的营养模式和功能属性如何，伴生无脊椎动物的数量和生物量不仅受到捕食者的保护，而且还受到贻贝群落的存在的影响。与贻贝群落相关的无脊椎动物密度的增强在无保护的基质上高于受保护的基质，这表明无脊椎动物的促进作用随着捕食压力的增加而增加。与十年前进行的一项类似研究的比较表明，经过20年的入侵，在帕拉纳<e:1>河三角洲，贻贝的繁殖潜力、对其殖民地的捕食压力以及对其他无脊椎动物的促进作用都有所增加。
The invasive golden mussel Limnoperna fortunei is known to strongly affect benthic communities in South American freshwaters, but the evolution of these effects after the early invasion stages is poorly understood. Using predator exclusion (covered with 15- and 40-mm meshes) and inclusion (unprotected) substrates, we investigated the interaction between golden mussels and benthic invertebrate communities at different levels of exposure to predators in the Paraná River delta. Colonization of the substrates was largely dominated by the mussels. Oligochaeta, Nematoda, and Hirudinea were the most abundant accompanying groups, while Rotifera, Tardigrada, Copepoda, Cladocera, Chironomidae, Gastropoda, Hydracarina, Amphipoda, and nauplii appeared sporadically. Regardless of their different trophic modes and functional attributes, the numbers and biomass of associated invertebrates were not only enhanced by protection against predators, but also by the presence of mussel colonies. Enhancement of invertebrate densities associated with mussel colonies was higher on unprotected than protected substrates, suggesting that invertebrate facilitation increases with increasing predation pressure. Comparisons with a similar study carried out a decade earlier suggest that, after two decades of invasion, the reproductive potential of the mussel, the predation pressure on its colonies, and its facilitation effects on other invertebrates have increased in the Paraná River delta.