Few studies have examined the effects of freshwater mussels on zooplankton in their native regions. We undertook an outdoor mesocosm-scale experiment to examine the effects of Echyridella menziesii, an endemic New Zealand mussel, on zooplankton composition. Experiments were undertaken in 125-L cylindrical drums that were randomly separated into the following three groups: seven control tanks with no mussels, seven treatment tanks with five mussels, and seven treatment tanks with 10 mussels each. Tanks were seeded with algae and zooplankton from a variety of small local water bodies, and monitored on Days 0, 5, 14 and 42. ANOSIM indicated that zooplankton composition among control and treatment tanks differed from Day 5 onward. Small, planktonic rotifers were commonly found to be most greatly affected by the presence of freshwater mussels. Benthic rotifers and larger crustacean zooplankton were typically unaffected or favoured when mussels were present. Overall, our results are consistent with removal of zooplankton by filtration, rather than competition for resources, being the primary driver of mussel influence on zooplankton community composition.

中文翻译：

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新西兰本地淡水贻贝对浮游动物组合的影响，包括非本地水蚤：中胚层实验

很少有研究调查淡水贻贝对其原生地区浮游动物的影响。我们进行了一项户外中宇宙尺度实验，以检查 Echyridella menziesii（一种新西兰特有贻贝）对浮游动物组成的影响。实验在 125 升圆柱桶中进行，这些桶被随机分为以下三组：七个没有贻贝的对照罐，七个有五个贻贝的处理罐，以及七个每个有 10 个贻贝的处理罐。水箱中种植了来自各种小型当地水体的藻类和浮游动物，并在第 0、5、14 和 42 天进行监测。ANOSIM 表明控制水箱和处理水箱中的浮游动物组成从第 5 天开始有所不同。通常发现小型浮游轮虫受淡水贻贝的影响最大。当贻贝存在时，底栖轮虫和较大的甲壳类浮游动物通常不受影响或受到青睐。总体而言，我们的结果与通过过滤去除浮游动物一致，而不是竞争资源，这是贻贝影响浮游动物群落组成的主要驱动因素。