European freshwater habitats are experiencing degradation and fragmentation, and this is causing population declines and range reductions in associated gastropod species. Accurate and time-efficient sampling methods are required for effective monitoring of such species, including Segmentina nitida, a priority species in the UK Biodiversity Action Plan. The diminutive size of S. nitida (adult shell width: 5–7 mm) and other small gastropods often makes them difficult to find among the vegetation in field samples. Here, we compare two sampling methods for gastropods from freshwater habitats with dense vegetation: a sift method where vegetation in a sample is examined by hand, and a wash method, where vegetation is washed in water that is then examined for gastropods. When sift and wash methods were compared for a single sample, there was no difference in the number of species detected with the two methods in all but 1 of 48 assessed samples. However, combining two wash steps and a sifting step yielded significantly more snail individuals and more S. nitida individuals. Though species richness as expressed by Menhinick’s index was significantly higher for the wash method compared to the sift method, index values for the two methods had a significant linear relationship. Splitting samples to assess each half with either wash or sift method indicated no significant difference in the number of species or number of individuals found with the two methods. The likelihood of detecting S. nitida in a sample and the number of S. nitida found was significantly higher for the wash method, and the wash method was significantly more time-efficient, saving c. 5 min per sample. We conclude that washing vegetation from freshwater samples without sifting through the vegetation by hand has the potential to accelerate surveys for freshwater gastropods and can increase the likelihood of detecting species of interest, especially S. nitida, without significantly affecting data accuracy. Further testing in various freshwater habitat conditions would allow wider use of this method in malacological and invertebrate studies.

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评价淡水植被样品中腹足动物采样的洗涤和筛选方法

欧洲的淡水生境正在退化和破碎化，这导致相关腹足纲物种的种群减少和范围缩小。需要有效且准确的采样方法来有效监测此类物种，包括英国生物多样性行动计划中的优先物种nititina nitida。尼氏链球菌的小尺寸（成虫的壳宽：5-7 mm）和其他小型腹足动物通常使它们很难在田间样本的植被中找到。在这里，我们比较了两种具有浓密植被的淡水生境中腹足类动物的采样方法：一种是筛查方法，即用手检查样本中的植被；另一种是洗涤方法，即在水中洗涤植物，然后检查腹足类动物。当比较单个样品的筛分和洗涤方法时，除48个评估样品中的1个以外，用两种方法检测到的菌种数量没有差异。但是，将两个洗涤步骤和一个筛分步骤相结合，会产生更多的蜗牛个体和更多的尼氏链球菌。个人。尽管用Menhinick指数表示的物种丰富度在洗涤方法中比在筛查方法中要高得多，但两种方法的指数值具有显着的线性关系。用洗涤或筛分方法将样品分开以评估每一半，表明用两种方法发现的物种数量或个体数量没有显着差异。的检测的可能性S.箭竹的样品中和的数量S.箭竹发现显著较高的洗涤方法，洗涤方法是显著更加节省时间，节约Ç。每个样品5分钟。我们得出的结论是，从淡水样本中清洗植被而无需手工筛选，可以加快淡水腹足类动物的调查速度，并且可以增加检测目标物种（尤其是nit。nitida）的可能性，而不会显着影响数据准确性。在各种淡水生境条件下进行进一步测试，将使该方法在乳汁和无脊椎动物研究中得到更广泛的应用。