Abstract The aim of the study was to evaluate the changes in abundance, species richness, and diversity of epiphytic Gastrotricha in the littoral of a mesotrophic lake. The influence of pH and oxygen on their occurrence was also investigated. Gastrotricha occurred throughout the year: 27 species were identified together, and species richness varied at different seasons. The highest number of species on water vegetation was found in the summer (26 species), while in the winter season only 7 species were present. Species diversity expressed by the Shannon index, in spring, summer, and autumn was high and amounted 2.10, 2.37, and 2.31, respectively. In winter, the value of the index was significantly lower and amounted 0.59. Three species were found to be dominant from spring to autumn with the dominance over 9.0%: Heterolepidoderma macrops Kisielewski, 1981, H. ocellatum (Mečnikow, 1865), and Lepidodermella squamata (Dujardin, 1841). The GLM analysis revealed that number of collected species in spring, summer, and autumn does not depend either on season or on pH and oxygen content. The lowest density of gastrotrichs was found in winter (average of 33 10−3 indiv. m−2), whereas the highest was found in summer (average of 1392 10−3 indiv. m−2). The density differed with season and neither pH nor oxygen content had an effect upon gastrotrich densities.

中文翻译：

---

附生Gastrotricha多样性和丰度的季节性变化

摘要 本研究的目的是评估中营养湖沿岸附生Gastrotricha 的丰度、物种丰富度和多样性的变化。还研究了 pH 值和氧气对其发生的影响。Gastrotricha全年均有发生：共鉴定27种，不同季节物种丰富度不同。夏季发现的水生植物种类最多（26 种），而在冬季只有 7 种。香农指数表示的物种多样性在春季、夏季和秋季较高，分别为 2.10、2.37 和 2.31。在冬季，该指数的值显着降低，为 0.59。春季至秋季有3种优势，优势度均在9.0%以上：Heterolepidoderma macrops Kisielewski, 1981, H. ocellatum (Mečnikow, 1865) 和 Lepidodermella squamata (Dujardin, 1841)。GLM 分析表明，春季、夏季和秋季收集的物种数量不取决于季节或 pH 值和氧含量。冬季（平均 33 10-3 个个体 m-2）的胃垂体密度最低，而夏季最高（平均 1392 个 10-3 个个体 m-2）。密度因季节而异，pH 值和氧含量均不影响胃营养密度。冬季（平均 33 10-3 个个体 m-2）的胃垂体密度最低，而夏季最高（平均 1392 个 10-3 个个体 m-2）。密度因季节而异，pH 值和氧含量均不影响胃营养密度。冬季（平均 33 10-3 个个体 m-2）的胃垂体密度最低，而夏季最高（平均 1392 个 10-3 个个体 m-2）。密度因季节而异，pH 值和氧含量均不影响胃营养密度。