Species diversity of gastrotrich communities on elodeids and in bottom sediments of lakes of different trophic status was compared. Thirty-eight species of Gastrotricha (34 in bottom sediment and 21 on elodeids) were found, which belong to the only family of Chaetonotidae Zelinka, 1889. Species diversity of both habitats was reflected in the diversity indices ranging from 2.02 (a dystrophic lake) to 2.67 (a strongly eutrophic lake) for bottom sediment, and from 2.01 (a mesotrophic lake) to 2.54 (a strongly eutrophic lake) for elodeids. The similarity of gastrotrich fauna from the two habitats was low, and varied from 17% (a mesotrophic lake) to 38% (a strongly eutrophic lake). Low similarity of elodeid fauna from lakes of different trophic status was also found, in spite of similar plant species composition. The lowest similarity in elodeid fauna (23%) was recorded for dystrophic and mesotrophic lakes, whereas the highest one (68%) was observed for eutrophic and strongly eutrophic lakes. That allows to conclude that the diversity of epiphytic fauna is affected by trophic status rather than by vegetation type. The comparison of the gastrotrich fauna from elodeids and bottom sediments in lakes of different trophic status provides additional autoecological characteristics of Heterolepidoderma ocellatum (Mečnikow, 1865) and allows to recognize this species as belonging to a group of species closely related to macrophytes.
4
Dostęp do pełnego tekstu na zewnętrznej witrynie WWW
Composition and abundance of Gastrotricha in lake psammon were studied and compared with those compared with those from other lake habitats. Samples were taken from April till October 2004 from 3 sites at the edge of zone frequently wetted by waves (hygropsammon) in a deep (38 m) mesotrophic lake situated in Łęczyńsko-Włodawskie Lakeland (south-eastern Poland). A total of 11 gastrotrich species belonging to Chaetonotidae family were found. Three species: Lepidodermella squamata Dujardin, Chaetonotus macrochaetus Zelnika i Ch. heideri Brehm dominated (52%) in total abundance. According to the previous studies the number of species occurring in bottom sediments of the same lake was higher by 11 - 14 species. Species diversity index H., amounted 2.19 being lower than that calculated for the gastrotrichs of inshore bottom and littoral sediments (2.88 and 2.58, respectively) and similar to the value given for epiphytic fauna (2.01) of that lake. The fauna of psammic Gastrotricha showed the greatest similarity (38%) to epiphytic fauna of that lake as measured by the index of homogeneity. Peak densities of psammic Gastrotricha were found in May (37.5 10[^3] ind. m[^-2]) and in September (32.8 10[^3] ind. m[^-2]) and marked decrease of density was observed in August and October (18.1 10[^3] m[^-2] and 13.6 10[^3] ind. m[^-2], respectively). Mean density and biomass were 25.35 10[^3] ind. m[^-2] and 3.8 mg m[^-2] respectively. Density and biomass of Gastrotricha were by two orders of magnitude lower in psammon than in bottom sediments of the lake.
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.