The body size distribution of Filinia longiseta (Ehrenberg) in different types of small water bodies in the Wielkoposka region

Abstract

Small water bodies are often characterised by specific macrophyte species composition and different levels of predation. This may also have an effect on the body size and shape of rotifer specimens. The aim of the study was to determine the relation of the size of rotifer Filinia longiseta (body and appendages length), with respect to three specific kinds of pond (mid-forest, pastoral and anthropogenically changed) and to three kinds of hydromacrophytes (nymphaeids, elodeids and helophytes) as well as comparatively to the open water zone. The examined water bodies also differed in fish presence or absence. Morphometric analysis of specimens of F. longiseta showed that both factors-the type of water body relating to different land-use in the catchment area as well as the microhabitat type-were significant predictors, influencing their body size and spine length. Filinia longiseta specimens were significantly smaller in ponds situated within the pastoral catchment area. The largest specimens were found among stands of nymphaeids, while the smallest were found within the open water zone, which may indicate both the ecological requirements of this species as well as the marked influence of fish in the unvegetated area. © Asociación Ibérica de Limnología, Madrid. Spain.