The Diurnal Distribution of Rotifers (Rotifera) within a Single Chara hispida Bed

ABSTRACT

I examined the diel abundance of rotifers within, above, and around a single stand of Chara hispida in Lake Wielkowiejskie. There were no significant differences among times of day (irrespective of sampling site). However, differences were found between particular locations (irrespective of time of day) for the total rotifer numbers and for Keratella cochlearis, Keratella quadrata, Polyarthra vulgaris, and Trichocerca similis. The total rotifer numbers differed only in the middle part of the stonewort stand (regarding the morning and dusk samplings) and in the open water above the macrophyte bed (morning and day). Additionally, such differences were also recorded for Colurella uncinata, P. vulgaris, and T. similis, which in most cases differed between two pairs of times—the light hours (morning or day), when their densities were higher, and the dark hours (dusk or night), when there was a density decrease.