Disturbance and population dynamics of rotifers in bed sediments

摘要: Rotifers inhabiting the sediment surface and hyporheic interstitial of a gravel stream were investigated between October 1991 1992. At surface, samples taken with modified Hess sampler at five randomly chosen sites roughly weekly intervals. In interstitial, collected using standpipe traps permanently installed two four depths (0–40 cm), every fifteen days. The distribution rotifer species revealed different temporal spatial patterns. Two species, Notholca foliacea (Ehrb.) squamula (O.F.M.) co-occurred having their peaks beginning summer in autumn. Cephalodella gibba Proales theodora (Gosse) occurred throughout year, while Parencentrum longipes (Wulf.) showed clear peak during spring only interstitial. effect variables such as water level, discharge variation groundwater level was tested upon densities each species. Despite spate, are able to persist due presence low-flow refuge habitats or dispersion into deeper layer