Population dynamics of mayflies in a constant temperature spring stream in West Carpathians

We examined the life history and secondary production of four Ephemeroptera species (Baetis alpinus Pictet, 1843–1845, Baetis rhodani Pictet, 1843–1845, Rhithrogena carpatoalpina Klonowska, Olechowska, Sartoriet & Weichselbaumer, 1987 and Habroleptoides confusa Sartori & Jacob, 1986) in a temperature stable cold spring stream at Prosiek valley (Cho?ské vrchy Mts., West Carpathians, Slovakia). We have found asynchronous bivoltine life cycle for the most abundant species B. alpinus with growth rate positively correlated to photoperiod length. R. carpatoalpina have shown unusual asynchronous univoltine life cycle and B. rhodani have shown uncommonly low abundance in mayfly community. Total secondary production of mayfly community was very low, reaching 1654.8 mg DW m^?2 y^?1. We suggest that the observed asynchrony in growth could be related to the lack of temperature control.