Life cycle and secondary production of mayflies and stoneflies in a Karstic spring in the west Carpathians

摘要

This study focused on life strategies of Ephemeroptera and Plecoptera species found in a karstic spring stream at the Malé Karpaty Mts. (West Carpathians, Slovakia), which is characterized by low thermal fluctuations throughout the year (6-10 °C). We examined the life cycle and secondary production of three mayfly species (Baetis alpinus, Baetis rhodani and Rhithrogena semicolorata) and three stonefly species (Protonemura nitida, Protonemura hrabei and Nemurella pictetii). We found an unusually slow univoltine cycle for P. nitida and an asynchronous life cycle for B. alpinus, with first-stage nymphs occurring almost all year round. Uncommonly low abundances of B. rhodani were found, which indicates that the population lives at its ecological limit. Moreover, for the first time we acquired and analysed the data on secondary production of P. nitida, which reached the highest values (3335 mg DW m~(-2) y~(-1)) among all investigated species. In summary, the total annual secondary production of the mayfly community (889 mg DW m~(-2) y~(-1)) was seven times lower than the annual secondary production of the stonefly community (6233 mg DW m~(-2) y ~(-1)).