engleski

Larval community structure and emergence of mayflies at Plitvice Lakes NP, Croatia

Mayflies are often used in bioassessment and monitoring of freshwater bodies because of their relative abundance in a wide variety of substrates and their sensitivity to pollution. Previous research on mayflies at the Plitvice Lakes NP considered only the larval stage while there were no data on their emergence. The goal of this research was to determine larval and adult abundance, community composition, phenology, and substrate and current velocity preference at Bijela Rijeka and Crna Rijeka springs. Sampling was conducted monthly from February 2007 till February 2008. The more shaded Crna Rijeka spring had a higher number of species and higher larval abundance, while more adults emerged at the open canopy Bijela Rijeka spring. Overall, four species were found as larvae, of which Baetis rhodani whose larvae preferred moss substrates was the most abundant. Other taxa showed no significant preferences towards particular substrate. In emergence traps we recorded only two species, B. rhodani and Rhitrogena semicolorata. B. rhodani had two generations per year, first was from April until August, and second in late autumn (October-November) while emergence of R. semicolorata was from May until August. In B. rhodani males and females emerged at the same time but with greater female abundance, while in R. semicolorata male emergence began one month earlier. The current study provides an important contribution to the knowledge of mayfly ecology in karstic freshwater habitats that forms a basis for further investigation and monitoring of mayflies in this area.

Ephemeroptera; Emergence; Community structure

nije evidentirano