Spatio-temporal variations of macroinvertebrate community in the Tisza River (NE Hungary)

Investigations were carried Out On spatial and temporal distribution of benthic macroinvertebrate assemblages at a cross-section of the River Tisza. The macrozoobenthos showed significant spatial and seasonal changes in number of individuals and taxa, and Margalef's species richness. The spatial and temporal differences were shown by discriminant analysis (DA) too. These variations were most pronounced in chironomids. When all macroinvertebrate groups were taken into consideration, the identification of chironomids to genus and species level increased the sensitivity of DA in characterization of spatial distribution. However, the chironornids themselves less showed the spatial differences along the cross-section. In contrast with spatial distribution, the temporal variations in the benthic community were most remarkable by DA when the chironomids were identified to family level, and the sensitivity of DA decreased according to genus and species level identification of chironornids. The same situation was detected if only the chironomids were taken into account. Present results suggest that species level identification can be important in characterizing habitat-dependent variations of benthic community. In contrast, the family level identification of chironomids is enough for characterization of temporal distribution of benthic macroinvertebrates.