Diversity and structure of macroinvertebrate communities in permanent small streams and rivers in Eastern Balkans

We present data on the taxonomic diversity and structure of macroinvertebrate communities in small, mostly 1st and 2nd order permanent streams from Struma, Mesta and Vardar watersheds (7th Ecoregion “Eastern Balkans”) and analyse similarity in communities between/within studied basins. We reveal the characteristic elements of the macrozoobenthos from representative sites of R3- (mountainous) and R5- (semi-mountainous) river types. In total 69 samples from 38 sites were collected in autumn 2017 and spring 2018. The variation of the number of taxa, total abundance, relative abundance, species diversity and richness, evenness and index of dominance were analysed. A total of 280 taxa were recorded, and insects dominated the macroinvertebrate communities (> 70%). Overall, site similarities reflected the key macroinvertebrate metacommunities in R3- and R5-river type sections that provided higher β-diversity and lower similarities compared to the remainder of the watersheds. MDS- and dbRDA analyses separated the river basins by stream size and substratum heterogeneity. The highest α- and β-diversity were recorded within the Struma River watershed, which contributed to the higher γ-diversity and reflected the typical macroinvertebrate assemblages from the studied rivers of this Ecoregion. These results are important in application of management protocols especially when alike activities involve such river ecosystems.