Aquatic Macroinvertebrates Diversity in the Upper Stretch of Una River (Una National Park, SW Bosnia and Herzegovina)

The karstic Una River is one of the larger tributaries of the Sava River. Although being a part of Balkan biodiversity hot-spot, aquatic macroinvertebrates of the Una are rarely studied. The aquatic macroinvertebrates sampling was performed in the summer of 2015 throughout the upper river stretch covering the Una and its tributaries situated in the Una National Park (Una NP). A rich community consisting of 130 macroinvertebrate taxa, with dominance of Trichoptera and Ephemeroptera, was detected. A snail Sadleriana sp. and endemic gammarid Echinogammarus acarinatus were found to be dominant taxa in terms of percentage participation and frequency of occurrence. Mollusca and Crustacea were found to be the most abundant groups, with higher abundance in the Una River than its tributaries. Although a higher overall taxa richness was found in tributaries, calculated biotic indices and evenness pointed to greater diversity in the Una River. Additionally, BMWP and ASPT scores were also higher in the Una River than its tributaries. Calculated Jaccard index value pointed to moderate faunistic similarity between investigated communities. Obtained results suggest that investigated upper stretch of the Una River harbours a high diversity and rather homogenous macroinvertebrate community.