Ecological status of the Danube river (Serbian stretch) based on macroinvertebrate assemblages

Abstract

Aim: This study was carried out to assess the ecological status of the Danube throughout Serbia based on the macroinvertebrate assemblages. Materials and Methods: The research was performed in April and September 2011 at 11 sampling sites. Samples were collected with the Van Veen type of grab. The total number of taxa, Diversity Index, Saprobic lndex, BMWP and ASPT Scores were used for the ecological status assessnment. All indexes were calculated using the ASTERICS software package. Results: A total of 69 taxa were recorded. Chironomidae with 24 identified taxa, followed by Mollusca (18) and Oligochaeta (16) were found to be the dominant groups. Ledinci was the site with the number highest of taxa both in April (25) and in September (19). The highest diversity was recorded at Ram (2.67 April) and at Ledinci (2.46 September). The values of the saprobic index varied from 2.25 (Tekija. April: Kladovo - September) to 3.21 (Kusjak April: Tekija - September). The BMWP Score varied from 3 at Kusjak (most downstream site) to 37 at Ledinci (the most upstream site) during April, while the ASPT value ranged from 1.5 at Kusjak to 4.83 at Novi Sad. Conclusion: The ecological status in the year 2011 varied from good (class I) at most upstream sites to generally poor (class IV) in Iron Gate stretch. The higher diversity and abundance of macroinvertebrates were recorded in April (high water level) in comparisson to September (low water level).