Indicative Ecological Status Assessment of the Južna Morava River Based on Aquatic Macroinvertebrates - page 02

Results and Discussion

A total of 83 aquatic invertebrate taxa were identified (Table 3). Insecta was the most dominant component of the community with 51 taxa, followed by Mollusca (12 taxa), Oligochaeta and Hirudinea, both with 6 taxa. Diversity of other groups was significantly lower. Among Insecta, the dominant groups were found to be Trichoptera (17 taxa) and Ephemeroptera (15 taxa), while subdominant were Diptera (7 taxa) and Odonata (5 taxa).


Table 3: List of taxa recorded at the Južna Morava River


Snails were represented with 8 taxa: Holandriana holandrii, Lithoglyphus naticoides Physella acuta, Planorbiidae sp., Radix ampla, R.labiata, Theodoxus danubialis and T. transversalis. Bivavles were not frequent in samples, a four species were recorded: Sinanodonta woodiana, Unio crassus, U. pictorum and U.tumidus.

With regard to the relative abundance/percentage participation in the community, Trichoptera, Hirudinea and Gastropoda were found to be principal components of the community. The most abundant taxa were: Hydropsyche incognita (Trichoptera), Limnephlius species (Trichoptera), Erpobdella octoculata (Hirudinea) and Chironomidae species (Diptera).

The total number of taxa per sample varied from 21 and 19 (Mojsinje, June,September) to only 8 (Ristovac, September). The average number of total taxa recorded points good status of the river (Class II).

The greatest diversity was noticed in Mojsinje (values of Shannon-Weaver Diversity Index is 2.94 in September and 2.87 in June). On the other hand, the lowest diversity was in Ristovac in September (Shannon-Weaver value is 2.00). Average values of Shannon-Weaver Diversity Index indicate an overall high water quality (Class I).

Number of Ephemeroptera, Plecoptera and Trichoptera (EPT) taxa ranged from 10 (Grdelica, September) to 0 (Aleksinac and Ristovac, September). Average values of EPT taxa corresponds to Class III (moderate status).

Values obtained for Zelinka & Marvan Saprobic Index varied from 1.93 (β-mesosaprobity; Mojsinje, September) to 2.60 (α-β-mesosaprobity; Ristovac, September),which indicate moderate presence of organic pollution. Average values of Zelinka & Marvan SI correspond to Class II (good status), as shown is in Figure 3.


Figure 3: Average values of Zelinka & Marvan Saprobic Index