Application of Trophic Indices in Ecological State Assessment of Riverine Water Bodies

Bulgarian Academy of Sciences, Institute of Biodiversity and Ecosystem Research, BG – 1113 Sofia, Bulgaria


KERAKOVA, M., M. IHTIMANSKA and E. VARADINOVA, 2013. Application of trophic indices in ecological state assessment of riverine water bodies. Bulg. J. Agric. Sci., Supplement 2, 19: 277–281


Benhtosological data from 39 potentially referent sites situated on 33 Bulgarian rivers are used for this study. Functional feeding group distribution and the main indicator macroinvertebrate groups along the studied sites are analyzed. Current ecological state, based on German Feeding Type index and Index of Trophic Completeness, of the studied sites was determined. Assessment was compared with the one made in the adapted version of Irish Biotic Index, widely applied in Bulgarian benthosological practice. Percentage distribution of the species in the main indicative groups demonstrates that SC and SH are dominant in macrozoobenthic trophic structure of the studied sites. Benthic species, which belong to functional group SH, are sensitive, while SC, PR, CL and FL are more or less tolerant. DF is characterized as most tolerant. Applicability of two trophic indices showed that the highest coincidence in assessment between the BI and RETI/PETI is observed. RETI/PETI is closer in ecological assessment to the BI and more relevant for conditions of the Bulgarian riverine ecosystems.

Key words: macrozoobenthos, referent sites, functional feeding groups, ecological state
Abbreviations: SH – shredders; SC – scrapers; FL – collectors filterers; CL – collectors gatherers; DF – deposit feeders; RETI/PETI– German feeding type index, ITC – Index of trophic completeness, BI – Irish Biotic index, EQR – Ecological quality ratio

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