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    Benthic invertebrates as ecological indicators in the rivers of the Northern Aegean Basin (Turkiye)
    (Springer, 2024) Ozbek, Murat; Cil, Eylem Aydemir; Tasdemir, Ayse; Topkara, Esat T.; Yildiz, Seray
    This study aimed to determine the water quality classes of seven rivers in the North Aegean Basin (Turkiye) according to their benthic macroinvertebrate groups. In order to determine water quality levels, water and benthos samples were taken from 17 localities in May and June 2014, and the collected material was examined. As a result, a total of 22,348 benthic macroinvertebrate individuals belonging to 47 taxonomic groups were identified. The main groups and individual numbers were as follows: Chironomidae (8948 ind.), Baetidae (3910 ind.), Oligochaeta (1715 ind.), Gammaridae (1667 ind.), Potamanthidae (1401 ind.), Asellidae (1113 ind.), Melanopsidae (968 ind.), Physidae (618 ind.), Dugesiidae (475 ind.) and Hydropsychidae (107 ind.). The relationships between benthic macroinvertebrates and environmental variables were examined by canonical analysis. The dominance, BMWP (Biological Monitoring Working Party) and ASPT (Average Score Per Taxon) indices among benthic invertebrate groups were calculated. The dominant group was Chironomidae with similar to 40%. Considering the BMWP scores, stations S2, S3, S12 and S17 were classified as polluted, station S5 was classified as unpolluted. ASPT scores indicated that station S3 was heavily polluted and S16 was the cleanest station.
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    Öğe
    Determination of the ecological status of an Aegean river (Turkiye) using benthic macroinvertebrates as an indicator of water quality
    (Springer, 2023) Ozbek, Murat; Aygen, Cem; Tasdemir, Ayse; Yildiz, Seray; Topkara, Esat T.; Cil, Eylem Aydemir
    Bakircay is one of the important rivers of Western Anatolia, Turkiye. The objectives of this study are (a) to determine the diversity of benthic invertebrates distributed in Bakircay, (b) to evaluate the obtained data using various biological indices, (c) to determine the interactions of species with environmental variables, and (d) to estimate the water quality level of the river using BMWP and ASPT analyses. Samplings were carried out at 15 stations between October 2017 and July 2018, seasonally. A total of 11,897 specimens belonging to 136 benthic macroinvertebrate taxa were determined. Diptera and Oligochaeta were the dominant groups with 32 (24%) and 25 taxa (18%), respectively. Station 4 has the highest species richness with 49 taxa (36%). The highest individual number (3421) was at the 14th station. Tubifex tubifex and Physella acuta have the highest dominancy (25.76%) and frequency (51.67) values, respectively. Diversity (H') values of the stations fluctuated between 1.367 (st. 13) and 3.154 (st. 12). Similarity analysis showed that the 3rd and 11th stations have the highest similarity (> 90%), while the 14th station was an outgroup and has 28% similarity ratio. BMWP and ASPT scores gave similar results, and there was no 1st class water quality in the river. On the other hand, the results of the TR-BMWP score suggested that the 1st, 4th, and 6th stations had 1st class water quality. Although some stations are classified as good conditions, the adverse effects of pollution were mainly observed in the main channel and downstream of the river.
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    Öğe
    Diversity and spatio-temporal distribution of benthic macroinvertebrate communities in a transboundary river basin in the Caucasus region (Aras river, NE Türkiye)
    (Bmc, 2025) Ozbek, Murat; Tasdemir, Ayse; Yildiz, Seray; Topkara, Esat T.; Cil, Eylem Aydemir
    This study evaluates the ecological status of the Aras River Basin (T & uuml;rkiye) by analyzing benthic macroinvertebrate communities in relation to seasonal variations and anthropogenic pressures. During 2014-2015 sampling campaigns, we identified 126 taxa, of which 107 were identified at the species level and 19 at the genus level across 17 stations, with Insecta (87 taxa, 69%) showing the highest richness, followed by Clitellata (23 taxa, 18%). The dominant species Tubifex tubifex (15.87%), Chironomus riparius (15.60%), and Gammarus balcanicus (15.11%) served as key bioindicators, revealing significant organic pollution impacts, particularly in lentic habitats. Canonical Correspondence Analysis (CCA) for the summer period identified dissolved oxygen (DO) and pH as the primary environmental drivers, with pollution-tolerant taxa (e.g., Chironomus riparius) clustering in low-DO areas, while sensitive species (e.g., Baetis rhodani) were predominantly associated with well-oxygenated, alkaline conditions. Seasonal analyses demonstrated autumn as the most productive period (3,765 ind., 91 taxa), with Station 9 maintaining pristine conditions (BMWP score: 66, Good) year-round. Conversely, spring showed the poorest water quality (BMWP < 25 at most stations), while summer exhibited intermediate conditions. Multivariate analyses (UPGMA, TWINSPAN) confirmed spatial clustering based on pollution gradients, with tolerant taxa (e.g., aquatic leeches, Chironomus spp.) dominating organically enriched sites and sensitive species (e.g., Plecoptera) restricted to high-quality habitats. Our findings highlight: (1) severe degradation at stations receiving agricultural/domestic waste (Stations 1-6), (2) the critical role of seasonal monitoring in detecting climate-driven stressors, and (3) the utility of macroinvertebrate-based indices (BMWP/ASPT) for basin-scale water quality assessment. The study provides a scientific basis for conserving transboundary freshwater ecosystems through targeted pollution control and habitat protection measures.