In this study benthic macroinvertebrate fauna of Balaban Stream was detected and appropriate biometric approaches were applied on this organisms. A total 62 taxa were revealed during the research, and most dominant group between the benthic macroinvetebrates was found to Insecta. Researchers like Arman et al., (2019); Musonge et al., (2018); Zeybek et al., (2014); Galdean et al., (2008); Azrina et al., (2006) were found the similar results in different freshwater ecosystem. Water temperature, dissolved oxygen and oxygen saturation were affected by seasonal conditions at all station except the first station in Balaban Stream.
According to Tanyolaç (2004), water temperature at the upstream part of the streams doesn’t change much.The highest average water temperature was measured at station #5 in the downstream part of the stream. The water temperature in the streams are expected to reach higher water temperature values as a result of expansion of the stream bed, the decrease at the slope and water flow intensity and the accumulation of the alluvial particules from the upstream towards the downstream.
The station where the lowest dissolved oxygen content is measured is the station #5 in summer season. High air temperatures due to the summer season and organic pollution caused by agriculturel activity, caused the decrease of dissolved oxygen at the station #5. Simic (1996), Barlas et al., (2001), Uyanık et al., (2005), Kalyoncu and Zeybek (2010) stated that lowest oxygen values are expected in under the areas of pollution pressure. The flow rate at station #5 is also very slow. Tanyolaç (2004), states that the amount of oxygen in slow-flowing water is low, and that the amount of high oxygen is measured in fast-lowing water.
The highest amount of dissolved oxygen was measured at station #1 because of station #1 is the station of Balaban Stream in the upstream part. At this station, the stream flows from elevation and therefore has the highest dissolved oxygen value. Kalyoncu et al., (2005), obtained similar results in Aksu Stream.
As a result of all this findings, Balaban Stream is a abundant stream in terms of dissolved oxygen. In this study, species diversity values ranged from 0.918 to 6.424, and the lowest species diversity value was found at the station #2. Mason (2002) reported, if the Shannon and Weaver values ranges from ˃3 it indictes clean water, 1-3 indicates moderate pollution, and 1˂ indicates heavy pollution. According to Ghosh and Biswas (2005), the diversity value ranges from 0 (low density) to 1 at Simpson diversity indice. According to Gamito (2010), the datasets consists of two matrices that specify absolute numbers at Margalef diversity indice. The first is the total number of individuals of each species sampled at each station, and the second is the number of individuals per square meter at each sampling station based on density. Accordingly, the studied stream has high water quality in terms of species diversity indices. Higher values of species diversity in Balaban Stream can be imputed to less human impact. Boyle and Fraleigh (2003) reported that the aquatic ecosystems with high species diversity are in better condition and illustrates low degradation, while on the other hand, low diversity frequently detect in area with high degradation. DeWalt et al. (2012), Meyer (1987), Metcalfe (1989) stated that individuals belong to order of Plecoptera are sensitive of pollution. In this study, presence of individuals belong to Plecoptera at all station can be concluded that agriculturel activity and animal farms on Balaban Stream have not yet caused a pollution pressure.
Jazdzweska (1995), Vilenica et al. (2015), Barber et al. (2008) stated that the individuals belong to the Ephemeroptera were found extensively near the upstream part of the stream. Tercedor et al., (1990) stated Baetidae family is the most tolerant family at Ephemeroptera order. Fifth station has a lower water quality compared to other stations in Balaban Stream. At this station, individuals belong to Hydropsychidae family are more intense. Ephemeroptera is another dense group at this station.The individuals belong to Diptera are found at all stations. The order of Diptera can be found in all environments from clean water to polluted water. On the basis of statistical analysis, similarity matrix was grouped by hierarchical clustering using the UPGMA linking method, and moreover cornerstone of UPGMA analysis is used to solve natural groupings of data items (Loewenstein et al., 2008; Zeybek, 2017). Main purpose of hierarchical clustering methods is categorize datasets into the hierarchical clusters organized in a tree diagram, and this study, benthic macroinvertebrates are used as a dataset (Loewenstein et al., 2008).
The station #3 was found to be the most different from the other sampling stations according to benthic macroinvertebrates. The similarity values for the station #1 and #2 were found to be very close to each other. The similarity values for the station #4 and #5 also were found to be very close to each other. All of this close similarities are probably related to the ecological and physical properties of the sampling stations. Besides, the bottom structure and physical properties of these stations are quite similar while the station #3 is quite different from the others. The station #4 and #5 are close to the dam effect and has a sandy-muddy sediment type. As a result of all factors, it is expected that the closer the ecological characteristics of the stations are, the higher their similarity values. Table 6, summarizes the correlations of biological indices. Among biotic indices the highest significant correlation was found between BMWP (Spanish) and BMWP (Hungarian) (r value 0.997, p˂0.01) followed by BMWP (Original) and ASPT (Czech) (r value 0.995, p˂0.01). Another high significant correlation was found between BMWP (Original) and BMWP (Spanish), BMWP (Hungarian) (r value 0.993, p˂0.01). Another high significant correlation also was found between ASPT (Original) and ASPT (Hungarian), ASPT (Czech) (r value 0.994 and 0.993, p˂0.01). The significant negative correlations was found between BMWP (Spanish) and FBI. However an increase in the results in ASPT index and BMWP, BBI score systems shows good ecological quality while an increase FBI and SI score systems shows bad ecological quality. The highest ecological water quality was determined in the 1th station according to SI in winter season. All biotic indices were in accordance between each other except FBI (Figure 5). Yorulmaz et al. (2015), stated that all performed biotic indices were in accordance between each other except FBI in Esen River.
From the biotic indices and score systems applied at Balaban Stream, SI, BMWP (Original), BMWP (Spanish), BMWP (Hungarian), BMWP (Polish), BMWP (Czech), ASPT (Original), ASPT (Hungarian), ASPT (Czech), and BBI were adequate in assessing water quality while FBI was inadequate. Kantzaris et al. (2002), applied nine biotic indices at two streams in Greece, and BMWP, ASPT and LQI were determined inadequate in assessing water quality while BBI and IBE were suitable. Kazanci et al. (2010), applied BMWP and ASPT indices in Aksu Stream, and BMWP and ASPT were determined adequate in assesing water quality. Ogleni and Topal (2011), applied four biotic indices in Mudurnu River, and BMWP and ASPT were determined adequate in assessing water quality. Yorulmaz et al. (2015), applied five biotic indices in Esen River, and FBI was determined inadequate in assessing water quality while ASPT, BMWP, SI and BBI were suitable. Zeybek et al. (2014), applied five versions of BMWP and three versions of ASPT indices in Değirmendere Stream and obtained different score values because of applied versions of biotic indices were based on the geological and ecological futures of their source countries. Zeybek (2017), applied BBI, six versions of BMWP and three versions of ASPT indices in Kargı Stream and also obtained different score values because of applied versions of biotic indices were based on the geological and ecological futures of their source countries. Conclusion As a result of the study, using of benthic macroinvertebrates as bioindicators for the assessment of water quality for Aegean region of Turkey is appropriate.
In conclusion of this study, the biotic indices that different versions of BMWP and ASPT , BBI and SI seem to be more suitable than FBI. According to the physical and biological datas obtained from Balaban Stream, it is foreseen that due to the pollution factors as intense agriculturel activities and animal farms may cause pollution presure on Balaban Stream in the future. Intermittent monitoring researches should be carried out on both Balaban Stream and all other surface water resources in the Tahtalı Dam Lake basin in order to prevent the negative effect of wastes. As a result of this study, there is a importantly need for the establishment of a Turkish Biotic Index in order to assess with high accuracy surface waters in Turkey. With this regional index to be created, we may take into account high accuracy benthic macroinvertebrates, and their abundance, ecology and biology in the lakes, rivers and streams.