Doğu Karadeniz Bölgesi Trichoptera (Insecta) Faunası Üzerine Su Çerçeve Direktifi İle İlişkili Olarak Ekolojik Araştırmalar

Abstract

Within the scope of Water Framework Directive, reference conditions have to be determined and compared with stations of the same type to understand habitat quality condition of aquatic ecosystems. Functional characteristics can be used for comparison as well as species composition, richness. In this study, instead of taxonomic diversity of organisms in aquatic ecosystems, functional diversity of them was used. Feeding behavior was used to determine functional diversity and order Trichoptera was used as benthic macroinvertebrate. Order Trichoptera includes lots of species with different ecological requirements in aquatic ecosystems. Because of this feature, order Trichoptera is widely used in water and habitat quality studies in stream ecosystems. Trichoptera larvae use their mouth secretions and they can create new niches, so they use almost all feeding behaviors observed in aquatic ecosystems. In this study, 66 stations were determined in 5 streams located in Giresun, Trabzon and Rize in Eastern Black Sea Region in 2008, 2009 and 2011. 5375 Trichoptera larvae collected from the stations were identified at genus level, and 13 family and 22 genera were determined. Two multivariate analysis were applied to understand relationship between genera and their habitats. The abundance of genera were assessed with 10 independent variables (temperature, pH, electrical conductivity, stream width, riparian forest, percentage of riparian vegetation, percentage of gravel and sand, altitude and dissolved oxygen) in first analysis. The relationship between 22 genera and 11 independent variables (temperature, pH, electrical conductivity, disolved oxygen, nitrogen of nitrate and nitrite, magnesium hardness, zinc, copper, ferrous iron, nickel and stream velocity) were analized in second analysis. The feeding ratios are calculated over the feeding behaviors of Trichoptera larvae to test the applicability of the River Continuum Concept in Turkey. Due to the fact that streams in the Eastern Black Sea Region originated from the upper part of tree line, different patterns were observed. It was determined that predator larvae were independent of altitude and that they were related to forests along the streams. Scraper larvae were predicted to be predominate in the lower regions of the river and in the regions where the shadows had disappeared, but it was dominant above the tree line in the Eastern Black Sea Region streams. It has been observed that riverside forests nearby the stream are a major factor that influence the distribution of the Trichoptera larvae. It may be useful to use functional diversity when working with some groups that are difficult to identify at species level, where fauna elements are unknown, or when it is intended to reduce the loss of time, labor and money.