Abstract: First faunistic and ecological survey of interstitial fauna of streams in Turkey

First faunistic and ecological survey of interstitial fauna of streams in Turkey N. Kazanc1, B. Oz, M. Dügel, G. Türkmen and O. Ertunç The upper part of the hyporheic zone of the river bed is known as the interstitial zone. The interstitial and hyporheic habitats act as refuge areas for benthic macroinvertebrates for survival during floods and droughts. The temperature-sensitive epigean taxa may use the interstitial habitats to escape high surface water temperature. Also, they migrate to interstitial habitats for the deposition and incubation of eggs, growth of small instars, and feeding (JACOBI & CARY 1996). In Turkey, the ecology o f running waters has been scarcely investigated, an d to our knowledge their interstitial fauna has never been studied. The Blacksea Region is one o f the most biologically rich regions on Earth and accepted as a biodiversity hotspot ( especially Eastem Blacksea Region) with otherpart ofthe Caucasus Region. Despite this, limnofauna and limnoecology of freshwater ecosystems ofEastem Blacksea Region are not known. The objective o f this first research was to investigate the composition of aquatic insects of interstitial fauna and some ecological characteristics o f inerstitial habitats o f streams in the Black Sea Region. The 13 study streams were first, second, and third order, (A1adag, Devrek, Ezine streams in Westem Blacksea Region; Altmdere, F1rtma, Maral streams in Eastem Blacksea Region) and belong to the hydrographic basins in Westem and Eastem Black Sea Regions. The collecting sites had reference site characteristics. Interstitial fauna was sampled using the Karaman-Chappuis technique. The 13 sites (one site on each stream) were sampled once between Ju1y and August 2006. Samp1es of2 L of interstitial water were filtered through a 55-l.lm mesh net. The conductivity values recorded were between 199.9 and 27.9 1.1S. The disso1vedoxygenrangedfrom6.8to0.7mg!L. ThepHmeasured was from a minimum o f 7.2 to a maximum o f 8.16. The temperature values recorded were between 12.2 and 24.6 °C. For all taxonomica1 levels, 29 taxa were sampled. Baetis was recorded with 33.3% dominancy, Paraleptophlebia with 53.3 %, and Habroleptoides with 34.78%. Electrogena were found with 11.1 % dominancy in site 8 and 6.6% in si te 6 in this study. Within the Plecoptera, Perla was recorded with 21.7 % dominancy, Leuctra with 50 %. Plecoptera actively search for prey by foraging in the interstices of the stream. Adu1t Coleoptera are seldom found in the hyporheic zone (WILLIAMS 1984). The 1arvae of Noterus clavicornis was found with 5.5% dominancy. Hydroptilidae and Linmephilidae were found with 22.2% and 11.1 % dominancy, respectively. Ceraclea was found with 9.1% dominancy. The caseless Trichoptera species was found with highest dominancy (100%). Pentaneurini with highest dominancy (80% ), Orthocladius with 16.6 %, Chironomus with highest dominancy (20 %) and Tanytarsus with 13.0% dominancy. Ceratopogonidae was found with highest dominancy (20% ), Bezzia with highest dominancy (77. 7 % ), Palpomyia with highest dominancy (6.7 %) and Ceratopogon with 16.6% dominancy. According to results of canonical correspondence analysis Isotomurus, Baetis, Linmephilidae, Probezzia, and Pentaneuriella were associated with high pH. Leuctra was correlated positive1y with pH and temperature. Chironomus was positive1y correlated with temperature. Hydropti1idae, Electrogena, Perla, Paraleptoplebia, Palpomyia, Plecoptera, and Baetis were associated with high dissolved oxygen. Ceratopogon, Podura, Dicranota, and Orthocladius were positively correlated with high conductivity. These preliminary results show that the interstitial zone of studied streams in Blacksea Region are important habitat for aquatic insects. Further work is required to better understand structure of hyporheic macroinveretebrate assemblages and relationships between macroinveretebrate assemblage composition and changes in water chemistry.