Turkish Journal of Zoology Turk J Zool (2017) 41: 102-112 http://journals.tubitak.gov.tr/zoology/ © TÜBİTAK Research Article doi:10.3906/zoo-1512-56 Spatial and temporal distribution of aquatic insects in the Dicle (Tigris) River Basin, Turkey, with new records Fatma ÇETİNKAYA, Aysel BEKLEYEN* Department of Biology, Faculty of Science, Dicle University, Diyarbakır, Turkey Received: 21.12.2015 Accepted/Published Online: 01.06.2016 Final Version: 25.01.2017 Abstract: We investigated insects of the Dicle (Tigris) River Basin in terms of their composition and spatiotemporal distribution. Larvae, pupae, pupal exuviae, and nymphs of insects were obtained from samples collected by a plankton net monthly during a 1-year period in 2008 and 2009 at seven different sites of the Dicle (Tigris) River Basin. A total of 35 taxa from the orders Trichoptera (1 taxon), Ephemeroptera (3 taxa), and Diptera (31 taxa) were identified. Chironomidae (Diptera) was the most diverse group and was represented by three major subfamilies, namely Tanypodinae (2 taxa), Orthocladiinae (19 taxa), and Chironominae (7 taxa). Among these species, Nanocladius (Nanocladius) spiniplenus Saether, 1977 is a new record for Turkey as well as for western Asia. In addition, the Psychomyia larvae found for the first time in the Dicle (Tigris) River Basin (Turkey) were described. Both taxa have been illustrated to warrant validation. Taxa number varied spatially from 6 to 14 and temporally from 2 to 12 during the sampling period. Along the river, Cricotopus bicinctus and Orthocladius (S.) holsatus were the most common taxa. Key words: Diptera, Ephemeroptera, Trichoptera, Insecta, Dicle (Tigris) River 1. Introduction Kazancı, 2010; Özkan, 2010; Özkan et al., 2010; Özyurt Aquatic macroinvertebrates are critical to ecosystem and Tanatmış, 2011; Türkmen and Kazancı, 2011; Kazancı functioning through their regulation of many essential top- and Türkmen, 2012; Zeybek et al., 2012). However, our down and bottom-up ecosystem processes such as energy knowledge on aquatic insects of the Southeastern Anatolia translocation, nutrient flow, and detrital decomposition Region (Mesopotamian Turkey) is still incomplete (Şahin, (Hellmann et al., 2015). Aquatic insects are among the 1984; Koch, 1985; Kazancı, 2009). important components of the aquatic communities in The Dicle (Tigris) River is an important water source terms of taxa richness and their role in the food web. They for the Southeastern Anatolia Region of Turkey, and have been used as bioindicators of pollution and water it serves mainly for irrigation, fishing, recreation, and quality in environmental studies (e.g., Rae, 1989; Zamora- receiving wastewater. Moreover, the dam reservoirs on the Muñoz and Alba-Tercedor, 1996; Kazancı and Dügel, river and its tributaries are used for irrigation and fishing, 2000; Türkmen and Kazancı, 2008; Kalyoncu and Gülboy, in addition to their function as a source of drinking water 2009; Girgin et al., 2010). supply. However, the Dicle (Tigris) Basin is particularly Due to the strategic geographic position of Turkey, affected by a variety of anthropogenic influences, from which is a transcontinental Eurasian country, it is important damming, impoundments, and other hydromorphological to conduct species inventories to fill gaps in the known alterations (e.g., gravel and sand extraction) to various distributions of many species in Eurasia, particularly for types of pollutions (Varol et al., 2012). Although the Dicle the Turkish insects. Aquatic insects have been generally (Tigris) is one of the most important transboundary rivers well documented from a wide variety of inland aquatic in Turkey, the information on invertebrate communities of biotopes in Turkey (e.g., Geldiay, 1949; Kazancı, 1984, the main stretch of the river is still incomplete. Moreover, 2009; Şahin, 1984; Balık et al., 1999; Tanatmış, 1995; Narin as part of the Southeastern Anatolia Project, when the and Tanatmış, 2004; Ahiska, 2005; Taşdemir and Ustaoğlu, construction of the Ilısu Dam is completed, a large part 2005; Ustaoğlu et al., 2005, 2008; Dik et al., 2006; Ozkan of the Dicle (Tigris) will lose the river property. Therefore, and Camur-Elipek, 2006; Sipahiler, 2006, 2008; Duran we investigated the actual insects of the Dicle (Tigris) et al., 2007; Taşdemir et al., 2008, 2009; Gültutan and River basin with special reference to the composition and * Correspondence: [email protected] 102 ÇETİNKAYA and BEKLEYEN / Turk J Zool distribution of the taxocoenosis and biogeographically trend towards its downstream stretches due to inputs from interesting elements through regular monitoring of the its tributaries. The continental climate of the Dicle (Tigris) river during a period of 1 year at seven different sites Basin is referred to as a subtropical plateau climate. The spread over a stretch of the river of approximately 500 km. continental climate features of the basin are most similar to those of the Mediterranean Region. The summer season 2. Materials and methods is hot and dry, and the winter season is not as cold as the 2.1. Study area climate observed in the Eastern Anatolia Region. The The portion of the Dicle (Tigris) River flowing through highest annual total rainfall value was recorded as 611.1 Southeastern Anatolia represents one of the largest rivers mm, in Maden town (upstream region of the river), and in Turkey with a catchment area of approximately 57,614 the lowest annual total rainfall value was found to be 294.1 km2 (Akbulut et al., 2009). The river originates in the Toros mm, in Cizre town (downstream region of the river). The Mountains of Turkey and follows a southeastern route mean annual air temperature ranged between 14.6 °C in Turkey to Cizre, where it forms the border between (Maden) and 21.8 °C (Cizre) (Varol et al., 2012). The Dicle Turkey and Syria for 32 km before entering Iraq. The (Tigris) River has the highest water temperature of all of total length of the river is approximately 1900 km, 523 the Eastern Anatolian rivers (Akbulut et al., 2009). km of which is within Turkey. The Batman Stream is one The locations of the selected sampling sites in the of the major tributaries of the river. Diyarbakir, Bismil, Tigris River are shown in Figure 1. In the present study, Hasankeyf, and Cizre are the four major urban settlements a total of seven sites, specifically Maden “Site 1”, Hantepe on the banks of the river, which serves as a major source “Site–2”, Diyarbakır “Site 3”, Bismil “Site 4”, Batman “Site of the domestic water supply of the city of Diyarbakir 5”, Hasankeyf “Site 6”, and Cizre “Site 7”, were selected (population of approximately 851,000) as well as directly on the Dicle (Tigris) River as part of a river monitoring receiving the partially treated domestic wastewater from network. Two of these sites, Hantepe (Site 2) and Batman Diyarbakir; the untreated domestic wastewater from the (Site 5) are situated downstream of the Dicle and Batman Bismil, Hasankeyf, and Cizre townships; and effluents dam reservoirs, respectively. Some features of the sampling from several industries along its course. The maximum sites are given in Table 1. flows in the river occur from February through April, 2.2. Collection and identification of samples whereas the minimum flows occur from August through All specimens were obtained from collections of a October (Varol et al., 2012). The river discharge varies limnological research project funded by the Scientific and considerably at different locations, showing an increasing Technological Research Council of Turkey (TÜBİTAK, Figure 1. The locations of the selected sampling sites in the Tigris River Basin. 103 ÇETİNKAYA and BEKLEYEN / Turk J Zool Table 1. Locations, geographical coordinates, altitudes (m), widths (~m), and substrates of the sampling sites in the Tigris River Basin. Site no. Location Coordinates Altitude (m) Width (~m) Substrate Site 1 Maden 38°20′N, 39°41′E 860 7 Gravel Site 2* Hantepe 38°06′N, 40°08′E 616 35 Stones Site 3 Diyarbakır 37°53′N, 40°13′E 576 80 Sand, mud Site 4 Bismil 37°50′N, 40°39′E 538 90 Sand, mud Site 5* Batman 37°54′N, 41°05′E 540 65 Gravel, sand Site 6 Hasankeyf 37°42′N, 41°24′E 471 80 Gravel, sand Site 7 Cizre 37°19′N, 42°11′E 371 97 Sand, mud *: Sites situated downstream of the dam reservoirs. project no. 107Y216). In that research project, plankton was the most diverse group including 31 taxa. Among samples were collected by a standard plankton net (25 cm Diptera families, Chironomidae was the dominant group in radius, 50 cm in length, 55 µm in pore size) within the represented by three subfamilies, which are Tanypodinae period from February 2008 to January 2009 from different (2 taxa), Orthocladiinae (19 taxa), and Chironominae habitats of the study sites spread over a river stretch of (7 taxa). It seems that orthoclad midges are the most approximately 500 km. The material collected mainly from advantaged group in terms of species richness in the Dicle stagnant or slow-running and vegetation-rich areas at the (Tigris) River Basin, accounting for 74.2% of the species shores throughout the length of the river was preserved in composition. 70% ethanol until laboratory processing. The larvae, pupae, From Trichoptera, Psychomyia larvae could not be pupal exuviae, and nymphs selected from these samples identified to the species level, because some characteristics were then transferred to an alcohol-glycerin solution of the larvae were not typical for described species of (1:1) and mounted in glycerin (50% glycerol and water) this genus. So far three species of the genus Psychomyia on microscope slides. Specimens were examined and have been recorded from Turkey: Psychomyia dadayensis identified under an Olympus-B51 compound microscope Sipahiler, found in northern and southeastern Turkey; P. at 40–1000× magnifications. Images were collected with mengensis Sipahiler, found in certain streams and rivers an Olympus DP71 digital camera (12.5 megapixels) using in the western, northwestern, and southwestern parts of Image Analysis Pro 5.0 software (Olympus Soft Imaging Turkey; and P.