Supplement 1 Ecological Engineering and Environment Protection, IX, 2017, p. 16-21 NEW DATA ON THE CHIRONOMIDAE (DIPTERA) FAUNA FROM THE UPPER ISKAR RIVER CATCHMENT (BULGARIA) – SPATIAL DISTRIBUTION AND ECOLOGICAL NOTES Dimitriy Dashinov Abstract: The Chironomid composition was studied in 23 sites from 12 rivers along the upper part of the Iskar River catchment (Danube basin). Samples were gathered using Surber sampler in the summer period of 2015-2016. A total of 54 taxa (from 39 genera and 5 subfamilies) were identified from which 33 taxa were new for the upper Iskar River catchment. Two species were new for Bulgaria: Potthastia montium (Edwards, 1929) and Symbiocladius rhithrogenae (Zavrel, 1924). Two taxa belonged to genera not reported for the Bulgarian fauna – Cryptotendipes sp. and Sympotthastia sp. For most of the rivers the chiro abundance was relatively low with a mean of 60 ind.m-2, which is about 12% of the marozoobenthos community. Key words: Chironomidae, Iskar, Potthastia montium, Symbiocladius rhithrogenae, new records INTRODUCTION The period of sampling was in July - August 2015 and 2016. An overall macrozoobenthos sample On the Chironomidae fauna there is overall data was taken from each site using Surber sampler, for the whole Iskar River [5] [11] as well as from sections according to the adapted for Bulgaria version of the upstream and downstream of Sofia [17]. Along the multi-habitat sampling method [3]. The collected upper Iskar catchment studies of the Chironomidae samples were preserved in 70% alcohol and stored family are few. There is more data on the glacial lakes in the laboratory for further analysis. of Rila Mountain [12] [13] [14] [16]. There is some Chironomids were mounded in permanent slides consequential data on the chironomid composition of using Canadian balsam and stored in the Diptera the Iskar River below and above the Town of Samokov collection in laboratory “Hydrobiological [5] [6]. Regarding the whole system of rivers springing monitoring and saprobiology” department of from the Rila Mountain an extensive checklist of General and Applied Hydrobiology, Sofia terrestrial and aquatic Diptera was recently published University. Larvae were identified to the lowest [4]. But these studies give only a small fraction of the possible level using several keys [1] [2] [7] [10] [15]. chiro biodiversity of the upper stream of Iskar River Relative abundance per square meter and portion of and new data is needed for a more detailed knowledge the Chironomidae family from the whole on these aquatic Diptera. macrozoobentos sample were calculated. The aim of the study is to present new data on the Chironomidae biodiversity from the upper Iskar River RESULTS AND DISCUSSION catchment with notes on the chiro distribution and abundance. A total of 54 taxa (from 39 genera and 5 subfamilies) of the Chironomidae family were MATERIALS AND METHODS recorded (Tab. 2) from which 33 are new for the upper Iskar River catchment. The list includes two A total of 23 sites from 12 rivers were surveyed. species new for Bulgaria –Potthastia montium Date, geographic coordinates, and place of sampling (Edwards, 1929) and Symbiocladius rhithrogenae are shown in Table. 1. The upper part of Iskar River (Zavrel, 1924). Two taxa belong to genera no yet catchment extends from above the Iskar Reservoir to reported for the Bulgarian fauna – Cryptotendipes the streams flowing on the northern slopes of the sp. and Sympotthastia sp., but adults or pupa are Rila Mountain. The Iskar River below Samokov needed for identification to species level. Town can be characterized as a semi-mountain river, For the identification of P. montinum the distinctive while most of the sections above Samokov are of feature was an irregular dark spot present between typical mountain rivers, some with very narrow bases of antennae [2]. This species was reported only valleys, steep run and high water velocity (the in the Cherni Iskar River (site 10). Specimens of the tributaries of Cherni Iskar). Palakaria and Lakatica parasitic species [9] Symbiocladius rhithrogenae Rivers are exceptional – with moderate flow and (larvae and pupa) were found in two sites attached to fine substratum and only site 18 of Palakaria River the larvae of Rhithrogena sp. For destinguishing the shows typical mountain river features. genus Sympotthastia from Potthastia the features of the maxilla were used [8]. 16 Supplement 1 Ecological Engineering and Environment Protection, IX, 2017, p. 16-21 The following taxa can be considered common for were noted in previous studies [4] [5] [6]. Above the upper Iskar catchment – T. calvescens, P. gaedii, species level taxa like Conchapelopia / Rheopelopia P. gr. convictum, most of the Tanitarsini, sp. and Cricotopus / Orthocladius sp. probably Conchapelopia / Rheopelopia sp. and Cricotopus / include several species and seemingly decrease the Orthocladius sp., also T. calvescens and P. gaedii biodiversity. Table 1. List of studied sites with date and geographic coordinates № Site location Date Longitude and Latitude 1 Iskar River downstream of the mouth of Palakaria River 11.8.15 N42°25'55.07" E23°31'58.08" 2 Iskar River near Zlokuchene Village 11.8.15 N42°23'35.38" E23°33'9.80" 3 Iskar River near Dragoshinovo Village 11.8.15 N42°21'50.30" E23°33'19.61" 4 Iskar River upstream of the Town of Samokov 18.8.15 N42°19'17.40" E23°33'12.96" 5 Iskar River after the merger of Beli and Cherni Iskar Rives 19.8.15 N42°17'21.06" E23°32'8.37" 6 Musalenska Bistrica River 28.7.16 N42°16'44.22" E23°35'34.01" 7 Beli Iskar River upstream of Beli Iskar Village 19.8.15 N42°15'31.08" E23°32'31.38" 8 Levi Iskar River upstream of Mala Tsarkva Village 21.8.15 N42°14'36.71" E23°31'0.19" 9 Levi Iskar River downstream of Mala Tsarkva Village 12.8.16 N42°16'17.40" E23°30'26.10" 10 Cherni Iskar River after the inflow of Urdina River 21.7.15 N42°14'14.86" E23°23'18.13" 11 Cherni Iskar River upstream of Govedartsi Village 7.8.15 N42°15'17.33" E23°27' 6.00" 12 Cherni Iskar River before merging with Beli Iskar River 7.8.15 N42°16'38.99" E23°31'21.19'' 13 Lakatica River before mouth 19.8.2015 N42°15'57.36" E23°28'11.64" 14 Palakaria River before mouth 19.8. 15 N42°25'24.90" E23°31'43.00" 15 Palakaria River upstream of Shirokydol Village 19.8.15 N42°23'53.20" E23°31'36.20" 16 Palakaria River upstream of BelchinskiBani Village 19.8.15 N42°22'12.87" E23°25'20.15" 17 Palakaria River southwest of Kovachevtsi Village 11.7.16 N42°25'35.94" E23°17'53.77" 18 Palakaria River upstream Yarlovo Village 11.7.15 N42°28'50.60" E23° 16 18.00" 19 Lopushka River 30.7.16 N42°13'31.40" E23°26'00.31" 20 Preka River 11.8.16 N42°13'47.82" E23°24'22.54" 21 Urdina River 10.8.16 N42°11'12.66" E23°20'42.79" 22 Pravi Iskar River 4.8.16 N42°12'54.18" E23°20'30.44" 23 Malyovishka near Malyovitsa Hut 10.7.16 N42°12'31.03" E23°23'13.63" A total of 22 taxa were found only in single sample in % and number of taxa (NTchir) for each sites. In some cases this can be connected with the sample are given in Tab. 3. In every sampled river ecological preference of the species. For instance chironomids were present and ranges from several Robackia demeijerei is related to sandy bottoms [7], species, to almost half of the whole macrozoobentos found in site 3 were fine substratum was common, community. The substratum composition (sandy or species like Orthocladius (S.) lignicola and bottom) may explain some of the low abundances Brillia longifurca which feed on wood debris [8] and like in sites 2, 3 and 13. In other cases very fast were found in small mountain rives (sites 6, 20, 21 water velocity could explain the low abundance respectively) were submerged branches and logs estimated in site 8 and probably slight organic were noted. Palakaria River showed the highest pollution can constitute the great abundance biodiversity – 26 taxa from the 5 studied sites. recorded downstream in site 9. For the last The relative abundance (RA) of the mentioned site this would explain the enhanced Chironomidae family from the upper Iskar River number of species and the high chironomid density catchment, portion from the whole macrozoobentos per square meter. The dominant taxon in site 9 17 Supplement 1 Ecological Engineering and Environment Protection, IX, 2017, p. 16-21 Micropsectra sp., although present in other sites, extremes the chiro abundance along the catchment only in Levi Iskar River has the impressive was relatively low with a mean of 60 ind.m-2 or 12% abundance of 455 ind.m-2. Other sites with high of the marozoobenthos, values common for abundance like site 4 and 7 are more likely to bea Mountain Rivers. result of specific habitat conditions. Excluding this Table 2. Chironomidae checklist from the upper Iskar River catchment, site number as in Table 1 Taxon Site Number Faunistic notes Subfamily Chironominae Tribe Chironomini Cf. Parachironomus sp. 17 First record for the catchment Chironomus sp. 16 The genus has been reported in previous studies [5] [6] Cryptochironomus (Cryptochironomus) defectus 14, 16, 17 The genus has been reported in (Kieffer, 1913) previous studies [5] [6] Cryptotendipes sp. 14 First record of the genus for the Bulgarian fauna Einfeldia gr. pagana (Meigen, 1838) 16 First record for the catchment Polypedilum gr.