kuchurgan storage reservoir - as one of … 3...dniester river. figure no. 1 the estuary system of...

J. Wetlands Biodiversity (2013) 3: 67-75

Istros – Museum of Braila

KUCHURGAN STORAGE RESERVOIR- AS ONE OF THE KEY COMPONENT OF THE WETLANDS -

OF THE LOWER PORTIONS OF DNIESTER RIVER

Sergey Philipenko, Elena Philipenko and Vladimir Fomenko

Received: 20.07.2013 / Accepted: 15.12.2013

Abstract: The article provides an evaluation of the nowadays’ biological diversity of the ecosystem ofthe Kuchurgan storage reservoir. Records are provided about the levels of phytoplankton, the flora ofthe reservoir and its macrophytes overgrowth. A description is submitted about the main hydrobiontgroups (zooplankton, benthos, ichthyofauna).

Keywords: avifauna, estuary, firth, hydrobionts, ichthyofauna, overgrowth, phytoplankton, storagereservoir, zoobenthos, zooplankton, wetlands

Introduction:1

The Kuchurgan storage reservoir – which inthe past was a river firth – is included in theestuary system of the Dniester river and,before its regulation and transformation in1946 into the cooling pond of the Moldovacentral steam power station, it representedthe preserved remains of the former largerDniester firth (Yaroshenko 1957), a factindirectly demonstrated by the presence in itsbenthic fauna of relict hydrobionts of thePonto-Caspian fauna complex.

The flowing of the Dniester river into theDniester estuary forms no delta, but one isformed by another river, Turunchuk, both

Sergey Philipenko, Elena Philipenko andVladimir Fomenko:Faculty of Geography and Natural SciencesT.G. Shevchenko Nistrian State University25th October Street no. 128MD 3300, Tiraspol, Republic of Moldovae-mail:Sergey Philipenko:[email protected] Fomenko:[email protected]

being a part of the lower course up to theTiraspol-Bendery district, covered with lakesand marshland reed beds and representing anancient fluvial sedimentary (Morduhai-Boltovskoi 1960). The remains of this bay isthe Kuchurgan storage reservoir, situated 50km to the north of the Dniester estuary (Fig.1).

Till the 1960s the physical and chemicalproperties of the Kuchurgan estuary had notdiffered much from other natural waterreservoirs. After the building of the Moldovacentral steam power station in 1946, thebanks of the estuary were laden with leveesand the dam stopped the natural waterexchange, and so the Kuchurgan estuary wastransformed into a cooling pond of theMoldova central steam power station.According to the type of water supply, theestuary is an inlet water reservoir with areverse water supply of the power station.Till the construction of the dam and thecreation of the storage reservoir, theKuchurgan firth was a spawning and nurseryground for a considerable amount of fishtypes of the lower Dnister river (Gorbatenskiand Bizgu 1990).



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Nowadays, the water area of thereservoir is about 2730 hectares with anaverage depth of 3.5 meters and maximal -5.0 meters, the water volume - 88 millioncubic meters. The Kuchurgan reservoir canbe classified as an elongated narrow, shallowwater basin, whose vertical axis is mixedwith an upper water outlet.

The Kuchurgan reservoir, althoughsubjected to a strong anthropogenic influenceand, above all, to a thermic impact, it plays acrucial role in the maintaining the wetlandsbiodiversity of the lower basin of theDniester river.

Figure no. 1 The estuary system of Dnister River(by Y.М. Маrkov)

Materials and methods:

The materials for the articles were takenfrom the results of the studies of theKuchurgan reservoir, conducted in theresearch laboratory “Biomonitoring” of theTransdniestrian State University.

Results and discussion:

Among all the water basins of the lowerDniester within the Moldova territory, theKuchurgan reservoir is remarked by a richdiversity of species, thus playing the role of acentral (key) component of the wetlands inthe southern part of Transdniestria.

The phytoplankton of the Kuchurganreservoir is characterized by a rich speciesdiversity and nowadays includes 366 speciesof algae: Cyanophyta - 69 species,Chrysophyta - 2, Bacillariophyta - 127,Pyrrophyta - 13, Euglenophyta - 38,Volvocophyceae - 24, Chlorococcophyceae -73, Desmidiales - 20 species (Ungureanu1999).

Despite all the changes that took place atdifferent times in the taxonomic structure ofthe reservoir’s phytoplankton, the ratiobetween the main groups of algae remainedunchanged. In all the periods of the operationof the reservoir its flora was dominated byBacillariophyta, Chlorococcophyceae andCyanophyta.

In the period 2011-2013 as part of theaquatic and semi-aquatic flora of theKuchurgan reservoir, there were recordedabout 66 species of land plants belonging to25 families (Philipenko et al. 2013). Apartfrom the macrophytes of the Kuchurganreservoir, its waters are overgrown mainlywith Potamogeton crispus, and its bankswith Phragmites australis.

The intensive overgrowing of thereservoir with Potamogeton crispus occurs inthe first or second decade of May, when thewater surface is covered by long stems andthe inflorescences raise above the surface ofthe water. The Potamogeton crispusovergrowth is more prone to open the water



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area of the lower and upper portions of thereservoir - about 80 % of the water surface(Fig. 2, Annexes). The intensity of theovergrowth is so high that not only does itprevent the normal reservoir water exchange,but also the passage of motor boats.

If the open water areas of the reservoirwere overgrown with Potamogeton crispus,then the “windows” among the bank reedthicknesses mainly were overgrown withMyriophyllum spicatum and Ceratophyllumdemersum.

In May and June the dominating specieswhich condition the overgrowing of thereservoir are Potamogeton crispus,Ceratophyllum demersum, Myriophyllumspicatum, Potamogeton pectinatus andVallisneria spiralis. In the first decade ofJuly the most massive forms of macrophytesare Ceratophyllum demersum andMyriophyllum spicatum with a smallerparticipation of Potamogeton perfoliatus. InAugust along the bank areas of the reservoiramong the dense thickets of reeds there areformed totally overgrown “windows” withHydrocharis morsus-ranae, as well as theTransdniestrian Red Book species - Salvinianatans (Fig. 3, Annexes), with a mixture ofLemna minor and Lemna trisulca. On themargins of the thickets Phragmites australisand Typha angustifolia, Salvinia natans alsoform small congestions.

Nowadays as before, among the rigidoverwater plants of the Kuchurgan reservoirit is the Phragmites australis that prevails.The upper portions of the reservoir ischaracterized by a denser overgrowth incomparison with the middle and lowerportions. All the shoreline of the reservoir iscovered by thickets of Phragmites australiswith a width of 30 meters, in some places upto 50 meters. In the upper parts of thereservoir one may notice numerous isles ofreed thickets with a surface of about 100 sq.m., many of which are situated about 300meters from the bankline. The upper portionof the reservoir, which is the narrowest partof the water basin, is totally overgrown withPhragmites australis. The width of thethickets is over 1000-1500 meters.

The middle-portion of the reservoir isless subjected to the overgrowing withPhragmites australis than the upper and thelower portions. The width of the thicketsnear the bank is in the limit of 5-10 meters,at places more than 15 meters. Closer to theupper portion of the reservoir the width ofthe thickets is up to 25-30 meters(Philipenko and Tischenkova 2010).

The lower portion of the reservoir, moreexactly its coastline, is overgrown withPhragmites australis in a smaller degree thanin the upper and more than in the middleportion. The width here is about 35-40meters. One may find here groups of thicketsof Phragmites australis interspersed withsmall groups of Typha angustifolia with asurface of 40 sq. m.

On the whole coastline, with theexclusion of the territory of the right bank,Phragmites australis grows in the form of athick wall, excluding the access to the bankfrom the water area. The density of theovergrowth of the coastline by Phragmitesaustralis in the reservoir is in average about50-70 plants/sq. m.

Visual observations from the boat wereconfirmed by the satellite photos of the“Google Maps”, on the basis of which wedraw a map of the Kuchurgan reservoir withthe areas of the overgrowing rigid leafvegetation (Fig. 4, Annexes).

With the help of the application programMATLAB we had processed the map of theKuchurgan reservoir and designed the areaof the overgrowth (highlighted in gray).Computer simulations have shown that thearea overgrown with reeds at the Kuchurganreservoir is of 498 hectares, accounting for19 % of the total cooling reservoir surface.(Philipenko et al. 2013).

The fauna of the reservoir is also rich inspecies composition.

The basis of zooplankton in Kuchurganreservoir is formed of around 40 species ofinvertebrates, of which Rotatoria represents54 %, Copepoda 16 % and Cladocera 30 %.

The dominant forms, which form thebasis of zooplankton in Kuchurgan reservoirin recent years are Rotatoria (Keratella



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quadrata, Brachionus angularis, Brachionusbudapestinensis, Brachionus calyciflorus,Brachionus diversicornis, Asplanchnapriodonta, Polyarthra dolichoptera) andCladocera (Bosmina longirostris).

The subdominant forms are Rotatoria(Keratella cochlearis, Synchaeta pectinata,Synchaeta tremula), Cladocera (Chydorussphaericus), Copepoda (members of thegenus Cyclops) (Chur 2012).

The average reservoir zooplanktonabundance in 2008-2012 was of 51855ex./m3, including Rotatoria 38178 ex./m3,Cladocera - 7025 ex./m3, Copepoda 6652ex./m3; zooplankton biomass – 701.4 mg/m3,including: Rotatoria 462.6 mg/m3, Cladocera169.22 mg/m3, Copepoda 69.58 mg/m3.

The dynamics of the changes inabundance and biomass of zooplankton inKuchurgan reservoir are shown in Fig. 5(Annexes).

The benthic fauna of the Kuchurganreservoir before the commissioning of theMoldova power station was quite rich andvaried, and was represented by 167 species.During the period of weak thermal load inthe cooling pond there were observed 190taxa of benthic aquatic organisms, of which16% were from Ponto-Caspian species. Inthe 1980s the species diversity of benthiccommunities of the reservoir has decreasedby almost 70 types (Vladimirov andToderash 1998). At the same time, at thisstage of hydrobiological regime wereregistered 25 previously unmentionedspecies, mainly chironomids and mollusks.As a result, by nowadays the benthos faunahas consisted of about 168 taxa types.

The zoobenthos reservoir over the pastyears has maintained a quality characteristicof this body of water which has been formedas a result of the conversion of the estuaryinto the cooling pond of the Moldova powerstation. The "soft" benthos, as before, isformed by oligochetes, polychetes, highercrustaceans, chironomid larvae and otherinsects. Malacofauna in number and biomassis determined by the zebra mussel(Dreissena polymorpha).

The dynamics of changes in abundanceand biomass of the "soft" (aft) zoobenthiccomposition of the Kuchurgan reservoir areshown in Fig. 6 (Annexes).

The host, both in number and biomasscomponent of the diet of zoobenthosreservoir is the oligochaeto-chironomidcomplex. The oligochetes of the reservoir(about 40 species) are mainly represented bytubificids. The most spread types are therepresentatives of the species Тubificidae: Limnodrilus hoffmeisteri, L. claparedeanus,Psammoryctes barbatus, Tubifex tubifex andother ubiquitous species. The number ofoligochetes during 1997-2012 remainedconsistently high with an average of 6571ex./m2 with a biomass of 11.3 g/m2.

Among the 56 chironomid species inKuchurgan reservoir the majority isrepresented by: Chironomus plumosus,Leptochironomus tener, Limnochironomusnervosus, Cryptochironomus defectus,Procladius ferrugineus, Polypedilumbicrenatum and others. The changes in thelevel of the thermic status of the reservoirbrought about a change concerning thecommon species of chironomids, whileChironomus plumosus strengthened itsdominance, obtaining a share of totalchironomids accounting for about 40 % andabout 70 % of the biomass. The averageindices in the density of the chirinomids in1997-2012 were 1249 ex/m2 with a biomassof 15.8 g/m2.

The malacostraca of the reservoirs ismainly represented by gammaridae andkorofiidae, rarely by cumaceans crustaceansand mysids. Among the gammaridae, whichare quite common in the reservoir, are thefollowing: Dikerogammarus haemobaphes,D. villosus, Pontogammarus robustoides, P.crassus, and among the corophiidae –Corophium maeoticum. During the years2004-2012 the number of higher crustaceansremained small, in average about 65 spec./m2

with a biomass of 0.3 g/m2. In the recentyears the numbers of the samples ofcrustaceans, were significantly reducedcompared to the years 1981-2000. Amongthe macrophytes of the reservoir the



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introduction in 1984 of the freshwater prawnMaсrobrachium nipponense has becomecommon.

The fauna of the insect larvae (withoutchironomids) is formed by Ceratopogonidae,Ephemeroptera, Odonata, Trichoptera andDiptera. All these groups of the zoobenthosare not significant. Among the oligo- andmezosaprobes we may mention the followingspecies: Palingenia longicauda,Potamanthus luteus, Cloen dipterum,Heptagenia sulfurea. Among the larvae ofdragonflies the following are common:Coenagrion puella, Coenagrion pulchellum,Aeschna sp., Gomphus vulgatissimus; amongthe caddisflies (Trichoptera) - Orthotrichiatetensii and Agraylea multipunctata.

Currently, at the bottom of theKuchurgan reservoir the malacofauna countswith about 35 species of molluscs includingTheodoxus fluviatilis, Valvata piscinalis,Lithoglyphus naticoides, Viviparus contectusand others. Among the bivalve, particularlyabundant is Dreissena polymorpha. Besidesthis one, from the Ponto-Caspian relics typesthere was found Hypanis pontica.

The ichthyofauna of the Kuchurganestuary, before its transformation into thecooling pond, consisted of 46 species of fishfrom 13 families. Currently, it is inhabitedby 40 species of fish belonging to 12families: Cyprinidae - 19 species, Gobiidae -8 species, Percidae - 3 species, Clupeidae - 2species and families Esocidae, Cobitidae,Siluridae, Ictaluridae, Atherinidae,Gasterosteidae, Singnathidae, Centrarchidae- one species of each. In the period of 1991-1995 a new invasive non-target speciesappeared - the Black Sea Silverside(Atherina boyieri), which due to aneuribionthic and high reproductive potentialhad taken a leading position in the fish fauna(25.5 %) (Krepis et al. 2013). In recent yearsthe growth of another invasion type has beenobserved: that of - Lepomis gibbosus.

The ecological succession during theintensive thermic impact of the reservoir(1981-1985) led to a significant reduction inthe number of walleye and pike and a slightdecrease for bream and roach. On the other

hand, the new environmental conditionsallowed the forming of a highly productivefish reservoir complex on the basis of theintroduction of phytophagous fishes.

The avifauna of the Kuchurgan reservoiris typical of the wetland ornithine-complexesof large bodies of water such as the lakes andmarshes in the south of Moldova. Among thewetlands of the Kuchurgan reservoir and thesurrounding area there are 99 bird speciesbelonging to 12 order. About 43 species arenesting, 30 species are on flight (only duringmigrations), 44 species are wintering, 4species can be attributed to stray types.

The most numerous nesting species areAcrocephalus arundinaceus, Fulica atra,Gallinula chloropus, the common species arePodiceps cristatus, Ixobrychus minutus,Panurus biarmicus, Aythya ferina, Remizpendulinus and others.

The Kuchurgan reservoir is also a habitatfor a number of rare birds introduced in theRed Book: Cygnus olor, Botaurus stellaris,Aythya nyroca, Egretta alba, Phallacrocoraxpygmeus, Haliaeetus albicilla, Pandionhaliaetus, Mergus serrator and others.(Tischenkov 1998).

Conclusions:

The Kuchurgan reservoir is subjected to anactive human intervention, particularly to thethermal pollution. It plays an important rolein maintaining the biological diversity of thewetland basin of the Lower Dniester. Thecurrent state of the water ecosystem can beestimated as tense. Unstable ecologicalcondition of the reservoir leads to successiveovergrowing of the pond, accompanied byfixing in the ecosystem of atypical invasivespecies. The monitoring of the ecologicalstatus of water bodies will lead to thedevelopment of a system of measures aimedat maintaining its biological balance.



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Rezumat:

BAZINUL DE ACUMULAREKUCHURGAN – O COMPONENTĂ CHEIE A ZONELOR UMEDE DIN

PORȚIUNEA INFERIOARĂ A RÂULUI NISTRU

Articolul oferă o evaluare a biodiversității actuale din ecosistemul existent în bazinul deacumulare de la Kuchurgan. S-au realizatînregistrări ce evidențiază nivelurile fitoplanctonului, flora bazinului deacumulare și creșterea excesivă a macrofitelor. Este prezentată o descriere a pricipalelor grupe de hidrobionți (zooplancton, bentos, ihtiofaună).

References:

CHUR S.V. (2012), Izmenenie chislennosti ibiomassy zooplanktona Kucherganskogovodohranilishcha perioda 2008-2011 godov.Geoekologicheskie i bioekologicheskieproblemy Severnogo Pricernomorya:Materialy IV Mejdunarodnoi nauchno-prakticheskoi konferentsii, Tiraspol: Izd-voPridnestrovsckogo universiteta, pp. 349-351.

GORBATENSKI G.G., BIZGU S.E. (1990),Gidrologicheskaia harakretiristika Denstra,Ekosistema Nijnego Dnestra v usloviahusilennogo antropogennogo vozdeistvia,Stiinta, Kisinev, pp. 4-21.

KREPIS O., USATYI M., STRUGULYA О., USATYI А., SHAPTEFRATSI N. (2013),Izmenenie bioraznoobrazia ihtiofaunyKuchurganskogo vodohranilischa v protseseego ekologicheskoi suktsesii,Mejdunarodnaia konferentsia “Upravleniebasseinom transgranichnogo Dnestra vramkah novogo basseinovogo dogovora”,Kishinev 20-21 sentyabrya 2013, pp. 178-182.

MORDUHAI-BOLTOVSKOI F.D. (1960),Kaspiiskaya fauna v Azovo-Chernomrskombasseine, M.L., 286 p.

PHILIPENKO Е.N., TISHCHENKOVA V.S. (2010), Zarastanie trostnikom (Phragmitesaustralis) Kuchurganskogo vodohranilisha –ohladitelya Moldavskoi GRES, Bassein rekiDnestr: ekologicheskie problemy iupravlenye transgranichnymi prirodnymiresursami, Materialy Mejdunarodn.Nauchno-prakt. konf., Tiraspol, IzdatelistvoPGU, pp. 248-250.

PHILIPENKO E.N., TISHCHENKOVA V.S.,PHILIPENKO S.I. (2013), Zarastanievodoyoma ohladitelya Moldavskoi GRESmassovymi vidami makrofitovKuchurganskogo vodohranilisha,Mejdunarodnaia konferentsia “Upravleniebasseinom transgranichnogo Dnestra vramkah novogo basseinovogo dogovora”,Kishinev 20-21 sentyabrya 2013, pp. 445-449.

TISHCHENKOV А.А. (1998), Nekotoryesvedenia o redkih ptitsah SrednegoPridnestrovya, Problemy sohraneniabioraznoorazia Srednego i Nijnego Dnestra,Ekologicheskoe obshestvo «BIOTICA», pp.155-158.

UNGUREANU L. (1999), Succesiunile structuriitaxonomice a fitoplanctonului lacului deacumulare refrigerent Cuciurgan,Conservarea biodiversităţii bazinului Nistrului, Materialele Conferinţei Internaţionale, Chişinău, 7-9 octombrie 1999, Societatea Ecologică «BIOTICA», pp. 234-236.

VLADIMIROV M.Z., TODERASH I.K. (1998),Kachestvenyi sostav i kollichestvennoyerazvitie makrozoobentosa,Bioproduktsionnye protsesy vvodohranilishah ohladitelyah TES, Stiinta,Kisinev, pp. 130-138.

YAROSHENKO M.F. (1957), GidrofaunaDnestra, М. Nauka, 169 p.

Annexes:



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Figure no. 2 Overgrown water area of the Kuchurgan reservoir Potamogeton crispus in May2013.

Figure no. 3 Thickets of Salvinia natans on Kuchurgan reservoir.

Figure no. 4 The surface of Kuchurgan reservoir overgrown area of the rigid vegetation.



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Figure no. 5 The dynamics of the changes in abundance (a) and biomass (b) of zooplankton inKuchurgan reservoir (2007-2012).

a)

100292

5432963533

222721815311988

0

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Rotatoria Cladocera Copepoda Total

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341,92208,18197,62

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Figure no. 6 The dynamics of changes in abundance (a) and biomass (b) of the "soft" (aft)zoobenthic composition of the Kuchurgan reservoir in 1997-2012.

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6321

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65596415

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20,75

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kuchurgan storage reservoir - as one of … 3...dniester river. figure no. 1 the estuary system of...

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