Research into the flora and fauna of Kopački rit, the flood area of the Danube and Drava rivers, was not possible in the period between 1991–1997, due to ongoing hostilities. The research into the mosquitoes in Kopački rit started in 1990 was continued in 1998. The research results obtained in 1998 were compared to the 1990 results (MERDIĆ, 1993). The total number of mosquitoes collected in 1998 was 7788, which is approximately 25 times smaller than the total number of mosquitoes collected in 1990 (199952). The mosquito fauna is characterised by species that have their breeding sites in the marsh itself, among which Aedes vexans is dominant, and by species whose breeding sites can be found in the oak forest, the Genisto elate – Quercetum roboris community, in the nearby Nature Park. The dynamics of the mosquito population, which is in correlation with the water level of Danube, are significantly different in 1990 and 1998, but we do not suppose this was due to the influence of the war, but rather to the different ecological conditions in 1998.Istraživanja flore i faune u Kopačkom ritu, poplavnom području rijeke Dunava i Drave, nisu bila moguća od 1991. do 1997. godine, zbog ratnih djelovanja. Proučavanja komaraca Kopačkog rita započeta 1990. nastavljena su u sezoni 1998. godine. Rezultati dobiveni istraživanjem faune komaraca Kopačkog rita 1998. godine uspoređeni su sa rezultatima iz 1990. (MERDIĆ, 1993). Ukupan broj jedinki komaraca prikupljenih 1998. godine iznosio je 7788, što je približno 25 puta manje od ukupnog broja komaraca prikupljenih 1990. godine (199952). Faunu komaraca karakteriziraju vrste koje svoja legla imaju u samom poplavnom području, među kojima dominira vrsta Aedes vexans, te vrste čija legla možemo naći u hrastovoj šumi zajednice Genisto elate – Quercetum roboris u obližnjem Parku prirode. Dinamika populacija komaraca, koja je u korelaciji s vodostajem Dunava, značajno se razlikuje 1990. i 1998. godine, ali ipak pretpostavljamo da se ne radi o utjecaju rata na faunu komaraca nego o razlici u ekološkim uvjetima u 1998. godini

Enrih Merdić

Tomislava Lovaković

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ISSN 1330-0520 original scientific paper / izvorni znanstveni radUDK 574.9:595.771(497.5/1-11)COMPARISON OF MOSQUITO FAUNA INKOPA^KI RIT IN THE PERIOD 1990–1998ENRIH MERDI] & TOMISLAVA LOVAKOVI]Institute of Biology, Faculty of Education, J. J. Strossmayer University,L. Jägera 9, 31000 Osijek, CroatiaMerdi}, E. & Lovakovi}, T.: Comparison of mosquito fauna in Kopa~ki rit in the period1990–1998, Nat. Croat., Vol. 8, No. 4., 431–438, 1999, Zagreb.Research into the flora and fauna of Kopa~ki rit, the flood area of the Danube and Drava rivers,was not possible in the period between 1991–1997, due to ongoing hostilities. The research into themosquitoes in Kopa~ki rit started in 1990 was continued in 1998. The research results obtained in1998 were compared to the 1990 results (MERDI], 1993). The total number of mosquitoes collectedin 1998 was 7788, which is approximately 25 times smaller than the total number of mosquitoescollected in 1990 (199952). The mosquito fauna is characterised by species that have their breedingsites in the marsh itself, among which Aedes vexans is dominant, and by species whose breedingsites can be found in the oak forest, the Genisto elate – Quercetum roboris community, in the nearbyNature Park. The dynamics of the mosquito population, which is in correlation with the water levelof Danube, are significantly different in 1990 and 1998, but we do not suppose this was due to theinfluence of the war, but rather to the different ecological conditions in 1998.Key words: mosquitoes, Kopa~ki rit Special Zoological Reserve, population dynamics, impact ofwar on natureMerdi}, E. & Lovakovi}, T.: Usporedba faune komaraca Kopa~kog rita u razdoblju1990.–1998., Nat. Croat., Vol. 8, No. 4., 431–438, 1999, Zagreb.Istra`ivanja flore i faune u Kopa~kom ritu, poplavnom podru~ju rijeke Dunava i Drave, nisubila mogu}a od 1991. do 1997. godine, zbog ratnih djelovanja. Prou~avanja komaraca Kopa~kog ritazapo~eta 1990. nastavljena su u sezoni 1998. godine. Rezultati dobiveni istra`ivanjem faune koma-raca Kopa~kog rita 1998. godine uspor|eni su sa rezultatima iz 1990. (MERDI], 1993). Ukupan brojjedinki komaraca prikupljenih 1998. godine iznosio je 7788, {to je pribli`no 25 puta manje od ukup-nog broja komaraca prikupljenih 1990. godine (199952). Faunu komaraca karakteriziraju vrste kojesvoja legla imaju u samom poplavnom podru~ju, me|u kojima dominira vrsta Aedes vexans, te vrste~ija legla mo`emo na}i u hrastovoj {umi zajednice Genisto elate – Quercetum roboris u obli`njemParku prirode. Dinamika populacija komaraca, koja je u korelaciji s vodostajem Dunava, zna~ajnose razlikuje 1990. i 1998. godine, ali ipak pretpostavljamo da se ne radi o utjecaju rata na faunu ko-maraca nego o razlici u ekolo{kim uvjetima u 1998. godini.Klju~ne rije~i: komarci, Specijalni zoolo{ki rezervat »Kopa~ki rit«, dinamika populacija, utjecajrata na priroduNAT. CROAT. VOL. 8 No 4 431¿438 ZAGREB December 31, 1999Croatian Natural History Museum, Demetrova 1, Zagreb, CroatiaINTRODUCTIONKopa~ki rit is one of the few marshes in Europe. The value of such areas is, firstof all, in their biodiversity. With respect to fauna, Kopa~ki rit is famous for its birds,and is protected by the Ramsar Convention, one of four such areas in Croatia. Al-though fauna and bird ecology are among the most frequently studied, there havebeen several articles on the diversity, value and specific qualities of other faunas ofmammals, nematodes, roundworms and insects. After being untouched for manyyears, Kopa~ki rit became a centre of military activities during the war. The firstline of defence ran right through the very heart of the special zoological reserve.Devastation was unavoidable. Big game was the first target, being shot at from allkinds of weapons. The bird fauna also suffered heavy losses due to extraordinaryharassment. During the military activities of 1991–1995, the major part of Kopa~kirit was mined and thus made inaccessible. After the reintegration of the occupiedarea in 1997, research teams entered Kopa~ki rit (1998), finding significant eutrophi-cation. As well as a changed picture due to the eutrophication, the researchers cameacross a number of mines that prevented them from pursuing further research. Theresearch into mosquitoes started in 1990 (MERDI], 1993) and continued in 1998. Itwas hypothesized that changes must have occurred, particularly with respect to in-sects that spend most of their lives in water. The aim of the 1998 research was tonote the differences in the states before and after the war, and determine the causesthat might have led to those changes. This research needs to be continued for thecollection of data on this valuable ecological flood system.MATERIALS AND METHODSMosquitoes were collected in Kopa~ki rit with the same methods as in 1990,from May to September 1998, at one-month intervals and in the second half of eachmonth. CDC traps were set in four locations: 1. ^onakut (next to the canal leadingto the central lake), 2. Hordovanj (the elevated part next to the lake), 3. Kopa~koLake (in the centre of the lake, below the colony of cormorants), 4. Tikve{ (north ofthe special zoological reserve within the Nature Park, in the oak forest, Genisto elate– Quercetum roboris community Hor. 1938, RAU[ et al., 1985). A total of 7788 mosqui-toes were collected. The mosquitoes were caught in CDC traps, using dry ice as theattractant. CDC traps were made following the instructions of SERVICE (1976). Thetrap includes a plastic tube of 10 cm diameter, inside which there is a fan for thesuction of mosquitoes. The lid that is attached to it is used to increase the suctionspace and to stop the trap from falling. Mosquitoes are sucked into a net that is fas-tened to the plastic tube. The fan uses 6 V batteries, type ICE R25. To make the trapefficient, the attractant used was dry ice, about 8 kg per trap. Traps were opera-tional 22–24 hours a day.All mosquitoes collected at each location were determined using the key of GUT-SEVITCH et al. (1974) and stored in the entomological collection of the Institute of Bi-ology at the Faculty of Education in Osijek.432 Merdi}, E. & Lovakovi}, T.: Comparison of mosquito fauna in Kopa~ki rit in the period 1990–1998RESULTSDuring 1998, 7788 mosquitoes were caught and 12 different species were deter-mined. Aedes vexans Meigen, 1818; is the dominant species, it makes up from 87%to 52% of the mosquito fauna at particular locations. It is followed by Aedes cinereusMeigen, 1830; Coquillettidia richardii Ficalbi, 1889; Anopheles maculipennis Meigen,1818 complex, Aedes cantas Meigen, 1818; Aedes sticticus Meigen, 1838; Aedes caspiusPallas, 1771; Culex pipiens Linneaus, 1758; Aedes excrucians Walker, 1856; Anophelesplumbeus Stephanus, 1828; Aedes rossicus D.G.M. 1830 and Anopheles claviger Meigen1804 (Tab. 1).The number of mosquitoes noted during 1998 was not particularly high, thehighest figure being recorded at the Hordovanj site, followed by ^onakut, Kopa~koLake and Tikve{. The mosquito activity was the most intensive in July, when a totalof 3036 mosquitoes were caught at all four locations (Tab. 2).Nat. Croat. Vol. 8(4), 1999 433Tab. 1. Mosquito fauna in Kopa~ki rit in particular locations in 1998.LocalitySpecies^onakut Hordovanj Tikve{ K. jezero TOTAL% % % % %Aedes vexansAedes cinereusCoquillentidia richrdiiAnopheles maculipennis c.Aedes cantansAedes sticticusAedes caspiusCulex pipiensAedes excruciansAnopheles plumbeusAedes rossicusAnopheles claviger8932017124229215––1–72,1316,245,741,940,162,340,161,21––0,08–3591380265–2010285–––87,569,270,051,58–0,490,240,680,12–––3616173198616–1294–152,550,8725,182,7712,522,33–1,751,310,58–0,15144113924491216917––1–81,797,881,362,780,061,193,910,96––0,06–6286726270157898681721442180,719,323,472,021,141,101,040,920,180,050,030,01TOTAL 1238 4101 687 1763 7788Tab. 2. The number of mosquitoes at four locations in Kopa~ki rit in 1998.Site Date 26. V. 29. VI. 25. VII. 27. VIII. 25. IX. TOTAL^onakutHordovanjTikve{K. Jezero198237101234677140024758102000320716360463172313120123841016871762Total 770 2905 3036 1071 6 7788The participation of species in the total number is different for different loca-tions. Whereas at locations in Kopa~ki rit itself, only flood species were caught,among which Aedes vexans was the dominant one, followed by Aedes sticticus andAedes cinereus, thee Tikve{ location the species that breed in such type of forestwere noted. This refers first of all to Aedes cantans, Aedes excrucians and Anophelesplumbeus.The total number of mosquitoes showed an increase in June and July, and asmall decrease in August, but the values never surpassed 2000 individuals. Thiscorrelates with the water level of the Danube, which provides the water for Ko-pa~ki rit. Fig. 1 shows the fluctuation of the number of mosquitoes in Kopa~ki rit.The Tikve{ location is presented separately to enable the comparison with the 1990data. It is necessary to draw attention to the very high water level at the end ofSeptember and October 1998, which triggered the development of a higher numberof mosquito larvae in October. In 1998, at the Tikve{ location a maximum of 320 in-dividuals was caught after the water level at Apatin reached the critical level of 300cm, i.e. when it was 385 cm.The comparison of the number of mosquitoes caught by CDC traps in the areaof Kopa~ki rit and the corresponding water level of the Danube at Apatin is shownin Fig. 2. During the two-year research period, 15 mosquito species were deter-mined, with differences in the composition of species over the period (Tab. 3).434 Merdi}, E. & Lovakovi}, T.: Comparison of mosquito fauna in Kopa~ki rit in the period 1990–1998Fig. 1. The number of mosquitoes in Kopa~ki rit (^onakut, Hordovanjand Kopa~ko Lake) and Tikve{.Nat. Croat. Vol. 8(4), 1999 435Fig. 2. The number of mosquitoes in 1990 and 1998 as correlated with thewater level of the Danube at Apatin in 1990 and 1998.Tab. 3. Comparison of the mosquito fauna in 1990 and 1998.No. Species 1990 19981 Aedes cantans (Meigen, 1818) +2 Aedes rossicus (D. G. M., 1830) +3 Anopheles claviger (Meigen, 1804) +4 Anopheles plumbeus (Stephanus, 1828) +5 Aedes caspius (Pallas, 1771) + +6 Aedes cinereus (Meigen, 1830) + +7 Aedes excrucians (Walker, 1856) + +8 Aedes sticticus (Meigen, 1838) + +9 Aedes vexans (Meigen, 1818) + +10 Anopheles maculipennis c. (Meigen, 1818) + +11 Coquillettidia richardii (Ficalbi, 1889) + +12 Culex pipiens (Linnaeus, 1758) + +13 Aedes geniculatus (Olivier, 1791) +14 Anopheles hyrcanus (Pallas, 1771) +15 Culiseta annulata (Schrank, 1776) +DISCUSSIONIn normal conditions, the increased water level in the marsh is a result of themelting of snow in the Alps, i.e. it occurs in spring (MIKUSKA, 1979). In 1998, thespring wave did not take place, but occurred only as a minimum short-term in-crease of 385 cm at the end of June. The very specific water-level situation for thegiven year is characterised by an extraordinarily high water level in the autumnalperiod, which reached its maximum in November, 632 cm. The autumnal rise in thewater level in September triggered a great development of mosquito larvae, whichresulted in the appearance of adult mosquitoes at the beginning of October. Since ithad been planned to make records only till the end of September, the traps werenot set in October, so this mosquito invasion was not recorded.If we compare the results obtained in 1998 with those from 1990, it is easy tonote a significant difference. In 1990, at the Hordovanj location, in June alone thetotal number of mosquitoes caught (40500) was higher than in the whole of 1998 atall four locations (7788). The number of mosquitoes in 1990 was 25 times greaterthan in 1998, although the schedule of the appearance and the reduction of thenumber was the same during the season. It can clearly be seen that the water levelregime was similar, only it was lower in 1998 and, unlike in 1990, the high waterlevel occurred at the end of the season. Furthermore, the water level in 1990 sur-passed the critical level of 300, which causes the flooding of the marsh, more thanonce (and for longer). Except for the above, the maximum water level in 1990 was520 cm in July, and in 1998, 632 cm in November (Fig. 2).The 1990 research determined 11 mosquito species (MERDI], 1993), compared to12 in 1998. There is no difference in the composition of the fauna. Eight mosquitospecies appeared in both research years. This refers first of all to mosquitoes thathave their breeding sites within the flood area of the marsh. Those are Aedes vexans,Aedes sticticus, Aedes cinereus, Culex pipiens, Coquillettidia richiardii and Anophelesmaculipennis, and the species Aedes caspius that requires saltier habitats and Aedesexcrucians, whose breeding sites are mostly in oak forests. The only difference be-tween the species that have breeding sites within the marsh is the presence of Aedesrossicus in 1998. Since the individuals if this species are not numerous, they wereprobably not caught in the first year of research. The difference in the compositionof fauna in the years of research is related mostly to the Tikve{ location, wherethere is the oak forest, the Genisto elate – Quercetum roboris community. In 1990, theAedes genicluatus species, that has its breeding sites in the trunks of trees, was re-corded, whereas at the same location in 1998, the species Anopheles plumbeus wasfound. These two species do not exclude each other, but they can be found in thegiven forest community throughout Slavonia (MERDI], 1995), and individuals of theAnopheles hyrcanus and Anopheles claviger species are very rare in this part of thePannonian plain (MINAR, 1986).A comparison of the data obtained before and after the war revealed differencesin the number and composition of the mosquito fauna. The differences in numberare the result of the different water level regimes in the years of research, and thedifferences in composition of the mosquito fauna are the result of the different dy-436 Merdi}, E. & Lovakovi}, T.: Comparison of mosquito fauna in Kopa~ki rit in the period 1990–1998namics of populations of some mosquito species, which in certain ecological condi-tions have a larger (or smaller) number, and thus a bigger (or smaller) possibility ofgetting caught. The differences observed are related to the on-going process ofeutrophication that eliminated the breeding sites at lower water levels, a higher wa-ter level being needed now to start the development of a larger number of mosqui-toes. The invasion of mosquitoes in October is a proof that there are mosquitoes inthe marsh.Received January 14, 1999REFERENCESGUTSEVICH, A. V., MONCHADSKII, A. S. & A. A. SHTAKELBERG, 1974: Fauna of the USSR. Dip-tera. III 4. Jerusalem p. 34–381.MERDI], E., 1993: Mosquitoes (Diptera, Culicidae) of the Kopa~ki rit Special Zoological Re-serve (NE Croatia). Nat. Croat. 2(1), 47–54.MERDI], E., 1995: Distribution of mosquitoes in some forest communities in Croatia. Nat.Croat. 4(3), 143–149.MIKUSKA, J., 1979: Ekolo{ke osobine i za{tita Specijalnog zoolo{kog rezervata »Kopa~ki rit« sposebnim osvrtom na ekologiju kralje{njaka. PMF, Disertacija, Zagreb p. 24–25.MINAR, J., 1986: Zoogeography of the family Culicidae in the Paleartic region. Dipterologicabohemoslavica 4, 21–28.RAU[, \., [EGULJA, N. & J. TOPI], 1985: Vegetacija sjeveroisto~ne Hrvatske. [umarski fakultetZagreb, p. 223–243.SERVICE, M. W., 1976: Mosquito ecology. Field sampling methods. Applied science publishers,London p. 306–375.SA@ E TAKUsporedba faune komaraca Kopa~kog rita u razdoblju 1990.–1998.E. Merdi} i T. Lovakovi}Istra`ivanja komaraca kao dio istra`ivanja biodiverziteta Specijalnog zoolo{kogrezervata obavljala su se prije Domovinskog rata u razli~itom obliku i intenzitetu.Sustavna istra`ivanja obavljena su tijekom 1990. godine, da bi zbog ratnih zbivanja1991–1995(7) na ovom podru~ju bila prekinuta. Tijekom rata Kopa~ki rit bio je linijarazdvajanja i u samom ritu obavljane su neke vojne operacije. U tom razdoblju usam rit su postavljene mnoge mine, koje jo{ i danas ote`avaju slobodno kretanje.Prestankom ratnih djelovanja i reintegracijom tog podru~ja u ustavno-pravni pore-dak Republike Hrvatske, omogu}en je pristup i daljnja istra`ivanja u tom izuzetnovrijednom ekolo{kom sustavu.Istra`ivanja komaraca su obavljena 1998. od svibnja do rujna metodom CDCklopki uz suhi led kao atraktant. Uzorkovanja su obavljena jedanput mjese~no utrajanju od 24 sata, identi~no kao i 1990. godine.Nat. Croat. Vol. 8(4), 1999 437Sveukupno je uhva}eno 7788 jedinki komaraca od kojih je determinirano 12vrsta komaraca. Najve}i broj komaraca zabilje`en je u srpnju, potom je opadaoprema kraju sezone. Postaja u kojoj je uhva}eno najvi{e komaraca bila je Hor-dovanj. Najbrojnija vsta je Aedes vexans s ukupnim udjelom od 80.71 %, uz nju trebaspomenuti Aedes cinereus s udjelom od 9.32%. Sve ostale vrste ~ime udio od 9.97%.Uspore|uju}i podatke dobivene 1998. godine s onima iz 1990. vidi se da je brojuhva}enih komaraca u 1990. oko 25 puta ve}i, i da se razlikuje faunisti~ka slika(Tab. 3). Glavni razlog toj razlici su razli~iti ekolo{ki uvjeti, prije svega vodostaj usamom Kopa~kom ritu koji je u 1990. puno bolje odgovarao razvoju ekstremno ve-likih populacija komaraca (pojava visokog vodostaja u travnju). Tijekom 1998. izo-stao je proljetni val visoke vode, te nije pokrenut razvoj komaraca u prolje}e ililjeto, nego tek nakon pojave visokog vodostaja krajem rujna koji je rezultirao ve-likim brojem komaraca u listopadu. Razlika u sastavu vrsta odnosi se prije svegana postaju Tikve{ gdje je klopka postavljena u hrastovoj {umi zajednice Genisto elate– Quercetum roboris, a sve vrste koje su tamo prona|ene utvr|ene su ve} prije u toj{umskoj zajednici (MERDI], 1995).438 Merdi}, E. & Lovakovi}, T.: Comparison of mosquito fauna in Kopa~ki rit in the period 1990–1998

Usporedba faune komaraca Kopačkog rita u razdoblju 1990.–1998.

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