Analele Ştiinţifice ale Universităţii Al. I. Cuza Iaşi, s. Biologie animală, Tom LIV, 2008

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1 STUDIES UPON THE COMPOSITION AND DYNAMICS OF THE MACROZOOBENTHIC INVERTEBRATE FAUNA FROM TWO TEMPORARY PONDS IN POIANA TĂŞAD REGION (BIHOR COUNTY, ROMANIA) Diana CUPŞA 1, Severus Daniel COVACIU-MARCOV 1 and Ioan TODORAN 2 1 University of Oradea, Faculty of Sciences, Department of Biology, University Street no. 1, Oradea, Romania, dcupsa@uoradea.ro 2 student MSc, University of Oradea, Faculty of Sciences, Department of Biology Abstract. During the present study we have investigated the macrozoobenthic invertebrate communities from two temporary ponds from Poiana Tasad region, Bihor county. The samples were taken between March and May, because after that period the ponds dry out. The macrozoobentice communities in the two ponds are very alike, because the small distance between the ponds, and the almost same dimension. The macrozoobenthic invertebrates are represented by species which are not very exacting to the quantity of solved oxygen in the water, and which can support oxygen deficit (for example Oligochaeta and Chironomida ) and from eurithermic species, considering the fact that the water temperature in the ponds can raise during the day and become very low during the night, when it can froze at the shores. These temporary ponds are important habitats for the reproduction of the insects which have aquatic and which can spread in regions where no rivers or permanent ponds are. These ponds are also important habitats for reproduction and feeding of some amphibian species. Keywords: temporary ponds, macrozoobenthos, structural composition, dynamics. Rezumat. Studii privind compoziţia şi dinamica faunei de nevertebrate macrozoobentice din două bălţi temporare din regiunea Poiana Tăşad (jud. Bihor, Romania). In cursul prezentului studiu am investigat comunităţile de nevertebrate macroozoobentice din două bălţi temporare din zona Poiana Tăşad, judeţul Bihor. Studiul s-a desfăşurat în perioada martie-mai, perioadă după care bălţile seacă. Comunitatea în cele două bălţi este asemănătoare, datorită distanţei mici la care sunt situate una faţă de cealaltă şi datorită mărimii asemănătoare. Nevertebratele macrozoobentice sunt reprezentate de specii care nu sunt foarte pretenţioase faţă de cantitatea de oxigen dizolvat din apă şi care chiar suportă deficitul de oxigen (de exemplu Oligochete şi larve de Chironomide) şi din specii euriterme, având în vedere că temperatura în aceste bălţi variază foarte mult în decursul a 24 de ore, încălzindu-se în timpul zilei şi răcindu-se puternic în timpul nopţii, când pot apărea chiar şi fenomene de îngheţ. Aceste bălţi temporare reprezintă un habitat important pentru reproducerea unor insecte cu larve acvatice care se pot răspândi şi în zone unde nu există râuri sau ape permanente şi de asemenea constituie un habitat important pentru reproducerea şi hrănirea unor specii de amfibieni. Cuvinte cheie: bălţi temporare, macrozoobentos, compoziţie structurală, dinamică. Introduction Temporary ponds are important habitats for conserving the biodiversity of aquatic organisms. Here we can find some rare aquatic species which find refuges in temporary ponds, especially now when many of the permanent rivers and lakes are polluted and their biodiversity lowers. Here we will find species which can resist to the dry periods of the year by resistant eggs or anabiosis and also insect which have short aquatic stage and emerge as adults before the pond dry out (Williams, 1997). Also in these ponds some amphibian species as Triturus cristatus, Triturus vulgaris, etc. can find feeding and reproduction habitats and they can spread in environments where these temporary ponds are found (Covaciu-Marcov et al., 2002; Cogălniceanu & Venczel, 1993; Cicort-Lucaciu et al. 2006). So, we appreciate that temporary ponds are very important

2 Diana Cupşa et al. habitats for maintaining the biodiversity of the ecosystems from which they belong and they need protective measures (Bănărescu, 1995). Similar studies in the western part of our country were made in Stâna de Vale region Bihor County (Cupşa et al., 2002) in Turţ Băi (Cupşa et al., 2007b) and Foieni area Satu-Mare County (Cupşa et al., 2007a). Material and Methods Our study took place between March and May. During this period we took a number of 7 samples from two temporary ponds. The first sample was taken on 30 th March, after the snow melting and when the pond wasn t covered by ice even during the night. In April and May we took 3 samples from each pond. After this period the ponds dried out. The samples were collected with a Surber collector 25 cm 2 and 500 µm mesh size. The samples were preserved in field in 4% formalin, labeled and transported to the lab. In the lab, the samples were analyzed under a 400X magnifying dissecting microscope and the major taxa were determined for each sample (Bouchard, 2004; Chiriac & Udrescu, 1965). We calculated for each sample site: the relative abundance in each period, the mean abundance, the frequency and constancy of the taxa, the Shannon Wiener Diversity Index and the evenness (Sîrbu & Benedek, 2004). Sample site description Poiana Tasad is situated in the central part of the Bihor County in the region of Tasad Hills (Fig. 1). These hills are a western extension of the Padurea Craiului Mountains. Tasad Hills are limited to north by Crişul Repede depression, to south by Crişul Negru depression, to west by Miersigului Plain and to east by Padurea Craiului Mountains (Zaha, 1997). The highest altitude in the region is 400 m, the average altitude is around 250 m. The area is relatively unaffected by the anthropic factor and it is mostly covered by forests. The two investigated ponds are situated in the western region of Poiana Tasad village, at an altitude of 350 m. The two ponds are situated close one to the other (less than 100 m). The southern pond is smaller - approximately of 12 square meters, and the northern one has approximately 20 square meters. Between the two ponds is a stretch of the forest which is situated to west from the investigated habitats. The maximum depth of the two ponds is around 60 cm, the substratum is covered by mud, but the water is clear. The ponds have a rich aquatic and especially semi-aquatic vegetation, considering the fact that there are temporary ponds and dry out often during the month of June. Results and Discussion In the study period we identified a number of 12 invertebrate taxa (Tables 1 and 2) in both ponds. In both ponds we found all these 12 groups even through they are separated by a stretch of forest and even through these are temporary ponds. From these 12 groups, 5 (Cladocera, Ostracoda, Copepoda, Heteroptera, Coleoptera adults) are not typically benthic ones, but because the depth of the ponds is very large, we can also find them in the benthic community and they can also occur in the samples, during the sampling procedures. The community is made up from insect larva and adults which can populate the ponds by releasing their eggs in the water or, in the case of adults, by arriving in the ponds by flight. From the typically aquatic groups we found those which can survive the dry period by resistant eggs or by anabiosis. In the former studies in temporary ponds from the western part of Romania we found that, at the almost same altitude, the

3 macrozoobenthic invertebrate community always contains Oligochaeta, Coleoptera and/or adults, Trichoptera and Chironomida. In some cases we also found Ephemeroptera and Odonata. These ponds also contained groups which we didn t found in Poiana Tasad area as: Gasteropoda, Isopoda and Plecoptera (Cupşa et al., 2002; 2007a; 2007b). Similar benthic community structure we can find in some sand-pit lakes unaffected by pollution (Celik, 2002). Poiana Tăşad Figure 1. Poiana Tăşad localization in Bihor County. In the first pond, the number of groups per sampling period varied between 7 and 10 (Table 1). The most abundant groups were Oligochaeta or Chironomida excepting when the most abundant were Ostracoda which were probably at the peak of their population development. The Chironomida together with Ephemeroptera are abundant in mountain streams with high water level oscillations (Ribeiro & Uieda, ). The less abundant groups vary depending the sampling period. Analyzing the mean abundances we can see that the less abundant groups are the Trichoptera which are not characteristic for temporary ponds, followed by Nematoda and Heteroptera. The highest mean abundance have the Chironomida followed by Oligochaeta (Fig. 2). These groups are characteristic for muddy, poorly oxygenated waters. The frequency is high for many groups (Fig. 3); from the 12 identified taxa 9 were euconstant in the study period, 2 accessory and one accidental (Fig. 4). The high number of euconstant groups shows that the community in this pond was stable in the study period even though this is a temporary pond. Maybe the short study period determined this high constancy of the benthic community in the pond.

4 Diana Cupşa et al. Table 1. The relative abundance, mean abundance, frequency and constancy of the macrozoobenthic invertebrates from P1. No. Systematic group Mean abund. F% C 1 Nematoda Euc 2 Oligochaeta Euc. 3 Bivalvia Euc. 4 Cladocera Euc. 5 Ostracoda Acs. 6 Copepoda Euc. 7 Ephemeroptera Euc. 8 Odonata Euc. 9 Heteroptera Acs. 10 Coleoptera Euc. adults 11 Trichoptera Acc. 12 Chironomida Euc. Total groups no. Shannon Wiener Diversity Evenness Chironomida 31.24% Nematoda 0.74% Oligochaeta 22.44% Bivalvia 6.81% Trichoptera 0.06% Coleoptera adults 1.78% Heteroptera 0.96% Cladocera 9.22% Odonata 1.03% Ephemeroptera 3.97% Copepoda 15.06% Ostracoda 6.64% Figure 2. The mean abundance of the benthic macroinvertebrate groups from P1.

5 The Shannon-Wiener Diversity Index was not very high in the first part of the study period (30.03., ) when even though the number of the benthic groups is high, there is one very abundant group (Chironomida in and Oligochaeta in ). The mean diversity is higher than the diversities per sample periods excepting The Evenness was low, especially in the first two sample periods, and the mean evenness was not very high either (Table 1) Nematoda Oligochaeta 100 Bivalvia Cladocera 100 Ostracoda Copepoda 100 Ephemeroptera Odonata Heteroptera Coleoptera adults Trichoptera Chironomida Figure 3. The frequency of the benthic macroinvertebrate groups from P1. Accessory 2 Accidental 1 Euconstant 9 Figure 4. The constancy of the benthic macroinvertebrate groups from P1. In the sampling site 2 we found the same 12 groups (Table 2) as in the first pond. The number of taxa in each sample period was relatively constant, between 8 and 10 excepting when we found Odonata only. This fact can be only explained as a sampling error because there wasn t any factor which can affect so bad the

6 Diana Cupşa et al. community and also in pond one in that period we found 10 invertebrate groups. The most abundant groups were also the Oligochaeta and Chironomida as in the first sampling site, except the first sampling period (30.03.) when the most abundant were the Bivalvia. This fact is probably due to the fact that we sampled an aggregated population of shells and the rest of the organisms are not very abundant because of the low temperature of the water and environment. Table 2. The relative abundance, mean abundance, frequency and constance of the macrozoobenthic invertebrates from P2. No. Systematic Mean F% C group abund. 1 Nematoda Acs. 2 Oligochaeta Euc. 3 Bivalvia Acs. 4 Cladocera Euc. 5 Ostracoda Con. 6 Copepoda Con. 7 Ephemeroptera 8 Odonata 9 Heteroptera 10 Coleoptera adults 11 Trichoptera 12 Chironomida Euc Euc Euc Euc Acc Con. Total groups no. Shannon Wiener Diversity Evenness This second pond is smaller than the first and the zooplanktonic species are less abundant and frequent than in P1. The mean abundance also is the highest in the case of Oligochaeta followed by Chironomida. The rest of the groups have very small abundances, below 10% (Fig. 5). The frequency is very different from the pond 1; no group has 100% frequency (Fig. 6). 6 groups have high frequencies (85.71%) (Oligochaeta, Cladocera, Ephemeroptera, Odonata, Heteroptera, Coleoptera adults). The number of euconstant species is lower than in P1; only 6, but there are 3 constant species, 2 accessory and one accidental (Fig. 7). So, here also the community is stable because most species are euconstant and constant.

7 Coleoptera adults 1.57% Trichoptera 0.09% Chironomida 16.02% Nematoda 0.16% Oligochaeta 34.98% Heteroptera 1.05% Odonata 14.8% Ephemeroptera 5.24% Copepoda 5.34% Ostracoda 5.12% Cladocera 9.26% Bivalvia 6.92% Figure 5. Mean abundance of the benthic macroinvertebrate groups from P2. F% Nematoda Oligochaeta Bivalvia Cladocera Ostracoda Copepoda Ephemeroptera Odonata Heteroptera Coleoptera adults Trichoptera Chironomida Figure 6. The frequency of the benthic macroinvertebrate groups from P2

8 Diana Cupşa et al. Accessory 2 Accidental 1 Constant 3 Euconstant 6 Figure 7. The constancy of the benthic macroinvertebrate groups from P2. The diversity is a little higher in this pond excepting when is 0. The mean diversity is also a little higher than in pond 1. The evenness is a little higher in the first periods of the study and smaller than in P1 in rest. The mean evenness is almost the same in this second pond (Table 2). This fact is expectable considering that the two ponds are situated in the same environment, very close one to the other, with almost similar dimensions and with similar substrates. The nature of the substrate is an essential factor for the structure of the benthic community (Silveira et al., 2006). Conclusions The community of macrozoobenthic invertebrates in the two investigated ponds is very similar, containing the same 12 groups of invertebrates. The most abundant of these are the Oligochaeta and Chironomida with rare exceptions. The frequencies of the groups are different in the two ponds. In the first the most frequent are the Oligochaeta, Cladocera, Copepoda and Chironomida and in the second the Oligochaeta, Cladocera, Ephemeroptera, Odonata, Coleoptera adults, Heteroptera. The communities in both ponds are stable, containing a high number of euconstant and/or constant species. The diversity and evenness are not very high in the two ponds due to the fact that in most cases one or two groups are very abundant and the rest with very low abundances. The two investigated temporary ponds are good refuges for amphibians especially newts that visit the ponds to feed and reproduce. Here also reproduces the insect species with aquatic mentioned as found in the benthic community. So, the importance of the maintenance of these ponds is high because they are a key element for the conservation of the zoological diversity of the area. References Bănărescu, P. M., An aquatic habitat that deserves protection: the temporary pools. Ocrot. nat. med. înconj., 39 (1-2): Bouchard, R.W. Jr., Guide to aquatic macroinvertebrates of the Upper Midwest. Water Resources Center, University of Minnesota, St. Paul, M.N. Celik, K., Community structure of macrobenthos of a southeast Texas sand-pit lake related to water temperature, ph and dissolved oxygen concentration. Turkish Jornal of Zoology, 26: Chiriac, E., Udrescu, M., Ghidul naturalistului în lumea apelor dulci. Editura Ştiinţifică, Bucureşti. Cicort-Lucaciu, A., St., Bogdan, H. V., Toth, A., Benzar, M., Balaj, L., Vidican, A. M., Research upon the feeding of the species Triturus vulgaris (Amphibia) from Poiana Tasad (Bihor County, Romania). Analele Univ. Craiova, Biologie, Horticultura, Tehnologia prelucrarii produselor agricole. Ingineria mediului, XI (XLVII):

9 Cogălniceanu, D., Venczel, M., Consideraţii privind ocrotirea şi conservarea populaţiilor de amfibieni şi reptile. Ocrot. Nat. Med. Înconj., 37 (2): Covaciu-Marcov, S. D., Cupşa, D., Telcean, I., Cicort, A., Study of the trophical spectrum of some Triturus cristatus (Laurentus, 1768) populations from Tasad Hills (jud. Bihor). Nymphaea, Folia naturae Bihariae, XXIX: Cupşa, D., Telcean, I. C., Covaciu-Marcov, S. D Aspecte ale structurii faunei bentonice din apele permanente şi temporare din zona Stâna de Vale (jud. Bihor). An. Univ. Oradea, Fasc. Biologie, IX: Cupşa, D., Covaciu-Marcov, S. D., Kovacs, E. H., Făgărăşan, Şt. L., 2007a. Contributions to the study of the macrozoobenthic invertebrate fauna from two temporary pools from Foieni area (Satu-Mare County). Muzeul Olteniei Craiova, (in press). Cupşa, D., Covaciu-Marcov, S. D., Kovacs, E. H., Cristea, M. I., 2007b. Studies upon the macrozoobenthic invertebrates community in Turt Bai Area (Satu-Mare County, Romania). Analele Univ. Craiova, Biologie, Horticultura, Tehnologia prelucrarii produselor agricole. Ingineria mediului, XII (XLVIII): Ribeiro, L. O., Uieda, V. S.,. Estrutura da comunidade de macroinvertebrados bentonicos de um riacho de serra em Itatinga, Sao Paolo, Brasil. Revista Brasileira de Zoologia, 22 (3): Silveira, M. P., Buss D. F., Nessimian J. L., Baptista D. F., Spatial and temporal distribution of benthic macroinvertebrates in a southeastern brasilian river. Brasilian Journal of Zoology, 66 (2B): Sîrbu, I., Benedek, A. M., Ecologie practică. Editura Universităţii Lucian Blaga Sibiu: 44. Williams, D.D., Temporary ponds and their invertebrate communities. Aquatic conserve. Mar. Freshw. Ecosyst. 7: Zaha, N., Bihor County Physical, touristic and administrative map. Editura Brevis, Oradea.