Limnological characteristics and recent ostracods (Crustacea, Ostracoda) of freshwater wetlands in the Parco Oglio Sud (Northern Italy)
ABSTRACT We report the results of a study carried out in 2002 on the main limnological characteristics and on the ostracod communities of 16 wetlands of the Parco Oglio Sud (Northern Italy). Physical and hydrochemical variables were measured and ostracod samples were collected in different seasons (April, June, August, and October). Most of the considered sites were characterised by high concentrations of nitrogenous compounds due to washing out from cultivated areas, intermittent river flooding and internal recycling. Observed differences in macrophyte communities were consistent with trophic status of waters, with pleustonic forms dominating most degraded areas. Both morphology of valves (by scanning electron microscopy) and anatomy of soft parts were analysed for ostracod species identification. Nineteen ostracod species in five families were found. Two species, Candona weltneri and Pseudocandona compressa, are new records for Italy. Cypria ophthalmica was collected from all sampling sites; other relatively common species were Cypridopsis vidua, Cyclocypris ovum, and Candona weltneri. No clear seasonality was observed in community structure; highest species diversity occurred in June in most of the studied wetlands. The maximum number of species per site was seven, and a maximum of six species was found in a single sample. Ostracod occurrence in relation to environmental factors was examined using Canonical correspondence analysis (CCA). Total alkalinity and pH were the most important variables structuring the species assemblages. The ostracod fauna found in this area was compared to the known distribution of recent non-marine ostracods in Italy, and the validity of published checklists is discussed.
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ABSTRACT: We sampled Lake Çubuk, a shallow lake in Bolu (Turkey), for 26 months to investigate the effect of limnoecological changes on the composition of ostracod species. Seventeen ostracod species were identified from the six stations sampled between 2008 and 2010. Numbers of species and individuals were both significantly reduced during 2010, which corresponded to a 3 m water level increase. Ostracod Watch Model (OWM) displayed distinct seasonal occurrences of five species (Candona neglecta, Cypria ophtalmica, Cypridopsis vidua, Limnocythere inopinata, Fabaeformiscandona cf. japonica) when Physocypria kraepelini was the only species encountered all year round. Approximately 77.2% of the relationship between species and environmental variables was expressed by the first two axes of Canonical Correspondence analyses (CCA). Electrical conductivity and water temperature (P = 0.002) were the most influential variables on species. There was a significant negative correlation of seven species to conductivity. Of those, (F. cf. japonica and C. vidua) showed a significant positive correlation to water temperature, while C. candida was negatively correlated to water temperature (P < 0.05). Candona neglecta was the only species to show a positive correlation to dissolved oxygen. Tolerance limits for the most common species were higher than the mean water temperatures, but lower than mean levels of electrical conductivity. Finding the ratio of noncosmopolitan to cosmopolitan species “pseudorichness” as 1.13 suggested significant role of cosmopolitan species to species diversity.Limnologica - Ecology and Management of Inland Waters 03/2014; · 1.66 Impact Factor
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ABSTRACT: Although Turkey has a variety of wetlands of different types and sizes, many of them are threatened by human activities. To show the biological importance of these habitats, samples were randomly collected from 173 different wetland sites in the Ankara region during the summer of 2011. 31 ostracod taxa belonging to 14 genera were identified, including two species (Eucypris elliptica and Cavernocypris subterranea) that are new reports for the Turkish ostracod fauna and 19 taxa that are new reports for the region. Canonical Correspondence Analyses was able to show 58.9 % of the correlation between species and environmental variables. Water temperature, moisture and dissolved oxygen were the most important (P = 0.05) factors influencing species occurrence. Increasing sampling size (number of sites) did not significantly increase the numbers of species collected at sites located at elevations between 442 and 1,520 m.a.s.l. This also implies that altitude may have a secondary role on species diversity. Unweighted Paired Group Mean Analyses illustrated four main clustering groups of ostracods, in which species are clustered according to their ecological preferences. Based on our results, suitability of habitats appears to drive ostracod distribution and diversity in these wetland sites. Results clearly showed that these habitats can harbor diverse ostracod communities that warrant conservation.Wetlands 01/2014; 34(2). · 1.44 Impact Factor
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ABSTRACT: The sometimes sharp thermal variations and irregular precipitations and force concentrated over short periods characterize the Mediterranean climate. The structure of the zooplanktonic settlement was analyzed during one year in three Algerian reservoirs (lakes) with different geographical and climatic situation, in relation to abiotic factors (temperature, dissolved oxygen, pH, suspended matter, carbonates, nitrogenized and phosphorated nutritive salts). A canonical correspondence analysis was used to estimate the influence of the abiotic factors on the temporal distribution.The studied lakes are located, on the one hand, in northern Algeria, in a sub-humid area (Lake Boukourdane) and, on the other hand, in the South of the country, in the arid region (Foum El Ghorza and Djorf Torba). Analysis of the environmental parameters indicates that there is a seasonal variation in the three reservoirs. In Lake Foum El Ghorza, the temperature and hydrology variations, linked with the arid climate, affects the concentration of dissolved oxygen, which strongly decreases (1.5 mg/l), involving a pH reduction; suspended matters are sometimes high, coming from the stripped catchment area, causing a turbidity in this not very deep lake. The study of the distribution of the species allowed us to highlight a seasonal temporal variation. Lake Boukourdane, in the sub-humid zone, has an increased specific richness (SR=13). The various species evolve in alternation during the annual cycle. The representative species of this lake is Copidodiaptomus numidicus, characteristic of the rainy and endemic zone of the western Mediterranean; it is dominant (67%) in the spring. The Stenothermal species Diaphanosoma brachyurum, endemic of hot waters, is common to the two lakes; it evolves particularly in the summer (51.3%) at Boukourdane, whereas it is perennial and dominant (55%) in the spring at Djorf Torba. The specific richness is lower in Djorf Torba (SR=7) and in Foum El Ghorza (SR=6). The species collected in these two lakes are common and cosmopolitan, but they are adapted to the extreme conditions of the arid climate. Nevertheless, the species evolving in Lake Foum El Ghorza have undergone a significant decline, which has reduced the number of species and their density in the summer–autumn period. Thus, we can say that in the studied lakes, the hydrological factors and the temperature related to the Mediterranean climate would be two of the principal causes of the temporal distribution of the species. To cite this article: M. Cherbi et al., C. R. Biologies 331 (2008).Comptes Rendus Biologies 09/2008; 331(9):692-702. · 1.68 Impact Factor