oalib

OALib Journal期刊

ISSN: 2333-9721

费用:99美元

投稿

时间不限

2017 ( 77 )

2016 ( 108 )

2015 ( 1989 )

2014 ( 2556 )

自定义范围…

匹配条件: “Severus-Daniel Covaciu-Marcov” ,找到相关结果约32553条。
列表显示的所有文章,均可免费获取
第1页/共32553条
每页显示
Comparison of Terrestrial Isopod (Isopoda, Oniscidea) Assemblages from Two Types of Forests from North Western Romania
Sára Feren?i,Severus-Daniel Covaciu-Marcov
Ecologia Balkanica , 2012,
Abstract: In 2008 we compared the terrestrial isopod assemblages from two different habitats, a beech forest and a mixed beech and spruce forest, from north western Romania (Huta Certeze locality). The samples were taken from April to September using pitfall traps. We identified a total of 7 species: Ligidium germanicum, Trichoniscus sp., Hyloniscus transsilvanicus, Protracheoniscus politus, Porcellium collicola, Trachelipus difficilis and Porcellio scaber. A greater diversity and species richness were noticed in the beech forest. The poverty of species in the mixed forest was a consequence of the forest type, the anthropogenic impact and the dry environment. High surface activity of individuals was noticed in the summer months. Even if the species compositions of the two compared isopod assemblages were not identical, there weren’t statistically significant differences between them.
Studies on the dynamics of the macrozoobenthic invertebrate groups in the thermal lake Ochiul Mare natural reserve (Bihor county, Romania)
Diana CUPSA,Istvan SAS,Ilie TELCEAN,Severus-Daniel COVACIU-MARCOV
Analele Universitatii din Oradea, Fascicula Biologie , 2005,
Abstract: In the thermal lake from Ochiul Mare the environmental conditions and especially the temperature of the water which do not drop under 200C in the substrate even in winter period determine a different dynamics of the macrozoobenthic populations than in other natural waters. Also the major groups in the communities differ from those of the non thermal waters. For these reasons we have studied the dynamics of the macroinvertebrate groups from the benthos to find out if they adapted their life cycles to the thermal environment. Also we wanted to find out which are the groups which have the greatest densities in the thermal environment and for which this environment is a limitating factor of the development.
Lissotriton vulgaris paedomorphs in south-western Romania: a consequence of a human modified habitat ?
Severus-Daniel Covaciu-Marcov,Istvan Sas,Alfred-Stefan Cicort-Lucaciu,Horia-Vlad Bogdan
Acta Herpetologica , 2011,
Abstract: A Lissotriton vulgaris paedomorph population was identified for the first time ever in south-western Romania. The occurrence of this paedomorphosis is explained by the particularities of the area, the newts inhabiting a permanent but artificial habitat, surrounded by agricultural fields. Thus, the presence of an acceptable aquatic habitat together with the absence of a suitable terrestrial one triggered the occurrence of paedomorphosis.
New cases of winter-active amphibians in the thermal waters of Banat, Romania
Bogdan Horia-Vlad,Covaciu-Marcov Severus-Daniel,Antal Cornel,Cicort-Lucaciu Alfred-?tefan
Archives of Biological Sciences , 2011, DOI: 10.2298/abs1104219b
Abstract: In the winter of 2010/2011 we identified 6 new thermal habitats, with winter-active amphibian populations in the Banat region of south-western Romania. The diversity of the amphibian species was small, only 2 species were observed: Bombina bombina and Pelophylax ridibundus. In waters with high flow and temperature, the number of winteractive frogs reached several hundred. All the new thermal habitats are artificial, being subjected to a powerful anthropogenic pressure.
Comparative Data on the Trophic Spectrum of Syntopic Bombina variegata and Rana temporaria (Amphibia: Anura) Populations from the Iezer Mountains, Romania
Sára Feren?i,Severus-D. Covaciu-Marcov
Ecologia Balkanica , 2011,
Abstract: In August 2009, we compared the trophic spectrum of syntopic Bombina variegata and Rana temporaria populations from the Bratia Valley in the Iezer Mountains. The separation of the trophic niche observed between the juveniles and the adults of R. temporaria is caused by the differences in size between them, differences that influence their jump. The main consumed prey taxa by Rana temporaria is represented by Arahnida, Gastropoda and Hymenoptera. Furthermore, the differences between the sizes of their mouths separate the trophic niche between the two species. Our results indicate a trophic selectiveness for B. variegata, which prefers ants. Despite the fact that the two species share the same habitat, the ants were consumed mostly by B. variegata. This is probably a consequence of the fact that B. variegata is a poisonous species, the toxins being able to originate from their preys – as are ants as well. The lack of competition for the two species indicates a rich trophic offer, enough to satisfy the energy needs of both species in contact in a limited space.
On the presence of Rana (Pelophylax) lessonae in south-western Romania: distribution, biogeographical signification and status
Severus D. COVACIU-MARCOV,István SAS,Diana CUPSA
North-Western Journal of Zoology , 2008,
Abstract: During 2006 and 2007 we encountered in south-western Romania four populations of Rana lessonae. Their determination was made on the basis of both the morphological and chromatic features. All of the pool frog records in Romania are found at the proximity of the species’ general range; being practically in connection with it. Thus, aside from the glacial refuge from Italy, the populations from south-western Romania are amongst the most southerly populations of the species at entire Europe level, making up the south-eastern limit of its range. The populations from south-western Romania seem to be isolated from the other populations from Romania both geographically, ecologically (temperature and humidity), and as habitat type (mountain brook). It can therefore be theorized that the species Rana lessonae had in south-western Romania a secondary glacial refuge.
Lissotriton vulgaris paedomorphs in south-western Romania: a consequence of a human modified habitat?
Severus D. Covaciu-Marcov,Istvan Sas,Alfred ?. Cicort-Lucaciu,Horia V. Bogdan
Acta Herpetologica , 2011,
Abstract: A Lissotriton vulgaris paedomorph population was identified for the first time ever in south-western Romania. The newts inhabiting a permanent but artificial habitat, surrounded by agricultural fields.
Are the hibernating water frogs from Pelophylax (Rana) esculentus complex (from North-Western Romania) able to adapt to the thermal water conditions?
István Sas,éva-Hajnalka Kovács,Severus D. Covaciu-Marcov
Advances in Environmental Sciences , 2009,
Abstract: We were interested to determine if the hibernanting Pelophylax ridibundus and the othertwo forms of water frogs from the Pelophylax esculentus complex (Pelophylax lessonae, Pelophylaxesculentus) fulfil the requirements of thermal resistance in order to become adapted to the thermalhabitats. During the experiment we had determined for each frog the value of two parameters: VTMaxand CTMax. The experimental determination of the resistance to temperature of the water frogs fromthe P. esculentus complex has revealed a great resistance of these frogs to high temperatures.Although the difference among the analysed frogs is not significant concerning the values of thevoluntary and critical thermal maximum, it still can be observed a specific hierarchical order. Thisresistance (an average of 34.52oC), observed in the case of the hibernating populations of P.ridibudnus indicates the reason why the marsh frogs can adapt so easily to the conditions fromthermal waters. The voluntary thermal maximum obtained for the hybrid Pelophylax kl. esculentusdoes not differ noticeably, having an average value of 33.31oC. The lowest values for this parameterwere recorded for the Pelophylax lessonae species (an average of 33.02oC).
Data on Population Dynamics of Three Syntopic Newt Species from Western Romania
Alfred-S. Cicort-Lucaciu,Nicoleta-R. Radu,Cristiana Paina,Severus-D. Covaciu-Marcov
Ecologia Balkanica , 2011,
Abstract: We studied the population dynamics of three syntopic newt species [Mesotriton alpestris (Laurenti, 1768), Lissotriton vulgaris (Linnaeus, 1758) and Triturus cristatus (Laurenti, 1768)] in Zarand Mountains (Arad County, Romania). M. alpestris had the shortest aquatic phase, approximately two months, out of which the nuptial display was 2-3 weeks long. L. vulgaris and T. cristatus spent three months in the habitat, having a nuptial display of 2-3 weeks for L. vulgaris, and of 4-5 weeks for T. cristatus. M. alpestris had the highest degree of reproductive synchronization, while this was the lowest at T. cristatus. Males from all three species had a higher affinity for the aquatic habitat than females. The population size was estimated at 769 for L. vulgaris, 588 for T. cristatus, and 294 for M. alpestris. Balanced sex ratio was observed in the peak of breeding activity for all species.
Implication upon Herpetofauna of a Road and its Reconstruction in Carei Plain Natural Protected Area (Romania)
Alfred-S. Cicort-Lucaciu,Severus-D. Covaciu-Marcov,Horia V. Bogdan,Istvan Sas
Ecologia Balkanica , 2012,
Abstract: In autumn 2011 we monitored a 5 km long road, paved with cobblestone, situated in Carei Plain Natural Protected Area, a road that is due to be modernized and continued across the border into Hungary. Dead bodies from eight different animal groups were observed on the road, amphibians presenting the greatest amount. The most frequent were the Triturus dobrogicus corps, a species with conservation importance. The amphibians were affected in the areas where the road is neighboring the wetlands, while on the opposite pole sits the area with acacia plantations. The high number of mortalities recorded on the road, despite the low traffic speed, is alarming. It is likely that the modernization of the road that will surely increase its traffic and the speed of the vehicles, will make the situation even worse. However, the rebuilding could contribute to the reduction in the impact on amphibians, if certain measures are considered while planning the action. Thus, in the areas near the wetlands, there should be undercrossings, fences and speed limits. In this way, the modernization would at least represent an experiment regarding the diminution of the road’s impact on amphibians.
第1页/共32553条
每页显示


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.