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Updated Information on the Habitat Distribution and Diversity of the Freshwater Malacofauna of Sarnena Gora Mountain (Bulgaria)
Dilian G. Georgiev
Ecologia Balkanica , 2012,
Abstract: According to the recent research and the critical overview of the literature it can be summarized that a total of 13 species of freshwater snails and 6 species of mussels are known to occur in Sarnena Gora Mountain. The highest richness of freshwater molluscs species in the surveyed area were found in the medium sized rivers having microhabitats favorable for the aquatic molluscs such as fast flowing oligotrophic stretches combined with slow moving eutrophic parts and small floods on the banks. The species community of the freshwater molluscs known to live in the mountain studied was consisted mainly by some widely distributed species with Holarctic and Palearctic distributions, followed by the European species. Two local endemics were also registered in the mountain.
Diet of the Golden Eagle (Aquila chrysaetos) (Aves: Accipitridae) in Sarnena Sredna Gora Mountains (Bulgaria)
Dilian G. Georgiev
Ecologia Balkanica , 2009,
Abstract: The material of pellets and food remains (as bone and shell fragments, hair, and feathers) was collected after the breeding season from below and within one nest of Golden Eagles on rocks at Sarnena Sredna Gora Mts., north-east of Stara Zagora town. Our study was carried out during a three year period (1999, 2000 and 2002). Total 65 specimens from minimum 10 species of preys were identified among the food remains from which the reptiles dominated. Mostly preyed by the Golden Eagles couple were the tortoises (Testudo sp.) with 55.4% from all registered individual preys. The most common prey from mammals was the hedgehog (Erinaceus roumanicus) with 13.8%. Interesting fact was and the relatively high percentage of the cats with 7.7% (possibly most of them domestic ones).
On the Fruit Consumption of Eurasian Badger (Meles meles) (Mammalia: Mustelidae) during the Autumn Season in Sredna Gora Mountains (Bulgaria)
Dilian G. Georgiev
Ecologia Balkanica , 2009,
Abstract: This case study was carried out at one badgers family territory by asingle collection (11.11.2002, north of Stara Zagora City, near Tabashka River) of faeces from the animal latrine sites. Total of 1361 individual food items were identified in Eurasian badger (Meles meles) faeces from which the fruits of the Cornel-tree (Cornus mas) strongly dominated (n=1332, 96.5% from all items, 98.2% from all fruits).
Data on the Environmental Conditions and Diversity of the Animal Ecological Groups in Gargina Dupka Cave
Stanimira R. Deleva,Dilian G. Georgiev
Ecologia Balkanica , 2009,
Abstract: Air and water temperature, air humidity and water oxygen levels were studied in Gargina Dupka Cave (Rhodopes Mts., Bulgaria). These environmental factors were considered for three zones of the cave: 1 – cave entrance, 2 – typical cave in the central gallery, and 3 – an area occupied by bat guano. During two visits all animals were collected from these areas. In the laboratory, after identification they were classified according to their ecological features as: relation to light, way of moving, diet, and substrates on which they were collected.
Preliminary Information on the Vertebrate Fauna (Animalia: Vertebrata) of the NATURA2000 Site “Rice Fields Tsalapitsa” (Bulgaria)
Ivayla L. Klimentova,Dimitar G. Plachyiski,Dilian G. Georgiev
Ecologia Balkanica , 2011,
Abstract: The study was carried out by tree visits in different areas of the Natura 2000 site “Rice Fields Tsalapitsa” BG 0002086 (West of Plovdiv city, near village of Tsalapitsa). Our preliminary research showed that in the area vertebrates with high conservation status occurred included in the Bulgarian Bidiversity Act, Appendix II and III, Appendix II of the Bern convention, Natura 2000 species list, the Bonn convention, Appendix II, the Convention of the International Trade of Endangered Species, and the list of the International Union for Conservation of the Nature. This information will help in future preparation of the management plan of the Natura 2000 site and showed the need of studies focused on such areas which will help undertaking adequate measures for their proper way of conservation.
Aquatic Macrophytes as Microhabitats of Radix auricularia (Gastropoda: Pulmonata): A Case Study from Southeast Bulgaria
Stanislava Y. Vasileva,Dilian G. Georgiev,Gana M. Gecheva
Ecologia Balkanica , 2009,
Abstract: The aim of the current study is to investigate the abundance of thefreshwater pulmonate snail Radix auricularia among different aquatic plants communities, with the view of understanding if there is any particular habitat preference, comparing two freshwater basins having similar environmental conditions. The freshwater plant species were collected by net from two ponds at the end of May 2009 - 650 g wet plant mass, micro dam at Chernoochene Village, East Rhodopes Mts.; 138 g wet plant mass, small flood pond near the Maritza River, Plovdiv City, Upper Thracian Lowland. The plant mass was weighted in the laboratory after the alive snails were collected from the plant surface. Totally three species of freshwater plants were inhabited by R. auricularia, but its abundance and possible preference was highest on the Rigid Hornworth (Ceratophyllum demersum).
A Study of the Survival and Oxygen Deficiency at the Zebra Mussel (Dreissena polymorpha) Treated with Zinc (Zn)
Bogdan N. Nikolov,Stanka D. Salapatiyska,Dilian G. Georgiev
Ecologia Balkanica , 2009,
Abstract: The current paper studies the change of respiratory rate and survival of Dreissena polymorpha at short exposure to zinc under laboratory conditions. The experiment is lasted 96h and three different concentrations of ZnSO4.7H2O were used - 0.5mg/l, 1.5mg/l; 2,0 mg/l. Survival and intensity of breathing of Dreissena polymorpha decreases with the increasing concentration of zinc in the water.
On the Communities of Freshwater Gastropods on Aquatic Macrophytes in Some Water Basins of Southern Bulgaria
Stanislava Y. Vasileva,Dilian G. Georgiev,Gana M. Gecheva
Ecologia Balkanica , 2011,
Abstract: The research was conducted through the period 2008 - 2009 in the Upper Thracian Lowland: Maritsa River in the city of Plovdiv, flood area near the bridge at UFT; Eastern Rhodopes: Varbitsa River at around 3 km south of the town of Kardzhali; Perperek River, within the village of Perperk; a pond in the village of Chernoochene. The material was collected from total of 3427 g herbage biomass from 7 plant species. On the aquatic macrophytes we generally found approximately the same diversity of species of freshwater gastropods during the cold and during the warm seasons. During the warm period we found a total of 6 species, and during the cold - 7 species. Most species we found on C. demersum, and E. canadensis. Overall for the studied water basins and seasons, the species R. auricularia, Ph. acuta and G. albus were most numerous and prefer to live on C. demersum. We calculated a narrow ecological niche of the species in most cases, where slightly wider ecological niches were registered for R. auricularia and G. albus. Largest diversity of snail communities we found on C. demersum and E. canadensis. The value of the diversity index was very low for the other species of macrophytes. We calculated low values of S rensen’s index between most of the freshwater macrophytes in relation to communities of gastropods. High similarity between the communities we indicated for C. demersum and P. pussilus, and C. muricatum, and Lemna sp., and very high between P. pussilus, and Lemna sp. We found an aggregated distribution on the macrophytes of the following species of gastropods: R. auricularia, Ph. acuta, P. corneus, P. planorbis, G. albus and occasional one for V. piscinalis, A. lacustris, and L. stagnalis.
Recent Vertebrate Animal Bones (Animalia: Vertebrata) from Yubileyna Cave (Rhodopes Mountain, South Bulgaria)
Georgi S. Dudin,Dilian G. Georgiev,Slaveya B. Stoycheva
Ecologia Balkanica , 2011,
Abstract: Excavations (area of 50 x 50 cm and 20 cm depth) at about 15 m from the cave entrance revealed various vertebrate fauna. As individual numbers the mammals and the frogs predominated as bone remains. All other taxa were with low percent of occurrence. The trogloxenic species dominated than the troglophilic. Considering the cave characteristics and the taxonomical identity of the bones we proposed two main ways of bone accumulation in this cave in recent times.
Size of marsh frogs in the Eurasian Otter's diet in Southern Bulgaria
Dilian Georgiev
Hystrix : the Italian Journal of Mammalogy , 2008, DOI: 10.4404/hystrix-19.1-4415
Abstract: Our study was carried out in the south of Bulgaria, providing original data on the size of the marsh frog Pelophylax ridibundus (Pallas, 1771) in otter Lutra lutra (Linnaeus, 1758) diet. A method was devised for estimating the size of these anurans found as bone remains in otter spraints. A very strong positive correlation between the ileum’s maximum width and frogs' standard body length was highlighted. The linear regression equation was: standard body length = 10.4 + 14.1 × ileum’s maximum width. The mean body length of marsh frogs in otter spraints was 53.49 mm. During the warm season otters fed on about four times more diverse sized anurans. The size group 41-60 mm always dominated in otter diet, particularly in the cold season. It could be concluded that in the study area otters fed predominantly on juvenile and sub-adult marsh frogs. Riassunto Dimensioni di Pelophylax ridibundus predate dalla lontra nel sud della Bulgaria. La ricerca, condotta nella Bulgaria meridionale, ha fornito dati inediti circa le dimensioni degli esemplari di rana verde maggiore (Pelophylax ridibundus Pallas, 1771) predati dalla lontra Lutra lutra (Linnaeus, 1758), stimate a partire dai resti ossei indigeriti reperibili nelle feci del mustelide. Una netta correlazione positiva è stata evidenziata tra la larghezza massima dell’ileum e la lunghezza totale standard degli esemplari esaminati. La regressione lineare ha fornito l’equazione: lunghezza totale = 10,4 + 14,1 × larghezza massima dell’ileum. La lunghezza media degli esemplari predati è risultata pari a 53,49 mm. Durante la stagione calda, le lontre utilizzano una varietà di taglie quattro volte maggiore che nella stagione fredda. La classe 41-60 mm è risultata sempre predominante, particolarmente nel periodo freddo, suggerendo che le lontre predano soprattutto individui giovani e sub-adulti.
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