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Search Results: 1 - 10 of 305 matches for " Obratov-Petkovi? Dragica "
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Harmonization of the engineering and environmental objectives of the river management: Case study of the Ju na Morava river
Petkovi? Slobodan,Obratov-PetkoviDragica
Glasnik ?umarskog Fakulteta , 2005, DOI: 10.2298/gsf0592125p
Abstract: Harmonization of river engineering objectives and environmental aspects of river management is considered in the case study of Ju na Morava river. Investigation of morphological, hydraulic and sediment logical characteristics of the river, flora and vegetation were carried out in this study. During the field investigation, the assessment of riparian vegetation was made and large number of species were determined. More than 100 species are classified into 7 communities. Regarding the existing problems of the bank erosion, excavation in the floodplain and bad ecological conditions of the riparian zone, the new environmentally friendly approach is proposed. The technical measures consist of a special excavation in the floodplain on the inside bank of the river bends, with significant effect on the erosion intensity on the outside bank. Two ecological alternatives of management of floodplain are considered - the plantation of poplar in the deepened zone of the floodplain and the wetland formation in this zone.
Phyto-gegographycal analysis of Div ibare
Popovi? Ivana,Obratov-PetkoviDragica
Glasnik ?umarskog Fakulteta , 2005, DOI: 10.2298/gsf0591193p
Abstract: The aim of phytogeographical analysis is to determine the plant species origin, genesis and migrations. The study results contribute to the knowledge of phytogeographical classification of the particular regions. Different chorions, by their effects, determine the flora structure and composition. The aim of the floristic research of Div ibare was to identify the diversity of flora in this region, i.e., in a wider sense, the diversity of flora in Serbia. Phytogeographical analysis was based on floristic research. The identified plant species were classified into the corresponding floral elements, area groups and area types. The data on diversity and the degree of representation in the flora of Div ibare were obtained based on the percentage of each area type. It was concluded that the flora of Div ibare has a transitional, Central European-Mediterranean-Pontic character.
Morphological characters and the range of the species Echinops banaticus Rochel (Asteraceae) in the flora of Serbia
Dikli? Nikola,Obratov-PetkoviDragica
Glasnik ?umarskog Fakulteta , 2002, DOI: 10.2298/gsf0285051d
Abstract: The species Echinops banaticus Rochel. is one of the five plant species in the genus Echinops L. which have been found to grow in Serbia. The morphological descriptions in our and in foreign floristic literature contain a number of contradictory or incomplete data, which considerably impedes the regular and correct determination and identification of this species. This paper points to the above controversial morphological characters, presents the correct description of the species and the localities where it has so far been found in Serbia, according to field research and the inspection of herbarium material By morphological studies it was found that in the flower region, as correctly reported by Javorka (1925) and Nyarady (1964), pappus scales are joined together throughout their length, and that free tufts appear only at the top The leaves are, after Nyarady (1964), more or less pinnately lobed, green on the adaxial surface, covered with thin, soft, curved, glandular hairs As the range of the species in Serbia has not been sufficiently investigated, it was stated that the species Echinops banaticus Roch. was recorded at 14 localities in Serbia. All the localities are mainly situated in east parts of Serbia, east of the river Velika Morava as far as the borders of Romania and Bulgaria.
Analysis of biological spectrum of Div ibare flora
Popovi? Ivana,Obratov-PetkoviDragica
Glasnik ?umarskog Fakulteta , 2006, DOI: 10.2298/gsf0693143p
Abstract: One of the essential analyses which is performed during the floristic study of a region is the analysis of the biological spectrum. The analysis of the biological spectrum of the flora includes the determination of the type of life form for each taxon described in the flora of the study region. If it is considered that life form is a specific structural-functional response to the environmental effects and the result of the adaptation during the species evolution, it is clear that the basic characteristics of the site are more or less reflected in any life form. This fact is confirmed by the analysis of the biological spectrum of Div ibare flora. The study results are in correlation with the results of the analysis of the biological spectrum of the flora of Serbia and the Balkan Peninsula.
Floristic diversity of the Jadar river valley as a factor of river management
Obratov-PetkoviDragica,Petkovi? Slobodan,Popovi? Ivana
Glasnik ?umarskog Fakulteta , 2006, DOI: 10.2298/gsf0693129o
Abstract: Within the study of the River Jadar management, the biological and hydro-engineering characteristics of the watercourse and the riparian land were comparatively researched. The floristic diversity of the Jadar riparian area was studied and the existing plant species and communities, life forms and floral elements were identified. On the other hand, the study of the morphological and hydraulic characteristics of the water course included the basic factors of river channel and banks regulation - the variation of morphometric parameters, hydraulic resistance and the stability of the river banks. Based on the study results, the guidelines of river management were defined from the aspect of biodiversity conservation and ecosystem enhancement of the Jadar valley. .
The content of heavy metals in the leaves of Hypericum perforatum L. on serpentinite soils in Serbia
Obratov-PetkoviDragica,Bjedov Ivana,Belanovi? Sne?ana
Glasnik ?umarskog Fakulteta , 2008, DOI: 10.2298/gsf0898143o
Abstract: St John's wort is one of the best known and used medicinal plants. The demands for St John's wort in Serbia is still supplied by the collection of native plants. Therefore it was necessary to examine the concentration of heavy metals in the soil and in plant material on serpentinites and to assess the potential safe harvesting and further utilisation of this plant species. The research was performed on three serpentinite sites in Serbia: Zlatibor, Div ibare and Go . The main soil types were determined and the contents of 7 chemical elements were analyzed in the soil and in the plant material. It was determined that the soils of all three localities had increased concentrations of nickel, chromium and manganese. The St John's wort plant material (leaves) showed the increased concentrations of iron, nickel and chromium. It was concluded that St John's wort was a tolerant species regarding the heavy metal content, and it was recommended to avoid its harvesting on the investigated localities.
Galanthus gracilis elak. (Amaryllidaceae) in the flora of Serbia
Jovanovi? Filip,Obratov-PetkoviDragica,Zlatkovi? Bojan
Glasnik ?umarskog Fakulteta , 2012, DOI: 10.2298/gsf1206101j
Abstract: There are only ambiguous data in literature that suggest the presence of Galanthus gracilis elak. in the flora of Serbia. Throughout its range G. gracilis is often confused with closely related species G. elwesii Hook., with which it shares several morphological characteristics, and in some cases the same name is erroneously used for both species (G. graecus Orph.). Only about a decade ago, the genus was a subject of taxonomic revision by the English author Aaron P. Davis, whose work eliminated confusion created by the previous conflicting divisions. Therefore, further studies are required to determine the exact distribution of this species. In this paper, we officially report the presence of G. gracilis in Serbia, with a description of its habitat and estimation of the threatened status.
Adaptability of Paulownia tomentosa (thumb.) Sieb. et Zucc. on green areas in Belgrade
Stoji?i? ?ur?a,Ocokolji? Mirjana,Obratov-PetkoviDragica
Glasnik ?umarskog Fakulteta , 2010, DOI: 10.2298/gsf1001151s
Abstract: The taxa with the improved esthetical characteristics, increased or decreased productivity, higher resistance to diseases, insect attacks, air pollution, as well as with optimal adaptability in urban coenoses are of great importance to land-scape architecture, horticulture and forestry. The criteria for the selection of individual plants out of the number of many individuals depend on their future usage, but also on their esthetical features, morphology and physiology. One of the species that fulfils the above criteria is Paulownia tomentosa (Thumb.) Sieb. et Zucc. Different morphophysiological features of royal paulownia cultivated on green areas in Banovo Brdo, Dor ol, Ta majdan, Novi Beograd and Zemun are analyzed. The study results prove the adaptability of royal paulownia on green areas in Belgrade, but also the need to select the parent trees with the best combining features prior to production, aiming at the improvement and production of planting material for urban coenoses and specific-purpose plantations of this species.
Asteretum lanceolati: Xenospontaneous community on wet and riparian habitats
Obratov-PetkoviDragica,Bjedov Ivana,Sko?aji? Dragana,?unisijevi?-Bojovi? Danijela
Glasnik ?umarskog Fakulteta , 2011, DOI: 10.2298/gsf1103073o
Abstract: Invasive species Aster lanceolatus grows on moist habitats on the whole territory of Serbia. In Belgrade, this species is recorded with a higher degree of presence at a number of localities. With the aim to investigate the community in which this species is dominant, the wide area of Serbia was researched, and 8 localities on the territory of Belgrade were chosen for the analysis of the community. Floristic structure of the community was determined by the standard Braun-Blanquet method (1964), phytogeographical analysis was performed according to Gaji (1980, 1984), and determination of life forms according to Raunkier (Ellenberg, Mueller-Dombois, 1967). pH soil analysis and electric conductivity (EC) were performed at all investigated localities. It was established that the community dominates the moist habitats of Belgrade. It is composed of 104 species and among them Aster lanceolatus Willd., Cichorium intybus L., Agropyrum repens (L.) Beauv., Calystegia sepium (L.) R. Br., Cirsium arvense (L.) Scop., Symphytum officinale L. and Rumex obtusifolius L. are the most frequent. In relation to life forms, the community has hemicriptophytes character, and in relation to phytogeography Euroasian and Middle Europaean floral elements are dominant, with a high presence of cosmopolitan and adventive floral elements. On the locialities Veliko Ratno ostrvo (island) and Maki , EC values point to the fact that the amount of nutrient in the soil is higher than at other localities.
Analysis of the biological spectrum of vascular flora of Ravni Srem flood forests
Juri?i? Branislav,Obratov-PetkoviDragica,Bjedov Ivana,Bojat Nenad
Glasnik ?umarskog Fakulteta , 2011, DOI: 10.2298/gsf1104057j
Abstract: One of the essential analyses performed during the floristic study of a region is the analysis of the biological spectrum. The analysis of the biological spectrum of the flora includes the determination of the type of life form for each taxon described in the flora of the study region. If it is considered that life form is a specific structural-functional response to the environmental effects and the result of the adaptation during the species evolution, it is clear that the basic characteristics of the site are more or less reflected in any life form. This fact is confirmed by the analysis of the biological spectrum of the flora of Ravni Srem. The analysis of the Ravni Srem flora shows the domination of the hemicryptophytes and the subdomination of the phanerophytes with a considerable participation of the therophytes.
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