scholarly journals The Woody Flora of Bulgaria: A Review

2001 ◽  
Vol 152 (2) ◽  
pp. 52-60 ◽  
Author(s):  
Stefan Yurukov ◽  
Peter Zhelev

This review presents a brief survey of the Bulgarian dendroflora. The country is situated in the transition zone between the continental and Mediterranean climate and,therefore, considerable habitat diversity exists on its territory. About 370 species – trees, shrubs and sub-shrubs – have been established up until today. An overview of the species'diversity, woody formations and their distribution is presented. The data show that Bulgaria is characterised by a relatively rich dendroflora that needs appropriate close-to-nature management and measures for its conservation.

1990 ◽  
Vol 68 (5) ◽  
pp. 1139-1146 ◽  
Author(s):  
Ragan M. Callaway ◽  
Scott Jones ◽  
Wayne R. Ferren Jr. ◽  
Anuja Parikh

We examined seasonal changes in soil salinity in four different vegetative zones in a mediterranean-climate estuarine wetland in southern California. Each zone had a characteristic seasonal pattern of soil salinity: (i) the low marsh zone was high in salinity throughout the year; (ii) the salt flat zone was hypersaline throughout the year; (iii) the transition zone was hypersaline in the summer and fall, and low in salinity in the winter and spring; and (iv) the nonflooded grassland was low in salinity throughout the year. The transition zone was densely populated with winter annuals that were distributed along gradients of elevation and soil salinity. This occurrence of annuals is a characteristic feature of mediterranean-climate marshes. We found that the relative growth rates and the germination of each of these annuals in experimental solutions of different salinities corresponded with the winter and spring soil salinities of the subzones they occupied in the field.


2019 ◽  
Vol 325 (5) ◽  
pp. 65-69
Author(s):  
I.A. Trofimov ◽  
◽  
V.M. Kosolapov ◽  
L.S. Trofimova ◽  
E.P. Yakovleva ◽  
...  

Author(s):  
Georgiy Gulyuk ◽  
Aleksey Ivanov ◽  
Yuri Yanko

Current situation and agricultural management on the non-black earth area of Russia arebeing gradually worsen by the negative natural factors such as a significant increase of weather based climatic abnormal risks, deterioration of agro-meliorative conditions of agricultural lands because of colonization by tree and shrubbery vegetation and secondary bog formation, hidden degradation of soil fertility. When combined with functional loss of ameliorative complex and meliorative systems amortization, regional agriculture adaptation possibilities were rapidly limited. Production shortfall due no abnormal weather conditions for particular field crops was 19…48% during last five years, level of business realization of bioclimatic potential on a field was decreased by 7…12%.The complete realization of regional agricultural adaptive potential to weather based climatic changes and limitation of greenhouse gases emissions is possible on a basis of regeneration ofalll functions and aspects of ameliorative complex management. Toward this goal the coordinated actions of federal and regional management of Agricultural Complex, Scientific and Educational institutions, project foundations and managers are needed in a relation to human resources, scientific and regulatory supply. Any incomplete treatment in these fields inherent in visual negative consequences for food security and social economic development of rural areas of non-black earth zones not only at the current historical moment, but in a future also. Fundamental influence of solving of these problems deserves to scientific supply of innovative ameliorative complex, renewal of which should be based on principals of resources and energy preservation, nature management, computerization and digitalization management. During a long term research it was established that increase of average vegetation period temperature by lоСhas increased productivity of winter wheat, barley and summer wheat in average on 0,7 tons per ha, winter wheat and oat on 0,4 tons per ha, potatoes – 8,2 tons per ha, edible roots-6,4 tons per ha, cabbage 9,8 tons per ha, dry basis of herbage of multi and one age grasses–0,5 and 0,7 tons per ha. Increase of СО2 Concentration from 0,35 to 0,45% during last twenty years contributed into grow of yield in regional agriculture which can be estimated as 0,3 tons per ha per measure; searching remedy for agroclimatical risks decreasing production became drainage and irrigation systems (decrease 3…5 times);new method of reclamation of abandoned areas with transformation of biomass of tree and shrubbery vegetation into biochar makes it possible to decrease СО2 emissions up to times and get an adverse balance of СО2;secondary reclamation of lands covered by trees and shrubbery on area of 22ha used for vegetables and area of 37ha used for forage crops could supply a farmer with work and revenue sufficient for maintenance of one child what is on the major facts of population declaim in rural areas.


Author(s):  
I.G.C. Kerr ◽  
J.M. Williams ◽  
W.D. Ross ◽  
J.M. Pollard

The European rabbit (Oryctolagus cuniculus) introduced into New Zealand in the 183Os, has consistently flourished in Central Otago, the upper Waitaki, and inland Marlborough, all areas of mediterranean climate. It has proved difficult to manage in these habitats. The 'rabbit problem' is largely confined to 105,000 ha of low producing land mostly in semi arid areas of Central Otago. No field scale modifications of the natural habitat have been successful in limiting rabbit numbers. The costs of control exceed the revenue from the land and continued public funding for control operations appears necessary. A system for classifying land according to the degree of rabbit proneness is described. Soil survey and land classification information for Central Otago is related to the distribution and density of rabbits. This intormation can be used as a basis for defining rabbit carrying capacity and consequent land use constraints and management needs. It is concluded that the natural rabbit carrying capacity of land can be defined by reference to soil survey information and cultural modification to the natural vegetation. Classification of land according to rabbit proneness is proposed as a means of identifying the need for, and allocation of, public funding tor rabbit management. Keywords: Rabbit habitat, rabbit proneness, use of rabbit prone land.


Author(s):  
B. B. Shkursky

Theoretical modeling of regular olivine grains misorientations in mimetic paramorphoses after ringwoodite and wadsleyite, the formation of which during the ascension of matter from the Mantle Transition Zone is expected, has been carried out. The coordinates of the misorientation axes and the misorientation angles, characterizing 10 operations of alignment in the pair intergrowths of olivine grains, eight of which are twins, are calculated. Possible conditions for the formation of mimetic paramorphoses predicted here, and the chances of their persistence are discussed. The calculated orientations are compared with the known twinning laws of olivine.


2017 ◽  
Vol 7 (4) ◽  
pp. 30-34 ◽  
Author(s):  
O. A. Didur ◽  
Yu. L. Kulbachko ◽  
V. Y. Gasso

<p>The problem of transformation of natural landscapes resulted from the negative technogenic impact is highlighted. It is shown that mining enterprises are powerful anthropo-technical sources of organic and inorganic toxicants entering the environment. Their wastes pollute all components of the ecosystems and negatively influence human health by increasing a risk of disease. The nature of the accumulation of trace elements (Fe, Cu, Zn, Ni, Cd, and Pb) by invertebrate animals of various functional groups under conditions of anthropo-technogenic pressure was studied. The sample plots were located on self-overgrowing sites with ruderal vegetation located in the immediate vicinity of the Mangan ore-dressing and processing enterprise (Dnipropetrovsk region). It is quite naturally that among the studied biogenic microelements (Fe, Cu, Zn and Ni), the phyto-, zoo-, and saprophages in the investigated zone of technogenic pollution most actively accumulate Fe:<em> </em>22758, 17516 and 18884 mg/kg dry weight on average, respectively. There are significant differences (p ≤ 0.05) in the content of studied microelements between saprophages and phytophages. The saprophages accumulate such trace metals as Mn, Cu, Zn and Cd in high quantities, but Ni and Pb – in smaller ones. The saprophagous functional group of invertebrates is an active agent of detritogenesis, in the conditions of modern nature management it acts as a powerful element of ecosystem engineering (habitat transformation), the main ecological role of which is to modify the habitat of other soil biota. In addition, the saprophages fulfil their concentrating geochemical function. They actively participate in the most important soil biochemical process: the formation of humus, the migration of microelements along trophic chains, the biological cycle in general, and provide such supporting ecosystem services as increasing soil fertility and nutrient cycling.</p>


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