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VEGETATION DYNAMICS IN EUROPEAN BEECH FORESTS  [cached]
A. FISCHER
Annali di Botanica , 1997,
Abstract: Dynamic processes can be classified in terms of their time scale, their spatial scale, the elements observed, and the degree of human impact. Using these categories the regeneration of the tree layer, the regeneration of the herb layer as well as successional changes of supraregional importance (immissions, global change) are discussed. A virgin (mixed) European beech forest consists of a mosaic of sub-stands that can be typified by their structure and developmental stage (phase) of the tree layer; in some phases the tree individuals of each sub-stand are rather even-aged. Natural cyclic regeneration of virgin (mixed) European beech forests mainly includes the tree species of the terminal phases, expecially the beech itself. Changes of tree species composition within the cycle are the exception; in European beech forests light-demanding pioneers seem to be restricted to rather small patches under natural conditions. In contrast, the sequence (1) felled-area flora, (2) pioneer shrub/pioneer forest and (3) terminal forest is a characteristic feature of managed deciduous forests as a consequence of soil disturbances. During the cyclic regeneration of the tree layer of European beech forests the floristic content of the ground layer vegetation does not change fundamentally. Regeneration of many of the ground layer species of beech forests via generative diaspores is more or less restricted to micro-disturbances. In contrast disturbance of the topsoil and creation of open habitats for the establishment of saplings in the absence of competition is taking place all over a clear-cutting area. European beech forests are subject to changes of floristic structure caused by immissions. Especially nitrogen, emitted over decades in large quantities, causes a successive change in floristics: species requiring high amounts of nitrogen are increasing in beech forests all over Europe. Most of them are rapidly and tall growing species, outcompeting the slower and smaller growing acid-indicators. Soil acidification, although taking place, is therefore often not reflected in changes in the vegetation cover. Up to now, syntaxonomic changes are usually restricted to the levels below the association. Additionally some proportion of (beech) forest stands are presently changing since the regeneration following the abandonment of degrading land use practices has not yet been completed. As a consequence of changing climatic conditions (CO2-content, air temperature, precipitation, storms) it is expected that European beech forests will change in the future. However, details of the
THE ROLE OF ALTITUDE, LATITUDE AND LONGITUDE IN THE DISTRIBUTION OF MEADOW VEGETATION IN THE FLOODPLAINS OF THE NORTHERN UKRAINE  [cached]
A. KUZEMKO
Annali di Botanica , 2011,
Abstract: This paper presents a comparison of syntaxa at alliance level from Molinio-Arrhenatheretea, Koelerio-Corynephoretea and Phragmito-Magnocaricetea classes, considering altitude, latitude and longitude. The results show that the syntaxa may be divided into two groups: one geographically specific (with a narrow distribution and propensity for certain climatic zones or regions, e.g. Agrostio stoloniferae-Beckmannion eruciformis) and the other non-geographically specific (with a wide distribution and occurring in several climatic zones e.g. typical Festucion pratensis alliance). The role of climate in the differentiation of floodplain meadow vegetation is considerable in spite of the well known azonality of such vegetation. This can be explained by the changes in environmental conditions, especially soil reaction, temperature and continentality.
Vegetation recording in forests: Comparison of the Chinese and European approaches
Zhang Qiao-Ming,Wang De-Xiang,Fischer Anton
Archives of Biological Sciences , 2011, DOI: 10.2298/abs1102469z
Abstract: The field approach underlying a vegetation study influences the results of biodiversity assessments. In our paper we compared two main field survey approaches for forest vegetation recording, the Chinese and the European (“phytosociological”) one, for their differences and efficiency when applied to the plant communities of temperate forests. The Chinese approach uses a design with different plot sizes for recording the tree, shrub and herb layer species, respectively, while the European one uses the same plot size for recording all layers and species. The two approaches result in significant differences in species richness (Simpson’s diversity index and the Shannon-Wiener index), while there is no difference in the evenness index. The European approach has the ability to survey the number of different species more precisely than the Chinese one. For detecting the general patterns of diversity, however, the two approaches have the same ability, demonstrated here for the altitudinal gradient.
Impacts of changes in vegetation cover on soil water heat coupling in an alpine meadow of the Qinghai-Tibet Plateau, China
W. Genxu, H. Hongchang, L. Guangsheng,L. Na
Hydrology and Earth System Sciences (HESS) & Discussions (HESSD) , 2009,
Abstract: Alpine meadow is one of the most widespread grassland types in the permafrost regions of the Qinghai-Tibet Plateau, and the transmission of coupled soil water heat is one of the most crucial processes influencing cyclic variations in the hydrology of frozen soil regions, especially under different vegetation covers. The present study assesses the impact of changes in vegetation cover on the coupling of soil water and heat in a permafrost region. Soil moisture (θv), soil temperature (Ts), soil heat content, and differences in θv Ts coupling were monitored on a seasonal and daily basis under three different vegetation covers (30, 65, and 93%) on both thawed and frozen soils. Regression analysis of θv vs. Ts plots under different levels of vegetation cover indicates that soil freeze-thaw processes were significantly affected by the changes in vegetation cover. The decrease in vegetation cover of an alpine meadow reduced the difference between air temperature and ground temperature (ΔTa s), and it also resulted in a decrease in Ts at which soil froze, and an increase in the temperature at which it thawed. This was reflected in a greater response of soil temperature to changes in air temperature (Ta). For ΔTa s outside the range of 0.1 to 1.0°C, root zone soil-water temperatures showed a significant increase with increasing ΔTa s; however, the magnitude of this relationship was dampened with increasing vegetation cover. At the time of maximum water content in the thawing season, the soil temperature decreased with increasing vegetation. Changes in vegetation cover also led to variations in θv Ts coupling. With the increase in vegetation cover, the surface heat flux decreased. Soil heat storage at 20 cm in depth increased with increasing vegetation cover, and the heat flux that was downwardly transmitted decreased. The soil property varied greatly under different vegetation covers, causing the variation of heat conductivity and water-heat hold capacity in topsoil layer in different vegetation cover. The variation of heat budget and transmitting in soil is the main factor that causes changes in soil thawing and freezing processes, and θv Ts coupling relationship under different vegetation fractions. In addition to providing insulation against soil warming, vegetation in alpine meadows within the permafrost region also would slow down the response of permafrost to climatic warming via the greater water-holding capacity of its root zone. Such vegetation may therefore play an important role in conserving water in alpine meadows and maintaining the stability of engineering works constructed within frozen soil of the Qinghai-Tibet Plateau.
Impacts of changes in vegetation cover on soil water heat coupling in an alpine meadow, Qinghai-Tibet Plateau, China
W. Genxu,H. Hongchang,L. Yuanshou,W. Yibo
Hydrology and Earth System Sciences Discussions , 2008,
Abstract: Alpine meadow is one of the most widespread grassland types in the permafrost regions of the Qinghai-Tibet Plateau. The transmission of coupled soil water heat is one of the most important processes influencing cyclic variations in the hydrology of frozen soil regions, especially under conditions of changing vegetation cover. The present study assesses the impact of changes in vegetation cover on the coupling of soil water and heat in a permafrost region. Soil moisture (θv), soil temperature (Ts), soil heat content, and differences in θv Ts coupling were monitored on a seasonal and daily basis under three different densities of vegetation cover (30, 65, and 93%) upon both thawed and frozen soils. Regression analysis of θv vs. Ts plots under different levels of vegetation cover indicates that soil freeze-thaw processes were significantly affected by changes in vegetation cover. With decreasing vegetation cover upon an alpine meadow, the difference between air temperature and ground temperature (ΔTa s) also decreased. A decrease in vegetation cover also resulted in a decrease in the Ts at which soil froze and an increase in the temperature at which it thawed; this was reflected in a greater response of soil temperature to changes in air temperature (Ta). For ΔTa s outside the range of 0.1 to 1.0°C, root zone soil-water temperatures showed a significant increase with increasing ΔTa s; however, the magnitude of this relationship was dampened with increasing vegetation cover. At the time of maximum water content in the thawing season, the soil temperature decreased with increasing vegetation. Changes in vegetation cover also led to variations in θv Ts coupling. With increasing vegetation cover, the surface heat flux increased, along with the amplitude of its variations. Soil heat storage at 20 cm depth also increased with increasing vegetation cover, and the downward transmitted of heat flux decreased. In addition to providing insulation against soil warming, vegetation in alpine meadows within the permafrost region also slows down the response of permafrost to climatic warming via the greater water-holding capacity of its root zone. Such vegetation may therefore play an important role in conserving water in alpine meadows and maintaining the stability of engineering works constructed within frozen soil of the Qinghai-Tibet Plateau.
Comparative study of the net exchange of CO2 in 3 types of vegetation ecosystems on the Qinghai-Tibetan Plateau
Liang Zhao,Yingnian Li,Xinquan Zhao,Shixiao Xu,Yanhong Tang,Guirui Yu,Song Gu,Mingyuan Du,Qinxue Wang
Chinese Science Bulletin , 2005, DOI: 10.1360/04wd0316
Abstract: Using the eddy covariance method, from 1 July 2003 to 30 June 2004, we conducted the observation and analysis of ecosystem CO2 flux in 3 types of alpine meadow vegetation (Kobresia humilis, Potentilla fruticosa shrub and Kobresia tibetica swamp meadows) on the Qinghai-Tibetan Plateau. The results show that the Kobresia humilis meadow, the shrub meadow and the swamp meadow’s highest CO2 uptake rates are 16.78, 10.42 and 16.57 μmol·m 2·s 1 respectively, while their highest CO2 release rates are 8.22, 7.73 and 18.67 μmol·m 2·s 1 respectively. The Kobresia humilis meadow and shrub meadow’s annual atmospheric uptakes are 282 g CO2/m2 and 53 g CO2/m2, respectively, while swamp meadow’s annual atmospheric release is 478 g CO2/m2. This proves that the Kobresia humilis meadow and the shrub meadow on the Qinghai-Tibetan Plateau have relatively low potential for CO2 uptake and release compared to C4 grasslands, a number of lowland grasslands, and forests. Moreover, swamp meadow has relatively high release potential. This, in turn, reveals clear differences in carbon source/sink between different types of vegetation in the Qinghai-Tibetan Plateau alpine meadow ecosystem. These differences are mainly brought by differences in the vegetations’ photosynthetic capacity and soil respiration.
Successful modeling of the environmental changes' influence on forests' vegetation over North Eurasia  [PDF]
O. Khabarova,I. Savin,M. Medvedeva
Physics , 2010,
Abstract: Modeling of forests' vegetation in North Eurasia has been performed for 1982-2006 on the basis of remote sensing data. Four meteorological parameters and one parameter, characterizing geomagnetic field disturbance level, were used for this aim. It was found out that revealed formula is adequate both for coniferous evergreen and coniferous deciduous forests for accuracy to a coefficient. The most proper parameters' combination gives the correlation coefficients ~ 0.9 between modeling parameter and original data rows. These results could solve problems of climate-forests feedbacks' investigations and be useful for dendrological aims.
Single-tree influence on understorey vegetation in five Chinese subtropical forests  [cached]
Liu H-Y,Halvorsen R
iForest : Biogeosciences and Forestry , 2012, DOI: 10.3832/ifor0623-005
Abstract: The aim of this study is to examine the effect of individual canopy tree on the species composition and abundance of understorey vegetation in subtropical forests, by applying a model for tree influence on understorey vegetation of boreal spruce forests developed by kland et al. (1999), according to the principles of Ecological Field Theory (EFT). The study was based upon five vegetation data sets, each with two subsets (vascular plants species and bryophytes species) from subtropical forests in south and southwest China. Optimal value of tree influence model parameters was found by maximizing the eigenvalue of a Constrained Ordination (CO) axis, obtained by use of the EFT-based tree influence index as the only constraining variable. One CO method, Redundancy Analysis (RDA), was applied to five vegetation data sets. The results showed that the optimal EFT tree influence models generally accounted for only a small part of the variation in species composition (the eigenvalues of RDA axes were low, amounted to 1-10% of total inertia). The higher eigenvalue-to-total-inertia ratio with RDA was interpreted as due mainly to the low species turnover along the tree influence gradient. Vascular plants and bryophytes species differed with respect to optimal parameters in the tree influence mo-del, especially in a conifer dominated forest. Compositional turnover asso-ciated with tree influence indices was also generally low, although somewhat varies among study areas. Thus, it was concluded that single-tree EFT models may have limited suitability for studied subtropical forests; different optimal parameters in the tree influence model obtained for vascular plants and bryo-phytes species in two studied areas indicates that subtropical trees may impact vascular plants and bryophytes species in different ways; and trees may influence the understorey species composition more in a collective manner than through the influence of single individuals in studied subtropical forests.
A STUDY ON THE FIRE SUCCESSION OF MOUNTAINOUS MEADOW VEGETATION DISTRIBUTING IN THE SOUTH OF GANSU
甘肃南部山地草甸植被烧荒演替的研究

Chen Qmgcheng,
陈庆诚
,赵松岭

生态学报 , 1981,
Abstract: The authors have made observation and study on the Fire Succession of three subtypes of meadow vegetation which distributes in the mountain ranges of Southern Gansu, with the purpose to evaluate the influence of fire to the productivity of this type of vegetation. The results are as follows;1. After burning, the production of forage grass in green -weight increases by 14.35% on an average and the increasing rate of true meadow subtype reaches the value of 18.77%;2. In Spring, the forage grasses of these mea...
Applying the Global Disturbance Index for Detecting Vegetation Changes in Lao Tropical Forests  [PDF]
Chittana Phompila, Megan Lewis, Kenneth Clarke, Bertram Ostendorf
Advances in Remote Sensing (ARS) , 2015, DOI: 10.4236/ars.2015.41007
Abstract: Land cover change is a major challenge for many developing countries. Spatiotemporal information on this change is essential for monitoring global terrestrial ecosystem carbon, climate and biosphere exchange, and land use management. A combination of LST and the EVI indices in the global disturbance index (DI) has been proven to be useful for detecting and monitoring of changes in land covers at continental scales. However, this model has not been adequately applied or assessed in tropical regions. We aimed to demonstrate and evaluate the DI algorithm used to detect spatial change in land covers in Lao tropical forests. We used the land surface temperature and enhanced vegetation index of the Moderate Resolution Imaging Spectroradiometer time-series products from 2006-2012. We used two dates Google EarthTM images in 2006 and 2012 as ground truth data for accuracy assessment of the model. This research demonstrated that the DI was capable of detecting vegetation changes during seven-year periods with high overall accuracy; however, it showed low accuracy in detecting vegetation decrease.
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