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Transformation of meadow communities under the impact of hay harvesting and livestock grazing has been studied in the floodplains of the Vychegda and Pechora rivers. Changes in the floristic composition, structure, and productivity of meadows have been evaluated using synanthropization and adventization indices. On this basis, meadow phytocenoses at three different stages of pasture digression have been distinguished.  相似文献   

3.
Analysis of zonal patterns in the formation of synanthropic vegetation has shown that the intensity of manifestation of its zonal differentiation increases with the advancement of the successional stage of synanthropic communities. The rate of successional processes in these communities depends on the initial (potential) type of vegetation in the territory of the city.  相似文献   

4.
Vegetation distribution on Tibetan Plateau under climate change scenario   总被引:4,自引:0,他引:4  
The impact of climate change on distribution of vegetation is an important aspect in studies on the responses of ecosystems to the climate change. Particularly in the sensitive environments of the Tibetan Plateau, vegetation distribution may be significantly affected by climate change. In this research, the coupled biogeography and biogeochemistry model, BIOME4, was modified according to the features of vegetation distribution on the Plateau, and the Kappa statistic was used to evaluate the modeling results by comparing the simulated vegetation distribution with the existing 1:1,000,000 vegetation map of China. The comparison showed that modified model was appropriate for simulating the overall vegetation distribution on the Plateau. With the improved BIOME4 model, possible changes in the vegetation distribution were simulated under climate change scenarios. The simulated results suggest that alpine meadows, steppes, and alpine sparse/cushion vegetation and deserts would shrink, while shrubs, broad-leaved forests, coniferous-broad-leaved mixed forests, and coniferous forests would expand. Among these types, shrubs, alpine meadows, and steppes would change the most. The shrubs vegetation would expand toward the northwest, replacing most alpine meadows and part of steppes, and thus causing their shrinkages. Yet broad-leaved forests and coniferous-broad-leaved mixed forests demonstrated smaller changes in their distributions. For all the forest types, the area of coniferous forests would increase the most by spreading to the interior of the Plateau.  相似文献   

5.
Forests in and around the reserve located near the city of Chernogolovka (50 km northeast of Moscow), forests adjoining the city, and urban forests were examined during the period from 1992 to 2004. Differences between forests of the reserve proved to be less significant than those resulting from the impact of urban factors. The influence of a small city was found to change the structure of communities of small mammals in surrounding forests by reducing their diversity and enhancing the dominance of ecologically restrained synanthropic species.  相似文献   

6.
Consideration is given to the examples of suppression of restorative succession by invasive plant species (Solidago canadensis L., Helianthus subcanescens (A. Gray) E. Watson, Impatiens glandulifera Royle) in anthropogenic landscapes of southeastern Belarus. Characteristics of communities blocking the succession process have been revealed: low species richness, dominance of alien species in coverage, high level of synanthropization, and the absence of natural regeneration of trees and shrubs. It is suggested that a delay in succession is caused by the suppressing influence of transformer species on seed germination in apophytic trees.  相似文献   

7.
The occurrence of density compensation effect (DCE) has been estimated in areas occupied by synanthropic communities in the Western Caucasus. The density of dominant plant species has been estimated from their coverage, and that of subordinate species, from their frequency in 0.5-m2 squares within 15 (16)-m2 plots, using natural and seminatural communities as a reference standard. The factual material has been analyzed by the method of numerical experiments. The results show that the transformation of natural habitats into anthropogenic ones has led to a decrease in the species diversity of plant communities, but without causing a widespread occurrence of DCE. It is hypothesized that relatively high average values of species frequency in low-diversity synanthropic communities are more likely accounted for by random rather than compensatory processes.  相似文献   

8.
The dynamics of vegetation have been studied in forest-steppe pine (Pinus symvestris L.) forests affected by anthropogenic factors such as felling and fires. Gradient analysis has been used to reveal specific ecological features of plant communities and trace the main directions of succession. The results show that these forests are at different stages of progressive succession, with the development of theircommunities following similar trends over the past few decades.  相似文献   

9.
Traditional ecological knowledge and local experience of resource management and the usefulness of plant species can make important contributions to attempts to understand forest ecosystems and to develop effective sustainable management strategies for them. Therefore, the utilization of tree species by local people, their perceptions of changes in the surrounding forests, and suggested solutions for associated problems, were studied in the Sissili province of southern Burkina Faso. Information was collected through a combination of participatory rural appraisals, household interviews, and observational methods. Principal component analysis was used to analyze the consumptive values of woody species and their respective parts. A total of 82 species were identified, 90% of them were used for medicinal purposes, 78% for fodder, 73% for food, 67% for house construction, and 58% for wood carving. This suggests that forests play a key role in sustaining the rural livelihood and contributing to poverty reduction. The various stakeholders perceived that vegetation clearing for cultivation of cash crops (agribusiness) was the main driver of the change in forest cover. Species reported to be declining in the area included Parkia biglobosa, Pterocarpus erinaceus, Afzelia africana, Bombax costatum, Tamarindus indica, and Diospyros mespiliformis. Thus, a concerted effort should be made to manage the remaining natural forests in the country. Appropriate management strategies should be developed jointly by the local communities and external support groups to integrate the valuable local knowledge about forest species with the stakeholders’ suggestions in order to promote sustainable management of the region’s forest ecosystems.  相似文献   

10.
Topical connections between F. aquilonia ants and herbaceous plants in a fragmented forest area have been analyzed. The species composition of the group of herbaceous plants changing their occurrence frequency in response to the presence of F. aquilonia nests has been determined. Ecological and phytocenotic parameters of herbaceous plants contributing to the development of the myrmecotopic assemblage are described. Signs of meadowfication and synanthropization of the herbaceous layer around ant nests have been observed.  相似文献   

11.
Specific features of vegetation synanthropization under the effect of human activities and a long-term grazing load were studied in the subalpine and upper mountain-forest belts of the Seminskii Range.  相似文献   

12.
Trends in the anthropogenic transformation of flora in the city of Astrakhan and its environs over the past 100 years are discussed. In general, the process of flora synanthropization is observed, with natural aboriginal plant communities being replaced by anthropogenically altered communities.  相似文献   

13.
Data collected between 1987 and 2002 have been used to analyze the structure of small mammal communities in parks and public gardens of the city of Moscow. With regard to several ecological parameters, four categories of parks markedly differing in biotopic conditions have been distinguished. The least stable zoocenoses are formed in deteriorating parks. More favorable ecological conditions exist in public gardens and regular parks, where not only synanthropic but also hemisynanthropic rodents can be found. The fauna of small mammals in landscape parks is similar to that in forest cenoses, but this fauna in park forests better complies with the concept of forest community.  相似文献   

14.
The state of tree and ground vegetation layers in spruce-fir forests around the Middle Ural Copper Smelter (Revda, Sverdlovsk oblast) has been repeatedly evaluated in 25 permanent sampling plots at 5- to 10-year intervals (1989–2013). The results have been used to characterize the dynamics of plant communities in the period of reduction of emissions from the smelter. Although the annual amount of emissions has decreased from 150–225 × 103 t in the 1980s to less than 5 × 103 t after 2010, the vegetation in the impact zone (1 and 2 km from the smelter) remains severely suppressed: the trees continue to die off, and the diversity of ground vegetation layer is very low. In zones with low and moderate levels of industrial pollution (30 and 4–7 km from the smelter), natural factors associated with windfall disturbance after the 1995 windstorm with snow have played a more important role in the dynamics of forest communities than the reduction of emissions itself.  相似文献   

15.
The estimated net primary production (NPP) of Russian terrestrial ecosystems (annual average over the period from 1988 to 1992) is 9544 Tg of dry matter, or 4353 Tg of carbon. Of the total amount, forests account for approximately 39.2% (here and below, comparisons are made with respect to carbon content); natural grasslands and brushwoods, for 27.6%; farmlands (arable land and cultivated pastures), for 22.0%; and wetlands, for 11.2%. The average NPP density on lands covered with vegetation (1629.8 million hectares in Russia) is 267 g C/m2per year. The highest value (498 g C/m2per year) is characteristic of arable lands. Other land-use/land-cover (LULC) classes have the following NPP densities (in areas covered with vegetation): grasslands and brushwoods, 278 g C/m2; forests, 224 g C/m2; and wetlands, 219 g C/m2per year. In general, Russian terrestrial ecosystems accumulate 59.7% of the total NPP in the aboveground phytomass (47.8% in green parts and 11.9% in wood) and 40.3% in the underground phytomass. The latter parameter differs significantly in different LULC classes and bioclimatic zones. According to calculations, the uncertainty in estimating the total NPP is 11% (a priori confidential probability 0.9).  相似文献   

16.
Tendencies in plant cover synanthropization depending on the pattern and intensity of anthropogenic impacts on natural complexes have been revealed in specially protected areas of different classes (a nature reserve and a nature park).  相似文献   

17.
The structure of the long-eared owl (Asio otus L.) settlements in anthropogenic landscapes has been studied in the Zhuravlinaya Rodina protected territory in the northern Moscow region in 2001–2005. The possible factors that cause the formation of such settlements have been analyzed. The differences in the breeding success between owls nesting near and away from human settlements have been estimated. Aggregated nesting of owls is assumed to be mainly related to a lower predator pressure in the vicinity of human dwellings in the incubation period. Aggregated nesting is regarded as an expression of synanthropization of the species.  相似文献   

18.
Forest structure and regeneration were studied along the altitudinal gradient in the Binsar Wildlife Sanctuary of Uttarakhand Himalaya in India. Stratified random sampling of tree species was done by placing minimum 15 quadrats of 10 × 10 m at each aspect and altitude. The results reveal that along the altitudinal gradient there were three types of forest communities in the Sanctuary viz., chir pine (Pinus roxburghii), oakchir pine (Quercus leucotrichophora and Pinus roxburghii) and oak (Quercus floribunda and Quercus leucotrichophora). Rhododendron arboreum, Cornus macrophylla and Lyonia ovalifolia were main associates of these forest communities. The oak forests had larger shrub population as compared to chir pine. Myrsine africana was the most dominant shrub across the altitudinal gradient, whereas few shrub species were restricted to a certain altitudinal range. The regeneration of chir pine was best at lower altitude on south and east aspects, which indicates that it mostly regenerates on warm and dry slopes. In general, the regeneration potential in most of the tree species declines with the altitude. The density of saplings and seedlings also represented the dominant species at each altitudinal range, which indicates the cyclic regeneration of forests in the Sanctuary area.  相似文献   

19.
Trends in plant cover synanthropization along a plain-foothills-mountains gradient have been revealed in the reserve. Characteristics of plant communities in anthropogenically disturbed habitats, centers of concentration of anthropophytes and apophytes, and pathways of their migration are described.  相似文献   

20.
Understanding changes in forest composition and structure is important to help formulate effective policies that promote future ability of forests to provide local livelihood needs, habitat and ecosystem services. This is particularly important in dry tropical forests that are ecologically different from other forests and are heavily used by local, forest-dependent residents. In this study, we identify biophysical, demographic and use factors associated with differences in species diversity, vegetation structure (abundance at different size classes), biomass and relative abundance of species across the Kanha–Pench landscape in Central India. We sampled vegetation in twenty transects across different human and livestock population densities and frequencies of use. We found that biomass, species diversity and vegetation (abundance at different size classes) are negatively associated with increasing population density, and species composition at different size classes is significantly different at higher frequencies of use at low population densities. Lack of difference in species composition at high population densities may be due to colonization and growth of individuals at some of these sites due to creation of new ecological niches and gaps at high human use. Relative abundance of species at different size classes also varies with frequency of use and population density. Results suggest that human use is altering relative abundance of species, which may change long-term forest composition and thus alter biomass and vegetation structure of the forest. We conclude that human use is an agent in altering long-term composition that can alter availability of tree species for local use and other ecosystem services.  相似文献   

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