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1.
To estimate the impacts of invasive plants on ecosystems, a survey has been conducted in three sites including both buffer zones and core zones. 13, 19 species are found in the Yuntai Mountain and Longchi Mountain natural reserve respectively, and 23 in the Purple Mountain Natural Park. Altogether 25 species belonging to 12 families, the majority of which are native to North America, some of them have set up stable reproducible populations. Among them, Solidago canadensis is found in Longchi Mountain and Purple Mountain. Communities of Galinsoga parviflora, Gynura crepidioides, Ageratum conyzoides, and Ambrosia artemisiifolia pose a serious threat to local biodiversity.  相似文献   

2.
Alternaria alternata spores are considered a well-known biological contaminant and a very common potent aeroallergen source that is found in environmental samples. The most intense exposure to A. alternata allergens is likely to occur outdoors; however, Alternaria and other allergenic fungi can colonize in indoor environments and thereby increase the fungal aeroallergen exposure levels. A consequence of human exposure to fungal aeroallergens, sensitization to A. alternata, has been unequivocally associated with increased asthma severity. Among allergenic proteins described in this fungal specie, the major allergen, Alt a 1, has been reported as the main elicitor of airborne allergies in patients affected by a mold allergy and considered a marker of primary sensitization to A. alternata. Moreover, A. alternata sensitization seems to be a triggering factor in the development of poly-sensitization, most likely because of the capability of A. alternata to produce, in addition to Alt a 1, a broad and complex array of cross-reactive allergens that present homologs in several other allergenic sources. The study and understanding of A. alternata allergen information may be the key to explaining why sensitization to A. alternata is a risk factor for asthma and also why the severity of asthma is associated to this mold. Compared to other common environmental allergenic sources, such as pollens and dust mites, fungi are reported to be neglected and underestimated. The rise of the A. alternata allergy has enabled more research into the role of this fungal specie and its allergenic components in the induction of IgE-mediated respiratory diseases. Indeed, recent research on the identification and characterization of A. alternata allergens has allowed for the consideration of new perspectives in the categorization of allergenic molds, assessment of exposure and diagnosis of fungi-induced allergies.  相似文献   

3.
Eomecon chionantha Hance, the only species in the genus Eomecon, is an angiosperm species endemic to China. Here we investigated the pollination syndrome, pollinator generalization of E. chionantha. Our results showed that the individual flower longevity of E. chionantha was 3–5 days. The flowering phenology of E. chionantha can be divided into five phases. We found significant differences in the pollination efficiency of the different insects visiting E. chionantha with bees and flies being the most efficient pollinators. This, in addition to floral morphology and phenology, suggests that E. chionantha is generalized on bees and flies and possesses an outcrossing, partially self-compatible and pollinator-dependent breeding system.  相似文献   

4.
It can be stated in general that (with the exception of agriculture) the Hungarian economy, because of its outdated technologies, is a bigger threat to the environment than countries of Western Europe. However, as the volume of economic output, per capita consumption and the number of motor vehicles is considerably lower than those in more advanced industrial nations, by most indicators low per capita figures put Hungary in a better position. Still, we must remember that the EU's environmental policy puts heavy emphasis on the efficient utilization of resources and environmental efficiency, calculated against pollution generated in the course of creating units of national wealth and the amount of energy and natural resources required to it. By these standards, Hungary lags far behind the West European model.The problem is compounded by the fact that, while nations of Western Europe had created environmental infrastructure (i.e., wastewater disposal and treatment, waste management) in an earlier phase of their economic development, Hungary is only now embarking on a similar project. Indeed, the existing gap between utility services of drinking water and sewage disposal and treatment, and large amounts of untreated and illegally dumped waste lead to serious environmental damage. Although the state of the country's natural environment is considered satisfactory, factors outlined above indicate there are many responsibilities ahead of us if we are to meet western environmental standards.  相似文献   

5.
In this study we investigated the size-dependent reproductive pattern of Inula racemosa and I. royleana (Asteraceae) growing at different reaches in the environs of the Kashmir Himalaya. Size effects on reproductive pattern were evaluated by determining the size-dependency of flowering probability and reproductive effort. The results showed that the probability of flowering increased significantly with the size of the plant in all populations, indicating that individuals do not flower until they reach a threshold size and considerable between-site differences were found in the slope and the intercept of the regression between plant size and flower production. In I. racemosa, populations at high altitudes had significantly lower threshold sizes for reproduction and showed sharp increase in flowering probability with plant size, compared to other populations at lower altitudes. However, no pattern in size-dependent flower production was found relative to the altitude in I. royleana, as flower production at some sites, at high altitudes, increased more steeply with plant size than at other sites. For both taxa, reproductive effort decreased allometrically as adults grew, as can be interpreted from the allometric relationship between reproductive and vegetative biomass. Further studies are required to determine whether population differentiation in size-dependent reproductive pattern is maintained by selection.  相似文献   

6.
Climate change is one of the main factors that will affect biodiversity in the future and may even cause species extinctions. We suggest a methodology to derive a general relationship between biodiversity change and global warming. In conjunction with other pressure relationships, our relationship can help to assess the combined effect of different pressures to overall biodiversity change and indicate areas that are most at risk. We use a combination of an integrated environmental model (IMAGE) and climate envelope models for European plant species for several climate change scenarios to estimate changes in mean stable area of species and species turnover. We show that if global temperature increases, then both species turnover will increase, and mean stable area of species will decrease in all biomes. The most dramatic changes will occur in Northern Europe, where more than 35% of the species composition in 2100 will be new for that region, and in Southern Europe, where up to 25% of the species now present will have disappeared under the climatic circumstances forecasted for 2100. In Mediterranean scrubland and natural grassland/steppe systems, arctic and tundra systems species turnover is high, indicating major changes in species composition in these ecosystems. The mean stable area of species decreases mostly in Mediterranean scrubland, grassland/steppe systems and warm mixed forests.  相似文献   

7.
The results of monitoring the dates of the onset of flowering and leaf budding in eight herbaceous and woody plant species and the first appearance of three insect species in the Il’men Reserve (1972–2005) were processed by means of regression and correlation analyses. No significant changes in test parameters were revealed in the majority of these species. Only two early spring plants, coltsfoot (Tussilago farfara L.) and goat willow (Salix caprea L.), showed a weak tendency toward earlier flowering in the 1980s and 1990s. This is explained primarily by the absence of any significant trends in spring and summer air temperatures in the study region over the observation period. On the other hand, interannual fluctuations in the dates of plant flowering and insect appearance were well manifested not only in early spring but also in late-spring species. These fluctuations proved to depend largely on spring temperatures: in years with early and warm springs, flowering and leaf budding in plants and the appearance of first individuals in insects were recorded on significantly earlier dates.  相似文献   

8.

Subrecent spore–pollen spectra have been analyzed for the occurrence Carpinus, Fagus, Tilia, and Quercus pollen in the East European Plain to evaluate the possibility of long-distance pollen transfer. Analysis was based on the material from the Russian Palynological Database on 250 points in different regions of European Russia and neighboring countries and on data from published sources. Pollen of oak, linden, and hornbeam has been found in surface samples taken within the natural ranges of these species and in regions of their introduction, with linden and oak pollen being transferred by air for several tens of kilometers, and hornbeam pollen, for about 200 km. Beech pollen can be transferred by wind for long distances, and its presence in spectra has been recorded farther than 1000 km from the species range boundaries. The proportion of components transferred from long distances increases in spore–pollen spectra from regions with sparse or poorly developed plant cover, and single occurrences of broadleaf tree pollen are also possible in such regions.

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9.
根根据长江荆江段沿江牛轭湖天鹅洲和尺八沉积钻孔柱样,在建立了高分辨率的年代框架的基础上,分别进行了沉积物孢粉、炭屑分析,并结合荆州市1955~2012年的气候数据、史志记载的洪水和火灾等环境事件进行了综合分析。结果显示:天鹅洲、尺八两湖泊钻孔沉积物的孢粉和炭屑特征均较好地响应了近百年来湖区周边的环境变化;牛轭湖在裁断成湖之前、成湖之后的孢粉、炭屑特征不同:成湖之前,沉积物总孢粉浓度与乔木、灌木孢粉浓度都相对较低,水生植物和蕨类植物孢粉浓度相对较高,成湖之后乔木孢粉浓度仍呈减小趋势,但灌木、水生植物孢粉浓度呈波动增加趋势;利用沉积物炭屑浓度与孢粉浓度的比值(C/P值)指标,可以较好地指示自然山火与人类聚居地火灾等燃烧事件在沉积物中的记录,而且综合利用C/P值与沉积物孢粉特征,有可能厘清长江全流域洪水与局地洪涝事件的沉积记录。  相似文献   

10.
In 1985, just over 30 years ago, the “ozone hole” made its appearance in the press as a truly global environmental threat. As one of the most important environmental issues of the twentieth century, the “ozone hole” is also a remarkable metaphorical, visual, and imaginary construction. This essay examines the historical trajectory of the famous “ozone hole” from its birth within the astronomical community at the beginning of the twentieth century to its contemporary framing as a global environmental threat. The article provides evidence why metaphors constitute a valuable object of historically informed studies of scientific practice, and shows in particular how metaphorical landscapes shift over time, mapping at the same time larger social and political developments. The essay ends by showing how scientific images and metaphorical framings interact and how they shape scientific and popular discourse on nature, as well as our understanding of the global environment.  相似文献   

11.
There is evidence for overall spring advancement and phenology shift across the northern hemisphere, including northern Europe, where cereals are grown despite the very short growing season. This study focused on one of the principal risks associated with the short growing season, weather-induced variability in sowing time. The aim was to characterize variation in sowing time, quantify the impacts on crop growth and document associations with weather conditions and variability. We also assessed whether any systematic changes occurred as potential signs of autonomous adaptation to changed conditions. Shifts in spring cereal sowing time had no consistent impact on time of maturity as a result of variable weather conditions. All spring cereal cultivars required fewer days, although more cumulated degree-days, to mature after delays in sowing. In the 1990s and 2000s, sowing tended to start earlier than in the 1970s and 1980s. This was attributable to earlier onset of the growing season. Furthermore, more favorable harvest conditions facilitated harvest after maturity. As more land has been allocated to late-maturing wheat (Triticum aestivum L.) compared with early-maturing barley (Hordeum vulgare L.) during recent decades, autonomous adaptation to climate change has already begun in the northernmost agricultural region of Europe.  相似文献   

12.
The results of long-term observations (1983–2013) on the dates of arrival of migratory birds to the Ilmen State Reserve are presented. Based on their analysis, it is conclude that (1) there is no significant positive trend of spring temperatures in the territory of the reserve, and (2) an earlier arrival of the majority of bird species is not observed, unlike in Europe. The arrival has shifted to earlier dates in the Common Chaffinch (Fringilla coelebs), White Wagtail (Motacilla alba), and Black Kite (Milvus migrans). On the other hand, the arrival of the Tree Pipit (Anthus trivialis) is observed later than usual. Multiple regression analysis has shown that the arrival dates of most species that nest in the reserve are determined by the temperature regime of spring months in their nesting area.  相似文献   

13.
Many factors such as human activities threat brown bears (Ursus arctos) in Southern Asia, and limit it to small populations in remote and rocky mountainous regions. Brown bears are generally studied in North America and Europe, but there is little information about its conditions and requirements for survival in Asia. During the recent years, brown bear populations in Iran have decreased sharply. Therefore, they are now officially listed as a threatened species in local scale. Therefore, we tried to recognize brown bear habitat relationships in northern Iran using species distribution model (SDM). Maxent method was applied using multiscale approach to predict suitable habitats and habitat relationships of the species. Our results revealed that the predictive ability of environment variables and species distribution maps varied across scales strongly. Also, our findings showed that identifying a proper scale is important issue to improve habitat modeling accuracy. Only 17% of the protected areas was found suitable for brown bear and divided to 5.1% poor, 8.8% suitable, and 3.1% high-quality habitat. Consequently, it is suggested that the protected area of northern Iran reconsiders with interventions aimed at maintaining suitable habitats of brown bear.  相似文献   

14.
Environmental change is likely to have a strong impact on biodiversity, and many species may shift their distribution in response. In this study, we aimed at projecting the availability of suitable habitat for an endangered amphibian species, the Fire-bellied toad Bombina bombina, in Brandenburg (north-eastern Germany). We modelled a potential habitat distribution map based on (1) a database with 10,581 presence records for Bombina from the years 1990 to 2009, (2) current estimates for ecogeographical variables (EGVs) and (3) the future projection of these EGVs according to the statistical regional model, respectively, the soil and water integrated model, applying the maximum entropy approach (Maxent). By comparing current and potential future distributions, we evaluated the projected change in distribution of suitable habitats and identified the environmental variables most associated with habitat suitability that turned out to be climatic variables related to the hydrological cycle. Under the applied scenario, our results indicate increasing habitat suitability in many areas and an extended range of suitable habitats. However, even if the environmental conditions in Brandenburg may change as predicted, it is questionable whether the Fire-bellied toad will truly benefit, as dispersal abilities of amphibian species are limited and strongly influenced by anthropogenic disturbances, that is, intensive agriculture, habitat destruction and fragmentation. Furthermore, agronomic pressure is likely to increase on productive areas with fertile soils and high water retention capacities, indeed those areas suitable for B. bombina. All these changes may affect temporary pond hydrology as well as the reproductive success and breeding phenology of toads.  相似文献   

15.
The causes and ecological consequences of alien plant species invasions in the Southern Urals are analyzed. Aggressive invasive species of North American origin??Ambrosia trifida L., A. psylostachya DC., Cyclachaena xanthiifolia (Nutt.) Fresen., Hordeum jubatum L., Oenothera biennis L., Bidens frondosa L., etc.??have invaded synanthropic and natural plant communities and became dominant, with their proportion varying from 10 to 99%. The biomass of these plants may reach 6 kg/m2; density, more than 1000 shoots per square meter; and seed production, up to 30000 seeds per plant, which explains their dominance in communities. The ecological hazard they pose lies in the displacement of native species, overgrowing of disturbed land areas, and allergenicity of their pollen.  相似文献   

16.
This paper empirically examines the terminology used in the titles of corporate social responsibility (CSR)/sustainability reports in Europe. Our data supports the claim of the rise of the sustainability concept in corporate communication in comparison to other concepts. In detail this research analysed CSR/sustainability reports to support Matten and Moon’s [Acad Manage Rev 33(2):404–424, 2008] hypothesis regarding a recent European trend towards a more voluntary and explicit CSR practice. The second and main objective of the research was to describe statistically significant trends in the use of terms and concepts in CSR/sustainability reporting to better understand how European companies interpret CSR and sustainability and how they communicate it to their stakeholders. To this end, a content analysis was conducted on 329 CSR/sustainability reports from 50 leading European companies from Euro Stoxx 50 that were published between the beginning of online CSR/sustainability reporting in 1998 and 2010. Our data analysis clearly indicates that the use of social and environment-related terms occurred more frequently in the past and demonstrates the establishment of sustainability in corporate non-financial reporting. Based on the results of our empirical research, the final discussion explores the development and diffusion of the sustainability concept in both the academic and business fields and examines economic, environmental, and social implications. Different propositions are presented to explain the recent rise of the sustainability concept in European CSR/sustainability reporting, adding to the formation of sustainability as a concept and as a science.  相似文献   

17.
Sustainable Development: The Need for a New Paradigm   总被引:3,自引:2,他引:1  
At present, the term sustainable development is misleading because we actually live in a markedly unsustainable world and conditions will become even more unsustainable in the 21st century. Indeed, the 21st century will be the defining period in man's occupation of this planet. Either we take very positive steps to ameliorate our environmental excesses now or we face the prospect of major environmental catastrophes in the future. It is a fact that advanced civilizations have collapsed twice within the last 5000 years in Europe and we must face up to the fact that a third collapse, this time on a global scale, is not beyond the realms of possibility. It is therefore up to us to begin using our considerable ingenuity to prepare for the future in a more rational manner than is presently the case. This article demonstrates clearly the dilemma that we now face.  相似文献   

18.
中国东部季风区末次冰期以来古气候模拟   总被引:5,自引:0,他引:5  
通过对我国东部季风区现代青土样品孢粉组合与气候因子间的回归分析,分别建立了孢粉组合与一月,七月气温和年降水量的转换函数,进而建立了本区末次冰期以来的孢粉-气候数据库,模拟末次冰期盛冰期,消冰期,全新世前北方期-北方期,大西洋期,亚北方期等五个古气候期的冬季和夏季温度场,降水场。  相似文献   

19.
Current trends in organic agriculture have led to the need of seeking alternative methods of pest control. For that reason the influence of weather conditions, some morphological and chemical traits of common vetch (Vicia sativa) cultivars–“Liya”, “Loryna”, “Villena”, “Moldavskaya 82” (Moldovan cultivars) and “Obrazets 666” (Bulgarian cultivar), and hairy vetch (V. villosa)–“Violeta” and “Viola” [Moldovan cultivars]) on the dynamic and preference of Acyrthosiphon pisum were determined. Moldovan cultivars belonging to V. sativa were distinguished by lower aphid numbers as they had shorter duration of the flowering period unlike the V. villosa cultivars, where that duration was significantly longer. The plant morphological traits as height, branch, flower and leaflet numbers influenced on the aphid density. The aphid density was affected by branch and leaflet numbers more than by height and flower plant. “Villena” had a shorter vegetative period, lowest flower and leaflet numbers as well as low nitrogen and phosphorus content, which resulted in the lowest A. pisum population. The use of vetch cultivars with some characteristics of tolerance would result in a reduction of losses due to pea aphids. That will provide an environmentally safer option for aphid control.  相似文献   

20.
Health has been the main driver for many urban environmental interventions, particularly in cases of significant health problems linked to poor urban environmental conditions. This paper examines empirically the links between climate change mitigation and health in urban areas, when health is the main driver for improvements. The paper aims to understand how systems of urban governance can enable or prevent the creation of health outcomes via continuous improvements in the environmental conditions in a city. The research draws on cases from two Indian cities where initiatives were undertaken in different sectors: Surat (waste) and Delhi (transportation). Using the literature on network effectiveness as an analytical framework, the paper compares the cases to identify the possible ways to strengthen the governance and policy making process in the urban system so that each intervention can intentionally realize multiple impacts for both local health and climate change mitigation in the long term as well as factors that may pose a threat to long-term progress and revert back to the previous situation after initial achievements.  相似文献   

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