首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到13条相似文献,搜索用时 0 毫秒
1.
Wetland stores substantial amount of carbon and may contribute greatly to global climate change debate. However, few researches have focused on the effects of global climate change on carbon mineralization in Zoigê al-pine wetland, Qinghai-Tibet Plateau, which is one of the most important peatlands in China. Through incubation ex-periment, this paper studied the effects of temperature, soil moisture, soil type (marsh soil and peat soil) and their in-teractions on CO2 and CH4 emission rates in Zoigê alpine wetland. Results show that when the temperature rises from 5℃ to 35℃, CO2 emission rates increase by 3.3-3.7 times and 2.4-2.6 times under non-inundation treatment, and by 2.2-2.3 times and 4.1-4.3 times under inundation treatment in marsh soil and peat soil, respectively. Compared with non-inundation treatment, CO2 emission rates decrease by 6%-44%, 20%-60% in marsh soil and peat soil, respec-tively, under inundation treatment. CO2 emission rate is significantly affected by the combined effects of the tempera-ture and soil type (p < 0.001), and soil moisture and soil type (p < 0.001), and CH4 emission rate was significantly af-fected by the interaction of the temperature and soil moisture (p < 0.001). Q10 values for CO2 emission rate are higher at the range of 5℃-25℃ than 25℃-35℃, indicating that carbon mineralization is more sensitive at low temperature in Zoigê alpine wetland.  相似文献   

2.
Variations in leaf functional traits of Abies georgei var. smithii at 3700, 3900, 4100, 4300, and 4390 m altitude were investigated in 15 typical plots in the Southeastern Tibetan Plateau. In each plot, three seedlings were selected, of which functional leaves in current-year sunny branches were chosen for the measurement of morphological, photosynthetic, and physiological and biochemical characteristics, and their variations were analyzed. Results showed that significant variations existed among the leaf functional traits of A. georgei var. smithii along the altitudinal gradient, as well as their physiological adaption indicators. Leaf area decreased, while the mass per area and thickness of leaf increased at an altitude above 4,100 m. The maxima of pigment, total nitrogen concentration, net photosynthesis rate during light-saturated, and when water use efficiency appeared at 4100 m altitude. In addition, A. georgei var. smithii seedlings regulated the activities of superoxide dismutase and ascorbate peroxidase to resist abiotic stress under 4100 m altitude. Meanwhile, malondialdehyde concentration and the dark respiration rate rapidly increased, which indicates that A. georgei var. smithii seedlingssuffered from heavy abiotic stress from 4100 m to 4390 m altitude. Basing on variations in leaf functional traits along the altitude gradient, we inferred that 4100 m altitude was the suitable region for A. georgei var. smithii growth in the Sygera Mountain. Moreover, the harsh environment was the main limiting factor for A. georgei var. smithii population expansion to high altitude.  相似文献   

3.
Line integral convolution(LIC) is a useful visualization technique for a vector field. However, the output image produced by LIC has many problems in a marine vector field. We focus on the visual quality improvement when LIC is applied in the ocean steady and unsteady flow field in the following aspects. When a white noise is used as the input in a steady flow field, interpolation is used to turn the discrete white noise into continuous white noise to solve the problem of discontinuity. The "cross" high-pass filtering is used to enhance the textures of streamlines to be more concentrated and continuity strengthened for each streamline. When a sparse noise is used as the input in a steady flow field, we change the directions of background sparse noise according to the directions of vector field to make the streamlines clearer and brighter. In addition, we provide a random initial phase for every streamline to avoid the pulsation effect during animation. The velocities of vector field are encoded in the speed of the same length streamlines so that the running speed of streamlines can express flow rate. Meanwhile, to solve the problem of obvious boundaries when stitching image, we change the streamline tracking constraints. When a white noise is used as an input in an unsteady flow field, double value scattering is used to enhance the contrast of streamlines; moreover, the "cross" high-pass filtering is also adopt instead of two-dimensional high-pass filtering. Finally, we apply the above methods to a case of the surface wave field in typhoon condition. Our experimental results show that applying the methods can generate high-quality wave images and animations. Therefore, it is helpful to understand and study waves in typhoon condition to avoid the potential harm of the waves to people's lives and property.  相似文献   

4.
《山地科学学报》2021,18(10):2698-2721
Rosa arabica Crép. is a perennial shrub belonging to the family Rosaceae. It is endemic to the high mountain area of St. Catherine Protected Area(SCPA) in southern Sinai, Egypt, and is listed as one of the most 100 threatened plants in the world. Recently, it has been listed as critically endangered by IUCN Red List due to its small extent of occurrence and tiny population size. We reported the continuous decline in habitat quality for this species and the urgent need to carry out on-ground conservation actions. So, this research aims to conserve Rosa arabica through in situ practices by implementing the following steps, respectively: a) evaluate the current conservation status through IUCN Red List to extract the environmental factors controlling the species' distribution necessary for establishing the recovery program, b) determine the potential species habitat suitability under the current climate conditions using Maxent, and c) based on the previous two steps, the translocation process for R. arabica in the suitable habitat will be done after the simple layering process as one of the most effective traditional vegetative methods for wild cultivation for this species. These steps aimed to reduce the impact of threats and the risk of extinction through increasing the population size, the Extent of Occurrence(EOO), and the Area of Occupancy(AOO). We extracted the environmental factors controlling the target species' distribution and habitat suitability range using the IUCN Red List assessment and Species Distribution Model(SDM). The most suitable habitat for R. arabica is predicted in the middle northern parts of SCPA, with the highest suitability in the High Mountains. Precipitation of driest quarter, precipitation of wettest month, precipitation of coldest quarter, and aspect are the highest mean contributors determining the distribution of R. arabica in SCPA. Rosa arabica potential distribution covers 324.4 km2(7.46%) of the total SCPA area(4350 km2). This area is divided into: 18.1 km2 high probability, 124.3 km2 moderate probability, and 182 km2 low probability. After one year of the simple layering process, ten branches rooted and were translocated into three sites that had been previously identified to cover three habitat suitability ranges(high, moderate, and low suitability). After a year of translocation in the wild, the survival rate ranged from 66% to 100%, the geographical range increased by 65%, and the population size by 6.8%. Therefore, if the new individuals continue to grow and adapt it may lead to the expansion of other environmental factors such as climatic and topographical factors that probably increase the resilience of the global population of the species to adverse events. Detailed information is provided in this research about the recovery program, from planning to implementation and monitoring, and recommendations for best practices.  相似文献   

5.
《山地科学学报》2020,17(1):42-49
In the alpine regions of Hindu Kush,Himalayas and Karakorum, climatic and topographic conditions can support the formation of peat,important for the livelihood of the local communities,and ecological services alike. These peatlands are a source of fuel for the local community, habitat for nesting birds, and water regulation at source for rivers.Ground-based surveys of high-altitude peatlands are not only difficult, but also expensive and time consuming. Therefore, a method using cost-effective remote sensing technology is required. In this article we assessed the distribution and extent of highaltitude peatlands in a 2000 ha area of Broghil Valley using Landsat 8 data. The composite image was trained using a priori knowledge of the area, and classified into peatland and non-peatland land covers using a supervised decision tree algorithm. The Landsat-based classification map was compared with field data collected with a differential GPS. This comparison suggests 82% overall accuracy, which is fairly high for high altitude areas. The method was successfully applied and has the potential to be replicated for other areas in Pakistan and the highaltitude regions of the neighbouring Asian countries.  相似文献   

6.
Achieving sustainable livelihood is the ultimate goal of poverty alleviation efforts in mountainous areas,and selecting an optimal livelihood strategy for different poverty-type farmers greatly improves farmers’livelihood capital,resists livelihood risks,and promotes sustainable development.For farmers,optimal livelihood strategy means better employment opportunities,higher family income(or better income structure),and stronger employability or development potential.This paper classifies different types of farmers’poverty on the basis of a quantitative evaluation of farmers’livelihood capital in the Qin-ba Mountain Area in South-Shaanxi by using the k-means clustering method and subsequently the fuzzy evaluation method to evaluate the effectiveness of farmers’livelihood strategies.Then,the multi-attribute decision-making model is used to analyze the selection of optimal livelihood strategies for different poverty-type farmers.The results suggest a significant difference in the selection of the optimal livelihood strategy for different poverty-type farmers.Farmers without financial and human capital choose to"go out to work,"farmers lacking natural capital choose to"acquire social insurance and government relief,"farmers without physical capital choose to"use loans,"and farmers lacking social capital choose to"use savings."Studying the selection of optimal livelihood strategies for different poverty-type farmers can help to propose targeted sustainable livelihood optimization programs for farmers and accelerate efforts to overcome poverty in mountainous areas.  相似文献   

7.
Communities in developing country mountain areas, in part due to their remoteness, find themselves excluded from social, political and economic systems; and excluded from access to resources. This paper aims to study the impact of information and communication technologies (ICTs) on remoteness and exclusion. It utilises two models - the resource movement framework, and the "information chain" - to analyse a telecentre in one district of mountainous Huancavelica, Peru's poorest region, set in the high Andes. It finds ICTs enabling new and positive resource flows for the two key user groups: teenaged school students and young farmers. These help to maintain social networks. They also support information searches that have improved agricultural practice where other information chain resources have been available. But non-use and ineffective use of the telecentre are found where information chain resources are lacking. ICTs have some impacts on intangible elements of remoteness. In this particular example, they also offer access to some previously-excluded resources. But they have not really addressed the systematic exclusions faced by mountain communities. And they so far appear to be a technology of inequality; favouring those residents who begin with better resource endowments. The paper concludes by offering some recommendations for mountain ICT project practice.  相似文献   

8.
In China, community tourism is still a relatively new phenomenon, but the villagers of a small Qiang village in the Qiang Autonomous County of Beichuan in Southwestern Sichuan have initiated tourism in a way which conforms to the basic theory of community tourism development. This demonstrates that community tourism possesses a strength and vitality that can promote the development of tourism in the rural and mountainous areas. In the district of Zhenghe Village, the tourism industry, based on the community tourism model, is the mainstay of its economy. The practice of community tourism in the village not only promotes the economic development of the village community, but also leads to the protection of the mountainous natural environment and of the culture of the Qiang people. This paper investigates the development process of community tourism in Zhenghe and shows how the local residents participate in this process. It also looks at how profits have been distributed within the community. It demonstrates that community tourism is a correct choice by the Zhenghe people as they have dearly been moving from poverty to prosperity, while the local ecology and environment have been simultaneously protected. The authors hope that other minority villages with similar local conditions and natural resources will be able to use this example to develop their own community tourism.  相似文献   

9.
The reasonable development and utilization of mountainous regions closely relates to local economic development and ecological security. The wine production region in the eastern foothills of the Helan Mountains in Ningxia, Ningxia Hui Autonomous Region, with its excellent terroir, is emerging as one of China’s three major geographical attractions. Based on surveys of tourism resources and spatial analysis for this wine producing region, we propose a highly representative and practicable path for wine tourism development. Based on China’s national standard in Classification, Investigation and Evaluation of Tourism Resources (GB/T 18972-2003), which recommended the types and grades of tourism resources in one area, we conduct an analysis of resource characteristics and the current state of development. Using ArcGIS software, spatial autocorrelation analysis, average nearest neighbor analysis, as well as clustering and outlier analysis, we are able to derive the spatial distribution characteristics of tourism resources. Our survey showed that tourism resources in this area are relatively abundant and have good quality and clear combination advantages. Nonetheless, there are resources shortage for wine tourism and poor integration of wine production with the tourism industry. Regarding the spatial distribution of resources, we revealed the current states of and issues surrounding regions with concentrated resources, as well as characteristics of this clustering. Finally, we proposed a development path for wine tourism in this region based on the five dimensions of management mode, industrial path, product development, spatial optimization, and market development.  相似文献   

10.
Hydrothermal fluid containing abundant matter erupts from seafloor, meets ambient cold seawater and forms chimneys. So the main matter origins of chimneys are seawater and matter which are taken by hydrothermal fluid from deep reservoir. However, because of seawater’s little contribution to the forming of chimneys, it is usually covered by the abundant matter which is taken by hydrothermal fluid. Therefore, chimneys formed in ordinary deep seawater hydrothermal activity, containing complex elements, cannot ...  相似文献   

11.
A stratus-sea fog event that occurred over the Yellow and East China Seas on 3 June 2011 is investigated using observa-tions and a numerical model, with a focus on the effects of background circulation and Sea Surface Temperature Front (SSTF) on the transition of stratus into sea fog. Southerly winds of a synoptic high-pressure circulation transport water vapor to the Yellow Sea, creating conditions favorable for sea fog/stratus formation. The subsidence from the high-pressure contributes to the temperature inversion at the top of the stratus. The SSTF forces a secondary circulation within the ABL (Atmospheric Boundary Layer), the sink-ing branch of which on the cold flank of SSTF helps lower the stratus layer further to reach the sea surface. The cooling effect over the cold sea surface counteracts the adiabatic warming induced by subsidence. The secondary circulation becomes weak and the fog patches are shrunk heavily with the smoothed SSTF. A conceptual model is proposed for the transition of stratus into sea fog over the Yellow and East China Seas. Finally, the analyses suggest that sea fog frequency will probably decrease due to the weakened SSTF and the reduced subsidence of secondary circulation under global warming.  相似文献   

12.
People′s environmental tropism has an effect on their understanding of tourism-nature relationship,and also influences their attitudes to natural resources utilization and environmental protection.Taking Jiuzhaigou National Park of China as a study case,the authors conducted some quantitative analyses with the tools of SPSS 16.0 and LISREL 8.7,to explore the influence of tourists′ environmental tropism on their attitudes to tourism and nature conservation in the natural tourist destination.Three hypotheses and the theoretic model of influences of tourists′ environmental tropism on their attitudes to tourism and nature conservation have been tested and accepted based on the Structural Equation Model analysis on survey data collected in Jiuzhaigou National Park of China.Some conclusions were drawn as follows: 1) tourists′ human-prioritized concept influences their cognition to tourism-nature relationship.This concept has a positive influence on their supportive attitudes to tourism,but a negative influence on their attitudes to nature conservation;2) tourists′ human-nature coordination concept has a positive influence on their supportive attitudes to both tourism and nature conservation,especially to the latter.This paper generally proves that human′s environmental tropism does have an influence on their attitudes to tourism and nature conservation in natural tourist destinations.  相似文献   

13.
There have been few in-depth quantitative studies on soil erosion control and the ecological effects of land use changes. Soil erosion is the first eco-environmental problem particularly in mountainous areas. A major problem in the conversion of farmland to forest is to control soil erosion and improve ecological environment and thus to improve land use sustainability. We report results of calculation and analysis on soil erosion from converted farmland parcels in city of Mangshi (near the SW frontier of China) and the surrounding areas before and after the nine-year (2000–2009) project of converting farmland to forest. There was increased water conservation effect, as a result of decreased soil erosion. The average erosion modulus of the farmland returning to eco-friendly uses decreased by 5,535.59 t/km2·a and the control degree of soil erosion modulus reached 71.00%. The increased soil erosion after the returning in the typical sample area “did not drop, but increased” as the terraced fields decreased but sloping farmland increased and yet woodland decreased.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号