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1.
Aboveground biomass in Tibetan grasslands   总被引:2,自引:0,他引:2  
This study investigated spatial patterns and environmental controls of aboveground biomass (AGB) in alpine grasslands on the Tibetan Plateau by integrating AGB data collected from 135 sites during 2001–2004 and concurrent enhanced vegetation index derived from MODIS data sets. The AGB was estimated at 68.8 g m?2, with a larger value (90.8 g m?2) in alpine meadow than in alpine steppe (50.1 g m?2). It increased with growing season precipitation (GSP), but did not show a significant overall trend with growing season temperature (GST) although it was negatively correlated with GST at dry environments (<200 mm of GSP). Soil texture also influenced AGB, but the effect was coupled with precipitation; increased silt content caused a decrease of AGB at small GSP, and generated a meaningful increase under humid conditions. The correlation between AGB and sand content indicated an opposite trend with that between AGB and silt content. An analysis of general linear model depicted that precipitation, temperature, and soil texture together explained 54.2% of total variance in AGB. Our results suggest that moisture availability is a critical control of plant production, but temperature and soil texture also affect vegetation growth in high-altitude regions.  相似文献   

2.
Environmental inequality scholarship has paid little attention to the disproportional exposure of immigrants in the United States (U.S.) to unfavorable environmental conditions. This study investigates whether new international migrants in the U.S. are exposed to environmental hazards and how this pattern varies among immigrant subpopulations (e.g., Hispanics, Asian, European). We combine sociodemographic information from the American Community Survey with toxicity-weighted chemical concentrations (Toxics Release Inventory) to model the relationship between toxin exposure and the relative population of recent immigrants across Public Use Microdata Areas (PUMAs, n = 2054) during 2005–2011. Results from spatial panel models show that immigrants tend to be less exposed to toxins, suggesting resilience instead of vulnerability. This pattern was pronounced among immigrants from Europe and Latin America (excluding Mexico). However, our results revealed that Mexican immigrants are disproportionately exposed to environmental hazards in wealthy regions.  相似文献   

3.
This paper examines new North European immigration into two Mediterranean regions and identifies the characteristics of North European entrepreneurs who work in small tourist businesses. Data used for analyses were gathered from 169 questionnaires addressed to small tourism firms and other tourism-related businesses in Cataluna (Spain) and Languedo (France). Also, the North European entrepreneurs are examined within the context of new migration flows into South European regions from the north of the continent. As for the reasons for moving to these South European regions, company formation and the style of running the businesses are found to be less motivated by the need for work than by lifestyle considerations. The results suggest that international migration theory offers little to explain these new migratory flows.  相似文献   

4.
"The chief objective of the present paper is to comprehend the broad spatial patterns of internal migrations in India." Aspects considered include data constraints, the magnitude of internal migration, interstate migration, migration to rural and to urban destinations, spatial patterns, and areas of origin and destination.  相似文献   

5.
Biodiversity and conservation in the Tibetan Plateau   总被引:1,自引:0,他引:1  
The Tibetan Plateau (Qinghai-Xizang Plateau) is a unique biogeographic region in the world, where various landscapes, altitudinal belts, alpine ecosystems, and endangered and endemic species have been developed. A total of 26 altitudinal belts, 28 spectra of altitudinal belts, 12,000 species of vascular plant, 5,000 species of epiphytes, 210 species of mammals, and 532 species of birds have been recorded. The plateau is also one of the centers of species formation and differentiation in the world. To protect the biodiversity of the plateau, about 80 nature reserves have been designated, of which 45 are national or provincial, covering about 22% of the plateau area. Most of the nature reserves are distributed in the southeastern plateau. Recently, the Chinese government has initiated the “Natural Forests Protection Project of China,” mainly in the upper reaches of the Yangtze and Yellow rivers. “No logging” policies have been made and implemented for these areas.  相似文献   

6.
Biodiversity and conservation in the Tibetan Plateau   总被引:1,自引:0,他引:1  
The Tibetan Plateau (Qinghai-Xizang Plateau) is a unique biogeographic region in the world, where various landscapes, altitudinal belts, alpine ecosystems, and endangered and endemic species have been developed. A total of 26 altitudinal belts, 28 spectra of altitudinal belts, 12,000 species of vascular plant, 5,000 species of epiphytes, 210 species of mammals, and 532 species of birds have been recorded. The plateau is also one of the centers of species formation and differentiation in the world To protect the biodiversity of the plateau, about 80 nature reserves have been designated, of which 45 are national or provincial, covering about 22% of the plateau area. Most of the nature reserves are distributed in the southeastern plateau. Recently, the Chinese government has initiated the “Natural Forests Protection Project of China,” mainly in the upper reaches of the Yangtze and Yellow rivers. “No logging” policies have been made and implemented for these areas.  相似文献   

7.
8.
Some variation in the growth rates of towns is more or less a universally accepted phenomenon. But why some towns are not even able to sustain the population added due to natural increase in an overall rapidly urbanizing environment is the central theme of this paper. An analysis of slow growing towns in India, conducted at both macro- and micro-levels, reveals that 1) the slow growing towns are concentrated in a few states which are characterized by a high urbanization level; 2) practically all of them have suffered net out-migration, barring those whose slow growth was due to reduction in the territorial jurisdiction; and 3) their slow growth is attributed to a low administrative status, poor transport, connectivity, inadequate developmental efforts, and the fast growth of nearby towns. (author's)  相似文献   

9.
Apart from a generalized discussion on the trends of population growth in India during the post-Independence decades and its socio economic implications, this paper examinies in some detail the spatal patterns of population change in India during 1971-1981. The discussion is mainly based on what has emerged on 3 maps depicting percentage change in general and rural and urban population change in India during this decade. While areas of rapid growth of population continue to be associated with net in-migration resulting from: 1) the development of manufacturing industries, mining, trade, and miscellaneous services, all leading to acceleration in the process of urbanization, 2) the development of irrigation and reclamation of land bringing about increased intensity and extension in farming, and 3) infiltration from neighboring countries, particularly from Bangladesh. The areas of relatively low growth are mostly those which have suffered net out-migration induced by pressure of population and paucity of resources or a desire to seek better avenues of employment elsewhere. Superimposed on this is the new trend of declining rate of natural increase, such as in Kerala and Tamil Nadu, which has played its own role in bringing down the overall growth rate. Likewise there are areas, such as in Uttar Pradesh, Bihar, and Rajasthan, where recent breakthroughs in the mortality rate, with the birth rate staying at a high level, has stepped up the process of demographic dynamism. A comparison of the spatial patterns of 1971-1981 with those witnessed in precious decades brings out important chnges in these patterns which are occurring as a result of the various areas of the country getting into different phases of the second stage of the "demographic transition." With a view to bringing the benefits of socioeconomic progress to the door steps of all sections of the society in all parts of the country, it is necessary to bring about a substantial decline in the birth rate without any further loss of time.  相似文献   

10.
"This paper explores the ?borderline community of migration'.... The placing of migrant identities is examined in the context of Hong Kong immigrants in Britain and Canada. Changes in identity and the meaning of the multiplicity of migrant identities are explored through interview material. The tensions between the multiple facets of migrants' identities reflect the sociopolitical relationships within and between places. The resolution of these tensions is partially revealed in the hybridity and fluidity of migrants' articulation of their identities, whilst maintaining a primary identification with their culture of origin."  相似文献   

11.
The field of population geography was first introduced during the 1960s in India and advanced under the direction of Gosal at the Punjab University. Teaching and research in population geography were introduced by Chandigarh at Punjab University, which today is the main center of research activity. Population geography in India has followed the main tenets of geography in general and is based on spatial perspectives. Deficits are apparent in the paucity of research on socioeconomic implications of spatial distributions, but there is infrastructural feedback to support theory development. Theoretical advances moving from theory to fact or from empirical fact to theory are limited. Comprehensive training in methodology and quantitative techniques is needed for further development of population theory: multivariate analysis, factor analysis, principal component analysis, model building, hypothesis testing, and theory formulation. Methodological sophistication will also help in understanding and interpreting the diverse and complex Indian demographic situation. The analysis of population geography in the Indian spatial, cultural, political, and historical context may be applied to other less developed countries of similar sociocultural background. The Indian Census has contributed over the 100 years of its existence reliable and efficiently produced data on a wide variety of measures at assorted scales down to the village level. Field work among geographers has not achieved a level of development commensurate with population censuses. Recent doctoral research has focused on qualitative studies of local situations. Research topics range from the distribution and structure of population, mortality, fertility, and migration to peripheral issues of social segregation. Popular topics include urbanization, labor force, sex composition, literacy, and population growth. Distribution of population and density studies have amounted to only 2 in 30 years. Population texts are in abundance. The Punjab University is the headquarters of the Association of Population Geographers, which publishes the journal "Population Geography." Many advances are still needed in a timely fashion.  相似文献   

12.
青藏高原城镇化与生态环境交互影响关系分析   总被引:3,自引:2,他引:3  
冯雨雪  李广东 《地理学报》2020,75(7):1386-1405
科学评估青藏高原城镇化与生态环境交互影响的总体状况,对优化城镇化速度和质量,修复和提升生态环境状态具有重要意义。在梳理青藏高原城镇化与生态环境交互影响研究进展基础上,本文尝试构建一套完整的城镇化与生态环境交互影响分析模型体系,实现从综合评价指数分析、耦合协调度量化、耦合类型识别、解耦路径探索到未来趋势预测的全过程解析。以青藏高原及其省域、地级单元多尺度分析对比为手段,尝试厘清尺度之间的差异性,识别出问题区域,并提出针对性的改进措施。研究发现,青藏高原不同尺度间城镇化综合评价指数呈阶段性上升趋势,青海的整体城镇化指数高于西藏;生态环境指数变化趋势不同,青海呈下降态势,西藏则趋向平稳,各地级单元生态环境指数存在分层现象。青藏高原不同尺度城镇化与生态环境耦合协调度总体呈上升趋势,协调类型由失调衰退类向濒临失调衰退类转变,最后转为勉强协调发展类,基本属于城镇化滞后型。城镇化指数与生态环境指数呈现出强脱钩、弱脱钩交互出现的波动态势,说明不同尺度间存在城镇化与生态环境的负相互作用,消极城镇化现象突出。通过预测,青藏高原各地级单元在未来10年内,系统耦合协调度将稳步上升,但各地增长速度将存在显著差距。  相似文献   

13.
青藏高原古地理环境研究   总被引:21,自引:2,他引:21  
本文综述了最近 5 0年青藏高原古地理演化中一些基本问题研究进展。分析了中新世~上新世青藏古地理环境 ,高原在 3 6MaBP海拔不超过 10 0 0m ,此后强烈隆升。青藏高原最近三次冰期年代分别为 72 5~ 5 81、 2 89~ 136、 82~ 10kaBP ,冰期中不存在“大冰盖”。高原晚新生代重大古地理演化阶段和事件为 :38~ 2 2MaBP行星风系控制的热带 亚热带低地、 2 2~3 6MaBP古季风出现与主夷平面发育、 3 6~ 1 7MaBP高原强烈隆升与现代季风形成和现代河谷发育、 1 1~ 0 6MaBP高原抬升进入冰冻圈与大冰期出现、 0 15MaBP以来强烈隆升与高原内部干旱化。本文还讨论了高原古地理尚需深入研究的一些重大问题  相似文献   

14.
青藏高原主要生态系统净初级生产力的估算   总被引:35,自引:2,他引:35  
利用青藏高原贡嘎山、海北、五道梁、拉萨等4个野外台站2000~2002年的观测数据、陆地生态系统模型与2001年MODIS遥感数据相结合的方法来估算青藏高原区域的净初级生产力。结果表明:青藏高原区域的净初级生产力空间分布趋势表现出由东南向西北逐渐递减的梯度,该趋势也与水热梯度表现基本一致;整个青藏高原的净初级生产力为302.44×1012 gC yr-1,其中森林的净初级生产力最高,120.11×1012 gC yr-1,占整个高原净初级生产力的39.7%;全年中夏季(6~8月) 的净初级生产力最高,246.7×1012 gC yr-1,约占全年总净初级生产力的80%。用实测数据验证模拟结果表明,二者非常相符。  相似文献   

15.
"The present endeavour has an emphasis on analysing distributional patterns of some...population characteristics [in India] as a case perceived at the physiographic-regional level, that is to say, the variability of population characteristics over different natural environments as well as within a similar physical entity. Specifically it aims at analysing the pattern of population density, growth, urbanisation level and literacy varying from one physiographic region to [another] and the relationship of these four variables with each other at the same level of regional structure."  相似文献   

16.
日本在中国、印度投资的比较   总被引:1,自引:1,他引:0  
近年来,中国和印度的崛起成为全球热点。根据2007年世界银行计算,中、印已分别成为世界第四大和第九大经济体。“关注中国和印度”已成为世界性的课题,欧美发达国家跨国公司纷纷在加快进入中国、印度市场的投资步伐。作为同是亚洲近邻的日本跨国公司更是不甘落后,在对华、对印投资的时机、方式和区位选择上既存在许多共性,更多的是寻求不同点和差异性,以期达到规避投资风险,实现投资效益最大化的目的。  相似文献   

17.
18.
"The main objective of the present paper is to discern the changing pattern of regional disparities in demographic development in India. The analysis pertains to the 1971-81 decade using district level data. Indicators have been selected from the demographic components of urbanisation, literacy and occupational dynamism."  相似文献   

19.
Feng  Yuxue  Li  Guangdong 《地理学报(英文版)》2021,31(2):298-324
A scientific evaluation of the broad reciprocal influences between urbanization and the eco-environment in the Tibetan Plateau region is of great significance for increasing the speed and quality of urbanization as well as restoring and improving the eco-environment.Based on a thorough look at the progress made by research on interactions between ur-banization and the eco-environment in the Tibetan Plateau region,this article attempts to construct a complete analytical model of the reciprocal influences that can achieve the whole process of analyzing evaluation indexes,quantifying coupling coordination,identifying cou-pling types,exploring decoupling paths,and predicting future trends.Using multi-scale analysis of the Tibetan Plateau and its provinces and prefecture-level units as a means of comparison,we attempt to clarify differences at different scales,identify problem areas and propose targeted improvement measures.The result shows that the urbanization evaluation indexes for the Tibetan Plateau at different scales rise in stages and that the urbanization index for Qinghai is higher than for Tibet;the changes in the eco-environment index of the two regions are also different,with a downward trend in Qinghai and a trend toward stability in Tibet,and with stratification in the eco-environment indexes of prefecture-level units;the de-gree of coupling coordination between urbanization and the eco-environment at different scales in the Tibetan Plateau region is increasing overall,with the type of coordination changing from uncoordinated deterioration to borderline uncoordinated deterioration,and ultimately changing into scarcely coordinated development,which basically puts the region into the logging urbanization category;and the urbanization and eco-environment indexes display a dynamic trend of alternating between strong decoupling and weak decoupling,in-dicating that there is a negative reciprocal influence between urbanization and eco-environment at different scales and that the phenomenon of passive urbanization is prominent.We predict that in the next 10 years,the system coupling coordination of prefec-ture-level units in the Tibetan Plateau region will steadily increase,but there will be significant discrepancies in the growth rates of different regions.  相似文献   

20.
Land use change is the result of the interplay between socioeconomic, institutional and environmental factors, and has important impacts on the functioning of socioeconomic and environmental systems with important tradeoffs for sustainability, food security, biodiversity and the vulnerability of people and ecosystems to global change impacts. Based on the results of the First Land Use Survey in Tibet Autonomous Region carried out in the late 1980s, land use map of Lhasa area in 1990 was compiled for the main agricultural area in Lhasa valley using aerial photos obtained in April, May and October 1991 and Landsat imagery in the late 1980s and 1991 as remotely sensed data sources. Using these remotely sensed data, the land use status of Lhasa area in 1991, 1992, 1993, 1995, 1999 and 2000 were mapped through updating annual changes of cultivated land, artificial forest, grass planting, grassland restoration, and residential area and so on. Land use map for Lhasa area in 2007 was made using ALOS AVNIR-2 composite images acquired on October 24 and December 26, 2007 through updating changes of main land use types. According to land use status of Lhasa area in 1990, 1995, 2000 and 2007, the spatial and temporal land use dynamics in Lhasa area from 1990 to 2007 are further analyzed using GIS spatial models in this paper.  相似文献   

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