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91.
利用1985年和1994年两期土地利用现状图及2003年遥感资料,在ArcGIS 9.0平台上,选取多样性、均匀度、破碎度、分离度和分维数等指数,分析了流沙河上游汉源县宜东乡的景观格局演变特征及其影响因素。结果表明,景观整体多样性指数和均匀度指数增大,优势组分有林地对景观的控制作用不断减弱;景观整体破碎度增大,斑块间离散度增大,景观形状变得较为复杂。影响因素分析表明,集镇和主要公路的影响使得其周围景观的分布以人为景观旱地为主。地形因素中,居民点、水田在坡度15^o以下区域和平地、阴坡上广泛分布;有林地、灌木林和荒草地等景观在15^o以上坡度级分布较广,其中有林地阴坡分布稍高于其余坡向,灌木林分布阳坡多于阴坡,旱地在半阳坡出现分布峰值。  相似文献   
92.
Small-scale mining is more prevalent in India. The maximum production capacity of 50,000 tonnes/year has been accepted as a criterion to Indian small-scale mine. Such mines constitute about 90% of total number of mines, 42% of the total non-fuel minerals and metals, 5% of the fuel minerals. Some 3000 small scale mines account for a work force of about 0.5 million people. Yet this sector is a neglected sector in Indian economy and still considered as an unorganized sector. This paper examines the contribution of small-scale mines to employment and national mineral production, practices, and Indian policy on small-scale mining. It identifies the drawbacks in the existing Government policy and discusses the role of Government for up gradation in this sector. It focuses the need for technical up gradation and to ensure the economic and social infrastructure. It also discusses how the pursuit of sustainable livelihoods, poverty alleviation and indigenous peoples right in artisanal and small-scale mining be more effective when these communities are disadvantaged or neglected by Government policies. This paper concludes that this sector can make significant contribution to Indian economy and employment generation. It recommends that by establishing mining centre consist of shared mining and processing facilities, educating and training related initiatives it can be achieved.  相似文献   
93.
Abstract

On the basis of applying quantitative and qualitative approaches as well as GIS technology, this paper established an index system to make a comprehensive evaluation on socioeconomic development of minority areas in China. The result showed that socio-economic development in minority area presents a series of characteristics that the north is high and the south is low, center-margin pattern is obvious and the areas with middle and lower development indices are distributed centrally and continuously. However, the causes of the socioeconomic characteristics mainly include natural conditions, economic development basic, population cultural quality, regional combination and development conditions of mineral and energy resources, informal institutional factors and distribution of major traffic lines.  相似文献   
94.
根据2000~2020年中国湖泊、河流和河口沉积物中多环芳烃(PAHs)的时空分布,并通过构建结构方程模型和重力模型分析了驱动PAHs时空分布的社会经济因素.结果表明,不同地区沉积物中PAHs含量由高到低依次为:北部沿海>东北>东部沿海>南部沿海>黄河中游>长江中游>西南>西北.南部沿海、长江中游和东部沿海地区高分子量PAHs的比例相对较高,东北、西北、北部沿海和黄河中游地区低环PAHs的比例相对较高.沉积物中PAHs的含量从2000年起逐渐增加,2006年以后逐渐减少,且不同地区沉积物中PAHs含量到达峰值的年份有显著差异.经济发达地区沉积物中PAHs的含量在达到峰值后逐渐下降;发展中地区由于经济发展较快导致污染物积累较快.偏远或欠发达地区PAHs含量逐渐增加,但累积率低于发达地区.城市化和工业化对沉积物中PAHs的影响显著,其中对沉积物中PAHs分布影响最大的因素为经济发展.  相似文献   
95.
A spatially explicit linear, additive model was developed for quantifying site characteristics of riparian areas of the lower Cedar River, Washington, USA. The spatial complexity and distribution of combined habitat and anthropogenic landscape features were used to define habitat indices that indicate the relative quality of riparian habitats. Patches of contiguous grid cells were measured in terms of their locations, sizes, and relative degree of fragmentation. Additionally, intrapatch heterogeneity was measured to identify unique combinations of habitat and anthropogenic factors for individual grid cells within patches. Model verification indicated that existing floodplain riparian habitats received positive indices more than 90% of the time. Mean patch sizes and fragmentation indices were similar for all positive indices throughout the reaches in the valley floor. Among all reaches, reach 7 had the highest number of positive patches due to a higher degree of meandering in this reach. This procedure and model outputs provide unique screening opportunities for prioritizing management of riparian areas (e.g., conservation, restoration and enhancement).  相似文献   
96.
Industrial ecology is sometimes referred to as the science of sustainability, but unlike mature sciences, it has yet to establish reliable modes of inquiry or a uniform framework for dialogue—partly because sustainability is difficult to characterize, and partly because industry–environment interactions are difficult to model quantitatively. A number of sustainability metrics have recently been proposed that partially address the quantification problem, but inevitably oversimplify the problem of sustainability characterization. This paper proposes an overarching taxonomy for classifying the quantitative criteria of sustainability as financial, thermodynamic, environmental, ecological, socio-political or aggregated. Several examples are presented. Pollution potential, which is an environmental metric related to the ideal thermodynamic work (of mixing) per mole required to remove pollutants from the environment, is discussed in particular. However, because no single metric can capture sustainability per se, industrial ecology may be limited to elucidating the trade-offs that exist between different types of complementary (rather than substitutable) criteria. The life cycle of polyurethane foam insulation in freezer applications is presented as a quantitative example of how different environmental criteria can lead to different design recommendations. Lastly, the framework proposed herein suggests a research agenda for industrial ecology, especially regarding the linkages between different measures of sustainability and cross-comparison of the investigative methods found in different sciences related to sustainability.  相似文献   
97.
Aftermath of natural disasters: Coping through residential mobility   总被引:1,自引:0,他引:1  
Belcher JC  Bates FL 《Disasters》1983,7(2):118-128
Most studies of population movement have concentrated on the more developed nations and on trends that have not been influenced by man-made or natural disasters. The experience of developing countries in the Caribbean basin, as studied after the Guatemalan earthquake of 1976 and the impact of Hurricane David in the Dominican Republic of 1979, highlights the importance of socio-economic factors in the decision to make permanent migrations after a disaster, regardless of whether the migrant had personally suffered losses. In many cases the opportunities for personal betterment created by the disaster acted as a catalyst and accelerated a previously-existing trend of migration.  相似文献   
98.
An interdisciplinary course was designed as an introduction to the applications of, and the socio-economic issues associated with, biotechnology. College students enrolled in the course were surveyed prior to the first formal lecture, and again upon completion of the course. Assessment was made of the impact of the educational materials on the attitudes and perceptions of the students toward the applications of biotechnology to agriculture. Data were collected for the first three semesters in which the course was offered. Answers to survey questions were analyzed on a before and after basis. It was found that students were very accepting of biotechnology prior to taking the course, despite a generally low level of exposure to this type of technology. The course was effective in increasing the knowledge base of the students, but not as effective in allaying their perceptions of risks associated with biotechnology.  相似文献   
99.
Abstract:  We examined spatial distributions of fishes native to the lower basin of the Colorado River (25 species) at three scales to determine percent decline from historical distributions based on a regional biodiversity database. We cumulated records from 1843 to 1980 to develop a "historical distribution" for each species and used those occurrences recorded from 1981 to 1998 as "modern" records. We then contrasted historical and modern distributions to (1) quantify losses in spatial distribution; (2) determine how strongly these losses and fragmentation patterns corresponded to the perceived risk of extinction of each species, as represented by its status under the IUCN Red List of Endangered Species; and (3) update extinction risk rankings for 15 fishes endemic to the lower Colorado Basin according to the IUCN criteria. Based on presence and absence data, fish fauna of the lower Colorado Basin have suffered massive distributional losses. On average, ranges of extant species have diminished more than 45% relative to their historical distribution, and 35% of species have lost 50% or more of their occurrences. We provide nine new IUCN rankings and six updates to reflect more accurately the heightened imperilment of these species. Based on our new rankings, 7 of the 15 lower Colorado Basin endemics are critically endangered, 1 is endangered, 2 are vulnerable, and 1 is already extinct. We categorize the remaining 2 endemics as lower risk. This work demonstrates the utility of matching quantitative spatial metrics such as the scale-area slope statistic to extinction risk criteria for species whose persistence is strongly influenced by spatial distribution.  相似文献   
100.
Water demands in arid and semi-arid areas, coupled with increased human populations and concomitant changes in land use, can greatly alter aquatic ecosystems. A good example of this type of system occurs along the eastern slope of the Colorado Rocky Mountains, U.S.A. Long-term macroinvertebrate metric data from the Big Thompson and Cache la Poudre Rivers, Colorado, were collected at one site above, and three sites in and downstream from urban areas. These data were compared both with regional reference and single reference sites in the respective rivers. Using the surrogate variables of potential urban impact (population and housing units), and the environmental gradient represented primarily by chemical factors, it was determined that there was an effect of urban land use that was reflected in the macroinvertebrate assemblages in both rivers. The most robust results were usually seen when regional reference data were used. However, even using only the upstream reference site in either river indicated some negative impacts from the urban areas. The long-term data, particularly in the Cache la Poudre River, showed that water quality has not been getting worse and there is some evidence of a slight improvement in downstream reaches, even with increased urban development.  相似文献   
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