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1.
Soil erosion response to climatic change and human activity during the Quaternary on the Loess Plateau, China 总被引:9,自引:1,他引:8
We review published stratigraphic, archaeological and pedosedimentary evidence in order to reconstruct the history of soil
erosion in China. Documentary evidence of climatic and flood events of the Yellow River and modern hydrological and meteorological
data are synthesised to analyse the history of past human activity and its effects on soil erosion intensity during four nested
periods of time during the Quaternary. The most intensive period of erosion during the Quaternary was in the Holocene. During
the Holocene, intervals of intensive soil erosion occurred at 7500–7000 BP, 200 BCE–0 CE, 1000–1600 CE (Christian era) and
during the 1930s, 1950s and the later part of the 1960s of the last century. Large-scale human activity including warfare
during early Chinese history, population migration, the inner wars in 1930s, the Cultural Revolution and the recent national
campaign to aid soil and water conservation are all closely related to the rate of soil erosion on the Loess Plateau and to
sediment loads in the Yellow River. Overall, soil erosion during the transition from dry-cool to wet-warm climates was more
intense than during wet-warm and cool-dry climatic episodes, but serious accelerated soil erosion has occurred during the
last 2,500 years because of man-induced devastation of vegetation and other anthropogenic disturbance of the environment.
Modern rates of soil erosion on the Loess Plateau are a combination of both intensive natural and human-induced erosions and
are some four times greater than occurred in the geological past. The recent implementation of soil and water conservation
measures has decreased sediment load in the Yellow River by 25%. 相似文献
2.
施少华 《中国人口.资源与环境》1994,4(2):44-48
本文统计分析了历史时期黄河决溢的变化。并从自然和人为因素两方面探讨其原因和规律。认为在湿润的气候时期黄河决溢频率增高,其原因是本地区高强度的暴雨造成了黄土高原严重的水土流失,从而使黄河中下游大量的泥沙沉积。人类特别是小冰期以来加强了对黄土高原的开发,破坏了原先的植被,从而造成了严重的水土流失,这是小冰期以来黄河决溢次数远远高于其它时期的主要原因。作者还认为在下世纪高温环境到来之际,黄河决溢的危险性大大增加。 相似文献
3.
Past and future perspectives upon landscape instability in Cumbria, northwest England 总被引:1,自引:1,他引:0
R. C. Chiverrell 《Regional Environmental Change》2006,6(1-2):101-114
Geomorphic and lacustrine evidence is used to identify phases of landscape instability in Cumbria, northwest England, British
Isles. The temporal and spatial pattern of erosion is used alongside palaeovegetation data from across the region to elucidate
the causes of landscape instability in the late Holocene. The lines of evidence include changes in sediment accumulation rate
and provenance within the region’s lakes; the hillslope alluvial fan and gully incision record; the lowland fluvial geomorphic
record; and pollen analytical data for the late Holocene vegetation history. The sediment supply driven hillslope and lacustrine
records suggest that only the 1,200–800 BP and post 600–500 BP erosion episodes were both catchment-wide and directly affected
upland hillslopes, with the earlier phases after 5,200 and 3,000–1,600 BP on a lower scale and more restricted spatially.
These episodes coincide with major expansions or changes in anthropogenic activity during Neolithic, Iron Age and Romano-British,
Norse and late Medieval times. The projected future trajectories of changes in both climate (UKCIP scenarios) and landuse
(CAP reform and ESA status) appear unlikely to increase landscape instability, although a shift to greater incidence of storms
and high magnitude flood events clearly could. The past shows that the largest increases in erosion and sediment movement
occur in the wake of major intensifications in land pressure that primarily affect previously wooded or protected hillslopes,
circumstances that land management strategists should mitigate against. 相似文献
4.
贵州地区在小冰期的气候环境状况及其对人类活动的影响研究缺乏,综合历史文献资料分析与地质记录的研究仍有待加强。基于1470~1949年贵州地区旱涝历史文献资料重建该区干湿变化序列,然后运用互信息的相关分析方法对此序列进行检验,再通过小波分析探究其干湿变化过程与周期。同时,结合高分辨率石笋δ18O序列、海洋热状况和国家与地方政权的动荡情况,讨论其控制因子及其对人类活动的影响。研究表明:(1)贵州地区15世纪末期气候偏干,16世纪整体较湿润,在经历了17世纪前期的干旱期后,从17世纪中期至20世纪前期为一个长期较稳定的湿润期,与众多古环境研究记录较为吻合;(2)小波分析表明干湿变化具有128~155年、32~55年、11~20年的周期,反映其干湿变化主要受太阳活动控制;(3)贵州地区湿润程度受南亚夏季风强度、ENSO、AMO等因素影响,且对当地政治活动和地表生态环境产生了重要影响。 相似文献
5.
Holocene fire history from the Greater Blue Mountains World Heritage Area, New South Wales, Australia: the climate, humans and fire nexus 总被引:2,自引:1,他引:1
This study presents a reconstruction of the fire activity of the last ~14,200 cal. years BP (before AD 1950) from Gooches Crater Right, located on the Newnes Plateau, approximately 150 km to the west of Sydney (~33°27′S, 150°16′E)
within the Blue Mountains National Park. Charcoal analysis and palynology were undertaken with the aim of untangling any inter-relationship
between climate, humans and fire. A chronology of the site was provided by radiocarbon dating. The dominant control on fire
in this environment during the Holocene appears to be climate. Periods of climate change, identified in previous studies,
are associated with higher levels of fire activity. Fire was less ubiquitous between ~9,000 and 6,000 years BP, a period normally
described as having a higher effective moisture in south-eastern Australia. The mid-Holocene fluctuations in charcoal may
reflect anthropogenic fire, climate forcing or alternatively human responses to any climate change. Coeval changes in palaeoclimatic
sequences elsewhere and palynology at the site support a climatic explanation or that Aboriginal people used fire within a
climatic framework. 相似文献
6.
Using diatoms to assess the impacts of prehistoric, pre-industrial and modern land-use on Danish lakes 总被引:2,自引:1,他引:1
Emily G. Bradshaw Anne Birgitte Nielsen N. John Anderson 《Regional Environmental Change》2006,6(1-2):17-24
The impact of contemporary agriculture on Danish lakes is acknowledged to be extreme. In particular, high loading of nutrients
from agricultural soils contributes to the eutrophic conditions found in many of Denmark’s lakes. Palaeolimnological studies
have shown that human disturbance of the Danish landscape since the introduction of agriculture around 6,000 years ago has
had a major impact on lake ecosystems. The European Union’s Water Framework Directive requires an evaluation of reference
conditions for lakes, the conditions expected with only minimal human impact. Monitoring data and palaeolimnological studies
of Danish lakes demonstrate that many of the most detrimental effects of eutrophication have been experienced in recent decades.
A new study has suggested that the reference status for Danish lakes may be set to the status in ad 1850–1900, probably providing attainable, realistic restoration targets for many sites. The aims of this study were to explore
the impacts of past and contemporary land-use on Danish lakes, and to consider how appropriate the use of 1850 as a date to
define reference status is for these sites. Catchment land-cover data for ad 1800, taken from historical maps, and sedimentary diatom assemblages of the same age, from dated sediment cores, were used
to assess the impact of pre-industrial land-use on 20 Danish lakes. Analysis of contemporary land-cover data and surface-sediment
diatom assemblages for the 20 sites was also made. In-lake total phosphorus (TP) concentrations were estimated using the sedimentary
diatom assemblages and an existing calibration dataset for Danish lakes. The percentage of the lake catchment that was agricultural
land in ad 1800 explained 8.8% of the total variation in the diatom data. The land-cover variables ‘built-up areas’ and ‘plantations’,
together explained 16.9% of the variation in the diatom data for the modern samples. Diatom-inferred TP concentrations were
high for both ad 1800 (mean 112 μg TP L−1) and the present (mean 122 μg TP L−1), the latter estimates reflecting efforts in recent decades to reduce nutrient loading to Danish lakes following very high
levels of nutrient enrichment post-1950. The data presented highlight the impact that human activities 200 years ago, particularly
agriculture, had on Danish lake systems. The long cultural history and major anthropogenic disturbance of the Danish landscape
mean that true reference conditions for lakes (or ‘baseline’ conditions, those found prior to human impacts) can be found
only by considering century to millennial timescales. 相似文献
7.
Masahiko Matsuda 《Environment, Development and Sustainability》2011,13(1):51-64
This study aims to estimate the intensification of rice farming in Myanmar particularly due to chemical fertilizer application,
using farm-level data obtained from field surveys conducted in the 2000s. Relatively high-input rice farming was found in
dry season crop in the delta zone and the double crop in well-irrigated lowlands of the central dry zone. The chemical fertilizer
used there was about 88–159 kg NPK (nitrogen, N; phosphate, P2O5; and potash, K2O) ha−1 (76–110 kg nitrogen (N) ha−1), and the average paddy yield ranged from 2.8 to 3.5 ton ha−1. On the other hand, nutrient input in survey sites of rain-fed lowland was between 11 and 53 kg NPK ha−1 (5 and 36 kg N ha−1), and the yield ranged from 1.1 to 2.3 ton ha−1. The national average of paddy yield and nutrient input of fertilizer was roughly estimated to be around 2.4 ton ha−1 and 60 kg NPK ha−1, respectively. A gap was observed between these calculated values and the official statistics. A comparison of fertilizer
use efficiency for rice production in Myanmar with that in China and Vietnam has shown that the efficiency in Myanmar has
not declined to an inappropriate level even in its intensive ones. Rice production in Myanmar has room for increasing the
yield by capital intensification. Nevertheless, considering its sustainability as well as productivity, further intensification
in rice farming technology in irrigated lowlands of Myanmar may neither be the best nor the only way. 相似文献
8.
WenJun Zhang 《Environment, Development and Sustainability》2008,10(6):717-730
The continuous growth of world population and the intensification of urbanization process create a challenge to environment
quality and sustainable development around the world. In this paper I tried to conduct a forecast analysis of near-future
urbanization related population growth worldwide, based on recent demographic trends. Such an analysis can provide important
insights into the prospects for changes in the size and composition of world population and in urbanization process. Optimal
polynomial functions were used to fit historical trajectories of population dynamics, and the detailed forecasts of the population
mainly over the period 2010–2030 were conducted and analyzed.
If the past pattern continues, world total population would increase to 7.94–8.33 billion in 2030 and the annual growth is
expected to continually decline in the forecast period. Global total population would stop increasing during the period 2050–2060
and would not exceed 9.5 billion in the future. The total population of Africa, Asia, Oceania, South America, North & Central
America would separately increase to 1.35–1.41, 4.86–5.65, 0.04–0.05, 0.44–0.45, and 0.71–0.72 billion in 2030. Europe’s total
population is forecast to decline to 0.64–0.67 billion in 2030.
World’s rural population is expected to grow to the maximum during the period 2015–2020 and would greatly decline after that
period. Global rural population would reach 3.12–3.41 billion in 2030. Rural population in Asia and Africa is estimated to
increase and achieve the maximum around 2025 and decline thereafter. For other regions, the rural population would continually
decline in the forecast period.
Urban population in the world would continually grow and reach 4.72–5.00 billion in 2030, an increase of 48.6–57.8%. However
the annual growth of urban population is expected to increase to the maximum (6.86 million/year) during the period 2020–2025
and then decline in the following years. Urban population is projected to continually grow in all regions excepting Europe.
Europe’s urban population is expected to decline in the period 2010–2030. Urbanization process worldwide, represented by the
ratio urban population versus total population (RUT) and the ratio rural population versus urban population, is expected to
continue during the period 2010–2030. The RUT of the world is projected to reach 0.5 before 2010 and would continue to increase
in the forecast period. Global RUT is estimated to reach 0.56 in 2030. However, the regional patterns of urbanization process
would be diverse. Europe’s RUT is estimated to continually decline in the forecast period and reach 0.68 in 2030. The RUT
for Africa and Caribbean would continually increase before 2030, while the RUTs for Asia and South America are estimated to
achieve their maximums around 2025 and decline in the following years. Oceania and North & Central America would thoroughly
realize urbanization (≈1) during the periods 2020–2025 and 2025–2030. The expansion of world population and urbanization will
continually exert a stronger stress to environment quality and sustainable development in a near future. However we may expect
this situation would start to change from mid-21st century after total population has achieved its maximum.
Readers should send their comments on this paper to BhaskarNath@aol.com within 3 months of publication of this issue. 相似文献
9.
Migration and reclamation in Northeast China in response to climatic disasters in North China over the past 300?years 总被引:5,自引:0,他引:5
Climatic disaster-induced migration and its effects on land exploitation of new settlements is a crucial topic that needs
to be researched to better understand the impact of climate change and human adaptation. This paper focuses on the process
and mechanism of migrant–reclamation in Northeast China in response to climatic disasters over the past 300 years. The research
used comparative analysis of key interlinked factors in this response involving drought/flood events, population, cropland
area, farmer revolts, administrations establishment, and land reclamation policies. It draws the following conclusions: (1)
seven peaks of migrants–reclamation in Northeast China were evident, most likely when frequent climatic disasters happened
in North China, such as the drought–flood in 1851–1859, drought in 1875–1877, and drought 1927–1929; (2) six instances of
policy transformation adopted to cope with extreme climatic events, including distinctive examples like changing to a firm
policy prohibiting migration in 1740 and a subsequent lifting of that prohibition in 1860; and (3) the fast expansion of the
northern agricultural boundary since the middle of the nineteenth century in this area benefited from a climate change trend
from a cold period into a warm period. Altogether, over the past 300 years, extreme climatic disasters in North China have
deepened the contradiction between the limited land resources and the rapidly increasing population and have resulted in migration
and reclamation in Northeast China. Climate, policy, and reclamation constructed an organic chain of response that dominated
the land use/cover change process of Northeast China. 相似文献
10.
Evaluation of carbon stock variation in Northern Italian soils over the last 70 years 总被引:1,自引:0,他引:1
Carbon (C) sequestration in soils is gaining increasing acceptance as a means of reducing net carbon dioxide (CO2) emissions to the atmosphere. Numerous studies on the global carbon budget suggest that terrestrial ecosystems in the mid-latitudes
of the Northern Hemisphere act as a large carbon sink of atmospheric CO2. However, most of the soils of North America, Australia, New Zealand, South Africa and Eastern Europe lost a great part of
their organic carbon pool on conversion from natural to agricultural ecosystems during the explosion of pioneer agriculture,
and in Western Europe the adoption of modern agriculture after the Second World War led to a drastic reduction in soil organic
carbon content. The depletion of organic matter is often indicated as one of the main effects on soil, and the storage of
organic carbon in the soil is a means of improve the quality of soils and mitigating the effects of greenhouse gas emission.
The soil organic carbon in an area of Northern Italy over the last 70 years has been assessed In this study. The variation
of top soil organic carbon (SOC) ranged from −60.3 to +6.7%; the average reduction of SOC, caused by agriculture intensification,
was 39.3%. This process was not uniform, but related to trends in land use and agriculture change. For the area studied (1,394 km2) there was an estimated release of 5 Tg CO2-C to the atmosphere from the upper 30 cm of soil in the period 1935–1990. 相似文献
11.
Luís Costa Kirsten Thonicke Benjamin Poulter Franz-W. Badeck 《Regional Environmental Change》2011,11(3):543-551
Within the changing fire regimes of Portugal, the relative importance of humans and climatic variability for regional fire
statistics remains poorly understood. This work investigates the statistical relationship between temporal dynamics of fire
events in Portugal and a set of socioeconomic, landscape, and climatic variables for the time periods of 1980–1990, 1991–2000,
and extreme fires years. For 10 of 15 districts, it was possible to observe moderate shifts in the significance of fire drivers
for the first two decadal periods. For others, pronounced changes of the significance of fire drivers were found across time.
Results point toward a dynamic (perhaps highly non-linear) behavior of socioeconomic and landscape fire drivers, especially
during the occurrence of extreme fire years of 2003 and 2005. At country level, population density alone explained 42% of
the inter-annual and inter-district deviance in number of fires. At the same temporal and spatial scale, the explanatory power
of temperature anomalies proved to explain 43% of area burnt. We highlight the necessity of including a broad set of socioeconomic
and landscape fire drivers in order to account for potential significance shifts. In addition, although climate does trigger
broad favorable fire conditions across Portugal mainland, socioeconomic and landscape factors proved to determine much of
the complex fire patterns at a subnational scale. 相似文献
12.
P. M. S. Jayathilaka Peeyush Soni Sylvain R. Perret H. P. W. Jayasuriya Vilas M. Salokhe 《Regional Environmental Change》2012,12(1):55-68
Climate change is the main global challenge of this century; it is therefore imperative to identify its effects on agriculture
in developing countries. This research makes spatial assessment of climate change effect on major plantation crops in Sri
Lanka, with emphasis on crop suitability of tea, rubber, and coconut. Geo-referenced maps of spatial and temporal changes
in crop suitability and production potentials are generated and compared. Data pertaining to six agro-ecological zones under
the study area are analyzed for a period of 1980–2007. Crop suitability maps are generated amalgamating yield maps and climatic
factors maps using AHP in multi-criteria analysis under two time frames of 1980–1992 and 1993–2007. Percent change in crop
suitability and crop yield classes is calculated based on five crop suitability and five crop yield classes during two time
frames. Dynamics of climatic parameters and crop yield are recognized using geo-referenced maps. The suitability maps of the
two time frames are compared to identify the changes with each crop in conjunction with changes in the prevailing climate
and yield. Geographic shift of suitability, yield, and climate classes are examined. Net gain or loss in crop production is
quantified. Long-term annual rainfall significantly decreased in mid-country wet zone, whereas the mean temperature of the
study area increased by 1.4°C. Results clearly showed that the climate and yield can be meaningfully related to the crop suitability
and management. 相似文献
13.
Biogeochemistry of Chinese estuarine and coastal waters: nutrients, trace metals and biomarkers 总被引:5,自引:0,他引:5
Jing Zhang 《Regional Environmental Change》2002,3(1-3):65-76
The dissolved and particulate trace metals in large and middle-sized Chinese rivers remain comparable with other less-disturbed
world systems. Levels of nutrients in Chinese rivers are high due to erosion over the drainage area and the application of
chemical fertilizers, which induces an N/P ratio up to 100–1,000. The concentrations of organic pollutants in Chinese rivers
are ranked at the lower end of those of world systems; however, pollution has been identified in coastal waters from north
to south of the country. In estuarine and coastal waters, dissolved trace metals illustrate a feature of remobilization, while
non-conservative distribution is observed, with exceptions for iron and aluminum. Particulate trace metals demonstrate a fairly
stable distribution along the salinity gradient, when the absolute concentration is normalized to reference materials. In
high-turbidity estuaries, seaward nutrient flux can be increased by a factor of 5–10. Finally, the N/P ratio approaches 10–20
at the interior of the East China Sea, indicating that in coastal regions photosynthesis changes from P to N and Si limitations.
Electronic Publication 相似文献
14.
为分析洪泽湖流域洪涝灾害在千年尺度序列上的演变趋势,采用统计历史洪涝记录的方法,分析了气候变化背景下洪涝灾害的响应过程,探讨了洪泽湖流域洪涝灾害同El Ni(n)o事件的关系.结果表明:近1 000 a来洪泽湖流域洪涝灾害的频度总体是趋于上升的,这种变化趋势同气候变化的趋势是一致的.研究结果显示:公元1000~1400年洪涝记录偏少,同我国东部地区尤其是中世纪暖期出现的一次200 a以上的干旱化过程有较好的对应性.1400~1800年是洪泽湖流域洪涝的多发期,这一事实同我国东部1550~1850年小冰期期间总体偏湿的环境特征相一致.分析洪涝灾害变化同El Ni(n)o事件对应性关系表明:在El Ni(n)o事件年及其次年是洪泽湖流域洪涝的多发年份.这可能是由于El Ni(n)o事件通过改变西太平洋副高的强度与位置,以及大气环流形势而引起的降水异常所致.了解洪泽湖流域洪涝的演变趋势及其同El Ni(n)o的关系对于长期防灾减灾策略具有重要的参考意义. 相似文献
15.
Water resources and soil erosion are the most important environmental concerns on the Chinese Loess Plateau, where soil erosion
and sediment yield are closely related to rainfall erosivity. Daily rainfall data from 60 meteorological stations were used
to investigate the spatiotemporal variations in annual rainfall, annual erosive rainfall and annual rainfall erosivity on
the Chinese Loess Plateau during the period 1956–2008. The annual rainfall, erosive rainfall and rainfall erosivity decreased
over the past five decades, as determined by the Mann–Kendall test. A comparison of the annual averaged rainfall, erosive
rainfall and rainfall erosivity from 1980 to 2008 with that from 1956 to 1979 revealed a remarkable spatial difference in
the rainfall trends on the Loess Plateau. Regions of the plateau with major decreases in rainfall were primarily in the Hekouzhen-Longmen
section of the middle Yellow River, especially in the Wuding River basin, the Fenhe basin and the northern-central Shanxi
province, where the annual rainfall and erosive rainfall decreased by more than 10% and the annual rainfall erosivity decreased
by more than 15%. The rainfall erosivity also decreased more than the annual rainfall. Because the annual rainfall has decreased
significantly on the Chinese Loess Plateau over the past 50 years, it is important to better understand the ecological and
hydrological processes affected by this climate change. 相似文献
16.
Birgit Schmook 《Regional Environmental Change》2010,10(3):233-246
Shifting cultivation around the Calakmul Biosphere Reserve of Mexico, part of the Mesoamerican Biological Corridor, appears
to be intensifying temporally through reductions in crop–fallow cycles, with potential impacts on species diversity in the
regenerating forest patches surrounding the reserve. This paper documents the temporal intensity of shifting maize cultivation
in the region and links it to the species diversity found in secondary vegetation of different ages following different crop–fallow
cycles. It finds that younger secondary growth, which is increasing under intensification, has less diversity in species composition.
Simultaneously, the concentration of cultivation practices appears to foster more patches in older and more species-diverse
vegetation. The implications for the preservation of the region’s forest remain uncertain, however, given the spatial concentration
of open lands along two key axes, one which dissects the reserve. 相似文献
17.
Vulnerability and adaptation of European farmers: a multi-level analysis of yield and income responses to climate variability 总被引:6,自引:3,他引:3
Pytrik Reidsma Frank Ewert Alfons Oude Lansink Rik Leemans 《Regional Environmental Change》2009,9(1):25-40
Climate change will affect crop yields and consequently farmers’ income. The underlying relationships are not well understood,
particularly the importance of crop management and related factors at the farm and regional level. We analyze the impacts
of trends and variability in climatic conditions from 1990 to 2003 on trends and variability in yields of five crops and farmers’
income at farm type and regional level in Europe considering farm characteristics and other factors. While Mediterranean regions
are often characterized as most vulnerable to climate change, our data suggest effective adaptation to variable and changing
conditions in these regions largely attributable to the characteristic farm types in these regions. We conclude that for projections
of climate change impacts on agriculture, farm characteristics influencing management and adaptation should be considered,
as they largely influence the potential impacts. 相似文献
18.
Detecting spatiotemporal change of land use and landscape pattern in a coastal gulf region,southeast of China 总被引:1,自引:0,他引:1
Geographic information system (GIS), remote sensing (RS), gradient analysis, and landscape pattern metrics were coupled to
quantitatively characterize the spatiotemporal change of land use and landscape pattern over the period 1988–2007 in a coastal
gulf region, southeast China. The results obtained show an increase in cropland, buildup land, and aquiculture area and decrease
in orchard, woodland, and beach area during 1988–2007. Landscape fragmented processes were strengthened and landscape pattern
structure became more complicated in the last two decades in Luoyuan gulf region. The dynamics intensity of landscape pattern
is stronger during 2002–2007 than that during 1988–2002. Spatial difference of urban–rural landscape pattern can be detected
distinctively in two transects in terms of landscape metrics. Urbanization processes and the policy developed to transfer
seawater into buildup land are two driving forces leading to the spatiotemporal change of landscape pattern in Luoyuan gulf
region in the last two decades. 相似文献
19.
Shanmugam Packialakshmi N. K Ambujam Prakash Nelliyat 《Environment, Development and Sustainability》2011,13(2):423-438
This paper describes the informal groundwater market existing in the urban–peri-urban interface of Chennai. The private water
tanker suppliers and packaged water industries utilize the land and water resources of the peri-urban villages. Thus, the
groundwater sources in peri-urban areas play a significant role in meeting the growing urban demand. The villages that are
experiencing the groundwater market are highly influenced by the urbanization and its related activities, due to their proximity
to the city. The transfer of groundwater from the peri-urban villages not only deprives the peri-urban areas of their water
rights but also leads to environmental damage. Agriculture declined in the water marketed villages in the range of 20–95 per
cent during 1990–2007. The pre-monsoon and post-monsoon groundwater level fluctuation varied from 2–6 m to 0–5 m, respectively,
during 1971–2007. The declining trend of the groundwater table and agriculture is highly significant in the water marketing
villages. Moreover, the present groundwater quality is also in a susceptible state due to over extraction. Hence, strengthening
the legal and institutional framework to ensure an equitable access to water for both urban and peri-urban areas is urgently
required. This paper also describes the characteristics of the groundwater transfer, quantification of the marketed water,
the role of the existing regulatory framework, and the institutional mechanisms. Many stakeholder’s meeting and focus group
discussions have been conducted in the villages under study for understanding the socio-economic implications of the water
market. The study ultimately emphasized a sustainable groundwater extraction/market which will safeguard the interests of
the peri-urban and urban communities. 相似文献
20.
A. J. Plater J. F. Boyle C. Mayers S. D. Turner R. W. Stroud 《Regional Environmental Change》2006,6(1-2):71-85
The limnological record of human impact on catchment land cover and on lake sedimentation during the historical period has
been established for Pinto Lake in Central Coastal California. In addition, the sedimentary record of the ‘pre-impact’ condition
preserves evidence of a climatic control on the nature of lake sedimentation. Chronological marker horizons have been determined
using pollen data in combination with the documented land-use history and introductions of exotic species. Further chronological
data have been determined using 14C and 137Cs. The impact of Mexican and Euro-American immigrants and their ‘imported’ land-use practices is clearly reflected in an
order of magnitude increase in the rate of lake sedimentation to c. 9 kg m−2 year−1 (c. 2 cm year−1) between 1770 and 1850. Here, the occurrence of exotic plant species indicates disturbance as early as c. 1769–1797, whilst
redwood deforestation between 1844 and 1860 represents the most significant human impact. Changes in the nature of sedimentation
prior to this reveal a high degree of sensitivity to changes in precipitation where subtle decreases in lake level and the
supply of runoff-derived mineral matter have resulted in two periods of organic lake sedimentation c. 650–900 and 1275–1750. Set against this background condition of high sensitivity, the dramatic impacts of Euro-American settlement
are unsurprising.
An erratum to this article can be found at 相似文献