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1.
This paper argues that research in political ecology would benefit from more explicit and careful attention to the question of scale and scalar politics. Although political ecologists have extensively considered scale as a methodological question, they have yet to develop an explicit theoretical approach to scale as an object of inquiry. We highlight one principal drawback to this underdeveloped approach to scale: what we call “the local trap” in which political ecologists assume that organization, policies, and action at the local scale are inherently more likely to have desired social and ecological effects than activities organized at other scales. Over the past 10 years or so, an increasingly sophisticated literature on scale has been developing among scholars in geography working in the political economy tradition. This literature has argued that scale is socially produced rather than ontologically given. Therefore, there is nothing inherent about any scale, and so the local scale cannot be intrinsically more desirable than other scales. We suggest that a greater engagement with this scale literature offers political ecology a theoretical way out of the local trap. As a first approximation of the kind of scalar analysis we advocate, we present a case study that examines the scalar politics that have shaped environmental change in the Brazilian Amazon. 相似文献
2.
Artificial recharge with surface water in Jordan has been discussed at length in several reports and papers, but so far this
technique has hardly been applied in the country. This article describes the site selection, design, construction and operation
of four small retention structures in Wadi Madoneh during the period 2003–2009. The catchment (37 km2) is located some 20 km east of Amman in a desert region (average annual precipitation is 160 mm). The project is based on
a feasibility study conducted in the 1990s. It is shown that in the previous study the retention structures have been largely
overdesigned, because of absence of discharge measurements and the negligence of climate change. For this pilot an extensive
hydrological study was carried out, based on historical data and contemporary measurements, to derive design parameters for
small in-channel dams with a height of 3–6 m. The retention structures are designed to retain the floods in order to slowly
release this water for infiltration in the Wadi bed downstream. Four retention structures were installed by a local contractor
in 2007. This study shows that virtually all surface runoff from the catchment has ceased which makes the method very effective
while the costs are low. Artificial recharge with small retention structures is recommended for application on a larger scale
and considered a cheap alternative for other non-conventional water resources supply methods. From experience with vandalism
and interaction with the local community, improvements to the design of the dams are recommended. 相似文献
3.
Wilfried Heller 《GeoJournal》1998,46(3):199-205
This study evaluates some aspects of the socio-economic transformation of rural Romania with reference to the views of representative
organisations (at national, regional and local levels) and other experts. Interviews conducted in ten communes of nine Romanian
counties (‘judete’) focus attention on the advantages and disadvantages of system change experienced since 1989; the most
important problems and constraints for future socio-economic change; and appropriate policies and perspectives for development
in the immediate future. Wherever appropriate the claims of interviewees are substantiated through reference to statistics,
drawn in many cases from Chambers of Commerce & Industry (CCI). Local level representatives presented much more negative views
on recent change than their national and regional level counterparts, but all agreed on the crucial problem of capital shortage.
Thus while specific programmes to assist rural areas are justified, they cannot fully succeed until the national economy is
able to grow more rapidly and attract greater foreign investment.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
4.
土地利用结构与生态过程 总被引：56，自引：0，他引：56
本文从土地利用与土壤水分、土地利用与土壤养分、土地利用与水土流失3个方面系统讨论了土地利用结构与生态过程研究的现状和特征,指出:1)土地利用结构对土壤水分的影响涉及生态系统、坡面、小流域和区域等系列尺度,土地利用的分布及景观特点影响土壤水分的时空变异;2)土地利用对土壤养分的影响表现在土地利用的镶嵌格局影响土壤养分的分布和迁移,土地利用的变化可以引起土壤养分的变化;3)土地利用与水土流失关系密切,土地利用的改变能够减少或增加径流和土壤侵蚀.尺度不同,土地利用与水土流失的机制也不尽相同.土地利用结构与生态过程的研究,还需要注重大尺度和多尺度上的综合研究. 相似文献
5.
《Quaternary Science Reviews》2007,26(15-16):1915-1926
The growing importance of understanding past abrupt climate variability at a regional and global scale has led to the realisation that independent chronologies of past environmental change need to be compared between various archives. This has in turn led to attempts at significant improvements in the required precision at which records can be dated. Radiocarbon dating is still the most prominent method for dating organic material from terrestrial and marine archives, and as such many of the recent developments in improving precision have been aimed at this technique. These include: (1) selection of the most suitable datable fractions within a record, (2) the development of better calibration curves, and (3) more precise age modelling techniques. While much attention has been focussed on the first two items, testing the possibilities of the relatively new age modelling approaches has not received much attention. Here, we test the potential for methods designed to significantly improve precision in radiocarbon-based age models, wiggle match dating and various forms of Bayesian analyses. We demonstrate that while all of the methods can perform very well, in some scenarios, caution must be taken when applying them. It appears that an integrated approach is required in real life dating situations where more than one model is applied, with strict error calculation, and with the integration of radiocarbon data with sedimentological analyses of site formation processes. 相似文献
6.
Summary The geometry of the rock joint is a governing factor for joint mechanical and hydraulic behaviour. A new method for evaluating
the aperture distribution, based on measurement of joint surfaces and three dimensional characteristics of each surface, is
developed. This method allows one to determine and visualize the aperture distribution under different normal stresses and
shear displacements, which is difficult to observe experimentally. A new laser scanner system is designed and developed for
joint surface measurements. Special attention is paid to both surfaces’ data gained by measurements and processing, such as
x-y coordinate table modification, data referencing, and matching between upper and lower surfaces. The surfaces of an artificial
joint in granite are measured, processed, analyzed and three dimensional approaches are carried out for surface characterization.
Parameters such as “asperity’s heights”, “slope angles”, and “aspects” distribution at micro scale, local concentration of
elements and their spatial localization at local scale are determined by Geographic Information System (GIS). These parameters
are used for joint surfaces matching and its real behavior quantitative analysis. The upper surface is brought down to make
contact with the lower surface and the distance between the two surfaces is evaluated from the joint mean experimental aperture,
which is obtained from normal and shear tests. Changes of aperture distribution at different normal stresses and various shear
displacements are visualized and interpreted. Increasing normal load causes negative changes in aperture frequency distribution
which indicates high joint matching. However, increasing shear displacement causes a rapid increase in the aperture and positive
changes in the aperture frequency distribution, which could be due to un-matching, surface anisotropy and spatial localization
of contact points with proceeding shear.
Author’s address: Mostafa Sharifzadeh, Department of Mining, Metallurgy and Petroleum Engineering, Amirkabir University of
Technology, Hafez 424, Tehran 15875-4413, Iran 相似文献
7.
The binational reality of border-crossing cities 总被引：1，自引：0，他引：1
Jan Buursink 《GeoJournal》2001,54(1):7-19
In a time of changing border functions city pairs on either side of national state borders have increasingly become objects
of attention, because of border crossing contacts and co-operation at the local level. This paper focuses on conceptual aspects
of such city pairs, owing their existence to either duplication of an already existing city or to partitioning of a once united
city. In search of a proper name that expresses the relations between such partner cities without metaphorical exaggeration,
the current vocabulary is reviewed. Especially the notion of the ‘binational city’ receives critical attention. A discussion
of selected cases of paired cities in Europe and North-America has been included to underline the importance of local conditions
and historical backgrounds with regard to the mutual relations and conditions of co-operation. In conclusion the author states
that for the time being ‘border–crossing’ cities seems to be the best name for city pairs of different national backgrounds,
the emergence of true ‘binational cities’ being a rather exceptional outcome in a far future.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
8.
A Shear Model Accounting Scale Effect in Rock Joints Behavior 总被引：1，自引：0，他引：1
F. Vallier Y. Mitani M. Boulon T. Esaki F. Pellet 《Rock Mechanics and Rock Engineering》2010,43(5):581-595
Understanding the scale effect on the mechanical behavior of a single rock joint is still very important in rock engineering.
Rock joints can be classified into three different categories depending on their scale: the “micro scale” which is the scale
of the asperities; the “meso scale” is the scale of the specimens tested in laboratory; and the “macro scale” which is the
scale of the rock mass. The purpose of this paper is to propose an effective way to model rock joints at both the meso and
macro scale. An original constitutive mechanical model, in which parameters are deduced from experimental results, has been developed.
This model is then extended to simulate the discontinuities occurring at a larger size. At the macro scale, the constitutive
modeling was carried out for both small and large relative displacements. Large displacements lead to substantial changes
in dilation. For both cases, the peak shear stress vanishes for joints longer than 2 m. 相似文献
9.
Hydrological impacts from climate change are of principal interest to water resource policy-makers and practicing engineers.
Predictive climatic models have been extensively investigated to quantify the impacts. Palaeoclmatic investigations, on the
other hand, show unequivocal and strong periodicity of climate variations in proxy evidence. Yet how to use the periodicity
in future hydroclimatic timing and forecasting has received less attention. This paper examines the periodicity in Pleistocene–Holocene
glacial–interglacial events and in modern precipitation records, and discusses a way in which the periodicity is used for
hydroclimatic predictions. The analysis, based on published CO2, ΔT (δ2H) and δ18O proxy data of polar ice cores and deep oceanic benthic fossils, shows a periodicity in a ~100, ~40 or 25 kyear duration
consistent with Milankovitch orbital regulations during the glacial–interglacial periods. On a fine time scale, millennium
and multi-decadal periodicity is observed in high-resolution proxy variations of Greenland ice cores and in instrumental precipitation
records of the contiguous USA. A basic periodicity of decadal and multi-decadal changes in ~20 and ~10–15 year duration is
apparent in wavelet frequency analysis of both ice core proxy and precipitation data. While the kyear-scale periodicity is
found of global prevalence, the millennium and decadal variations vary in space and are region-specific. Based on these findings,
a generalized time-downscaling hierarchy of periodicity is proposed as a potential approach for timing and forecasting future
hydroclimatic conditions at a resolution relevant to the water resources engineering and management. 相似文献
10.
Keltoum Chaouche Luc Neppel Claudine Dieulin Nicolas Pujol Bernard Ladouche Eric Martin Dallas Salas Yvan Caballero 《Comptes Rendus Geoscience》2010,342(3):234-243
This study is focused on the western part of the French Mediterranean area, namely the Pyrénées-Orientales and Aude administrative departments. The water resources (surface and groundwater) in the region are sensitive to climate change. The study addresses the question of whether any trend in the annual and monthly series of temperature, rainfall and potential evapotranspiration (PET) already appears at the scale of this region. Two data sources have been used: (a) direct local measurements using the meteorological network; and (b) spatially interpolated data from the French weather service model SAFRAN for the period 1970–2006. The non-parametric Mann–Kendall test was applied to identify significant trends at the local scale and, because of the natural spatial variability of the Mediterranean climate, regional interpretation was also performed. The trends observed in the 13 catchments of interest are consistent with those observed at a larger scale. An increase in annual mean temperature and annual PET was observed throughout the study area, whereas annual precipitation has not exhibited any trend. The monthly scale has revealed strong seasonal variability in trend. The trend for an increase in monthly PET has been observed mainly in the spring, and has not been seen in the coastal areas. A trend for an increase in monthly temperature has been observed in June and in the spring throughout the entire area. Monthly rainfall has been found to decrease in June and increase in November throughout the area. The significant trends observed in rainfall and temperature seem to be consistent between the different data sources. 相似文献
11.
At a time when the concept of ‘human and environmental symbiosis’ has taken on much significance, protection of suburban forests
(i.e. forests adjacent to or near developed areas) is a topic that has drawn much attention. Suburban forests have, since
ancient times, been places where people have gathered firewood and cultured trees. As a result, the vegetation of suburban
forests is only partially natural and continues to change as the forms of human activity in and around them changes. Accurate
forecasts of how suburban forests will change are, therefore, an important element in the debate over how to protect them.
In this study, a suburban forest was analyzed with laser radar sensing, multi-spectrum scanning, digital photogrammetry analysis,
aerial photograph interpretation, and a field survey. Data gathered using these techniques were compiled on a GIS to forecast
future changes in the forest. Aerial photographs taken over the past 50 years were analyzed to illuminate changes in the forest
over that period. Specifically, comparisons of precise Digital Elevation Models (DEMs) measured by using digital photogrammetry
workstations made it possible to estimate growth in forest height. The possible future conversion of such results to estimates
of amounts of carbon dioxide consolidated by forests should be very significant for discussions of global environmental problems.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
12.
气候变化与人类活动对水文过程产生了重大影响,估计和区分二者的影响是水科学研究中的热点问题。针对气候变化和人类活动(土地利用/覆盖变化)两个驱动因素,分别综述了气候变化、人类活动和两者综合对水文影响的研究进展;介绍了未来的气候情景和人类活动情景;阐述了区分气候变化和人类活动对水文要素过去和未来影响的研究方法,并总结了方法中常用的分布式水文模型。提出当前研究中存在气候和人类活动情景重复交叉、缺乏两者对水文极值事件的影响研究等问题。 相似文献
13.
This paper assesses how far community led rural visions accord with the current thrust of rural planning policy delivery in
the UK. Adapting conventional visioning methods, qualitative techniques were used on eight different communities across urban,
exurban and rural Wales to elicit views relating to the kind of local countryside(s) that were desired. The results show that
the communities’ visions reflect an emerging consensus around local countryside priorities: multifunctionality, integration,
wider countryside protection, development based on need, and local distinctiveness according with the thrust of current planning
policy at national and local levels. However, there is a clear dichotomy between this and the reality of what communities
actually experienced in developments affecting their countryside. Here, universal criticism was encountered over the type,
pace and scale of development, the lack of rural specificity and the failure to take account of local community needs and
priorities. It is hypothesized that tensions between national and local politics and stakeholder power relations are playing
a crucial role in distorting the delivery of town and country planning. It is recommended that rural policy delivery must
become more “joined up” and rural proofed at national and local levels concomitant with a change in the operational culture
of agencies at the forefront of rural delivery. Essentially, effective engagement of top down approaches synergising with
bottom up community led ideas is long overdue. 相似文献
14.
G. De Natale C. Troise F. Pingue P. De Gori C. Chiarabba 《Mineralogy and Petrology》2001,73(1-3):5-22
Summary We review recently obtained results about the velocity structure of the Somma-Vesuvius (Southern Italy) volcanic complex
and present an interpretation of structural features, both at local and regional scale, and of the local seismicity. The local
structure of Somma-Vesuvius is reviewed, referring to three depth ranges; i.e. shallow (0–5 km), intermediate (5–15 km) and
deep (from 15 km to the upper mantle). The shallow velocity structure is inferred by the joint inversion of shot and local
earthquake arrival time data. The main feature pointed out by this inversion is a high-velocity anomaly at the crater axis
extending down to a depth of about 5 km. This anomaly can be explained with the presence of residual magma crystallised in
the shallow conduits, which accumulated during the last eruptive cycles. The local seismicity is strongly clustered around
this anomaly, due to the focusing effect of the rigidity contrast. The space-time seismicity pattern at Somma-Vesuvius is
the result of the superposition of background seismicity, mainly due to gravitational instability of the volcanic edifice
and to small external stress perturbations, with intense episodic earthquake swarms possibly due to magmatic or hydrothermal
activity into the shallow system. The velocity structure in the 10–15 km depth range is characterized by the presence of a
low-velocity layer, which has been independently confirmed by multi-channel seismic reflection data and P-Sv conversions from
teleseismic waveforms. The study of the deep structure was performed by regional tomography with teleseisms; it confirmed
the presence of a low-velocity anomaly underneath the volcano, which appears to have roots at greater depths. The regional
structure between the Thyrrenian and the Adriatic sea has been inferred by tomographic inversion of teleseismic arrival times.
The main result from this study which is very important for geodynamic interpretations is the first evidence for a continuous
subducting slab under the Apennines, in an area where previous models hypothesized a slab window.
Received March 3, 2000 revised version accepted July 4, 2001 相似文献
15.
Streamflow changes and its influencing factors in the mainstream of the Songhua River basin,Northeast China over the past 50 years 总被引：4，自引：3，他引：1
The Songhua River plays a key role in the national development of China, owing to its unique natural condition and resources.
Recent changes in the streamflow in the Songhua River are important with regard to local sustainable development and management
under the background of global warming and aggravating soil erosion. In order to detect changes in the streamflow, two streamflow
series from 1955 to 2004 (observed at the Harbin and Jiamusi stations) in the mainstream of Songhua River basin were obtained,
and methods of statistical analysis, wavelet transform, and double mass analysis were employed to analyze the data. Reasons
for the changes to the streamflow are discussed with respect to natural and man-made drivers. The results show the following:
(1) From 1955 to 2004, the streamflow series present obvious declining trends. (2) The streamflow series followed the pattern
of a wet–dry–wet–dry cycle pattern over the past 50 years. In the mainstream of Songhua River, wet years mainly occurred during
the periods of 1955–1966 and 1984–1993, while dry years mainly occurred in the 1970s and after 2000. (3) Within the 50-year
scale, the streamflow series appeared in the main periods of circa 33-, 13- and 4-year, in which the 33-year periodicity is
the strongest. (4) Precipitation and temperature directly influenced the streamflow in the mainstream of the basin. The discharge
was positively correlated with the precipitation and negatively correlated with the temperature. In addition, human activity
was another important driving factor for streamflow change. (5) In the mainstream of Songhua River basin, the influences on
streamflow can be divided into three periods: 1955–1976, 1977–1997, and 1998–2004. In the first period climate change played
a dominant role, and during the latter two periods human influences were enhanced significantly. 相似文献
16.
《Applied Geochemistry》2004,19(7):1157-1175
Environmental legislation has reduced the anthropogenic loadings of Pb and Cd to the Great Lakes region over the past 3 decades. However, the accumulation rates of these metals still remain above background values. Because environmental legislation was targeted at major sources (e.g., Pb in gasoline) whose influence on the environment was on a regional scale, local sources (e.g., watershed scale) for the metals may now play a more significant role. The relative importance of regional versus local scale influences on metal inputs to the environment is poorly understood. In this study, sediment chronologies of Pb and Cd were examined from 12 inland lakes that cover the broad geographic area of the State of Michigan. These chronologies were compared temporally and spatially and to watershed population densities and metal production records to gain an understanding of local and regional influences on metal inputs to the Great Lakes region. Results show that anthropogenic Pb loading during the 1930s and 1970s was dominated by regional sources, such as coal burning and use of leaded gasoline. Current loadings are now more related to local influences such as watershed population densities, rather than atmospheric deposition. Anthropogenic Cd loadings to the Great Lakes region have been dominated by both regional and local sources over time. Lead may also have shown the influence of local sources over time, if the influence of emissions from gasoline had not been present. This work shows that Pb and Cd loadings in the Great Lakes region are strongly related to watershed population densities, however, the specific sources and pathways for the metal cycling are unclear. 相似文献
17.
Adrian M Harvey Department of Geography University of Liverpool Liverpool L BX England 《中国地质大学学报(英文版)》2000,11(1)
INTRODUCTIONHow fluvial systems respond to environmental changedepends on how rapidly the effects of changes in sediment loadsupplied from upstream or changes in base level affectingdownstream zones are propagated through the system.Thisproperty has been defined as the coupling of the system(Harvey,2 0 0 0 a,1997a;Brunsden,1993;Brunsden andThornes,1979) .Coupling therefore relates to connectivity between thedifferent zones of the fluvial system,defined by Schumm(1977) as source areas,tra… 相似文献
18.
《Geoforum》2014
Most studies on the causes of deforestation have sought to link the phenomenon to specific economic, political, or demographic factors, usually through statistical or spatial-statistical modeling. However, generalizations about the link between deforestation and specific variables or classes of variables are of questionable validity. Another approach, one that is receiving growing attention, seeks instead to identify particular contexts or situations, as created by an array of interacting factors, which encourage forms of land use or other economic activity that can generate deforestation pressure. Such an approach was used in this study to explore recent trends and dynamics in the Petén region of northern Guatemala. The research found a number of regional and national scale factors that in combination have led to a process of de-agrarianization and dispossession among smallholders, while large scale, commercial activities in agriculture, ranching and plantation forestry increasingly dominate. Rapid land concentration, in conjunction with limited employment generation through emergent activities, is intensifying pressure on remaining areas of forest. A focus on two distinct areas within Petén reveals how broader-scale trends and features can have differing outcomes at the local level, with contrasting socioeconomic and environmental effects. Finally, the paper explores the implications of recent dynamics in Petén for both policy and theory in relation to deforestation, agrarian change, and regional development. Key factors and questions are highlighted that should be considered when exploring influences on regional socioeconomic and environmental conditions. 相似文献
19.
Cross-border conservation in East Central Europe: The Danube-Carpathian complex and the contribution of the World Wide Fund for Nature 总被引：1，自引：0，他引：1
David Turnock 《GeoJournal》2001,55(2-4):655-681
Cross-border cooperation in environmental matters has become much more evident since 1989 because open frontiers facilitate
contact while common tasks emerge as protected areas in frontier zones lose their isolation. Pollution hazards have been discussed
more openly since 1989 while further stimuli arise from the harmonisation process in the run-up to EU enlargement and the
finance available from Brussels and other international donors to solve pollution problems and create international ecological
networks. The paper examines the progress made in the Danube Valley and the Carpathians which together constitute the core
of East Central Europe. Particular attention is paid to the role of environmental non-governmental organisations (ENGOs) –
and especially the World Wide Fund for Nature (WWF) – in the progress of conservation. Along with the World Conservation Union
(IUCN), WWF has demonstrated the value of floodplain wetlands and ensured that wetland restoration is an important part of
the Strategic Action Plan for the Danube. And by involving local ENGOs in specific projects the role of the non-governmental
sector in environment matters is enhanced. Also, with momentum growing for a pan-European ecological network ('Natura 2000'),
WWF has attracted the support of international donors for a ecoregion-based conservation (ERBC) in the Carpathians where priority
areas have now been identified. Ecological and diplomatic capacities are thus deployed to maximise the scope for biodiversity
conservation commensurate with sustainable socio-economic development.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
20.
B.F. Iyun 《GeoJournal》1998,44(2):129-139
The viewpoint that most health problems are environmentally related has always been promoted by medical geography. In recent
times, concern about environmental degradation has been of high priority for many national and international organizations
as ‘we human beings become a threat to our planet’. There is also a need to specifically focus attention on the impact of
so-called development efforts on the health of women and children, in particular those living in highly marginalized regions
which often contribute substantially to the overall development of their countries.
This paper uses the concept of vulnerability as a departure point from which to map the health risks to children in Igbekun
area of Ondo State, the ‘transgressive muddy’ oil-rich coastal area of Nigeria. The paper attempts to highlight the poor quality
of life and health of children in particular, and how it is becoming much more difficult to practice health intervention programmes,
especially oral rehydration therapy (ORT) in the area.
The Igbekun area is an unhealthy and harsh environment, complicated by the devastating effects of oil drilling in recent years.
The siltation and sedimentation of the creeks and lagoons have serious health dimensions as human faeces float in and around
villages because the ‘bush toilets’ can no longer be reached. The on-going environmental crisis has also deprived women of
their traditional means of livelihood; fishing.
There is a relatively high level of ignorance (compared with other women living in the same local government area (LGA) of
causes of the commonest diseases such as diarrhoea, acute respiratory infection (ARI) and measles. A majority of the women
have never heard of family planning, immunization against diseases and interventions such as ORT. Promotive health care services,
especially those that strive to reduce the high mortality of children have passed the mothers by. It is also becoming impracticable
to promote ORT because of the widespread ‘salty and oily’ water supply in the area.
The greatest concern of the women now is that oil drilling activities have further amplified their stressful conditions especially
their health and that of their children. Unfortunately, their plight is not acknowledged by the Nigerian authorities and the
oil companies are least concerned about alleviating the poor health status of the community, in particular the most vulnerable
groups, children under the age of five.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献