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1.
A series of policies on land tenure have been implemented in Vietnam following the doi moi restructuring. This study assesses the impacts of these policies, the extent to which they have had intended effects and coping strategies adopted by farmers. Data were collected in five upland villages in Nghe An Province, North Central Vietnam. The intended effects of the land allocation policies were poverty alleviation, intensification of agriculture, agricultural modernization and forest protection. The policies implemented to achieve these goals include changes in land allocation, purportedly to increase land tenure security. However, the policies have been implemented in a very uneven manner and the effects differ widely due to differences in the local contexts in which they have been implemented. In general, farmers perceive the impacts of policies as adverse and have attempted to cope with their impact in a variety of ways. The paper argues that land allocation policies have: (1) decreased the amount of land available, (2) not improved land tenure security and (3) had a limited impact on farming practices. The differences between the five villages are great, demonstrating the very different results produced by national policies depending on the specific implementation modality and the local context.  相似文献   

2.
Mediterranean environments have been subject to major land cover change since the end of the second world war. Housing, agricultural activities, forests, green spaces and other land uses have shifted due to urbanisation and tourism. These changes influence runoff, and municipal authorities often cannot estimate the net impact of complex land cover transitions. During this period, elected representatives have become increasingly sensitive to the risks of flooding and have implemented a number of channel management strategies. The main objective of this case study was to analyse the impact of land cover change on total storm runoff between 1950 and 2003 in a Mediterranean catchment near St Tropez, France. A secondary objective was to compare these changes to the impacts of channel management on bankfull discharge. Aerial photographs were used to classify land cover in 3 urban categories, vineyards and bare soil, forests, and green spaces. Stream discharge was estimated using a distributed event based total runoff approach. After validating the model for a large winter event (114 mm) for 1982, runoff was calculated for the same event for 1950 and 2003. Land cover changes occurred mainly in the alluvial plain area. Total gauge catchment urban area increased from 30.1 ha to 393.8 between 1950 and 2003 at the expense mainly of agricultural land, but this was compensated in part by an increase in grassed area. Some of the loss in vineyards was replaced by clearing forested land on the first hills close to the plain. Bank stabilisation and channel maintenance since the 1980’s reduced surface roughness and increased channel area, thereby greatly increasing bankfull discharge. While the impact of urbanisation on runoff was small, channel management effects increased bankfull discharge substantially. Flood damage from extreme events was not studied here.  相似文献   

3.
Meteorological records show a rise in temperature and decrease in precipitation in most parts of the farming-pastoral ecotone of Northern China over the last 50 years. During the last quarter of the 20th Century, the agrarian sector went through a series of reforms and changes in government policies on land use that have led to extensive changes in land cover. The objective of this study was to redefine the location and analyze the boundary variations under the effects of climate and land use changes in the farming-pastoral ecotone of Northern China. The results showed that the location of study area has been redefined as both a climatic ecotone from the perspective of suitability of precipitation and temperature for agricultural crops and vegetation growth, and also a land use ecotone based on the impacts of farmland restructuring by government policies on land use. In recent decades, the climatic boundary has moved southeast while the land use boundary has moved northwest, showing opposing directions of change. The extent of boundary changes in the northeast and northern sections are far greater than in the northwestern section of the farming-pastoral ecotone of Northern China.  相似文献   

4.
Land uses and their legacies are a major driver of human impacts on the environment. Decision makers have recognized that the legacies of land-use activities continue to influence ecosystems, particularly aquatic ones, for decades or centuries. The main objectives of this paper are to develop land use legacy maps to (1) assess historical and future (predicted) shifts in dominant land use classes (urban, agriculture, forest) in the Ohio River Basin (ORB), and (2) determine the past and future location of catchments in the ORB exceeding critical land use thresholds (10% and 38% urban and agricultural use of catchment respectively) for water quality and other aquatic resources. Our land use legacy simulations show that approximately 80% of the ORB has remained as agriculture (∼37%), forest (∼34%), urban (∼7%) and other classes (∼2%) from 1930 to 1990. Within the remainder of landscape, agriculture to forest (∼16%) and agriculture to urban (∼1.5%) transitions were the most common land use changes between 1930 and 1990. Our forecast model shows that approximately 94% of the ORB will remain as forest (∼47.46%), agriculture (∼35.77%), urban (∼8.84%) and other classes (∼2.07%) between 2000 and 2050. 1.44% and 1.37% of the ORB is predicted to transition from forest to urban and agriculture to urban between 2000 and 2050, respectively. Our results also demonstrate that 13% and 74% of the catchments in the ORB already exceeded critical urban and agricultural land use thresholds in 1930, respectively. We predict that 37% of catchments in the ORB will have exceeded critical urban land use thresholds by 2050, whereas the proportion of catchments to exceed critical agricultural use will decrease to 45%.  相似文献   

5.
Freshwater inflows, among the most important factors in the overall health of estuarine environments, can be altered both by regional climatic influences as well as changes in land use and land cover. We conduct a scenario analysis to study the individual and combined impacts of changes in land use and land cover and in precipitation patterns in a coastal Texas watershed. The watershed is one of the major sources of freshwater for the estuarine area within the Mission-Aransas National Estuarine Research Reserve (NERR). Our scenario analysis suggests that climatic changes are more influential than land changes at the watershed level. However, localized impacts of land change may still be significant on habitats within the NERR site. Results from our watershed-level analysis poorly agree with the recommended freshwater flows established for the region, which deserve further scrutiny. Our findings suggest that geomorphic characteristics of the streams in the watershed need to be taken into consideration in hydrological modeling. Further research on the interactions between land change and hydrological dynamics should also aim for tighter temporal integration of the two sets of processes.  相似文献   

6.
Land change was assessed in the Albertine rift region (ARR) using its central section of north-western Rwanda as case study. This region is one of Africa's most ecologically sensitive environments under severe pressure from human activities. The study maps and quantifies the spatial extent of land use-land cover (LULC) changes between 1987 and 2016 from Landsat images. Transitions between five major land classes were identified in order to understand the trajectory of observed changes. In terms of gains, the forest class, the urban built-up and bare land class increased by 9% and 4% respectively over the study period. The gains of forest were mainly derived from the afforestation of some agricultural lands in the southern part, whereas the gains of built-up and bare lands were mostly from cultivated land which was a net losing class. Forest increase is in line with government's policy to increase the national forest cover to 30% by 2020. Forest losses occurred mostly outside protected areas due to land conversion for settlement and agricultural purposes. Much needed information about changes in LULC over the last three decades is provided. This study demonstrates in a timely manner how to analyse and monitor LULC change and the drivers in an environment where field based research is a challenge due to the mountainous terrain. The ecological richness of the region, which coincides with heightened human population pressure, necessitates the monitoring of land change as input for improving land use planning with focus on conserving biodiversity.  相似文献   

7.
Satellite images have enormous potential for qualitative land use analysis. This paper presents empirical results that demonstrate how normally invisible dimensions produced by land use can be identified by enriching satellite data with qualitative information from field studies.Land use can be defined as the intentional use of a specific piece of land resulting in patterns of ecological responses that are visible in the land cover and landscape. Responses to land use often result in a heterogeneous combination of reflectance in satellite images. Statistical methods used in the classification of satellite imagery are limited in their capacity to handle categories consisting of heterogeneous combinations of spectral values. To overcome this limitation, a contextual post-classification method has been used to map land cover configurations as related to different agricultural practices in the district of Sodo, Ethiopia.The results show that it is possible to map socio-spatial distribution of different agricultural and socioeconomic practices on a regional level by combining field observations and spatial contextual information. The empirical findings show local agricultural activity variations in cash crop production and subsistence agriculture in the Sodo district of Ethiopia.  相似文献   

8.
Effective agricultural practices can enable and sustain rural livelihoods, particularly in rapidly developing and transforming areas such as the Chinese Loess Plateau. Drawing from the Sustainable Livelihoods Approach (SLA), a conceptual framework for agricultural practices and sustainable rural livelihoods for the Yangou watershed within the Chinese Loess Plateau is presented and discussed. It is found that agricultural practices that include building terraces, returning sloped farmlands to forestland and grassland, and expanding orchards all have had positive and significant impacts on farmers' livelihood assets, strategies, outcomes, and vulnerabilities. From 1997 to 2006, 48.4 ha (95%) sloped farmland in the Yangou watershed was converted to new land management, and the percentages of income from fruit sale and sale of labor to total income dramatically increased by 59% and 14%, respectively. The watershed community also experienced 159% raise in per capita net income from 1997 to 2003, while the watershed itself experienced a 99% decrease in sediment yield from 1998 to 2007. These positive and significant impacts of new agricultural practices on the sustainable rural livelihoods of the Yangou watershed are evident in the community's reduced dependence upon grain and subsidies income, the diversified strategies for livelihood, and the improved environmental indices. The successful implementation of new agricultural land management practices and policies in the Yangou watershed strongly suggest that similar transformations can be achieved in similar regions throughout China's vast rural areas of the Loess Plateau.  相似文献   

9.
Human activity has been recognized to be an important geomorphic agent, and the resulting changes to landforms and land cover are regarded as a global problem. Although there has been much research into the relationships between geomorphic processes and types of land use such as agriculture, mining, and urbanization, it is important to clarify spatiotemporal human impacts on topography on a regional scale when predicting future changes in land cover.This study examined changes in land use to clarify the distribution and impact of anthropogenic changes to landforms, as well as the influence of geology on the extent of these changes. In a case study from Fukuoka Prefecture, Japan, changes in land use over the last century were analyzed using a geographic information system (GIS). The study area, which covers approximately 4930 km2, has experienced urban development since 1950 and has a current population of over 5 million. Land use data were prepared using paper-based early editions of topographic maps. Subsequently, the distribution of anthropogenic landforms was evaluated by comparing landforms with regional geological data.GIS analysis using our prepared land use data, landform data, and regional geological data has clarified the following characteristics of the study area. (1) Land uses prior to 1950 were constrained by topographic relief. After 1950, land use was characterized by urban sprawl. Urban areas expanded and contained both higher elevations and steeper slopes at their margins. The relationships between land uses and landforms during this urbanization are unclear. (2) The area of urban land increased in the geological regions with Paleogene sedimentary rocks (PSD) and Mesozoic granitic rocks (GR) during the 20th century. The largest coal mining area in Japan was located in the PSD geological regions, and ancient iron working was common in the GR geological regions, particularly during the 7th century. This result indicates that the land use distribution, especially urban areas in sloping terrain, is related to the regional geology. (3) Deforestation related to land use resulted in steeper terrain in forest land in the PSD and GR geological regions. These changes to landforms in forest areas occurred as a result of rapid urban sprawl and have created many new boundaries between forest areas with steeper slopes and urban areas with gentler slopes. This phenomenon may have caused an increase in the frequency of sediment-related disasters.This case study indicates that predictions of anthropogenic changes to landform, which are important for the assessment of global climate change and natural hazards, must clarify the relationships between land uses, landforms, and regional geology.  相似文献   

10.
The environmental effects of disease are broadly recognized but still not fully understood. The impact of health on economic development has been well-documented, as have how changes in land cover can contribute to poor health. However, little is known about how changes in health may impact land use and land cover. Fallowing has long been regarded as an advanced, sustainable land use decision employed by subsistence agriculturalists. In the presence of a prolonged illness, however, subsistence agriculturalists may also potentially use fallowing as a coping mechanism. In this paper we seek to understand the extent to which fallowing is used as a coping strategy by households facing a prolonged illness. If illness threatens a household's labor supply, it could affect their ability to cultivate all of their land and may impact food security and general economic well-being. Additionally, it may also impact the actual landscape, as previously agricultural land may revert to a transitional state or land abandonment. This study employs mixed methods to determine if unhealthy agricultural households use fallowing as a coping strategy, identifies whether or not unhealthy fallowing households are more vulnerable agriculturally and economically than their healthier fallowing counterparts, and examines whether there is a land cover effect that can be detected using Landsat TM/ETM + satellite imagery.  相似文献   

11.
鲁西北地区土地资源条件与土地利用变化趋势的研究   总被引:14,自引:2,他引:12  
本文从分析鲁西北地区土地资源的基本特点入手,讨论了该地区土地需求、土地利用结构和土地利用方式的变化趋势,以及水土资源条件对未来土地利用变化的影响。本文还探讨了土地利用变化对环境和农业持续发展可能产生的影响,并提出了一些实现土地资源高效持续利用的措施。  相似文献   

12.
In Nepal, changing demographic patterns are leading to changes in land use. The high level of outmigration of men in the hills of Kaski District, Western Development Region of Nepal, is affecting the household structure but also land management. Land is often abandoned, as the burden on those left behind is too high. How do these developments affect the state of the land in terms of land degradation? To find out, we studied land degradation, land abandonment caused by outmigration, and existing sustainable land management practices in a subwatershed in Kaski District. Mapping was done using the methodology of the World Overview of Conservation Approaches and Technologies (WOCAT). While previous studies expected land abandonment to exacerbate slope erosion, we demonstrate in this paper that it is in fact leading to an increase in vegetation cover due to favourable conditions for ecosystem recovery. However, negative impacts are several, including the increase of invasive species harmful to livestock and a decline in soil fertility. Traditional land management practices such as terraces and forest management exist. To date, however, these measures fail to take account of the changing population dynamics in the region, making the question of how migration and land degradation are linked worth revisiting.  相似文献   

13.
闫小培  毛蒋兴  普军 《地理学报》2006,61(6):613-623
在评述国内外相关研究的基础上,利用遥感土地利用数据和统计资料,应用定量分析和GIS空间分析技术从定性与定量的角度系统全面地开展了珠江三角洲巨型城市区域土地利用变化的人文因素研究。定性分析结果表明:珠江三角洲土地利用变化与人口、经济发展、城市化与工业化及政策因素密切相关,这些因素深刻影响着该区域的土地利用变化。定量分析是对定性分析的验证,定量分析结果表明:影响珠江三角洲巨型城市区域土地利用变化的因子可归纳为人口、经济发展水平、城市化与工业化、农业产业结构调整、区域产业结构调整和外资等6个因子,并且各因子的影响作用大小不同。  相似文献   

14.
Iraq has experienced significant agricultural land use changes throughout its history, including recent changes initiated by the 2003 US-led military invasion, the end of United Nations' economic sanctions and the onset of overt domestic conflict. Conflict and sociopolitical forces are important drivers of land use/land cover change and often have disproportionate impacts on agricultural systems. However, there has been little research to investigate recent changes in agricultural land use/land cover in Iraq over the recent tumultuous period that has included war and the transition of its political system from a dictatorship to an emerging but beleaguered democracy. Our objectives were to (1) determine if cropland area in Iraq changed significantly between 2001 and 2012, (2) identify regional patterns of cropland area change, and (3) identify sociopolitical forces driving those changes. We used MODIS Land Cover Product yearly data to quantify the amount of land cover dedicated to croplands. We regressed cropland area (ha) on time (2001, 2002, 2003,…) and years with drought influence (yes, no). The results revealed significant changes in cropland area for Iraq as a whole, with cropland area decreasing over 30,000 ha per year. Regionally, there were significant decreases in the Kurdish Autonomous Region and central Iraq, and initial increases in the southern marshlands followed by decreases related to drought.  相似文献   

15.
土地利用变化的解释   总被引:135,自引:22,他引:135  
用途转移和集约度变化构成土地利用变化的两种基本类型。土地特性自身的变化、土地使用者个体经济行为分析及社会群体土地管理行为分析 ,构成土地利用变化解释的理论框架。从土地特性考察 ,多宜性和限制性是土地利用发生变化的基本条件。人类对土地利用的结果 ,总是趋向于使土地的多宜性降低和功能类型减少。竞租曲线、转移边际点以及打破土地利用空间均衡的条件分析 ,是土地利用变化经济分析的理论基础 ;“土地利用 -环境效应 -体制响应”反馈环的作用机制 ,构成社会群体土地管理行为分析的理论框架。土地利用变化的机理模型 ,目前主要以新古典经济学和地租理论为基础。多视角的探索可能是土地利用变化机理综合分析的有效途径。  相似文献   

16.
Since the early 2000s the Lao government has dramatically increased the number of large‐scale land concessions issued for agribusinesses. While studies have documented the social and environmental impacts of land dispossession, the role of Vietnamese labour on these Vietnamese‐owned rubber plantations has not previously been investigated. Taking a political ecology approach, we situate this study at the intersection between ‘land grabbing’ studies and work on ‘labour geographies’. Most of the remittances generated from Vietnamese working in Laos are used for non‐agricultural purposes, with people purposely choosing to not invest in agriculture in Vietnam. Vietnamese labour on Lao plantations still has significant spatial implications, both in Laos and in Vietnam, including through the norms, formal rules and practices introduced at rubber plantations by Vietnamese workers and management, but also through labour regime changes in Vietnam. In Laos, one of the most significant results has been to make certain spaces less welcoming to Lao labour. This study particularly points to the importance of geopolitics, as the close political relationship between Laos and Vietnam, and the fact that Vietnamese companies and managers are involved, is crucial for understanding the particular nature of the labour geographies associated with Vietnamese rubber plantations in Laos.  相似文献   

17.
Land use and land cover change (LULCC) dynamics have been particularly strong in the Mediterranean region, due to its historical development and to agro-pedoclimatic conditions favorable to human settlement. This area has undergone in the 1950s and the 1980s intense urbanization processes that has followed different trajectories. Urban expansion commonly occurs at the expense of agricultural land, leading to the fragmentation of natural areas and conflicts over access to land resources. These dynamics mainly concern the fringe between urban and agricultural land, e.g. the peri-urban areas usually included within functional urban regions. Here, to identify common features of LULCC in Western Mediterranean urban regions, we investigated two main features: direct changes due to urbanization and indirect changes affecting non-artificial land uses. We compared LULCC dynamics in 6 case studies from the north and south of the Western Mediterranean region: the urban regions of Montpellier and Avignon (France), Pisa (Italy), Madrid (Spain), Meknes (Morocco), and Constantine (Algeria), using a 30-year multitemporal spatial analysis (1980–2010). Two series of Landsat TM images were acquired for each case study and land cover data were analyzed both for dynamics and for land patterns, using landscape and class metrics. We found no significant north-south differences in LULCC dynamics between the investigated Western Mediterranean urban regions. Differences are more pronounced between small–medium cities and large metropolitan areas in type of urban diffusion, which is more sprawled in small–medium cities and more compact in large metropolitan areas. Rather, differences occur in LULCC not directly affected by urbanization, since in Northern Mediterranean urban regions afforestation and abandonment of agricultural areas are prevalent and closer to the urban areas, whereas transformation of natural areas into agricultural ones occurs mainly in Southern Mediterranean urban regions at a similar distance from urban areas than it happens for afforested or abandoned areas. In attempting for the first time to assess LULCC in these Mediterranean urban regions, we provide a preliminary comprehensive analysis that can contribute to the active LULCC research in the Mediterranean basin and that can be easily applied to other Mediterranean urban regions.  相似文献   

18.
Planning for source water protection in Ontario   总被引:2,自引:0,他引:2  
Ontario began developing a drinking water source protection planning process in 2000, after a rural community's water supply was contaminated by pathogens from agricultural runoff. An expert committee report has recommended legislating a new source protection “sphere of jurisdiction” for municipalities; however, no specific new municipal tools or authorities have been proposed as yet. This paper reports findings from an evaluation of the extent to which existing institutional arrangements for land use planning and water management facilitate or constrain source protection by municipalities. A case study of the Regional Municipality of Waterloo suggests there is the potential to link land use planning more strongly to water management through creative use of existing tools, forgoing the need for major institutional changes.  相似文献   

19.
The recent decoupling of deforestation and soybean production has raised optimistic expectations towards enhanced land use sustainability in the South-Eastern Amazon agricultural frontier. Nonetheless, assessing land use sustainability implies not only the consideration of how agricultural activities affect natural ecosystems but also how they impact on society and how society can cope with them. We review some of the forthcoming challenges that the agricultural sector should address to confirm its significant progress towards land use sustainability. Firstly, we assess the recent efforts to adopt environmentally friendly practices with regard to the ongoing intensification process mainly based on double cropping systems. Secondly, while rapid agricultural development has brought major social advances, we evidence a recent trend towards a decoupling of soy production and the Human Development Index at municipality level. We then put this result into perspective considering that the trend towards agricultural intensification based on the use of large amounts of agrochemicals could lead to major health concerns which are still too rarely considered. Finally, we discuss how the recent efficient policies to contain deforestation in the Amazon can cause indirect land use changes in the Brazilian Cerrados and in African Savannas, thus potentially leading to an “illusion of preservation” at global scale. We conclude that new indicators involving social sciences are necessary to better address the complexity of land use sustainability on the still very dynamic agricultural frontier in the South-Eastern Amazon.  相似文献   

20.
如何量化人为活动对土地利用格局变化的影响是国内外学者所关注的热点问题,目前涉及人为影响空间分布特征的研究尚不多见.塔里木河上游地区是典型的生态脆弱带和环境危机带,对以人类活动为主导的区域水土资源的开发反响强烈,主要表现在其土地利用的空间格局随水土资源开发程度而发生的变化.本研究借助于3S技术和地统计学的空间分析方法,较系统分析了1990-2002年塔里木河上游地区阿克苏绿洲土地利用的时空变化特征,建立人为影响指数,定量揭示人为开发利用活动的空间变异、强度分布.研究表明,以阿克苏绿洲中心所在的人工绿洲系统为人为影响程度相对高的区域,广大的荒草地、沙地和部分水域为人为影响低的区域.2002年的人为影响特征与1990年相比,出现了较大变化,人为影响指数较高的区域面积在不断扩大,这与近年来当地人口数量上升导致的城乡建设用地面积增加和通过毁林、毁草来拓垦耕地有直接关系.  相似文献   

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