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1.
Agricultural land-use change during economic reforms in Ghana   总被引:1,自引:0,他引:1  
Land-use change is driven by many interrelated factors including national policies formulated in response to the forces of globalization. This study integrates remote sensing data with social surveys to identify the role of demographic, technology and market-related variables in cropland expansion during economic reforms in Ghana. Macroeconomic changes increased the commercial orientation of farming as the sources of food supply changed from import to domestic production. However interest rates liberalization increased the use of labor at the expense of fertilizer and other complementary inputs. Demographic variables were more important in explaining cropland change after structural adjustment. Public agricultural support services are required for sustainable market-induced agricultural change in Ghana.  相似文献   

2.
Recently, dramatic flood disasters have occurred incrementally in several regions of the world. Land-use change as one of the main affecting factors becomes a key component in flood risk management. This study strives to deal with quantifying how changes in land use to affect the dynamic evolution of flood vulnerability. The floodplains of Wuhan, which are located in the Yangtze River Basin, have been selected as an example. In this paper, we use GIS to gather different historical geometric data as sources of land-use information. By proposing the Simpsons-dominance index and location index to analyze the characteristics of land-use changes, and building a quantitative model to measure flood vulnerability, a series of flood vulnerability maps demonstrate differential flood vulnerability of floodplains of Wuhan in three inundation scenarios and four historical periods. Finally, the non-parametric correlation is used to reveal the interactive effect of land use and flood vulnerability. Based on this study, comprehensive flood disaster management strategies for land-use planning are proposed for government decision-makers to reduce the flood vulnerability of Wuhan in future.  相似文献   

3.
Across the tropics, development banks and conservation donors are investing millions in property mapping and registration projects to improve accountability for deforestation. An evaluation of the effectiveness and accuracy of existing environmental registries is crucial to assure the success of future efforts. This study presents an evaluation of deforestation and registration behavior in response to one of the largest of these property registration programs to date — the Rural Environmental Registry (CAR) in the Amazonian state of Pará. From late 2007 to 2013, approximately 100,000 properties covering 30 million hectares of self-declared claims were entered in this digital registry. We used fixed effects regression models and property level data to assess how registration influenced deforestation on different sizes of properties. Registration had little impact on deforestation behavior, with the exception of a significant reduction on “smallholder” properties in the size range of 100–300 ha. We link this reduction to interacting incentives from forest protection and land regularization policies and suggest that desire to strengthen land claims motivates these landholders’ response to the environmental registry. We also present evidence that some landholders may be registering incomplete or inaccurate parcels into the self-declared system to strategically benefit from policy incentives. Our results for smallholder properties indicate that environmental registries may have potential to facilitate reductions in deforestation if combined with a favorable combination of incentives. However, in places where land tenure is still being negotiated, the utility of environmental registries for forest policy enforcement and research may be limited without ongoing investment to resolve uncertainty around land claims.  相似文献   

4.
Using case studies and concepts we suggest that constraints upon aggregate or global forest transition are significantly more severe than those upon local forest reversals. The basic reason is that one region's reversal can be facilitated by other regions that supply resources and goods, reducing the demands upon the region where forests rise. Many past forest reversals involve such interdependence. For ‘facilitating regions’ also to rise in forest requires other changes, since they will not be receiving such help. We start by discussing forest-transitions analysis within the context of Environmental Kuznets Curves (EKCs), for a useful typology of possible shifts underlying transitions. We then consider the historical Northeast US where a regional reversal was dramatic and impressive. Yet this depended upon agricultural price shocks, due to the Midwest US supplying food, and also upon the availability of timber from other US regions. Next we consider deforestation in Amazônia, whose history (like the Northeast US) suggests a potential local role for urbanization, i.e. spatial concentration of population. Yet inter-regional issues again are crucial. For cattle and soy, expansion of global demands may give to Amazonia a role more like the Midwest than the Northeast US. In addition, across-region interdependencies will help determine where reversal and facilitation occur. Finally we discuss the constraints upon very broad forest transition.  相似文献   

5.
The Brazilian Cerrado, a biodiverse savanna ecoregion covering 1.8 million km2 south and east of the Amazon rainforest, is in rapid decline because of the expansion of modern agriculture. Previous studies of Cerrado land-use and land-cover (LULC) change imply spatial homogeneity, report widely varying rates of land conversion, use ambiguous LULC categories, and generally do not attempt to validate results. This study addresses this gap in the literature by analyzing moderate-resolution, multi-spectral satellite remote sensing data from 1986 to 2002 in two regions with identical underlying drivers. Unsupervised classification by the ISODATA algorithm indicates that Cerrado was converted to agro-pastoral land covers in 31% (3646 km2) of the study region in western Bahia and 24% (3011 km2) of the eastern Mato Grosso study region, while nearly 40% (4688 km2 and 5217 km2, respectively) of each study region remained unchanged. Although aggregate land change is similar, large and contiguous fragments persist in western Bahia, while smaller fragments remain in eastern Mato Grosso. These findings are considered in the current context of Cerrado land-use policy, which is dominated by the conservation set-aside and command-control policy models. The spatial characteristics of Cerrado remnants create considerable obstacles to implement the models; an alternative approach, informed by countryside biogeography, may encourage collaboration between state officials and farmer-landowners toward conservation land-use policies.  相似文献   

6.
The present work explores the synergies between socio-metabolic energy use and landscape patterns, starting from the hypothesis that there is a complex and changing relationship between the efficiency in both the societal use of energy, and land-use, and the ecosystem functioning of the whole land matrix of the Barcelona Metropolitan Region (BMR). It first compares changes in the social metabolism (i.e. the total energy or material throughput of the economy) and in landscape structure and function from 1850 to the present in three municipalities of the Vallès county (N of the BMR), as a first attempt to establish a link between the societal uses of land and energy together with their impact on landscape patterns. Secondly, the study explores the role of natural versus rural landscapes on the maintaining of basic functional properties such as connectivity in the whole BMR. We base our analyses on parametric methodologies that describe both structural and functional properties of landscapes, aimed at assessing the landscape efficiency of both energy-use and land-use planning. The first comparison reveals that the simultaneous loss of energy efficiency and land-use efficiency from the mid-19th century to present can be tracked by changes in the functional landscape structure. The second study shows the importance of the traditional rural landscapes in maintaining the ecological quality of non-built-up land. In consequence, the organized complexity of the land system necessary to host biodiversity and basic ecological processes cannot be guaranteed if the agro-forestry mosaic is not taken into account, together with the network of protected areas.  相似文献   

7.
We propose a causal analysis framework to increase understanding of land-use change (LUC) and the reliability of LUC models. This health-sciences-inspired framework can be applied to determine probable causes of LUC in the context of bioenergy. Calculations of net greenhouse gas (GHG) emissions for LUC associated with biofuel production are critical in determining whether a fuel qualifies as a biofuel or advanced biofuel category under regional (EU), national (US, UK), and state (California) regulations. Biofuel policymakers and scientists continue to discuss to what extent presumed indirect land-use change (ILUC) estimates should be included in GHG accounting for biofuel pathways. Current estimates of ILUC for bioenergy rely largely on economic simulation models that focus on causal pathways involving global commodity trade and use coarse land-cover data with simple land classification systems. This paper challenges the application of such models to estimate global areas of LUC in the absence of causal analysis. The proposed causal analysis framework begins with a definition of the change that has occurred and proceeds to a strength-of-evidence approach that includes plausibility of relationship, completeness of causal pathway, spatial co-occurrence, time order, analogous agents, simulation model results, and quantitative agent–response relationships. We discuss how LUC may be allocated among probable causes for policy purposes and how the application of the framework has the potential to increase the validity of LUC models and resolve controversies about ILUC, such as deforestation, and biofuels.  相似文献   

8.
The paper assesses the impacts of a proposed policy, which suggests a ban on commercial timber harvest in the US national forests. Specifically, this study examines the effect of this policy on a small forest dependent county (Liberty County) in Florida and Florida State by applying a computable general equilibrium (CGE) model. The results indicate that the proposed policy would decrease overall economic output by $5 million in Liberty County. The decrease in economic output at the state level in response to this policy is only $1 million. Results suggest that the welfare index in response to the proposed policy will drop by 2.9% in Liberty County while the change at the state level is negligible. At the county level, where limited alternate opportunities for labor and capital mobility, the negative effect of the proposed policy is shown to have a multiplying effect.  相似文献   

9.
This paper explores the determinants of technical efficiency, and the relationship between farm size and efficiency, in the Center-West of Brazil. This is the region where agricultural production and total factor productivity have grown the fastest since 1970. It is also a region characterised by unusually large farms. Technical efficiency is studied with Data Envelopment Analysis and county level data disaggregated by farm size and type of land tenure. The efficiency measure is regressed on a set of explanatory variables which includes farm size, type of land tenure, composition of output, access to institutions and indicators of technology and input usage. The relationship between farm size and efficiency is found to be non-linear, with efficiency first falling and then rising with size. Type of land tenure, access to institutions and markets, and modern inputs are found to be important determinants of the differences in efficiency across farms.  相似文献   

10.
Fed by demand for beef within Brazil and in global markets, the Brazilian herd grew from 147 million head of cattle in 1990 to ≈200 million in 2007. Eighty-three percent of this expansion occurred in the Amazon and this trend is expected to continue as the industry bounces back from a recent agricultural downturn. Intensification of the cattle industry has been suggested as one way to reduce pressure on forest margins and spare land for soybean or sugarcane production, and is the cornerstone of Brazil's plan for mitigation of greenhouse gas emissions. To this end, federal credit programs and research and development activities in Brazil are aligning to support intensification goals, but there is no guarantee that this push for intensification will decrease the demand for land at the forest margin and as result curb CO2 emissions from deforestation. In this paper we use a spatially explicit rent model which incorporates the local effects of biophysical characteristics, infrastructure, land prices, and distance to markets and slaughterhouses to calculate 30-year Net Present Values (NPVs) of extensive cattle ranching across the Brazilian Amazon. We use the model to ask where extensive ranching is profitable and how land acquisition affects profitability. We estimate that between 17% and 80% of land in the Amazon would have moderate to high NPVs when ranched extensively if it were settled, i.e. if the rancher does not buy the land but acquires it through land grabbing. In addition, we estimate that between 9% and 13% of land in the Amazon is vulnerable to speculation (i.e. areas with positive NPVs only if land is settled and not purchased), which suggests that land speculation is an important driver of extensive ranching profitability, and may continue to be in the future. These results suggest that pro-intensification policies such as credit provision for improved pasture management and investment in more intensive production systems must be accompanied by implementation and enforcement of policies that alter the incentives to clear forest for pasture, discourage land speculation, and increase accountability for land management practices if intensification of the cattle sector is to deter new deforestation and displace production from low-yield, extensive cattle production systems in frontier regions of the Brazilian Amazon.  相似文献   

11.
After two decades of decreasing agricultural activities, in 2008 the Mongolian government started the “Third Campaign of Reclaiming Virgin Lands”, aiming at massive expansion and intensification of the agricultural sector. This policy motivated the study presented here, for which we used an integrated modelling approach to investigate the feedbacks between land-use dynamics, agricultural management and biophysical conditions, with a strong focus on assessing availability of water for irrigation. Our simulation results clearly show that under the current extend of irrigated agriculture in several years water demands exceeded water availability, indicating an overexploitation of water resources, mainly in the period 1995–2006. Consequently, the targeted expansion of agricultural water use will either severely deplete water resources with potential negative effects on other users and the environment, or policies are needed to mitigate or avoid potential adverse effects. As simultaneously Mongolian authorities struggle to implement integrated water resources management (IWRM), the latter might provide monitoring concepts and regulations needed to minimise the potential gap between water demands and availability. In this context, integrated modelling could be a scientific tool to support future land and water management decisions, as researchers already started to integrate views and demands of Mongolian authorities into scenario and model development (identified during stakeholder workshops), and will continue to do so during the coming years of collaborative research.  相似文献   

12.
Recent decades have witnessed substantial losses of biodiversity in Europe, partly driven by the ecological changes associated with intensification of agricultural production. These changes have particularly affected avian (bird) diversity in marginal areas such as the uplands of the UK. Future trends for upland birds will likely be impacted by changes in agricultural support regimes, such as those currently envisaged in on-going reforms of the Common Agricultural Policy. We developed integrated ecological-economic models, using seven different indicators of biodiversity based on avian species richness and individual bird densities. The models represent six different types of farms which are typical for the UK uplands, and were used to assess the outcomes of different agricultural futures. Our results show that the impacts of these future agricultural scenarios on farm incomes, land use and biodiversity are very diverse across policy scenarios and farm types. Moreover, each policy scenario produces un-equal distributions of farm income changes and gains and losses in alternative biodiversity indicators. This shows that generalisations of the effects of policy and pricing changes on farm incomes, land uses and biodiversity can be misleading. Our results also suggest that a focus on umbrella species or biodiversity indicators (such as total species richness) can miss important compositional effects.  相似文献   

13.
The purpose of this study was to assess the effect of grassland (GL) conversion to cropland (CL) and cropland conversion to forest (FL) and orchard (OL) on soil C and N distribution in dry aggregate size fractions in Nihegou catchment of the southern Loess Plateau, China. Four main land-use changes were analyzed in different agronomic management systems in 2006. The soil is wind-deposited loessial parent materials with a rather homogeneous silty clay loam texture classified as Calcic Cambosols. The GL was long-term over-used grassland. The CL was changed from GL after 33 years tillage with conventional tillage and fertilizer. The FL and OL originated from long-term CL after 23- and 7-year planted, respectively. Samples were taken at soil depths of 0–20 cm and 20–50 cm and were subjected to a physical fractionation process by way of aggregate size. Soil aggregate size fractions, total C and N contents and distributions were determined on all soil samples. Three dry aggregate fractions of very coarse (2.0–0.2 mm), coarse (0.2–0.05 mm) and fine (<0.05 mm) were obtained by shaking and sieving for 20 min. After 33 years of tillage, CL had 22% lower content of very coarse aggregates (2.0–0.2 mm) and 34% higher contents of fine aggregates (<0.05 mm) than GL. FL and OL soils had increased 9% and 10% contents of very coarse aggregates, and decreased 2% and 8% contents of fine aggregates compared to the CL. C and N losses in whole CL soils were 31% and 26% higher than those in GL. However, conversion of land uses from CL to FL (after 23 years) and OL (after 7 years) has increased C and N stocks by 76% and 40% in FL soils and by 66% and 63% in OL soils, respectively. This accessorial C and N stocks were higher in very coarse aggregate fractions (1.10 kg C m−2 and 0.13 kg N m−2 in FL soils, 1.43 kg C m−2 and 0.17 kg N m−2 in OL soils); moreover, the C and N stocks in fine aggregate fraction increased by 8% and 33% in FL soils and by 58% and 69% in OL soils, respectively. This results showed that C and N turnover and loss in aggregate fractions of this silty clay loam soils was very fast. Conversion of land uses from CL to FL and OL has obviously recovered the soil structure, and improved soil quality.  相似文献   

14.
This paper provides empirical and conceptual insights in analysing the factors that determine the prices of farmland within Protected Natural Areas that are close to densely populated urban areas, the changes in land use experiences as well as the additional control policies needed to curb this unsustainable trend.The Urdaibai Biosphere Reserve nearby the metropolitan area of Bilbao (Basque Country, Spain) is the case study considered and its bordering non-protected rural area is used as a reference for comparison. A spatial hedonic farmland price model is estimated and the willingness of land purchasers to pay for different farmland characteristics quantified both inside and outside the Urdaibai Biosphere Reserve. The main results are that: (1) residential development is taking place in all categories of farmland, (2) aside from neighbouring prices, farmland prices depend on different factors depending on whether the marketed plots stand inside or outside the Protected Natural Area, (3) the “reserve effect” on land prices is less powerful than the “proximity to the metropolitan area (and motorway) effect” observed from villages of the non-protected area located in the 3rd crown of Bilbao, (4) the reasons for farmers non-compliance with policy regulations is the necessary knowledge base for the farmland conservation policy design and (5) in the light of the results, three development-control policy instruments such as Payments for Ecosystem Services, Tradable Planning Permits and development-taxes are discussed considering the factors that could improve compliance.  相似文献   

15.
湖北省土地利用变化及其驱动力分析   总被引:20,自引:1,他引:20  
根据1985年和1995年两个时期的土地资源调查数据,运用数理统计与定性描述相结合的方法,全面分析了湖北省13个市1985~1995年间土地利用的变化情况;揭示了该省各种土地利用类型变化的幅度、速度和区域差异;阐述了这一土地利用变化的驱动力主要是地形、自然灾害等自然因素及城镇人口的迅速增长、第二产业的发展、对土地产品的需求变化和交通条件及政府政策等社会经济驱动力。  相似文献   

16.
One of the main causes of tropical forest loss is conversion to agriculture, which is constantly increasing as a dominant land cover in the tropics. The loss of forests greatly affects biodiversity and ecosystem services. This paper assesses the economic return from increasing tree cover in agricultural landscapes in two tropical locations, West Java, Indonesia and eastern Bangladesh. Agroforestry systems are compared with subsistence seasonal food-crop-based agricultural systems. Data were collected through rapid rural appraisal, field observation, focus groups and semi-structured interviews of farm households. The inclusion of agroforestry tree crops in seasonal agriculture improved the systems’ overall economic performance (net present value), even when it reduced understorey crop production. However, seasonal agriculture has higher income per unit of land area used for crop cultivation compared with the tree establishment and development phase of agroforestry farms. Thus, there is a trade-off between short-term loss of agricultural income and longer-term economic gain from planting trees in farmland. For resource-poor farmers to implement this change, institutional support is needed to improve their knowledge and skills with this unfamiliar form of land management, sufficient capital for the initial investment, and an increase in the security of land tenure.  相似文献   

17.
Land speculation by cattle ranchers is considered a principal cause of deforestation in Latin America, in particular in combination with (previously) widely provided interest rate subsidies. Proof for the hypothesis that land speculation leads to inflated rates of investment in land is, however, relatively limited and invariably related to the question of whether land prices tend to rise over time. Based on the Neoclassical investment theory with adjustment costs we develop a stochastic cattle ranching model in which land prices are modelled as geometric Brownian motion, to evaluate the effect of expected fluctuations in land prices on land investment decisions by cattle ranchers in Latin America. For a case study in the Atlantic Zone of Costa Rica, results show that the expected rate of investment is almost 35% underestimated in case land prices are assumed constant instead of fluctuating according to the standard deviation, while abolition of interest rate subsidies leads to an almost 15% decrease in the expected rate of investment. Consequently, it is shown that variability in land prices alone is a sufficient condition for land speculation, inflated rates of investment in land, larger farm sizes and, thus, higher rates of deforestation in agrarian frontier areas, while this process is further promoted by subsidized livestock credit or any other form of agricultural subsidy that increases the marginal production value of land.  相似文献   

18.
Increasing water scarcity combined with an increasing demand for food and water for irrigation call for a careful revision of water use in agriculture. Currently, less than 60% of all the water used for irrigation is effectively used by crops. Based on the new version of the GTAP‐W model we analyze the effect of potential water savings and the welfare implications of improvements in irrigation efficiency worldwide. The results show that a water policy directed to improve irrigation efficiency led to global and regional water savings, but it is not beneficial for all regions. The final effect on regional welfare will depend on the interaction of several different causes. For instance, higher irrigation efficiency changes opportunity costs and reverses comparative advantages, modifying regional trade patterns and welfare. For water‐stressed regions the effects on welfare are mostly positive. For nonwater scarce regions the results are more mixed and mostly negative. The results show that exports of virtual water are not exclusive of water abundant regions.  相似文献   

19.
Traditional measures of technological change, such as the rate of technical change, are based on producer-oriented prices. Here, we employ a general equilibrium analysis of an open economy to examine how the consumer welfare gain from a technological change, measured as Hicksian equivalent variation, is related to the rate of technical change, the biases of the technological change, and tax distortions in the economy. An analytical solution shows these relationships in a readily computable framework, and demonstrates that the rate of technical change will equal the rate of welfare change in only very unrealistic cases.  相似文献   

20.
This paper explores the theoretical debates on extraction and development in Amazonia, and the emergence of extractive reserves (ERs) as a tropical development alternative. It reviews the role of women in Amazonian rural economies and then analyzes the (often invisible) tasks of women within the reserves through an analysis of the gender division of labour in the collecting and processing of non-timber forest products and agriculture. It then considers how lack of attention to rural women's labour obligations played out in a development project, Projeto Castanha, that began as an urban factory, but was later recast as a neoliberal decentralized processing and outsourcing programme. The project failed to appreciate the demands on, and the opportunity costs, of women's time and thus had very limited success as women withdrew their labour. The paper argues that there may be many more options for supporting extractive economies (and the women who work in them) in more peri-urban and village projects even though extractive reserves are valuable ecologically and socially in the regional economy.  相似文献   

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