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1.
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   

2.
In Brazil, incorporating the environmental dimension to the planning process is a challenging process. Planning has historically been carried without considering environmental protection concerns. The country's large development projects have engendered a discussion on the feasibility of these works given the conflicts with environmental policies. The strategic environmental assessment (SEA) is a tool that has the potential to integrate the sectoral, territorial and environmental perspectives to promote sustainable development, as shown by international experience. Its use has not yet been regulated in Brazil, only been voluntary initiatives, both public and private, have been implemented. This paper presents the structure and results of the SEA of the plans to expand silviculture of eucalyptus and biofuels in the Extreme South Region of Bahia state, in the Brazilian Northeast, in a context of sectoral planning dissociated from government guidelines for land use policy and environmental protection. It portrays a practical case of methodological proposal for the use of socio-environmental criteria to establish limits for land occupation by monocultures, for each of the municipalities of the study region, according to their specific climate, soil, relief and environmental preservation characteristics. Various alternatives were identified to ensure areas with greater productivity for small family farming and areas with potential for preservation. SEA helped to a better understanding of the effects of the expansion of the planting areas in each alternative, which was essential to help all stakeholders visualize the consequences of their strategies. Consequently, as results the SEA outlined a series of guidelines and restrictions for the various levels of government and the production sector. For instance, SEA suggested for Federal, State and Municipality governments that areas with better soil and climate conditions could be reserved for public policies to incentive the diversification of the uses of the territory, such as food production. SEA also suggests the adoption of incentive programs to establish multiple-use forests. The SEA recommended that the state government integrate its program for strengthening family agriculture with land-use planning criteria, based on cooperative systems The methodology employed has evidences to be replicable in other regions of Brazil and in developing countries.  相似文献   

3.
The environmental, cultural and economic consequences of land use change, including abandonment of agricultural use, have been recognized for a long time. It has often been assumed that the transformations of the agricultural systems in developed countries (and particularly in Europe) took place, for the main part, in the immediate years after the Second World War. In this paper we present a review of different statistical and cartographic sources available for a peripheral region in Europe (Galicia, Spain) characterized by small-scale farming and a very fragmented property system, that suggests otherwise: modernization of agriculture apparently took place without major changes in agricultural area until the country gained access to the European Economic Community, and the effect of Common Agricultural Policy reforms during the decade of 1990 is suggested as a major driver for the net decrease of agricultural area in the region between 1956 and 2004. On the other hand, this paper emphasizes the spatial complexity of agricultural abandonment with a case study, showing a large degree of variability at municipal scale and thus the need of future EU-level projects to work at least at municipal (Local Administrative Units 2, LAU 2) level. Finally, a multinomial logistic model for observed changes is included that shows how biophysical limitations were the main drivers behind abandonment of agriculture at parcel scale, while structural qualities related to property structure were strongly associated to the incorporation of former shrublands to agricultural use. Besides, Farm Structure Surveys were revealed as an unreliable source for the assessment of changes in total agricultural area in the studied region.  相似文献   

4.
In the coming decades, an increasing competition for global land and water resources can be expected, due to rising demand for food and bio‐energy production, biodiversity conservation, and changing production conditions due to climate change. The potential of technological change in agriculture to adapt to these trends is subject to considerable uncertainty. In order to simulate these combined effects in a spatially explicit way, we present a model of agricultural production and its impact on the environment (MAgPIE). MAgPIE is a mathematical programming model covering the most important agricultural crop and livestock production types in 10 economic regions worldwide at a spatial resolution of three by three degrees, i.e., approximately 300 by 300 km at the equator. It takes regional economic conditions as well as spatially explicit data on potential crop yields and land and water constraints into account and derives specific land‐use patterns for each grid cell. Shadow prices for binding constraints can be used to valuate resources for which in many places no markets exist, especially irrigation water. In this article, we describe the model structure and validation. We apply the model to possible future scenarios up to 2055 and derive required rates of technological change (i.e., yield increase) in agricultural production in order to meet future food demand.  相似文献   

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