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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.
The year 2019 in Brazil was marked by environmental setbacks, which catalyzed the increase of illegal deforestation and fire rates in the Brazilian Amazon. In the Amazon region of Maranhão state, original forest cover diminished from 25 % (24,700 km2) in 2016 to 24 % (23,967 km2) in 2019, and 6,038 km2 of remaining forests were degraded by fires and/or illegal logging – processes related to high levels of violence against indigenous and rural communities. Almost half of all deforested areas in the region (36,060 km2) are considered a global restoration hotspot, however secondary vegetation remains unprotected and 8,294 km2 were cleared between 2014 and 2018. Due to uncontrolled deforestation and fragmentation, Maranhão has no more forest core areas (outside protected areas) with the minimum size to ensure sustainable forest management practices for timber production. New policies at the state level must promote old-growth and secondary forest conservation and restoration. However, the trends point to the opposite direction: the Ecological-Economic Zoning (ZEE) allows the reduction of forest protection and the State Forest Policy reinforces federal legislation setbacks. The Amazon region of Maranhão state has forest aptitude, and forest and agroforestry product chains would bring social and environmental benefits, making them the best opportunity for sustainable economic development in the region. Therefore, the forest must be re-planted for the benefit of people and nature.  相似文献   

3.
Changes in agricultural land use have important implications for environmental services. Previous studies of agricultural land‐use futures have been published indicating large uncertainty due to different model assumptions and methodologies. In this article we present a first comprehensive comparison of global agro‐economic models that have harmonized drivers of population, GDP, and biophysical yields. The comparison allows us to ask two research questions: (1) How much cropland will be used under different socioeconomic and climate change scenarios? (2) How can differences in model results be explained? The comparison includes four partial and six general equilibrium models that differ in how they model land supply and amount of potentially available land. We analyze results of two different socioeconomic scenarios and three climate scenarios (one with constant climate). Most models (7 out of 10) project an increase of cropland of 10–25% by 2050 compared to 2005 (under constant climate), but one model projects a decrease. Pasture land expands in some models, which increase the treat on natural vegetation further. Across all models most of the cropland expansion takes place in South America and sub‐Saharan Africa. In general, the strongest differences in model results are related to differences in the costs of land expansion, the endogenous productivity responses, and the assumptions about potential cropland.  相似文献   

4.
The Amazon forest in the state of Maranhão ensures ecosystem services that directly and indirectly affect the life quality of its population and economy, via hydrologic and climatic regulation, among other benefits. Currently, only 25% of the original forest cover (24.7 thousand km2) remains while illegal deforestation persists in a violent process that provokes visible social, economic and environmental harm. Simultaneously, Maranhão has seen record levels of burning, faces a water shortage and fights against the worst social and economic indicators in the country. Conversely, secondary vegetation covers 19.9 thousand km2 (27% of deforested area) and is completely unprotected. Contrary to the international commitments assumed by Brazil to combat deforestation and restore forests, some of the political representatives of Maranhão have sought legal mechanisms to further diminish forest cover in public and private areas. To promote the conservation and restoration of Maranhão Amazon Forest, a multi-institutional network of researchers was established in 2015. This viewpoint paper aims to draw attention to this endangered region of the Brazilian Amazon and give science-oriented recommendations to policy makers in order to avoid more setbacks. We argue that Maranhão state must urgently establish a policy of Zero Deforestation, protect secondary forests and comply with the national forest restoration policy, thus ensuring long-term economic sustainability.  相似文献   

5.
Desertification and land degradation are worldwide problems affecting soil, vegetation and the livelihoods of rural populations. Bowal (plural bowé) is a particular form of degraded land that occurs in tropical regions and leads to the exposure of ferricretes, which are unsuitable for farming. Bowé are more common on farmland and degraded savanna. Changes in land use/land cover were used to map a region of 6.7 million ha in northern Benin, West Africa in 1975, 1990 and 2010. The changes observed during these periods (1975–1990, 1990–2010 and 1975–2010) were used to predict the occurrence of bowé in the period up to 2050 using Markovian chain analysis. The results showed a considerable change in land use/land cover during the three periods. The types of land on which bowé occur (farmland and degraded savanna) increased in northern Benin by 5.4% per year during the period 1975–1990 and 9.5% per year during the periods 1990–2010, while the natural vegetation (forest, woodland and tree savanna) decreased by the same amount. The future scenarios also predicted the same trend. In the period 1975–1990, 1.28 million ha (26%) of natural vegetation was converted to degraded savanna and farmland while 2.23 million ha (53%) of natural vegetation was converted to degraded savanna and farmland in the period 1990–2010. Based on the dynamics recorded during the period 1975–1990 and 1990–2010 respectively, a total of 1.28 million ha (26% of the natural vegetation that was present in 1975) and 1.29 million ha (31% of the natural vegetation that was present in 1990) will be converted to farmland and degraded savanna in the study area by 2050.Thus bowalization will persist and increase in the period up to 2050. The natural vegetation could disappear if protection and restoration measures are not taken. It is thus important to take measures to stop the degradation and to implement programs to restore soils on bowé based on the soil and water conservation techniques used on highly degraded West African soils, such as zaï pit and stone rows with grass strips. Some native plants species adapted to bowalization and resistant to climate change in northern Benin (e.g. Asparagus africanus, Andropogon pseudapricus and Combretum nigricans) should be used in association with soil and water conservation techniques on bowé.  相似文献   

6.
Measuring the ability of a community to face climatic changes, or its adaptive capacity, is necessary in order to plan and guide development as the global climate continues to warm. One factor that has not been thoroughly addressed by previous attempts at measuring adaptive capacity is urbanization. This study looks to measure adaptive capacity in relation to urbanization, as many areas of the world are undergoing this rapid transition. An indicator system was created with land-use sensitive measures and applied to three different land use projection scenarios (A, BAU, and B − high, medium, and low growth, respectively) to 2030 and 2050 for two case study areas, Tamsui, Taiwan and West Palm Beach, USA. In Tamsui, the adaptive capacity decreased in all scenarios, but most dramatically for the high growth scenario. The low growth scenario decreased more slowly through each time slice. For West Palm Beach, the high growth scenario had the highest score in 2030, but declined in 2050. The medium growth Scenario BAU, also had a higher adaptive capacity score in 2030 than in 2050. The low growth Scenario B had a score that improved less dramatically but continued to rise through 2050. Scenario A would be ideal for short term gains, but its benefits would plateau in the long term. Scenario B, with conservation measures and more restricted growth would be the most ideal alternative. This study shows that urbanization has short term socioeconomic gains, but long term environmental consequences. The results also successfully incorporates the effect of land use change into an adaptive capacity indicator system, and can be applied in other localities expecting significant increases in urbanization.  相似文献   

7.
Land cover change in the Neotropics represents one of the major drivers of global environmental change. Several models have been proposed to explore future trajectories of land use and cover change, particularly in the Amazon. Despite the remarkable development of these tools, model results are still surrounded by uncertainties. None of the model projections available in the literature plausibly captured the overall trajectory of land use and cover change that has been observed in the Amazon over the last decade. In this context, this study aims to review and analyze the general structure of the land use models that have most recently been used to explore land use change in the Amazon, seeking to investigate methodological factors that could explain the divergence between the observed and projected rates, paying special attention to the land demand calculations. Based on this review, the primary limitations inherent to this type of model and the extent to which these limitations can affect the consistency of the projections will also be analyzed. Finally, we discuss potential drivers that could have influenced the recent dynamic of the land use system in the Amazon and produced the unforeseen land cover change trajectory observed in this period. In a complementary way, the primary challenges of the new generation of land use models for the Amazon are synthesized.  相似文献   

8.
Reducing carbon emissions from deforestation and forest degradation now constitutes an important strategy for mitigating climate change, particularly in developing countries with large forests. Given growing concerns about global climate change, it is all the more important to identify cases in which economic growth has not sparked excessive forest clearance. We address the recent reduction of deforestation rates in the Brazilian Amazon by conducting a statistical analysis to ascertain if different levels of environmental enforcement between two groups of municipalities had any impact on this reduction. Our analysis shows that these targeted, heightened enforcement efforts avoided as much as 10,653 km2 of deforestation, which translates into 1.44 × 10−1 Pg C in avoided emissions for the 3 y period. Moreover, most of the carbon loss and land conversion would have occurred at the expense of closed moist forests. Although such results are encouraging, we caution that significant challenges remain for Brazil's continued success in this regard, given recent changes in the forestry code, ongoing massive investments in hydro power generation, reductions of established protected areas, and growing demand for agricultural products.  相似文献   

9.
Grassland conversion to row-crop production in the north central United States has been a growing threat to socio-economic and environmental sustainability for producers, conservationists, and policy-makers alike. We used a system dynamics model of the region to forecast agriculturally driven land transformation through mid-twenty-first century. The base-case scenario projection showed that farmland area continued to increase, from under 200,000?km2 to over 230,000?km2. Unmitigated, the soil environmental risk (SER) of such changes reached conservative estimates of Dust Bowl-era externalities. Systems analyses show that reducing livestock production costs, doubling conservation compliance requirements, and livestock–cropping integration had the largest impact on grassland conservation and mitigating SER. The largest SER effects came from eliminating conservation incentives or raising cultivation incentives, despite improvements in reduced tillage and enhanced agronomy. Several system archetypes were identified within the policy scenarios: ‘fixes that backfire’ and ‘success-to-the-successful’. For scenarios creating favourable impacts, time delays caused some behaviours to worsen before positive gains were realized. If implemented, patience and persistence to ensure that these scenarios reach their full potential will be necessary. Our scenarios provide quantitative forecasts around measures for sustainable intensification. These projections can aid regional stakeholders in enhancing discussions currently taking place about sustainable agriculture in the region.  相似文献   

10.
In seeking to achieve poverty alleviation and environmental conservation, public policy has often centred on guaranteeing land titles to local peoples. However, such approaches have brought unintended outcomes, replacing small-scale economies and natural areas by intensive exploitation of resources with no clear improvement in local people’s wellbeing. To understand this, we go beyond a general political ecology framing to consider relations between sustainability and land tenure, focusing on the intersection of economics, ecology and anthropology to understand how land tenure, property and use play out on the ground. We draw together different concepts including bundle of rights, de facto and de jure resource use, property regimes, density-dependence and non-equilibrium theory. The significance of this three-discipline view is illustrated through a case study of the Pantanal wetland, Brazil, where conservationists, the government and the local population contest ownership of the Paraguay River floodplain. Government sought to address conflicts around tenure and access through a narrow view of property, which failed to encompass the overlapping layers of land tenure, property and use on the ground and only served to create further legal battles. This article concludes that a more complex view combining the three perspectives is needed in the case of the Pantanal, and in other cases of contested property rights, in order to resolve conflicting claims and foster sustainability. We dissect both the power plays involved between different groups competing for control of a valuable resource, and the legal frameworks which can and should provide checks and balances in the system. The more nuanced grasp that emerges of local systems of tenure and access, of how these diverge from western property concepts, and of their environmental implications favours a better understanding of local realities, allowing for better management policy and consequently contributing more effectively towards poverty alleviation and environmental protection.  相似文献   

11.
Evaluating the impact of rising fertilizer prices on crop yields   总被引:3,自引:0,他引:3       下载免费PDF全文
Because of tensions on fossil energy and phosphorus markets, the rise in fertilizer prices observed during the last decades may continue in the future, putting into question production pathways relying heavily on crop intensification. To evaluate how, in this context, economic choices may alter crop yields, we first construct different fertilizer price scenarios to 2050 based on an econometric relation with oil and gas prices. Other possible scenarios, such as the continuation of historical trends, are also considered. The resulting changes in fertilizer price range between +0.8% and +3.6% per year over the 2005–2050 period. These scenarios are tested in a global land‐use model incorporating an endogenous representation of the land–fertilizer substitution. We find that the supply‐side response to rising fertilizer prices could lower crop yields in 2050 from ?6% to ?13%, with a corresponding increase in global cropland area ranging between 100 and 240 Mha if the demand for food and nonfood products has to be met. The sensitivity of these results is tested with regard to assumptions on food consumption, change in potential yield and nutrient use efficiency.  相似文献   

12.
The loss and degradation of wetlands in the Mekong Delta has been caused by a combination of human activities (social systems) and natural events (ecological systems). However, the complexity and interaction of these socio-ecological factors are poorly understood. This study provides a better understanding of the complex social-ecological factors affecting land-cover change in the Phu My Lepironia grassland conservation area, part of Kien Giang Biosphere Reserve, Vietnam. A systems thinking approach was used to determine the interaction between the social system and land-use and land-cover changes. Results indicate that ensuring food supply and improving income are the key endogenous drivers of wetland degradation in the study area. Over-exploitation of wetland resources and inappropriate agricultural practices are accelerating wetland conversion and degradation. The conflict and unclear land tenure, coupled with a desire for higher income, has driven the community to convert and reclaim large parts of the wetland. This process is also driven exogenously by wetland access and the fluctuation of commodity prices, which in-turn results in transition from traditional to extensive cropping systems and expansion of cultivated land into the protected wetland. The relationship between people and wetlands must be central to the development of wetland policies and wetland management approaches. This will improve how land use policy supports sustainable sources of food and income for the local community and concurrently reduce pressures on wetland degradation. Any efforts made to protect the remnant wetland grassland and its diverse ecosystem by regulation should be supplemented by developing and sustaining the relationship between social systems and ecological systems.  相似文献   

13.
Agricultural land abandonment is a policy challenge, especially for areas with unfavorable conditions for agriculture and remote and mountainous areas. Agricultural abandonment is an important land use process in many world regions and one of the dominant land use change processes in Europe. Previous studies have shown that abandonment can have both positive and negative effects on several environmental processes, influenced by location and scale. Preferred policies and management of these areas are debated given concerns for the loss of (traditional) agricultural landscapes and potential impacts on biodiversity and ecosystem services. We present a European-scale impact assessment of the possible effects of agricultural abandonment, based on eight indicators that are on the forefront of the agricultural abandonment debate. Using a multi-scale modelling approach, we expect between 71.277 and 211.814 km2 of agricultural abandonment in 2040. Impacts on the indicators and trade-offs between the impacts are spatially variable. A typology of typical trade-off bundles at a 1 km2 resolution resulted in four typical trade-off clusters. All clusters identified are characterized by a loss of agriculture-related values, such as agro-biodiversity and cultural heritage. For two clusters, this was accompanied by positive effects on indicators such as carbon sequestration, nature recreation and mammal habitat suitability. Overall, our results indicate that location and scale are key to assess the trade-offs originating from agricultural abandonment in Europe. Identification of typical trade-offs bundles can help to distinguish potential desirable outcomes of agricultural abandonment and assist in targeting measures to areas that face similar management challenges.  相似文献   

14.
Land Use and Land Cover (LULC) changes have profound impacts on the functioning of (agro)ecosystems and have potential to mitigate global climate change. However, we still lack interdisciplinary methods to project future LULC scenarios at spatial scales that are relevant for local decision making and future environmental assessments. Here we apply an interdisciplinary approach to develop spatially explicit projections of LULC at a resolution of 30 × 30 m informed by historic relationships between LULC and their key drivers, within the context of the four qualitative scenarios of global shared socioeconomic pathways. We apply this methodology to a case study in the Zona da Mata, Brazil, which has a history of major LULC changes. The analysis of LULC changes from 1986 to 2015 indicates that pasture area decreased from 76 to 58 % of total area, while forest areas increased from 18 to 24 %, and coffee from 3 to 11 %. Environmental protection legislation, rural credit for smallholder farmers, and demand for agricultural and raw products were identified as main drivers of LULC changes. Projected LULC for 2045 strongly depends on the global socioeconomic pathway scenarios, and forest and coffee areas may increase substantially under strong government measures in the environmentally conscious Green Road scenario or decrease in the high consumption Rocky Road scenario. Our study shows that under the set of drivers during the past three decades reforestation can go hand in hand with increase of agricultural production, but that major and contrasting changes in LULC can be expected depending on the socioeconomic pathway that will be followed in the future. To guide this process, LULC scenarios at the local scale can inform the planning of local and regional development and forest conservation.  相似文献   

15.
With rapid increases in global food demand and production, oil palm expansion constitutes a major emerging challenge for forest conservation in Amazonia and other tropical forest regions. This threat is evident in the Peruvian Amazon, where local and national incentives for oil palm cultivation along with growing large-scale investments translate into accelerated oil palm expansion. Environmental sustainability of oil palm cultivation in the Peruvian Amazon is contingent on policy incentives for expansion onto already-cleared lands instead of biodiverse, high carbon primary rainforests. Previous research indicates that while industrial plantations use less land area than local smallholders, companies have a higher tendency to expand into primary rainforests. However, the motivations behind these differing expansion scenarios remain unclear. In this study we combine data from optical and radar satellite sensors with training information, field discussions, and review of public documents to examine the policy incentives and spatial patterns associated with oil palm expansion by smallholders and industries in one of Peru’s most rapidly changing Amazonian landscapes: the Ucayali region of the city of Pucallpa. Based on our satellite-based land cover change analysis, we found that between 2010 and 2016, smallholders utilized 21,070 ha more land area for oil palm than industries but industrial expansion occurred predominantly in old growth forests (70%) in contrast to degraded lands for smallholders (56%). Our analysis of national policies related to oil palm expansion reveal policy loopholes associated with Peru’s “best land use” classification system that allow for standing forests to undergo large-scale agricultural development with little government oversight. We conclude that both sectors will need careful, real-time monitoring and government engagement to reduce old-growth forest loss and develop successful strategies for mitigating future environmental impacts of oil palm expansion.  相似文献   

16.
Urbanization is a primary cause of wetland loss in coastal metropolitan regions. Therefore, it challenges the preservation of biodiversity and the provision of key ecosystem services for urban settlements. These services include leisure and recreation, climate and water regulation, water purification, and especially alleviation of natural hazards. Tsunami flood mitigation is a particularly valuable regulating service provided by these wetlands, as recently evidenced during the 2010 tsunami that hit the central coast of Chile.The Concepción Metropolitan Area (CMA), located on the central coast of Chile, has experienced noticeable wetland loss in recent decades. Our study focused on the Rocuant-Andalién wetland, which has been particularly affected by urbanization. This wetland strongly contributes to flood control, and has provided effective protection against the CMA’s latest tsunamis (1835 and 2010). Based on Strategic Environmental Assessment (SEA), we have quantified urban growth over the wetland, both executed and projected under the Metropolitan Urban Plan of Concepción (MUPC). Recent loss in wetland area by urban growth has been quantified using land use and cover change (LUCC) maps from 2004 to 2014, obtained from the classification of Landsat images. Prospective changes (considering the complete MUPC deployment) have been inferred by combining the MUPC with the 2014 land cover map. In addition, we quantified the observed effect and planned urban growth on the wetland protected area, geoforms and potential flooding based on the area affected by the last Tsunami. Results show that urban areas have increased by 28% between 2004 and 2014, while future increase is expected to reach 238%. In contrast, wetland area has decreased by 10% from 2004 to 2014 and is expected to decrease by up to 32 %. Thus, the MUPC is not contributing to the mitigation of wetland loss nor the preservation of its biodiversity and ecosystem services. Implications for coastal planning are discussed.  相似文献   

17.
Recent studies assessing plausible futures for agricultural markets and global food security have had contradictory outcomes. To advance our understanding of the sources of the differences, 10 global economic models that produce long‐term scenarios were asked to compare a reference scenario with alternate socioeconomic, climate change, and bioenergy scenarios using a common set of key drivers. Several key conclusions emerge from this exercise: First, for a comparison of scenario results to be meaningful, a careful analysis of the interpretation of the relevant model variables is essential. For instance, the use of “real world commodity prices” differs widely across models, and comparing the prices without accounting for their different meanings can lead to misleading results. Second, results suggest that, once some key assumptions are harmonized, the variability in general trends across models declines but remains important. For example, given the common assumptions of the reference scenario, models show average annual rates of changes of real global producer prices for agricultural products on average ranging between ?0.4% and +0.7% between the 2005 base year and 2050. This compares to an average decline of real agricultural prices of 4% p.a. between the 1960s and the 2000s. Several other common trends are shown, for example, relating to key global growth areas for agricultural production and consumption. Third, differences in basic model parameters such as income and price elasticities, sometimes hidden in the way market behavior is modeled, result in significant differences in the details. Fourth, the analysis shows that agro‐economic modelers aiming to inform the agricultural and development policy debate require better data and analysis on both economic behavior and biophysical drivers. More interdisciplinary modeling efforts are required to cross‐fertilize analyses at different scales.  相似文献   

18.
Drainage and loss of wetland sites is a major problem of the agricultural landscape, as it reduces the landscape’s ability to retain water, nutrients, matter, and minimize erosion. With this in mind, the issue of the ability of wet sites to retain radionuclides and contaminated water in the case of a radiation accident was studied. In 2013, field research examined the occurrence of wetland retention sites in the emergency planning zone (EPZ) of the Temelín nuclear power plant (NPP; Czech Republic). As data sources, wetland biotopes (European network Natura 2000) were considered; in addition, retention features were field mapped, i.e. landscape elements of a wetland nature not normally considered nationally significant for conservation. Within the emergency zone, 2854.7 ha of wetland biotopes were registered and 318.9 ha retention features mapped. Density of retention sites (in ha/km2) per cadastre (local administrative units) was used to represent their spatial distribution within the zone. For an assessment of possible revitalization measures, leading to an increase in the landscape’s retention ability, spatial changes in the area of retention sites between 2013 and the mid-19th century, a period before extensive drainage of landscape occurred and a simplification of its structure, were mapped. Historic land maps (The Imperial Obligatory Imprints of the Stable Cadastre) were used as a basis of information on the occurrence and area of fens and wet meadows (4771.5 ha).For spatial comparisons of drained and undrained landscape in the past and present, the density of retention sites per cadastre was calculated. In the mid-19th century, 80% of cadastres had a density of retention sites exceeded 5 ha/km2; in 2013 only 40% of cadastres achieved this. In the most part, drained areas of the zone belong to the central part (around the power plant), as well as the EPZ’s eastern and south-eastern regions. From the density maps of retention sites, as well as from the stable cadastre imprints, it is possible to identify areas and retention features suitable for wetland restoration, thus leading to an increase in the retention capacity of the landscape in terms of water and radionuclide retention. Suggestions as to how to restore and turn retention features into semi-natural wetlands, as well as integrating small wetlands into an agriculture landscape are outlined.  相似文献   

19.
Economic activities in coastal wetlands are often perceived as incompatible with nature conservation. This negative perception stems from the visible impacts resulting from a continuous process of coastal wetland reclamation, as human pressure increases significantly in global coastal areas. The largest coastal wetland area in southern Portugal, the Ria Formosa, shares a similar perception, where current nature protection status often conflicts with the needed economic development. Here we explore how the economic activities influenced the wetland reclamation process in Ria Formosa, addressing namely aquaculture identified as an activity with a significant compatibilization potential. Different datasets were merged in a Geographical Information System, tracking land use change in Ria Formosa wetlands over the last 130 years at decadal intervals. Our results show that since the end of the 19th century nearly 2000 ha of wetlands were converted to anthropic environments, resulting in a 20 % natural area reduction. From 1885 until the mid-20th century, land use policy was influenced by the significant regional seafood preservation industry, with large swaths of wetlands diked, drained and excavated to give place to traditional salt farms. The following economic downturn gave place for the late industrialization of salt farms, further increasing the reclaimed wetland areas, later stalling with the recognition of the environmental importance of Ria Formosa in 1978. Aquaculture only gained momentum in 1980’s with the support of European funding, resulting in the conversion of many unproductive diked areas. However, late 20th century and current land use policy shifted to a nature conservation focus, therefore limiting the use of previously reclaimed areas, a challenge that influenced the abandonment of the modified areas. By studying the long-term change of land use in Ria Formosa, we argue that in high conservation value areas new policies should be considered that stimulate the development of an ecosystem approach to economic activities, namely aquaculture, improving simultaneously the regional environmental status and socioeconomic sustainable development.  相似文献   

20.
The semiarid region in the state of Sergipe, Brazil, approximately 11,000 km2, has experienced high deforestation rates in the last decades, which ultimately contribute to global climatic changes. The valuation of ecosystem services of CO2 sequestration can support definition of environmental policies to decrease deforestation in that region. This study aimed to assess land use and land cover changes in the Sergipe semiarid region between 1992 and 2017 by applying remotely sensed data and technics; simulate the land use and land cover changes between 2017 and 2030 by applying a cellular automaton model, by assuming current land use trends (Business as Usual – BAU) as a reference scenario, and a more conservative scenario (Protected Forest – PF), in which was assumed an effective enforcement of the Brazilian Forest Code established in 2012; simulate the carbon stocks by 2017 assuming the BAU and PF scenarios by 2030, and estimate the Carbon balance between the 2030 and 2017 scenarios; and estimate the economic valuation of carbon emission and sequestration by using the InVEST software. The results showed that agriculture (cropped lands) was main driver of the landscape changes in the study area, which increased 14% by 2017, a net increase of 1494.45 km2. The results showed that the total Carbon emissions would reach 736,900 Mg CO2-eq by assuming the BAU scenario, which would increase the cost of opportunity up to US$ 17.7 million and a social carbon cost varying between US$ 10.3 and US$ 30.2 million. The restoration of the permanent preservation areas could contribute to increase Carbon sequestration up to 481,900 Mg CO2-eq by 2030, which is equivalent cost of US$ 11.6 million. The natural landscape in the Sergipe semiarid region was strongly affected by deforestation activities occurred between 1992 and 2017. It requires, therefore, effective actions to support and promote restoration of degraded areas. The forested areas within the Sergipe semiarid region were the most affected type of vegetation because of expansion of agricultural fields soil exposures (Exposed Land). Environmental assessments based on scenarios and economic valuations can provide crucial information to support policy and decision makers to improve strategies for environmental management and conservation.  相似文献   

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