Controlling deforestation in the Brazilian Amazon: Regional economic impacts and land-use change

Brazil confirmed targets for reducing greenhouse gas emissions in 2008, including an 80% reduction in deforestation in the Amazon by 2020. With this in mind, we investigated the trade-off between environmental conservation and economic growth in the Amazon. The aim of this study is to project the economic losses and land-use changes resulting from a policy to control deforestation and the rise in land productivity that is necessary to offset those losses. We developed a Dynamic Interregional Computable General Equilibrium Model for 30 Amazon regions with a land module allowing conversion between types of land. The results have shown that the most affected regions would be soybeans and cattle producers as well as regions dominated by family farms. To offset these impacts, it was estimated that an annual gain of land productivity of approximately 1.4% would be required.     

Quantifying land-use change impacts on the dynamic evolution of flood vulnerability

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.     

Social metabolism,landscape change and land-use planning in the Barcelona Metropolitan Region

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.     

The consequences of land-use change and water demands in Central Mongolia

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.     

土地利用变化对湿地生态系统温室气体排放的影响

湿地特殊的水热效应和温室气体代谢过程决定湿地是全球变化的影响和响应区。随着人口的增长和技术的进步,湿地生态系统成为人类活动破坏最严重的生态系统之一,而农业排水和开垦是湿地丧失的主要原因。湿地是地球上重要的碳储存库,其储碳量占地球陆地碳总量的15%。土地利用的变化改变了湿地生态系统碳循环的模式,大量温室气体被排放,对全球变化产生深远影响。湿地的恢复与重建能促进碳积累和减少温室气体排放。     

Effect of land-use conversion on C and N distribution in aggregate fractions of soils in the southern Loess Plateau,China

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.     

Farmland prices and land-use changes in periurban protected natural areas

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.     

湖北省土地利用变化及其驱动力分析

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。     

基于RS的佛山市土地利用变化的时空特征研究

对1988,1999年佛山市两期TM遥感影像数据加以处理。分析了土地利用程度变化值和土地利用动态度。土地利用变化的时空特征表现为近10年来城市用地面积沿主要道路迅速扩展,导致水域,耕地和林地面积大量减少,城市用地矛盾日益突出。     

Effect of land-use change on soil fertility characteristics within water-stable aggregates of two cultivated soils in northern Iran

Forest and pastureland soils in highland of northern Iran are being seriously degraded and destructed due to extensive agricultural activities. These land use changes are usually accompanied by decreasing in concentrations of soil organic carbon and nutrients and also deterioration of soil structure in these regions. However, studies on concentration of nutrients and carbohydrates in soils suggest that the location of nutrients within aggregates of each size should be determined. This study was to evaluate the nutrient elements and carbohydrate distributions within water-stable aggregates (WSA) of virgin forest and pasture lands under different land uses in Alborz maintain range, northern Iran. In September 2006, soil samples were collected from depths of 0–20 cm in Typic Haploxerolls soils. The overall pattern indicated that the mean weight diameter (MWD) and WSA were greater in the virgin pasture and forest soils compared with the adjacent cultivated (ex-forest and ex-pasture) soils and aggregates of >1.0 mm size were dominant in the virgin soils, whereas the cultivated soils comprised aggregates of the size ≤0.5 mm. Distribution of organic carbon, nitrogen, phosphorus and carbohydrates within the WSA showed preferential enrichment of these parameters in the macroaggregate fraction (4.75–1.0 mm) for the virgin soils and microaggregate fraction (>0.25 mm) for the exposed soils. Cultivation decreased the concentration of carbohydrates by 23.6% and 20.6% in ex-forest and ex-pasture lands, respectively. Average distribution of total exchangeable bases within WSA showed that the cultivation of forest and pasture soils significantly led to reduce in these nutrient in the 4.75–2.0 mm fraction and increase in concentration of these exchangeable cations in <0.25 mm fractions. In general, results indicated that cultivation significantly led to 71% and 6% reductions in total exchangeable bases within the 4.75–2.0 and <0.25 mm aggregate fraction, respectively, for virgin soil. Since smaller aggregates are preferentially removed by erosion, this study emphasizes the need for sustainable soil management practices that they will minimize nutrient loss when forest or pastures lands are converted to croplands.     

桂西北喀斯特山区土地用地结构变化及驱动因素分析

利用土地利用变化幅度、单一土地利用动态度、综合土地利用动态度、土地利用程度综合指数等模型,对河池市土地利用动态变化分析,采用因素相关性分析法对其驱动因素进行分析;2001-2007年农业用地面积减少,园地面积逐步增长,建设用地面积一直呈现增长态势,累计增长量达5990．380hm2,2001年、2004年、2007年河池市土地利用程度综合指数分别为178．56,178．80,178．41,土地呈现从高度开发利用向合理调整转变的趋势;政策因素、经济和交通的快速发展、人口增长等都是促进土地利用变化的主要驱动因素。     

Land change in the Brazilian Savanna (Cerrado), 1986–2002: Comparative analysis and implications for land-use policy

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.     

东北地区全新世气候变迁

东北地区是全球变化的敏感地区,对气候变化的反映尤为敏感。通过分析东北地区的气候以及气候和植被的关系,对东北地区全新世以来的气候变化作以综合描述;将全新世时期的气候划分为此前10000～此前8000年的早全新世、此前8000～此前2500年的中全新世和此前2500至今的晚全新世时期3个阶段;提出了今后一定时间内关于气候变化应关注环境指标的分析研究、气候分期界限研究、人类活动影响研究以及其它手段的研究。     

An assessment of the economic and environmental potential of biomass production in an agricultural region

The establishment of deep-rooted perennial species and their processing for biomass-based products such as renewable energy can have benefits for both local and global scale environmental objectives. In this study, we assess the potential economic viability of biomass production in the South Australian River Murray Corridor and quantify the resultant benefits for local and global scale environmental objectives. We model the spatial distribution of economically viable biomass production in a Geographic Information System and quantify the model sensitivity and uncertainty using Monte Carlo analysis. The total potentially viable area for biomass production under the Most Likely Scenario is 360,728 ha (57.7% of the dryland agricultural area), producing over 3 million tonnes of green biomass per annum, with a total Net Present Value over 100 years of A$ 88 million. The salinity in the River Murray could be reduced by 2.65 EC (μS/cm) over a 100-year timeframe, and over 96,000 ha of land with high wind erosion potential could be stabilised over a much shorter period. With sufficient generating capacity, our Most Likely Scenario suggests that economically viable biomass production could reduce carbon emissions by over 1.7 million tonnes per annum through the production of renewable energy and a reduced reliance on coal-based electricity generation. Our analyses suggest that biomass production is a potentially viable alternative agricultural system that can have substantial local scale environmental benefits with complimentary global scale benefits for climate change mitigation.     

快速经济发展下县级土地利用/覆被空间变化分析

土地利用/覆被变化(LUCC)是人类活动对自然环境施加影响的显著表现形式。本文以案例的形式,运用LUCC度量模型和LUCC转移矩阵分析研究区清新县2001-2007年的LUCC空间格局变化,并对全县土地利用/覆被进行了分区。研究结果表明,清新县2001-2007年面积增加最多的为林地,而减小最多的为耕地,期间全县综合土地利用/覆被动态度为2.77%、土地利用/覆被强度从2.163增至2.172;同时,清新县土地利用/覆被存在着较为明显的空间差异,全县土地利用/覆被区划可分为南部综合服务中心区、中部产业转移区和北部生态脆弱区三个功能区。     

泉州市快速城市化过程中土地利用景观格局变化研究

利用景观破碎度、分离度、分维数、多样性指数和优势度等景观格局指数分析1985～2000年泉州市景观变化情况。研究结果表明:在1985～2000年期间,景观结构转变的总规律为自然景观向人为景观的转变,表现为耕地、林地、未利用土地和水域斑块数目减少,城乡居民工矿用地和草地斑块数目增加;指出各景观类型转化的驱动力因子;泉州市整体上景观多样性指数略有增加,优势度指数降低,景观破碎度和景观分离度呈现减小趋势,分维数指数略有降低,但处在一个较高水平,各类景观较为复杂且景观比较不稳定,形状较不规则,在空间分布上趋向相对集中而均匀。     

清代黄渤海鲱鱼资源数量的变动——兼论气候变迁与海洋渔业的关系

本文对清代黄渤海鲱鱼种群数量的变化进行了分析。从清代初年至道光年间,渤海和黄海西部的鲱鱼种群数量都十分兴盛。道光、成丰之际,黄海西部和渤海鲱鱼数量开始下降,而黄海东部鲱鱼数量则呈上升趋势。鲱鱼数量的变化具有一定的周期性,而这种周期性又和气候变化与海洋水文变化密切相关。