Intensity of land use changes in a sugarcane expansion region,Brazil

In the last decades, Brazil has been consolidated as one of the world’s largest producers of food, with emphasis on soybeans, sugarcane and beef production. With the opening of new markets and the increase in demand, a competitive scenario was developed among farming activities, resulting in changes in land use and cover. Thus, this study aimed to verify the spatial and temporal land use changes, through intensity analysis, in the microregion of Presidente Prudente, São Paulo state, in two time intervals, 2004–2007 and 2007–2015, in addition to determining the relevance of pasture in this context. The identification of land uses occurred through the analysis of the spectrum-temporal pattern of the Normalized Difference Vegetation Index (NDVI) from Moderate-Resolution Imaging Spectroradiometer (MODIS), in such a way that six classes were identified, annual crop, water, sugarcane, forest, pasture and urban area. The categories annual crop and sugarcane had more intense variations of losses and gains in the studied time intervals. The category pasture was the primary supplying source of the area, showing a reduction of approximately 180,000 hectares in the analyzed period, losing area with greater intensity for the categories of annual crop and sugarcane.     

Land cover and land use changes in a Brazilian Cerrado landscape: drivers,processes, and patterns

The Cerrado is one of the most threatened biomes in South America. To create protection actions on any scale, understanding drivers and consequences of land cover and land use (LC and LU) is essential. This study defines the composition and configuration of a Cerrado landscape watershed from 1975 to 2011. Using Landsat images and socioeconomic census data, we determined the forces acting on LC and LU change processes and their consequences. LC classes differ from LU classes for landscape dominance and processes. Economic opportunities drove LU change and its spatial distribution was related to soil, streams, and roads. Deforestation was the main cause of forest loss but forest degradation was also important, with both presenting different patterns. The spatial distribution of bare soil was related to pasture in degradation and streams. Bare soil distribution was related to pasture in degradation and streams. We concluded that broad scale factors drove changes, but local features determined distribution, and that watershed conservation plans should act on different scales, with management being spatially explicit.     

Assessment of ecological risks induced by land use and land cover changes in Xiamen City,China

The landscape ecological risk (LER) in Xiamen City, China, from 1990 to 2030 was studied using an urban land use and land cover change (LUCC) model and LER analysis. The LUCC model was used to predict the LUCC of Xiamen from 2020 to 2030. We analyzed the characteristics of LUCC and landscape pattern changes and, finally, evaluated the effect of rapid LUCC on LER. Of the six landscape types investigated, built-up land and farmland demonstrated the most significant changes. The area of built-up land increased by 1.5 times in 2010 and is predicted to increase by 2.7 times in 2030 than that in 1990. The area of farmland increased from 34.5% in 1990 to 24.5% in 2010 and is predicted to decrease to 15.1% in 2030. The number of patches (NP) of built-up land decreased with increasing area, which promoted the dominance of built-up land over other landscape types. Five landscape types, those other than built-up land, increased in NP, landscape fragmentation, segmentation, and disturbance but decreased in dominance. The LER of Xiamen in 2010 was slightly lower than that in 1990. However, with the acceleration of urbanization, the LER in 2020 and 2030 will increase by 7.6% and 12.5% than that in 2010. The LER will significantly increase in areas such as the Huandong sea area, the second urban core of Xiamen, and northern Xiang'an. For the areas, some measures (e.g. optimum urban spatial growth patterns and control of coastal reclamation) must inevitably increase to reduce the LER posed by rapid urbanization.     

Chemical composition of rivers and streams in the forest and savanna zones of Nigeria

The aim of this study is to investigate the differences in the chemical conditions of lotic waterbodies in the two major ecosystems in Nigeria, the forest and savanna zones. The forest waters were slightly acidic (mean±SD pH = 6.72±0.58) while the savanna waters were slightly alkaline (pH = 7.11±0.33). The cationic order of dominance in the forest waters was Na⁺ > Ca²⁺ > Mg²⁺ > K⁺ in contrast to Ca²⁺ > Mg²⁺ > Na⁺ > K⁺ in savanna waters. The forest waters were chlorided (typical of coastal and/or marine waters) whereas the savanna waters were carbonated in nature, typical of the worldwide freshwater. Organic carbon was significantly higher in forest waters than in the savanna waters (p < 0.05) while nutrient compounds were significantly higher in savanna waters than in forest waters. The seasonal variation of the chemical parameters was generally more evident in savanna than in forest waters. The differences in water quality between the two major vegetation zones reflect the differences in the biogeochemical processes and nutrient cycling that characterise forest and savanna ecosystems.     

From meso- to macro-scale dynamic water quality modelling for the assessment of land use change scenarios

The implementation of the European Water Framework Directive requires reliable tools to predict the water quality situations in streams caused by planned land use changes at the scale of large regional river basins. This paper presents the results of modelling the in-stream nitrogen load and concentration within the macro-scale basin of the Saale river (24,167 km²) using a semi-distributed process-based ecohydrological dynamic model SWIM (Soil and Water Integrated Model). The simulated load and concentration at the last gauge of the basin show that SWIM is capable to provide a satisfactory result for a large basin. The uncertainty analysis indicates the importance of realistic input data for agricultural management, and that the calibration of parameters can compensate the uncertainty in the input data to a certain extent. A hypothesis about the distributed nutrient retention parameters for macro-scale basins was tested aimed in improvement of the simulation results at the intermediate gauges and the outlet. To verify the hypothesis, the retention parameters were firstly proved to have a reasonable representation of the denitrification conditions in six meso-scale catchments. The area of the Saale region was classified depending on denitrification conditions in soil and groundwater into three classes (poor, neutral and good), and the distributed parameters were applied. However, the hypothesis about the usefulness of distributed retention parameters for macro-scale basins was not confirmed. Since the agricultural management is different in the sub-regions of the Saale basin, land use change scenarios were evaluated for two meso-scale subbasins of the Saale. The scenario results show that the optimal agricultural land use and management are essential for the reduction in nutrient load and improvement of water quality to meet the objectives of the European Water Framework Directive and in view of the regional development plans for future.     

Monitoring land use/land cover change impacts on soils in data scarce environments: a case of south-central Ethiopia

To monitor land-use/land-cover (LULC) change and assess its impact on the soil property, the availability of benchmark data is indispensable, which is hardly available in the intensively cultivated regions of developing countries. Our study attempts to solve this problem by generating a benchmark soil data through the development of modified spatial analogue (MSA) method in the context of the Upper Dijo River catchment, south-central Ethiopia. The magnitude and patterns of LULC changes were extracted from air photos and satellite imageries, along with the acquisition of soil samples from the reference and target sites through ground survey. Analysis of digital image processing shows significant LULC changes in a period that spanned three decades. The impact of LULC change on soil quality was assessed by comparing the soil physico-chemical properties sampled from the reference and target sites. The result shows a decline in total nitrogen, organic matter, available potassium and pH levels in soils collected from target sites, which conforms to results reported by studies conducted in data-rich environment. With careful validation, MSA could be useful for monitoring soil property changes in data-scarce environment and generate soil-related parameters for agro-ecological models.     

Multi-temporal land use and cover changing analysis: the environmental impact in Mediterranean area

ABSTRACT

Human activity shapes the levels of anthropogenic pressure that depend on the land management method adopted. This has a fundamental role in the transformation of traditional landscapes. This study focuses on a representative region of the Mediterranean area with the objective to analyse the landscape’s dynamics, to detect the spatial arrangement of class patches, to identify the main agroecosystem characters and to provide a framework to assess ecosystems services. In order to assess land use/land cover changes and landscape persistence, the period between 1960 and 2012 was analysed, taking into consideration the years 1960, 2000 and 2012 using comparable land use maps. Land use and land cover analysis show an urban area growth of 24% during 2000–2012 and of 523% over between 1960 and 2012. The very high levels of land abandonment up to the year 2000 (+7216%) have reversed their trend between 2000 and 2012 (?95%). The orchards showed a relevant increase, particularly after 2000, while the vineyards were linked to the highest value of surface erosion (?74%). The outcomes showed that urban settlements can damage the ecological network with negative effects on the landscape’s environmental sustainability in proximity of significant urban centres. Instead, the ecological network is well preserved and highly associated to the agricultural areas when there is the persistence of many land uses and low urban density, despite the presence of dynamic changes.     

Exploration of spatial morphometry and socioeconomic variables in modelling urban land use change

The incorporation of land use (LU) data with socioeconomic data is a main issue in modelling. This is as a result of difference in data model and scale. This study proposed and tested the change–pattern approach, which allows the incorporation of these data sets in modelling LU change. Focusing on LU dynamics for a selected part of the Thames Gateway within the City of London, the approach tested two different methods of input selection for the modelling operations. Variables selected from these two methods serve as inputs into several neural networks tested in order to identify the direction of change for each of the LU types within the study area. The result shows that direction of LU change across the study area could be identified when spatial morphology of the area and socioeconomic variables are considered. Some classes of change could be identified fairly accurately using landscape metrics indicating level of fragmentation, extent of LU patches, shape complexity of LU patches in combination with some socioeconomic variables.     

Tenure diversity and dependent causation in the effects of regional integration on land use: evaluating the evolutionary theory of land rights in Acre,Brazil

In the complex causation behind land change, dependent causation can play a central role. A case in point concerns land tenure diversity, where contrasting use rules for different lands may affect the impacts of other drivers on land use outcomes. We therefore evaluate the evolutionary theory of land rights (ETLR), which assumes homogeneous private property rights, in order to test for dependent causation due to distinct use rules among various types of private lands. In the present analysis, we focus on whether land tenure type modifies the effects of highway infrastructure on key outcomes highlighted in the ETLR framework. We take up the case of rural settlements along the Inter-Oceanic Highway in the eastern part of the Brazilian state of Acre, where there is considerable land tenure diversity. Findings from multivariate models for land titling, the castanha nut harvest, and cattle pasture all indicate that the effects of infrastructure depend on land tenure type. These results confirm the importance of dependent causation behind land use and bear implications for theory on land change, infrastructure impacts, and land system science.     

吉林西部土地利用/覆被时空变化驱动力分析

针对吉林两部土地利用/覆被情况,基于TM影像,借助人机交互解译方法,结合1:10万地形图获得1986年、1996年、2000年和2004年的4期土地利用/覆被变化(LUCC)矢量数据.利用土地利用动态度模型、土地利用转移矩阵.全面揭示研究区15年的LUCC时空变化特征,结果表明.盐碱地扩张,湿地、水域萎缩和草地退化已经成为吉林西部生态环境恶化的突出表现.结合研究区的实际情况选取总人口数、农业人口数、粮食总产置等12个指标作为LUCC:变化的丰十会经济驱动因子,借助多元线性回归模型,建立主要土地利用类型的驱动力模型.结果表明吉林西部土地利用变化的最主要社会经济因子是农业人口数、农民人均纯收入、农业生产技术(农业机械总动力、化肥施用量)和农村用电量,同时提出相应的生态环境保护和社会经济措施.     

不同利用方式下黄壤旱坡地磷素状况及环境影响分析

通过对贵州黄壤进行采样以及采用无界径流小区法收集地表径流,探索不同利用方式下黄壤旱坡地磷素水平及其地表径流磷浓度的差异。结果表明,不同利用方式下黄壤旱坡地中全磷和有效磷(Olsen-P)含量的大小顺序为连作烟地>烤烟-玉米轮作地>连作玉米地>林地;CaCl_2浸提磷(土壤易解吸磷)和Na0H浸提磷(藻类可利用的土壤总磷)与土壤全磷和有效磷有显著的相关性;土壤富磷化的同时,其磷素的流失风险明显地提高。连作烟地地表径流总磷(TP)和磷酸根态磷(Ortho-P)浓度明显大于连作玉米地.而林地地表径流TP浓度明显小于旱地;黄壤旱坡地地表径流中TP和Ortho-P与土壤有效磷之间存在极显著的相关性(r为0.957、0.875),因而连作烟地磷素的环境影响潜能明显高于其它旱地以及林地。     

On the gains of committing to inefficiency: Corruption, deforestation and low land productivity in Latin America

We present a new explanation and empirical evidence showing that rural subsidies to large farmers tend to be associated with low land productivity and excessive deforestation. We develop a lobbying model where wealthy farmers trade bribes or political contributions to government politicians in exchange for subsidies; farmers are able to tilt the terms of the bargaining game with policy makers in their favor by pre-committing to an inefficient choice of semi-fixed inputs. Government proneness to accept political contributions or bribes and its willingness to provide subsidies cause farmers to adopt inefficient modes of production as a mechanism to capture such subsidies. Our predictions are consistent with stylized facts on land use in Latin America, and suggest that subsidy schemes have been counterproductive—distorting and constraining development, and triggering excessive depletion of natural resources. We validate some of the predictions of the model through econometric analyses using a new data set for nine countries in Latin America.     

利用方式对紫色水稻土有机碳与颗粒态有机碳的影响

土壤是陆地生态系统中重要的动态碳库,其微小的变化可能带来对全球大气CO2浓度的较大变化。颗粒态有机碳在土壤中周转速度较快,比土壤总有机碳更易受土地利用方式的影响,对于评价土地利用变化对土壤碳固定过程影响具有重要意义。采集不同的耕作、轮作和施肥处理的14年28茬的紫色土长期试验土壤,分析有机碳与颗粒态有机碳含量在土壤及不同深度分布特点,结果表明:长期垄作免耕并实行水稻(Oryza sativa)油菜(Brassica)轮作的利用方式下,0～10cm土层土壤有机碳与颗粒态有机碳含量明显高于其他利用方式下,而稻油水旱轮作平作利用方式下最低。整个耕层0～30cm深度的土壤有机碳含量介于8.92～29.98g·kg-1之间,颗粒态有机碳含量变幅为0.54～3.43g·kg-1之间,且存在随深度递增而降低的趋势。土壤有机碳与颗粒态有机碳都可用作评价利用方式影响紫色水稻土土壤质量变化与固碳能力的有效指标,但颗粒有机碳对于管理措施的响应更为敏感。从总有机碳与颗粒有机碳的关系来看,不同管理下有机碳的增加与土壤物理保护能力的提高有关。垄作免耕(稻油)的利用方式最有利于有机碳的保护和稳定。     

城市化趋势下城郊土地利用结构变化的区位分析--以杭州市为例

以杭州市区为研究区，利用近卜年的土地利用系列统计资料和遥感解译数据，采用统计分析和区位原理，经过数值计算，分析了杭州市区扩建过程中土地利用动态变化特点，重点讨论了耕地和农作物播种面积的时空动态过程。通过区位商数和分离指数的计算分析，揭示了未来土地利用方式的时空变化趋势。研究结果表明，居民工矿用地和耕地面积的变化最为明显；农作物播种面积的递减速率高于耕地面积的递减速率；蔬菜播种面积的区域不平衡性最大，集中程度高。萧山区是未来主要的菜篮子工程发展区。     

Competing land uses and fossil fuel,and optimal energy conversion rates during the transition toward a green economy under a pollution stock constraint

We study the transition to a carbon-free economy in a model with a polluting non-renewable resource and a clean renewable resource. Transforming primary energy into ready-to-use energy services is costly and more efficient energy transformation rates are more costly to achieve. Renewable energy competes with food production for land and the food productivity of land can be improved at some cost. To avoid catastrophic climate damages, the pollution stock is mandated to stay below a given cap. When the economy is not constrained by the cap, the efficiency of energy transformation increases steadily until the transition toward the ultimate green economy; when renewable energy is exploited, its land use rises at the expense of food production; food productivity increases together with the land rent but food production drops; the food and energy prices increase and renewables substitute for non-renewable energy. During the constrained phase, the economy follows a constant path of prices, quantities, efficiency rates, food productivity and land rent, a phenomenon we call the ‘ceiling efficiency paradox’.     

台湾泥岩地区不同刺竹林景观下之土壤与植被变异

台湾西南部泥岩恶地,由于其特殊之土壤,地力流失消耗与区域微气候型态之间的因果循环,在水土保持与景观上形成不易植生绿化的地区及特殊之世界地形。泥岩地区之不同刺林林相之土壤,其林相皆伐后复层植被区土壤性质变异高于其它位置,而其它区之土壤理化性质在时间及空间上之变异不大,可明显区分林相不同之显著差异。不同林相对泥岩地浅层土壤(0~20cm)理化性质的差异,以植物营养元素与植生覆盖因子可充分说明(约占变异范围之62%)。泥岩试区区中移动性物质(交换性钙、钠与镁)明显较少出现在复层林相处区,而易出现于淋洗、冲蚀量较大之刺林相保留区与隔丛择伐区。长效性植物营养元素因子(pH值与有效性磷),因长时间之林相不同,使其较明显趋于复层林相区堆积,并影响地表植生之种类、分布与覆盖情形。0～20cm土壤性质的分布和离子间的移动特性有关,移动性高的钠、镁离子会在冲蚀量高之区域出现,20～40cm土壤性质的分布则和土壤中之母质与植生有关并与因素分析结果相似,其次为可移动性离子的影响,且应用地理统计印证土壤性质在空间之变化,其分布确实与不同林相位置有关,即植生营养元素(pH值、有效性磷)大都朝向复层植被区之趋势。典型相关分析结果,地表覆盖度与入侵植物数量两变量主要系透过第一个典型因素与第二个典型因素而影响到复层植被区之pH值、有机质等土壤理化性质。     

中国北方农牧交错带农村土地利用变化因子分析--以内蒙古尧勒甸子村为例

以北方农牧交错带典型生态示范村尧勒甸子村为例,应用参与式农村评估法(PRA)并结合GPS与野外测量,恢复了该村1949年后50 a来的土地利用历史过程与格局,利用GIS分析其1950-1999年的土地利用变化特点.运用因子分析和逐步回归分析方法揭示了人类活动因素对土地利用变化的作用.结果发现1985年以前耕地面积扩大,草地面积减小,沙地面积迅猛持续增加;1985年以后土地利用变化向相反的方向发展,土地利用结构趋向合理.     

Assessment of the contribution of land use pattern and intensity to landscape quality: use of a landscape indicator

The objective of this research work is the evaluation of the impact of landuse pattern and intensity on landscape by means of an indicator. The method used to calculate a ‘landscape indicator’ (I_land) allows to take into account the objective as well as the subjective approach of landscape. I_land corresponds to the degree of agreement between landscape supply by farmers and landscape demand by the social groups. The supply and the demand are evaluated through four criteria: ‘diversity’, ‘upkeep’, ‘openness’ and ‘heritage’. The landscape supply is calculated from data of landscape objects (punctual, linear and spatial) for each criterion recorded at the field level. The values of the four criteria for the landscape demand are allocated by the user(s) of the indicator (decision makers, regional council, social groups…) into five classes (0–4). The value of the landscape indicator is the least favourable difference between supply and demand for the four criteria. An example of calculation of the ‘landscape indicator’ for an arable farm is given. The collection of data needs 2 h with the farmer and 2 h for a survey of the farm land.     

挠力河流域农垦开发中居民地景观生态特征的变化

运用G IS、景观格局分析与聚落分析方法定量分析了挠力河流域在快速农垦开发中居民地分布格局的时空变化,探讨了景观格局形成的机制。景观指数分析表明近50 a来居民地面积和数目激增,居民地斑块面积、聚集度增大,表明人类对挠力河流域景观扰动持续增强。在所有背景地类中,居民地与耕地的邻接比例最高。伴随居民地和耕地迅速扩张,两者邻接比例呈上升趋势,两者相互影响越来越大。不同时期居民地扩张强度高值区分布有所不同,主要分布在早期的耕地新增区,1954—2000年挠力河流域居民地扩张高值区最终主要分布于该流域的西部与中部。虽然居民地数目和面积均激增,各居民地之间的距离亦呈缩短趋势,但居民地最近邻点指数表明,近50 a来挠力河流域居民地分布类型一直为随机分布,农垦经济仍占主导地位,人为规划比城镇发达地区薄弱。     

森林土地利用变化及其对碳循环的影响

由于人口剧增，人类活动的影响不断加大，在过去100年全球土地利用／土地覆被发生了巨大的变化。最常见的土地利用变化是由森林转变为农业用地。森林砍伐使森林生态系统地上部生物量大大减少，砍伐后作农业用地，降低了植被生产力，减少了土壤有机质的输入，增强了腐殖质的矿化作用，有机质分解速率增加，有机碳贮量随之降低，从而影响到森林生态系统的碳循环，使大量碳元素释放到大气中，引起温室效应，导致全球变暖。另一个常见的土地利用变化是植树造林和森林恢复，这一过程可以增加森林生态系统的碳储量，从而减缓大气CO2体积分数的上升。