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.     

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.     

Modelling the potential impacts of land use/cover change on terrestrial carbon stocks in north-west Morocco

Terrestrial ecosystems store more carbon (C) than the atmosphere and provide ecosystem services (ES) such as global climate regulation, by sequestering carbon within biomass and soil. Land use land cover (LULC) change is considered a key factor, playing an important role in the dynamic variations of carbon storage. The aim of this paper is to assess the effects that LULC has had on carbon stocks and consequently on climate change regulation in north-western Morocco over 21 years. To achieve this aim, the Integrated Valuation of ES and Trade-offs (InVEST) model is used to assess status and variation in the net amount of carbon stored by the different types of LULC, and the economic value of the carbon sequestered in the remaining stock. The results show that the total carbon stock increased from 4.81TgC in 1996 to 4.98TgC in 2017. Over the 21 years, the LULC changes had the greatest effect on carbon storage - an increase of 6.87% with 0.17TgC of carbon sequestered, since the majority of unused land was changed to forest and cultivated land. Based on the global costs of atmospheric carbon, we estimate the economic value of carbon storage services to be between US$1,800,000 and US$3,570,000 for the whole period, with an average yearly increment of between US$86,000 and US$170,000. The results show that the ecosystem management has had a substantial climate mitigation effect. Also, the possibility of paying for ES could inform policy on the adoption of LULC to support livelihood and management choices.     

土地利用变化对生物多样性的影响

土地利用变化对生物多样性影响是生物多样性受到威胁的重要因素.文章对土地利用变化对基因多样性、物种多样性、生态系统多样性影响方面的研究进行了总结分析,并提出了新的展望.土地利用变化对基因多样性的影响涉及了对物种生境的隔离、农牧业活动对物种改良和生境条件的改变方面,目前还主要集中在对少数物种繁殖过程方面影响的研究;土地利用变化对物种多样性影响包括对物种优势度和丰富度、种间关系、物种分布格局、物种入侵和灭绝方面的影响,目前对物种丰富性和多样性影响方面研究较多,对物种灭绝、物种入侵和种间关系影响方面的研究极少,且还限于大型动物和植物,对微生物和小型动植物研究却很少;土地利用变化对生态系统的影响涉及了对生态系统结构组成及分布方面的影响.另外,目前缺少土地利用变化对基因多样性、物种多样性和生态系统多样性综合影响方面的研究,难以量化和预测土地利用变化对生物多样性影响效应.未来需要综合考虑基因多样性、物种多样性和生态系统多样性方面,系统开展土地利用变化对生物多样性影响的趋势和机制方面的研究,定量预测土地利用变化对生物多样性的影响.     

Simulation of soil carbon changes due to land use change in urban areas in China

Land use change can have a strong impact on soil carbon dynamics and carbon stocks in urban areas. Due to rapid urbanization, large areas of land have been paved, and other areas have undergone rapid land use change. Evaluation of the impact of urbanization on carbon dynamics and carbon stock (30 cm) has become an issue of urgent concern. The soil carbon dynamics, due to rapid land use change in Tianjin Binhai New Area of China, have been simulated in this paper using the RothC model. Because this area is saline, a modified version of RothC that includes a salt rate modifier provided more accurate simulations than the original model. The conversion to urban green land was not accurately simulated by either of the models because of the undefined changes in soil and plant conditions. According to the model, changes of arable to grassland resulted in a decline in soil carbon stocks, and changes of grassland to forest and grassland to arable resulted in increased soil carbon stocks in this area. Across the whole area simulated, the total carbon stocks in 2010 had decreased due to land use change by 6.5% from the 1979 value. By 2050, a further decrease of 21.9% is expected according to the 2050 plan for land use and the continuing losses from the soils due to previous land use changes.     

珠江三角洲土地利用变化空间自相关分析

通过对复杂土地利用地学现象的空间与时间上的综合表达和描述,可揭示土地利用时空结构演变的内在规律,可以为研究区土地资源的合理利用、优化配置和可持续发展提供科学依据。本文利用珠江三角洲1990-2005年的土地利用数据,采用空间自相关分析方法对珠江三角洲土地利用／覆盖变化的空间特征进行了实证研究。通过对研究区全域空间自相关、单变量区域空间自相关、双变量区域空间自相关的计算,表明研究区土地利用／覆盖的全域空间自相关较弱,土地利用和开发存在随机性。单变量区域空间自相关和双变量区域空间白相关在不同区域、不同时期显现不同形态,揭示了研究区内部发展的差异性。空间自相关分析方法可直观地显示分析结果,不失为一种深入理解区域土地利用格局和变化的重要和有益的方法。     

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.     

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。     

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.     

Climate change and urban land systems: bridging the gaps between urbanism and land science

ABSTRACT

Land science has generated critical knowledge about how humans modify Earth’s surface and has advanced our understanding of land as a coupled human–environment system. However, to date, most work has been in frontier environments with less attention – both conceptually and empirically – on how urban land systems affect the carbon cycle. Much of what is known about urban areas and the carbon cycle is limited to aggregate levels of activities within urban areas, usually by sector, with little focus on how the spatial configuration of urban land systems affects carbon-emitting activities. Given that urban areas produce about 70% of global energy-related CO₂ emissions, it is crucial to understand the relationship between urban environments, the activities they influence, and the resulting carbon emissions. This paper summarizes the current state of knowledge of how urban land systems affect carbon emissions and vulnerability, and identifies research gaps and opportunities for urban land science to contribute to climate change science, particularly through land architecture. We argue that more attention to urban land science conceptualization, measurement, and analysis would contribute to both fundamental knowledge about urban systems, as well as help identify policies and strategies for mitigation and adaptation to climate change at the urban scale.     

Soil quality evolution after land use change from paddy soil to vegetable land

A survey was done in 15 typical villages, 150 soil and 86 vegetable plant samples were taken in Jiaxin prefecture of the Taihu Lake region, northern Zhejian province. Results indicate that after 15-20 years land use changed from the paddy rice-wheat (or oilseed rape) double cropping system, to a continuous vegetable land has caused soil quality dramatic change. (1) Acidification: average soil pH was 5.4; about 61% of total samples were pH < 5.5. It was 0.9 units lower than 10 years ago with same upland vegetable cultivation and was 1.2 units lower than soil pH of paddy rice-wheat (or oilseed rape) rotation. (2) Fertilizer salt accumulation: the average salt content was 0.28%, among these about 36.2% of the total samples contained more than 0.3%. (3) Nitrate N and available phosphorus (P) over accumulation: on average it was 279 mg NO3-N/kg, and 45-115 mg P/kg. Nitrate N four times higher and available P 4-10 times more than it is in present paddy rice-wheat rotation soils respectively. This has caused wide concern because of possible groundwater and well drinking water pollution by leached nitrate N and the P losses to water by runoff from vegetable lands induce surface water eutrophication.     

Forecasting relative impacts of land use on anadromous fish habitat to guide conservation planning.

Land use change can adversely affect water quality and freshwater ecosystems, yet our ability to predict how systems will respond to different land uses, particularly rural-residential development, is limited by data availability and our understanding of biophysical thresholds. In this study, we use spatially explicit parcel-level data to examine the influence of land use (including urban, rural-residential, and vineyard) on salmon spawning substrate quality in tributaries of the Russian River in California. We develop a land use change model to forecast the probability of losses in high-quality spawning habitat and recommend priority areas for incentive-based land conservation efforts. Ordinal logistic regression results indicate that all three land use types were negatively associated with spawning substrate quality, with urban development having the largest marginal impact. For two reasons, however, forecasted rural-residential and vineyard development have much larger influences on decreasing spawning substrate quality relative to urban development. First, the land use change model estimates 10 times greater land use conversion to both rural-residential and vineyard compared to urban. Second, forecasted urban development is concentrated in the most developed watersheds, which already have poor spawning substrate quality, such that the marginal response to future urban development is less significant. To meet the goals of protecting salmonid spawning habitat and optimizing investments in salmon recovery, we suggest investing in watersheds where future rural-residential development and vineyards threaten high-quality fish habitat, rather than the most developed watersheds, where land values are higher.     

盐池北部风沙区土地利用格局变化对沙漠化的影响

以盐池北部风沙区为研究区域,利用1989、1995、2000、2007年土地利用现状图,借助地理信息系统软件提取有关格局分析的基础数据,基于景观生态学原理,构造主要土地利用类型和沙地景观格局指数,探讨不同时段内盐池北部风沙区土地利用格局变化对沙化景观的影响。结果表明：（1）沙地景观在1995年之前不断扩张,1995年以后开始减少,集中连片沙地被零星分布的小沙化斑块取代;（2）林地和草地经历了先减少后增大的过程,土地利用格局变化中,中、低覆盖度草地和灌木林地变动性大;中、低覆盖度草地、耕地、灌木林地不稳定性程度较高;（3）受农作活动影响,尤其在灌溉条件较好区域,草地沙化明显,而灌木林能起到很好的防沙作用;（4）盐池北部风沙区土地利用格局特征指标与沙地面积呈负相关,随着特征指标增大沙化面积减小。土地利用格局变化能够综合反映相应时段内的人类活动结果,以此为切入点研究其对沙漠化的影响,有利于揭示沙漠化的驱动机制。     

土地利用方式及母质对土壤有机碳的影响

运用物理分组方法分别对海南屯昌县花岗岩砖红壤地区天然次生林(白楸(Mallotus paniculatus (Lam.) Muell. Arg.)、岭南山竹子(Garcinia oblongifolia Champ.))土壤(TSF)和人工橡胶RRIM600 (Hevea brasiliensis. Muell. Arg.)林土壤(TR)以及白沙县紫色砂页岩砖红壤地区天然次生林(白楸 (Mallotus paniculatus (Lam.) Muell.Arg.)、岭南山竹子(Garcinia oblongifolia Champ.))土壤(BSF)和人工橡胶RRIM600 (Hevea brasiliensis. Muell. Arg.) 林土壤(BR)0100 cm土层土壤及其物理组分中的有机碳进行了研究,分析利用方式从天然次生林变为人工橡胶林后不同母质砖红壤及其物理组分有机碳含量变化.结果表明: TSF和TR土壤有机碳分别比BSF和BR土壤有机碳含量高.无论是花岗岩砖红壤还是砂页岩砖红壤,土地利用变化使土壤和微团聚体有机碳含量都极显著降低,TSF变为TR后还造成大团聚体以及粘粒和粉粒(Silt & clay)有机碳显著减少,可以看出土地利用变化引起的花岗岩砖红壤退化程度比砂页岩砖红壤大.土地利用变化主要对第一、二层土壤及其物理组分产生影响,且对第一层影响比第二层大.对比研究发现,砂页岩砖红壤Coarse POM和iPOM组分中有机碳稳定性比花岗岩砖红壤相应物理组分强.     

Integrated assessment of agricultural policies with dynamic land use change modelling

With about half of its territory being farmed, agriculture is the main land use in the European Union (EU). As over 10% of the total EU manufacturing output comes from the agri-food sector, it also is an economic factor of great importance. Moreover, EU policy in this sector has far-reaching consequences ranging from the EU's status as a global trade partner to landscape preservation and development. The LUMOCAP Policy Support System is targeted towards policy makers in the European Commission (EC) and its Member States (MS) and aims to provide support in the field of sustainable agricultural and rural development. To this end it incorporates an integrated model with socio-economic and bio-physical processes, operating at different spatial scales. For supporting integrated assessment, a large number of policy levers is included as inputs for these models and outputs are transformed into policy-relevant social, economic and environmental indicators. The whole system is framed in a flexible, modular and easy to use software package that is useable for process experts and policy-analysts alike.This paper describes the integrated model, the individual models and a first calibration of the system. It demonstrates the system's behaviour for typical scenario runs and concludes with a reflection on the current status of the system and some recommendations for further development.     

Risk-based modelling of diffuse land use impacts from rural landscapes upon salmonid fry abundance

Research has demonstrated that landscape or watershed scale processes can influence instream aquatic ecosystems, in terms of the impacts of delivery of fine sediment, solutes and organic matter. Testing such impacts upon populations of organisms (i.e. at the catchment scale) has not proven straightforward and differences have emerged in the conclusions reached. This is: (1) partly because different studies have focused upon different scales of enquiry; but also (2) because the emphasis upon upstream land cover has rarely addressed the extent to which such land covers are hydrologically connected, and hence able to deliver diffuse pollution, to the drainage network. However, there is a third issue. In order to develop suitable hydrological models, we need to conceptualise the process cascade. To do this, we need to know what matters to the organism being impacted by the hydrological system, such that we can identify which processes need to be modelled. Acquiring such knowledge is not easy, especially for organisms like fish that might occupy very different locations in the river over relatively short periods of time. However, and inevitably, hydrological modellers have started by building up piecemeal the aspects of the problem that we think matter to fish. Herein, we report two developments: (a) for the case of sediment associated diffuse pollution from agriculture, a risk-based modelling framework, SCIMAP, has been developed, which is distinct because it has an explicit focus upon hydrological connectivity; and (b) we use spatially distributed ecological data to infer the processes and the associated process parameters that matter to salmonid fry. We apply the model to spatially distributed salmon and fry data from the River Eden, Cumbria, England. The analysis shows, quite surprisingly, that arable land covers are relatively unimportant as drivers of fry abundance. What matters most is intensive pasture, a land cover that could be associated with a number of stressors on salmonid fry (e.g. pesticides, fine sediment) and which allows us to identify a series of risky field locations, where this land cover is readily connected to the river system by overland flow.     

Smoothing of land use maps for trend and change detection in urbanization

Urban sprawl and its evolution over relatively short periods of time demands that we develop statistical tools to make best use of the routinely produced land use data from satellites. An efficient smoothing framework to estimate spatial patterns in binary raster maps derived from land use datasets is developed and presented in this paper. The framework is motivated by the need to model urbanization, specifically urban sprawl, and also its temporal evolution. We frame the problem as estimation of a probability of urbanization surface and use Bayesian P-splines as the tool of choice. Once such a probability map is produced, with associated uncertainty, we develop exploratory tools to identify regions of significant change across space and time. The proposal is used to study urbanisation and its development around the city of Bologna, Emilia Romagna, Italy, using land use data from the Cartography Archive of Emilia Romagna Region for the period 1976–2008.     

Structurally-consistent estimation of use and nonuse values for landscape-wide environmental change

We address the problem of estimating the use and nonuse value derived from a landscape-wide programme of environmental change. Working in the random utility framework, we develop a structural model that describes both demand for recreational trips to the landscape's quality-differentiated natural areas and preferences over different landscape-wide patterns of environmental quality elicited in a choice experiment. The structural coherence of the model ensures that the parameters of the preference function can be simultaneously estimated from the combination of revealed and stated preference data. We explore the properties of the model in a Monte Carlo experiment and then apply it to a study of preferences for changes in the ecological quality of rivers in northern England. This implementation reveals plausible estimates of the use and nonuse parameters of the model and provides insights into the distance decay in those two different forms of value.     

广西土地利用变化及对粮食生产的影响

在统计软件SPSS支持下,深入分析了广西土地利用现状及1996—2001年土地利用结构变化的原因,在此基础上探讨了土地利用变化对粮食生产的影响,并提出了一些保障粮食安全的对策及建议。