Land change variability and human-environment dynamics in the United States Great Plains

Land use and land cover changes have complex linkages to climate variability and change, biophysical resources, and socioeconomic driving forces. To assess these land change dynamics and their causes in the Great Plains, we compare and contrast contemporary changes across 16 ecoregions using Landsat satellite data and statistical analysis. Large-area change analysis of agricultural regions is often hampered by change detection error and the tendency for land conversions to occur at the local-scale. To facilitate a regional-scale analysis, a statistical sampling design of randomly selected 10 km × 10 km blocks is used to efficiently identify the types and rates of land conversions for four time intervals between 1973 and 2000, stratified by relatively homogenous ecoregions. Nearly 8% of the overall Great Plains region underwent land-use and land-cover change during the study period, with a substantial amount of ecoregion variability that ranged from less than 2% to greater than 13%. Agricultural land cover declined by more than 2% overall, with variability contingent on the differential characteristics of regional human-environment systems. A large part of the Great Plains is in relatively stable land cover. However, other land systems with significant biophysical and climate limitations for agriculture have high rates of land change when pushed by economic, policy, technology, or climate forcing factors. The results indicate the regionally based potential for land cover to persist or fluctuate as land uses are adapted to spatially and temporally variable forcing factors.     

UK land use and soil carbon sequestration

This review explores the role of land use and land use change as a determinant of the soil's ability to sequester and store carbon in the UK. Over 95 percent of the UK land carbon stock is located in soils which are subjected to a range of land uses and global changes. Land use change can result in rapid soil loss of carbon from peatlands, grasslands, plantation forest and native woodland. Soil carbon accumulates more slowly (decadal) but gains can be made when croplands are converted to grasslands, plantation forest or native woodland. The need for land for food production and renewable forms of energy could have considerable influence on UK soil carbon storage in the future. There is a need to recognise the risk of soil carbon losses occurring when land use change to increase carbon storage is offset by compensatory land use conversions elsewhere that result in net carbon release. The protection of peatland and other organic soil carbon stocks, and the management of cropland, grassland and forest soils to increase carbon sequestration, will be crucial to the maintenance of the UK carbon balance. It will be necessary to develop policy to balance trade-offs between soil carbon gains with other land use priorities. These include the sustainable production of food, bio-energy and fibre crops and livestock, water quality and hydrology, greenhouse gas emission control and waste management, all of which are underpinned by the soil.     

“一带一路”典型区土地利用变化热点区判别与其影响因素

目的 土地利用与覆盖变化是监测区域变化的重要方法,而发生剧烈变化的热点区域更是研究的重要部分,有效识别热点区并分析其影响因素可以为保护土地生态环境、有效利用土地资源提供科学支撑。方法 文章利用欧洲航天局（ESA）气候变化倡议的长期时间序列土地覆盖数据集（CCI-LC）对“一带一路”典型区土地利用与覆盖变化进行分析,根据变化面积、相对变化速率及其聚集程度建立了热点区域的识别方法,并分析了影响因素。结果 （1）根据土地覆盖变化结果表明,1992—2020年“一带一路”典型区内总共有5.46%的面积发生了变化,建设用地净增加面积最多,为24.61万km²,相对变化速率在2000—2010年最高,为76.94%。（2）热点识别结果表明,2000—2010年土地覆盖变化最剧烈,不同时期的热点区域内主要的转型特征不同,1992—2000年主要表现为耕地的增加,2000—2010年主要表现为林地和建设用地面积扩张,2010—2020年主要表现为建设用地面积增多和林地的砍伐与恢复。（3）热点区域集中分布在0~200m的海拔范围内,热点区域内的像元数量随海拔升高不断减少。（4）热带多雨气候区域内热点占比最大,而其他气候类型对热点区域内的像元数量的影响较小。（5）社会经济因素对于热点区域内的像元数量有着显著的影响,其中城市人口数量和国内生产总值最重要,两者结合可以解释全部热点的86.46%。结论 研究探明的热点区域和影响因素可以为“一带一路”典型区土地利用格局演变、区域土地利用规划和土地资源可持续利用提供决策支持。     

Global food demand,productivity growth,and the scarcity of land and water resources: a spatially explicit mathematical programming approach

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

The relationship between land use and groundwater resources and quality

Groundwater has three major roles in our environment: providing the baseflow that keeps most rivers flowing all year long, maintaining good river water quality by diluting sewage and other effluents, and as an excellent source of water supply, providing over 75 per cent of the potable supply in some regions. Groundwater is intimately connected with the landscape and land use that it underlies, and most of the landscape and is vulnerable to the anthropogenic activities on the land surface above. Land use affects groundwater resources through changes in recharge and by changing demands for water. Inappropriate land use, particularly poor land management, causes chronic groundwater quality problems. Acute groundwater quality problems are common and arise from unsuitable land use and control, notably through point sources of hazardous chemicals. Current land use instruments have only been designed to address quality issues in groundwater and do not consider recharge. These instruments have been largely ineffective in protecting groundwater from diffuse pollution for several reasons including fragmentation, their general absence of teeth, and their lack of integration into the land use planning system. This paper argues for a more radical approach which would zone land according to its overall vulnerability and resilience to anthropogenic and climatic influence in order to sustainably support the ecosystem services it can deliver. Land use would be matched with the vulnerability of the soil, with geology and water, and with the whole ecosystem. The Water Framework Directive offers a mechanism to do this, but there is no evidence of enough political will to tackle the long-term conflicts between land use and groundwater.     

Carbon Sequestration and Conservation of Tropical Forests Under Uncertainty

Concern for global warming has focused attention on the role of tropical forests in the reduction of ambient CO₂ levels and mitigation of climate change. Deforestation is a major land use change in the tropics, with forest resources undergoing degradation through the influence of logging and conversion to other uses. Land use change is a product of varied local and regional resource use policies. Management of forest resources is one such major temporal factor, influencing resource stability and the carbon pool. Under a given management policy, both the long period of forest growth, and the slow turnover and decay of the carbon pool, enhance the relevance of stand level management policies as cost-effective mechanisms mitigating climate change. Apart from regional level uncertainties like the nature of land use and the estimation of carbon storage in vegetation and soil, the carbon flux of tropical forests is greatly influenced by uncertainty in regenerative capacity of forests and in harvest and management policies. A case study from India is used to develop a transition matrix model of natural forest management, and to explore the economic implications of maintaining and expanding existing carbon sinks. The study further explores the significance of investments in additional carbon sinks in plantation forests, given continued uncertainty in natural forest management.     

近10年崇州市土地利用变化基本特征与空间格局

[目的]土地利用变化研究是揭示土地利用对人类活动响应程度的重要途径,通过对其变化特征及空间格局的研究讨论人地关系在不同地域空间上的强度与作用模式。[方法]基于2002年、2014年TM/ETM+影像,在RS和GIS技术的支持下,采用人机交互图像处理方法提取了崇州市土地利用信息,应用土地利用动态度、土地利用程度、空间转移图谱、城市扩展指数、缓冲分析模型和方法对崇州市近10年来土地利用变化时空特征进行了研究。[结果](1)土地利用类型以林地、耕地、建设用地为主,建设用地动态度最大达到5.72;整体土地利用程度由254.25增长到260.93,各乡镇变动值差异较大。(2)土地空间转换面积达1.850 85万hm~2,占研究区总面积的16.94%;增长面积最大的图谱单元依次是新增建设用地、新增耕地和新增林地;建设用地、耕地、水体与高程、坡度之间负相关性显著,坡度0°~6°是人类活动最频繁的区域。(3)中心城区建设用地面积大幅增长,缓冲范围内建设用地面积增加了2 120.76hm~2,城市中心自河流向东、东南、东北3个方向扩展。[结论]崇州市土地利用整体处于快速发展时期,地域差异明显,受人类活动影响显著。     

Projecting future crop productivity for global economic modeling

Assessments of climate change impacts on agricultural markets and land‐use patterns rely on quantification of climate change impacts on the spatial patterns of land productivity. We supply a set of climate impact scenarios on agricultural land productivity derived from two climate models and two biophysical crop growth models to account for some of the uncertainty inherent in climate and impact models. Aggregation in space and time leads to information losses that can determine climate change impacts on agricultural markets and land‐use patterns because often aggregation is across steep gradients from low to high impacts or from increases to decreases. The four climate change impact scenarios supplied here were designed to represent the most significant impacts (high emission scenario only, assumed ineffectiveness of carbon dioxide fertilization on agricultural yields, no adjustments in management) but are consistent with the assumption that changes in agricultural practices are covered in the economic models. Globally, production of individual crops decrease by 10–38% under these climate change scenarios, with large uncertainties in spatial patterns that are determined by both the uncertainty in climate projections and the choice of impact model. This uncertainty in climate impact on crop productivity needs to be considered by economic assessments of climate change.     

A comprehensive framework on land-water resources development in Mu Us Sandy Land

Land and water resources are two basic factors for sustaining the development of agriculture. The two are scare resources with rapid social economic development gradually, especially in Mu Us Sandy Land (MUSL) with severe desertification. Arsenic sandstone is a special rock type of MUSL with strong water holding capacity, which appropriately makes up the shortage of sand on water and fertilizer losing. Based on it, a comprehensive framework on land-water resources development was proposed including engineering treatment measures, appropriate irrigation management and farming measures after a series of experiments designed for sandy land treated with arsenic sandstone. Results of the experiments showed that both water content and fertility increased after using a 1:2 arsenic sandstone/sand ratio by mixing both together. An area of 151.3 ha arable land was newly-increased by applying the framework in Dajihan village sandy land of the MUSL, which created direct economic efficiency of 14.1 million Yuan RMB by tomato planting, and obtained 61% of water saving effect compare to untreated sand. The application of the framework in Dajihan village also got huge social-ecological efficiency such as on soil and water conservation, sand-fixing and forming high quality farmland. The framework helped to completed the process from soil synthesize to agricultural production, then to real soil, which transformed the traditional sandy land treatment to sandy land development, and was proved to be practicable and sustainable in local sandy agriculture.     

河西地区土地生产潜力及人口承载力研究——以张掖市甘州区为例

河西地区是我国生态环境比较脆弱的地区,也是我国人口、资源、环境矛盾最集中的地方,由于长期对土地的不合理利用加剧了这一矛盾的激化。如何合理利用土地资源成为首先要解决的问题。文章以甘州区为例,来探讨该区土地潜力,通过应用生产潜力模型,并结合统计资料,建立了绿洲农区土地潜力评价系统和指标体系,通过应用气候(光温水)生产潜力模型和气候-土壤生产潜力(自然生产潜力)对该区的土地生产潜力进行评价。希望研究对于绿洲农区合理、有效、可持续的利用土地资源,使其最大程度的发挥土地生产潜力具有意义。     

Land allocation to meet sectoral goals in Indonesia—An analysis of policy coherence

Land is a scarce resource affecting the implementation of many sectoral policies. In Indonesia, the expansion of palm oil plantations has led to non-sustainable land use practices in past years, particularly deforestation. More recently, the government has set ambitious targets for the adoption of biodiesel which will require expansion of oil palm plantations, thus putting further pressure on land. Meanwhile, the need to guarantee food supply, forest conservation and climate change mitigation also imply challenges when it comes to land allocation and use. This paper examines the role that land plays in the implementation of sectoral policies in Indonesia, exploring the availability of land to satisfy the multiple goals defined in national policies. We explore land competition resulting from allocations made in official policy documents starting with biofuel policy. The analysis of policy goals and coherence when it comes to land allocation is made in relation to agriculture, climate and forestry policies. We conclude that adjustments need to be made in the policies to avoid overlappings and misinterpretations when it comes to land allocation. The area made available for meeting each sectoral policy goal when taking into account cross sectoral interactions is: 14.2 Mha for agriculture, 43 Mha for climate mitigation measures, 9.2 Mha for forestry, and 20.9 Mha for biofuels. A more uniform land classification and development of a common reference database will increase transparency on land allocation and use, and help to monitor land use change, ultimately supporting the achievement of multiple national goals.     

Evidence of climate change impacts on crop comparative advantage and land use

Relative agricultural productivity shocks emerging from climate change will alter regional cropland use. Land allocations are sensitive to crop profits that in turn depend on yield effects induced by changes in climate and technology. We develop and apply an integrated framework to assess the impact of climate change on agricultural productivity and land use for the U.S. Northern Great Plains. Crop-specific yield–weather models reveal crop comparative advantage due to differential yield impacts of weather across the region's major crops, that is, alfalfa, wheat, soybeans, and maize. We define crop profits as a function of the weather-driven yields, which are then used to model land use allocation decisions. This ultimately allows us to simulate the impact of climate change under the RCP4.5 emissions scenario on land allocated to the region's major crops as well as to grass/pasture. Upon removing the trends effects in yields, climate change is projected to lower yields by 33–64% over 2031–2055 relative to 1981–2005, with soybean being the least and alfalfa the most affected crops. Yield projections applied to the land use model at present-day input costs and output prices reveals that Dakotas’ grass acreage will increase by up to 23%, displacing croplands. Wheat acreage is expected to increase by up to 54% in select southeastern counties of North Dakota and South Dakota, where maize/soy acreage had increased by up to 58% during 1995–2016.     

Forest land consolidation and its effect on climate

Land use changes and forests both play an important role in combating climate change. The climate effects of forest land consolidation have, however, not been studied in detail. As such, this study identifies a number of possible climate effects of forest land consolidation. To specify these, the increased carbon storage in the Pahkakoski land consolidation project (Finland) due to increased forest growth is valued through substitution costs. The results show that the value of the increased carbon storage in the project area is approximately 750 000 euros, or €153/ha. This emanates from the increased growth due to remedial drainage and from the increased forested area. The result is, however, sensitive to changes in the shadow price of carbon. Likewise, the study recognises a need for studies concerning the total climate effect of measures, such as remedial drainage that may also release carbon from the ground. While the overall effects of forest land consolidation are difficult to estimate with current knowledge, this article highlights the potential of land consolidation to combat climate change.     

Land-use changes and policy dimension driving forces in China: Present,trend and future

China has extremely scarce land resources compared to the world average. There is an urgent need for studies of the current situation and the trends in land-use change and assessment of the performance of land policies in China. Assessment of land-use change has long been hindered by a lack of accurate and reliable data. This paper uses the data obtained from the national land surveys of 1996 and land-use change surveys from 1997 to 2008, to analyze changes in land use and the policy dimension driving forces related to the changes, especially cultivated land, forestry land, grassland, as well as developed land. The aim of this analysis will be to derive the physical, social and economical driving forces of those changes to grasp the trends in land-use change and the effects of land policies and to formulate strategies for the protection and sustainable use of agricultural land. The results indicate that, although the overall change in land use was not large, cultivated land was significantly reduced and developed land rapidly increased. A great deal of high quality cultivated land was changed to developed land and low quality cultivated land generated from unused land, which has resulted in a serious threat to food supplies in China. Predictions using the methods of linear extrapolation and a BP neural network indicate that it is impossible to keep to a target of 0.12 billion hectares of cultivated land in the future under the mode of economic development used between 1996 and 2008. The results also indicate that the implementation of the laws and regulations about controlling the developed land and preserving cultivated land had significant effects on changes in land use, especially cultivated land and developed land. The results suggest that the changes in land use are closely related to economic fluctuation and the enaction and implementation of these land policies had a little time lag for cultivated land protection. There is a pressing need for China to use its limited land resources more efficiently and effectively by enacting or re-enforcing the laws and regulations on land resources protection and economic development, not only for its own growing population, but also the world. Therefore, we must formulate strategies for the protection and sustainable use of agricultural land.     

2015年土地科学研究重点进展评述及2016年展望——土地管理领域分报告

研究目的:归纳分析2015年国内外土地管理领域的研究进展,展望研究趋势。研究方法:文献统计法。研究结果:2015年国外土地管理研究侧重于土地利用冲突及应对机制、土地权属效应、土地纠纷解决路径等方面,国内研究更多关注土地制度改革、土地市场管理与调控、不动产统一登记制度、自然资源资产管理、土地政策与法律,以及土地用途管制与耕地保护等方面。研究结论:2015年土地管理领域在土地管理体制机制建设等方面的研究进一步加强,针对改革实践中的热点问题研究比较突出,有价值的基础理论研究尚显薄弱;2016年将重点关注土地管理体制机制创新、农村土地制度改革、不动产统一登记制度、自然资源资产核算及管理体制、土地法学理论与实践等研究。     

Protecting Watershed Ecosystems through Targeted Local Land Use Policies

Land use change is the most pervasive force driving the degradation of watershed ecosystems. This article combines an econometric model of land use choice with models of watershed health indicators to examine the effects of land use policies on watershed ecosystems through their effect on land use. Our results suggest that incentive-based land use policies and property acquisition programs can have relatively large positive impacts on watershed health, while policies that change the returns to land use are less effective. The results suggest that there is potential for targeting these policies because their impacts vary across watersheds with different land use mixes.     

Land use and biodiversity relationships

The relationships between land use and biodiversity are fundamental to understanding the links between people and their environment. Biodiversity can be measured in many ways. The concept covers not only the overall richness of species present in a particular area but also the diversity of genotypes, functional groups, communities, habitats and ecosystems there. As a result, the relationships between biodiversity in its broadest sense and land use can be complex and highly context dependent. Moreover, the relationships between them are often two-way, so that simple relationships between cause and effect can be difficult to identify. In some places, specific land uses or land management practices may be important in sustaining particular patterns of biodiversity. Elsewhere, the uses to which land can be put are highly dependent on the biodiversity resources present.The review will consider how changes in the quantity, quality and spatial configuration of different aspects of land use can impact on different components of biodiversity, and what direct and indirect factors might drive these changes. The need to distinguish between land cover and land use will be discussed in relation to the economic and social drivers of land use change. The review will also consider whether framing biodiversity objectives involves society in placing constraints upon the types of land use and management practice that are possible, and will consider such arguments in relation to assessments of the costs of biodiversity loss. It would seem that while considerable progress has been made in mapping out plausible futures for land use and biodiversity at global and regional scales, closer integration of modelling, scenario and field-based monitoring is needed to strengthen the evidence base available to decision makers. Challenges that face us include how we take account of the qualitative changes in land cover, and the impacts of such modifications on biodiversity and ecosystem services. Broader perspectives on the value of biodiversity and ecosystem services are also needed as the basis for developing adaptive and flexible approaches to policy and management.     

基于分形理论的昆明市土地利用空间结构及重点审计地类分析

为揭示被审计地区土地利用空间结构变化特征,确定重点审计地类,提高土地资源审计效率,为自然资源资产审计提供新思路。本文基于昆明市2015年和2018年两期土地利用现状数据,利用GIS技术、统计分析软件以及分形理论对2015-2018年该区域的土地利用类型形态复杂度和结构稳定性进行研究,以深入揭示该区域土地利用分形动态特征,从而掌握土地资源变化情况,更好地服务于自然资源资产审计。结果表明,(1)基于分形理论构建的分形维数和稳定性指数能够表达土地利用类型的总体特征与空间形态结构变化,能够揭示被审计地区各地类土地资源资产的变动趋势,从而确定土地资源重点审计地类;(2)昆明市各土地利用类型分形维数都存在不同程度的变化,水域分形维数最大,土地利用类型形态最为复杂,但结构也最为稳定;建设用地、耕地、草地、园地及未利用地分形维数都呈上升态势,土地利用类型形态趋向复杂,结构趋向不稳定;林地分形维数减小,土地利用类型形态趋向规则,结构趋向稳定。结构不稳定的地类应该作为自然资源资产审计的重点关注内容。基于土地利用分形动态特征确定重点审计地类具有可操作性,能够提高土地资源的审计效率,可以作为自然资源资产审计的新思路。     

气候变化对农户生计的影响研究综述

气候变化是21世纪人类面临的最严峻挑战之一,加剧了许多国家和地区的脆弱性,对以自然资源为生计基础的农业人口的影响尤为显著,明确气候变化对农户生计的影响,对于制定有效的气候变化适应政策,增强农户的气候变化适应能力,减轻农村贫困人口生计脆弱性具有重要意义。目前,国内外围绕气候变化对农户生计影响开展了许多研究,主要集中在过去或当前气候变化对水资源、土地、农作物、病虫害、人类健康等农户生计资本的宏观影响以及局地或区域尺度上气候变化对农户生计策略选择的影响等方面。从发展趋势看,亟需开展气候变化对农户生计的影响机理及适应机制研究,建立合理的气候变化对农户生计影响的评估框架,加强对模拟、分析和预测气候变化及其与其他压力相结合对农户生计要素的可能影响进行广泛评估,科学把握农户生计对气候变化脆弱性的关键影响因素,这对人类科学地适应气候变化和促进人类福祉和恢复力的提升具有重大的科学价值和现实意义。     

The impact of water scarcity on food,bioenergy and deforestation

We evaluate the impact of explicitly representing irrigated land and water scarcity in an economy‐wide model with and without a global carbon policy. The analysis develops supply functions of irrigable land from a water resource model for 282 river basins and applies them within a global economy‐wide model. The analysis reveals two key findings. First, explicitly representing irrigated land has a small impact on global food, bioenergy and deforestation outcomes. This is because this modification allows irrigated and rainfed land to expand in different proportions, which counters the effect of rising marginal costs for the expansion of irrigated land. Second, changes in water availability have small impacts on global food prices, bioenergy production, land use change and the overall economy, even with large‐scale (c. 150 exajoules) bioenergy production, due in part to endogenous irrigation and storage responses. However, representing water scarcity and changes in water availability can be important regionally, with relatively arid areas and/or areas with rapidly growing populations fully exhausting our estimated maximum irrigation capacity that allows for improved irrigation efficiency, lining of canals to limit water loss, and expanding storage to fully capture average annual water flows.