An assessment of carbon stock for various land use system in Aravally mountains, Western India

Reducing carbon emissions from deforestation and degradation in developing countries is of the central importance in efforts to combat climate change. A study was conducted to measure carbon stocks in various land-use systems including forms and reliably estimates the impact of land use on carbon (C) stocks in the forest of Rajasthan, western India (23°3′–30°12′N longitude and 69°30′–78°17′E). 22.8% of India is forested and 0.04% is the deforestation rate of India. In Indian forest sector of western India of Aravally mountain range covered large area of deciduous forest and it’s very helpful in carbon sequestration at global level. The carbon stocks of forest, plantation (reforestation) and agricultural land in aboveground, soil organic and fine root within forest were estimated through field data collection. Results revealed that the amount of total carbon stock of forests (533.64?±?37.54 Mg·ha^?1, simplified expression of Mg (carbon) ·ha^?1) was significantly greater (P?<?0.05) than the plantation (324.37?±?15.0 Mg·ha^?1) and the agricultural land (120.50?±?2.17 Mg·ha^?1). Soil organic carbon in the forests (172.84?±?3.78 Mg·ha^?1) was also significantly greater (P?<?0.05) than the plantation (153.20?±?7.48 Mg·ha^?1) and the agricultural land (108.71?±?1.68 Mg·ha^?1). The differences in carbon stocks across land-use types are the primary consequence of variations in the vegetation biomass and the soil organic matter. Fine root carbon was a small fraction of carbon stocks in all land-use types. Most of the soil organic carbon and fine root carbon content was found in the upper 30-cm layer and decreased with soil depth. The aboveground carbon (ABGC): soil organic carbon (SOC): fine root carbon ratios (FRC), was 8:4:1, 4:5:1, and 3:37:1 for the forest, plantation and agricultural land, respectively. These results indicate that a relatively large proportion of the C loss is due to forest conversion to agricultural land.     

Spatial and temporal variability of greenhouse gas emissions from rural development land use operations

Climate change objectives of mitigation and adaptation are being mainstreamed into many policies and strategies around the world. In Europe, this has included the Rural Development Programme, which aims to tackle multiple social, economic and environmental objectives in rural areas, and the integration of climate change objectives adds another strand of complexity to the decision making process. When formulating policies determining the likely effectiveness of any particular measure can be challenging, especially with respect to the spatial and temporal variability of greenhouse gas emissions. This is a challenge faced by all countries and regions around the world. This study uses Europe as an example to explore this issue. It highlights the variability in emissions from land use operations that may be encountered under different conditions and time horizons and considers this in the context of policy formulation. The Optimal Strategies for Climate change Action in Rural Areas software has been adapted to derive net greenhouse gas emissions for rural development operations for all regions in Europe. Operations have been classified into five categories based on their benefit/burden over different time horizons. The analysis shows that it is important to understand the time period over which benefits or burdens are realised and determine how this fits with policy instruments, such as land management agreements and the permanency of actions. It also shows that in some regions an operation can have benefits, but in other regions it has burdens; thus, location can be critical. Finally, in the context of developing operations to meet multiple social, economic and environmental objectives, it is important to acknowledge that seeking options that only reduce emissions may not always be practical or possible. In some instances, we may have to accept an increase in emissions in order to meet other objectives. It is important that we evaluate the net greenhouse gas emissions of all operations, not just those aimed at climate change mitigation. We can then select those with the least burden in the process of developing optimal solutions to meet multiple objectives.     

Integrated assessment of future CAP policies: land use changes,spatial patterns and targeting

The recent and upcoming reforms of the Common Agricultural Policies (CAPs) aim at strengthening the multifunctional role of agriculture, acknowledging the differences in economic, environmental and social potentials within European regions. This paper presents results from an integrated assessment of existing and future policies within the framework set up in the FP6 EU project MEA-Scope. Spatial explicit procedures allow for the MEA-Scope modelling tools to provide information related to regional, environmental and socio-economics settings. The impact of different policy scenarios on structural change, land abandonment and cropping pattern of typical farms has been assessed based on linked agent-based (ABM) and Linear Programming (LP) models at regional and farm scale for two study areas. For the German case study area Ostprignitz-Ruppin (OPR), the issue of policy targeting has been addressed by relating non-commodity outputs (NCOs) to soil quality and protection status. For the Italian case study area (Mugello), changes in landscape patterns in terms of increased fragmentation or homogeneity as affected by changes in agricultural intensity have been analysed using semivariance analysis. The spatial explicit approach highlighted the relevance of case study research in order to identifying response structures and explaining policy implementation patterns.     

黄土丘陵区土地利用与土壤水分的时空关系

论文根据连续两年土壤水分的定点和观测数据,对黄土丘陵区不同土地利用类型及其结构与土壤水分的时空关系进行了分析。结果表明:①在欠水年,土地利用间土壤水分的差异显著,而在丰水年,土地利用间土壤水分的差异不显著;②在丰水年,土壤水分的年内变化只有灌木地为消耗型,间作地、果园、林地、草地、撂荒地和农地等6种土地利用类型为平衡型或增长型,欠水年所有土地利用均为消耗型;③从丰水年到欠水年,土壤水分的剖面结构类型降低型向波动型转化,波动型向增长型转化;④单一土地利用结构的土壤水分从坡顶到坡脚具有增长的趋势,而土地利用结构复杂的土壤水分沿坡面分布复杂。     

功能区土地利用碳收支空间分异及碳补偿分区——以武汉城市圈为例

开展功能区土地利用碳收支评估并构建碳补偿分区优化框架,对于制定适应各功能区低碳策略、指导补偿额度流向、推动区域协调发展具有重要现实意义。以武汉城市圈县域为基本单元,在分析主体功能区划下土地利用碳收支空间分异特征的基础上,借助标准显示性比较优势指数法、SOM-K-means模型、二维关联矩阵等方法,对武汉城市圈进行了碳补偿类型区划分及优化。结果表明：武汉城市圈各县域土地利用碳排放总量地区差异显著,呈现“西高东低,中心最高”空间分布格局;主体功能区划下土地利用碳排放、碳吸收均具有明显空间分异特征,碳吸收与碳排放呈现出一定程度的相对空间分布趋势;武汉城市圈共有16个碳补偿支付区、11个碳补偿获补区以及12个碳补偿平衡区;结合主体功能区规划战略目标,最终形成7类碳补偿空间优化区,并对每一类型区提出了相应的低碳发展方向及策略。     

REDD+ policy strategy in Cameroon: Actors,institutions and governance

Reducing emissions from deforestation and forest degradation (REDD+) is receiving increasing political and scientific attention as a climate change mitigation approach. The government of Cameroon has expressed an interest in participating in REDD+, and national deliberation on a policy strategy has attracted interest from different actors in the forest sector. This paper analyses the challenges of designing a governance structure for a REDD+ strategy in Cameroon. Theoretically, the paper builds on the literature on governance structures for resource management, focusing analytically on the interactions between actor constellations (state and non-state) and institutions (formal and informal) to produce policy outcomes. The paper draws on documentation of REDD+ policy events, policy texts and 23 in-depth interviews with members from government, civil society, research organizations, development partners and the private sector. It argues that although the actors involved in REDD+ are, to an extent, polarized around different issues and priorities, they are nonetheless increasingly distributing roles and responsibilities among themselves. The institutional arrangements within the policy process include: (1) rule-making systems for engagement; (2) expanding existing coordination mechanisms; (3) national safeguard standards; and (4) building on existing forest governance initiatives. The paper concludes that the multiple benefits promised by REDD+, such as poverty alleviation, biodiversity conservation and economic development, are critical for the legitimacy of the mechanism.     

基于NPP-VIIRS夜间灯光的长株潭地区县域土地利用碳排放空间分异研究

从县域尺度开展土地利用碳排放空间分异研究,对指导区域实现碳达峰及碳中和目标具有重要意义.基于2013-2019年NPP-VIIRS夜间灯光数据测算长株潭地区县域土地利用碳排放,并运用探索性空间数据分析和地理探测器,对长株潭地区县域土地利用碳排放空间分异特征及影响因素进行分析.结果 显示:①2013-2019年,长株潭地...     

Impacts of land use,restoration, and climate change on tropical peat carbon stocks in the twenty-first century: implications for climate mitigation

The climate mitigation potential of tropical peatlands has gained increased attention as Southeast Asian peatlands are being deforested, drained and burned at very high rates, causing globally significant carbon dioxide (CO₂) emissions to the atmosphere. We used a process-based dynamic tropical peatland model to explore peat carbon (C) dynamics of several management scenarios within the context of simulated twenty-first century climate change. Simulations of all scenarios with land use, including restoration, indicated net C losses over the twenty-first century ranging from 10 to 100 % of pre-disturbance values. Fire can be the dominant C-loss pathway, particularly in the drier climate scenario we tested. Simulated 100 years of oil palm (Elaeis guineensis) cultivation with an initial prescribed burn resulted in 2400–3000 Mg CO₂?ha^?1 total emissions. Simulated restoration following one 25-year oil palm rotation reduced total emissions to 440–1200 Mg CO₂?ha^?1, depending on climate. These results suggest that even under a very optimistic scenario of hydrological and forest restoration and the wettest climate regime, only about one third of the peat C lost to the atmosphere from 25 years of oil palm cultivation can be recovered in the following 75 years if the site is restored. Emissions from a simulated land degradation scenario were most sensitive to climate, with total emissions ranging from 230 to 10,600 Mg CO₂?ha^?1 over 100 years for the wettest and driest dry season scenarios, respectively. The large difference was driven by increased fire probability. Therefore, peat fire suppression is an effective management tool to maintain tropical peatland C stocks in the near term and should be a high priority for climate mitigation efforts. In total, we estimate emissions from current cleared peatlands and peatlands converted to oil palm in Southeast Asia to be 8.7 Gt CO₂ over 100 years with a moderate twenty-first century climate. These emissions could be minimized by effective fire suppression and hydrological restoration.     

基于土地利用和气候变化的北方农牧交错带界线变迁

基于1961~2005 年中国北方9 省、自治区的218 个气象站点的气象资料及1986 年和2000 年的土地利用数据,从全球气候变化和土地利用变化角度分别界定了北方农牧交错带的地理位置,并分析了其界线变迁特征.结果表明,北方农牧交错带的地理位置还存在一定争议.交错带整体上已向西北移动.西北界已向北深入到纯牧区,东南界附近也由农牧交错区转成纯农区.气候界线向东南变迁,土地利用界线向西北变迁,两者变迁方向相反.东北段和华北段的界线变迁幅度远大于西北段.     

Simulated dynamics of carbon stocks driven by changes in land use, management and climate in a tropical moist ecosystem of Ghana

Sub-Saharan Africa is large and diverse with regions of food insecurity and high vulnerability to climate change. This project quantifies carbon stocks and fluxes in the humid forest zone of Ghana, as a part of an assessment in West Africa. The General Ensemble biogeochemical Modeling System (GEMS) was used to simulate the responses of natural and managed systems to projected scenarios of changes in climate, land use and cover, and nitrogen fertilization in the Assin district of Ghana. Model inputs included historical land use and cover data, historical climate records and projected climate changes, and national management inventories. Our results show that deforestation for crop production led to a loss of soil organic carbon (SOC) by 33% from 1900 to 2000. The results also show that the trend of carbon emissions from cropland in the 20th century will continue through the 21st century and will be increased under the projected warming and drying scenarios. Nitrogen (N) fertilization in agricultural systems could offset SOC loss by 6% with 30 kg N ha⁻¹ year⁻¹ and by 11% with 60 kg N ha⁻¹ year⁻¹. To increase N fertilizer input would be one of the vital adaptive measures to ensure food security and maintain agricultural sustainability through the 21st century.     

The rules for land use,land use change and forestry under the Kyoto Protocol—lessons learned for the future climate negotiations

This paper provides an overview of the rules for accounting emissions of land use, land use change and forestry (LULUCF) for the first commitment period of the Kyoto Protocol. It first describes the rules in detail, it then provides an overview of the history of negotiations that led to these rules and provides resulting conclusions for future international climate negotiations. We conclude that the current rules can be better understood in the light of the negotiation history. For the future, we conclude that first an agreement on the objectives of including LULUCF in the future climate regime should be developed, e.g. to contribute significantly to the ultimate objective of the convention. Further, a solid set of data should be developed that can assess the magnitude of possible options. The rules should be scientifically sound, complete and balanced as well as unambiguous before the quantitative targets are defined. They should further be simple and inclusive to include all carbon pools, i.e. provide incentives to avoid deforestation and unsustainable logging in all countries.     

CLUE-S模型及其在奈曼旗土地利用时空动态变化模拟中的应用

在对目前常用的土地利用变化模型进行调研的基础上,认为CLUE-S模型是众多模型中适用于区域土地利用变化研究的一种较好的模型;它是根据系统论的观点,在深刻理解土地利用系统内土地利用变化特征(包括关联性、竞争性、稳定性以及等级性等)的基础上构建而成,具有同步模拟不同土地利用变化的能力。论文以奈曼旗为例,根据1985年的空间图形数据,结合道路、居民点、城镇、水域的分布、以及地形和土壤等驱动因素,对其2000年的土地利用变化格局进行模拟;并用2000年的土地利用现状图对模拟结果进行检验。结果显示,在基本单元(500m×500m栅格)的水平上,模拟的正确率为85%,Kappa指数值是0.80。说明CLUE-S模型具有成功模拟区域土地利用时空动态变化的能力,是值得向国内同行推荐的一种较好的LUCC模型。     

中国县域单元生态脆弱性时空变化研究

以中国2853个县(市、旗、区)为研究单元,以1980、1990、2000和2010年全国1 km格网土地利用数据和中国县级行政单元社会经济统计数据为基础,通过VSD模型,构建了基于自然和人为共同作用下的生态系统影响力指数和社会经济适应力指数,用以综合表达生态脆弱性空间分异,在此基础上对中国县域单元的生态脆弱性进行定量评价.结果表明:中国县域生态系统影响力指数持续降低,2000年之前呈现由"东北到西南"逐渐降低的趋势,2000年之后,基本呈现"中东部及新疆北部高、西南低"的格局.适应力指数空间分布差异十分明显,表现出东南沿海高于中部,中部又高于西部的格局.从生态系统脆弱性空间分布格局来看,东南部比西部地区更脆弱,从时间变化来看,中国生态脆弱度整体好转,局部恶化;从数量变化来看,1983个县域单元处于高度脆弱区和极度脆弱区,仅有327个县域单元于处于轻度和微度脆弱区.处于极度脆弱区和高度脆弱区的县域单元未来要合理规划土地利用,加强土地利用管理,调整用地布局并严格控制城镇规模扩张;对于轻度和微度脆弱区则应坚持以生态建设和环境保护为主,禁止污染型产业发展,有序引导人口转移,发展生态旅游业和高技术产业.     

基于InVEST-PLUS模型的碳储量空间关联性及预测——以广东省为例

构建土地利用碳储量数据库,基于InVEST模型Carbon模块,得到广东省1990~2020年碳储量时空分布情况.用Moran’s I指数和Getis-Ord Gi^*分析格网尺度下碳储量时空分布特征,用Anselin Local Moran’s I得到LISA集聚图.然后运用PLUS模型和14个土地利用驱动因子预测2050年土地利用及其碳储量分布.结果表明,土地利用变化直接影响区域碳储量高低,林地、草地等具有生态服务功能地类碳密度最高,分别是188.44,329.34Mg/hm².碳储量空间格局整体呈现出中部低、北部高、东西中等的特点.碳储量空间分布特征与土地利用特征一致,碳储量显著高值集聚区域分布在建设用地少、生态用地多且连片的粤北地区,显著低值区域分布在国土开发强度和生态用地破碎化程度高的珠三角地带.在自然发展情景下,到2050年广东省土地利用碳储量将减少4327.21万Mg,随着国土空间进一步开发,环珠江口沿岸城市碳储量持续下降.增加植被生态系统碳储量,是实现碳中和的重要手段之一.要继续维持粤北山区生态保护屏障的重要地位,减缓珠三角城市土地开发强度,提高建设用地集约节约能力,形成平衡协调的土地利用和碳储量格局.     

洱海湖滨带水质的时空变化规律

对洱海全湖128km湖滨带及其外围敞水区水质进行了为期1a的调查研究.结果表明,洱海湖滨带总氮、氨氮、总磷、高锰酸盐指数年平均处于Ⅲ类水平,主要污染因子是总氮和总磷;湖滨带水质季节性变化表现为夏、秋季水质污染重于冬、春季,最重时期是11月.水质空间变化表现为北部污染重于南部,西部重于东部;临近村落、农田区湖滨带总氮、总磷、高锰酸盐指数浓度均明显高于临近林地、山地区湖滨带;强风浪水动力扰动下,湖滨带近岸(离岸0~60m范围,水深￡2.5m)区域水体总氮、总磷、高锰酸盐指数浓度均明显高于远岸(离岸70~190m范围,水深3.0~8.0m)区域,而在弱风浪下,离岸远近水质差异不明显.     

黄海、东海颗粒有机碳的时空分布特征

分析研究了2007年秋季黄海、东海海域颗粒有机碳(POC)的时空分布情况,结果表明:POC的浓度为7.25～766.00μg/L,平均浓度为(97.37±86.35)μg/L,其平面分布呈现近岸高、远岸低的特征,近岸POC的等值线与海岸线平行;垂直分布呈现除底层外随着深度增加逐渐降低的趋势。海水中POC浓度与浊度呈显著正相关,而与叶绿素a无显著相关关系,这表明POC主要来自于陆源输入。对不同海区POC的垂直分布和周日变化的研究结果表明,黄海区由于水深较浅,POC的垂直分布比较均匀,POC周日分布除了受到生物周日活动的影响外还受到潮汐作用的影响。长江口附近海区悬浮颗粒物浓度大小是POC浓度和分布的主要控制因素,垂直分布上表现出表层低底层高的特征。东海陆架区POC的垂直分布和周日变化均受到生物活动和水文条件等因素的共同作用,受黑潮影响的海域POC的浓度都相对较低。     

气候和土地利用/覆被变化对宁波地区生态系统产水服务的影响

提供水资源是重要的生态系统服务功能之一,对区域经济和生态系统的可持续发展具有重要作用.近年来,人类活动对水资源的需求量增加,加之水环境污染和水资源浪费现象严重,造成了部分地区的缺水问题.在此背景下,本文以宁波地区为例,研究气候变化和土地利用/覆被变化对生态系统产水服务的影响.首先,利用InVEST模型中的产水量模块,估算了区域的产水量.然后,利用情景分析的方法设计6种情景,分析了气候变化和土地利用/覆被变化对区域产水量的影响.最后,量化了气候和土地利用/覆被变化这2种因素对生态系统产水服务的贡献程度,并讨论了形成机制.研究表明:①2000—2015年,宁波地区的降水量增加了6.44%,潜在蒸散量减少了8.35%.城镇化导致建设用地面积增加了120%,耕地面积减少了22.37%.在气候变化和土地利用/覆被变化的共同作用下,平均产水量增加了10.91%.②气候变化对生态系统产水服务的影响更为显著,而土地利用/覆被变化的影响较小.其中,2000—2015年气候变化对宁波地区产水量的贡献率高达97.56%,而土地利用/覆被变化的贡献率仅为2.44%.③城镇生态系统的产水量高于其他生态系统类型,农田生态系统的产水量高于森林和草地生态系统.因此,城镇化会增加产水量,退耕还林还草会导致产水量的减少.     

The sensitivity of the costs of reducing emissions from deforestation and degradation (REDD) to future socioeconomic drivers and its implications for mitigation policy design

Mitigation and Adaptation Strategies for Global Change - Climate change mitigation policies for the land use, land use change, and forestry (LULUCF) sector are commonly assessed based on marginal...