Understanding the impacts of ‘Grain for Green’ land management practice on land greening dynamics over the Loess Plateau of China

Land greening in China is regarded as contributing a great deal to greening of the Earth. The phenomenon is mainly attributed to climate change, arising atmospheric CO₂ and ‘Grain for Green’ (GFG) land management policies. However, limited knowledge is known how much land greening is from contributions of the GFG practice. Therefore, the study took the typical region of the GFG practice, the Loess Plateau, as the study area, and used 1982–2015 satellite-observed GIMMS3g normalized difference vegetation index (NDVI) data, ERA-Interim climatic variables (precipitation, temperature and solar radiation) and atmospheric CO₂ concentration data with the help of a developed TPRC-based NDVI model to derive GFG-induced NDVI after 1999. Furthermore, this study tracked the spatial-temporal dynamics of GFG-induced NDVI and assessed contributions of the GFG practice to regional vegetation changes. Results showed that satellite-observed NDVI and TPRC-based NDVI both exhibited an increasing spatial pattern from the northwestern to southeastern Loess Plateau, but their greening trends were separately 0.0022 and 0.0009 per year in 1982–2015 (p < 0.05). Note that the satellite-observed greening trend was much steeper with a slope of 0.0056 per year after 2006 (p < 0.05). The subsequent analyses documented that GFG-induced land greening were largely responsible for the steep trend. In space, evident greening patterns began to be observed in the central Loess Plateau from 2006 to 2008, afterwards expanded towards eastern and southwestern Loess Plateau. In 2011–2015, the increase magnitude of GFG-induced land greening in the Loess Plateau averagely accounted for 8.5 % in comparison to estimated TPRC-based NDVI, but in six natural zones were various, ranging from 3.2%–15.7%. In some regions of central Loess Plateau, GFG-induced NDVI contributed even more than 20 % to vegetation increase. This study highlights that land use management contributes more to land greening dynamics over the Loess Plateau compared to climate change and arising atmospheric CO₂ concentration. These findings likely provide some valuable information for curbing or enhancing specific-location vegetation changes in future regional land management and planning.     

A model of West African millet prices in rural markets

In this article we specify a model of millet prices in the three West African countries of Burkina Faso, Mali, and Niger. Using data obtained from USAID’s Famine Early Warning Systems Network (FEWS NET) we present a unique regional millet price forecasting model that takes advantage of the panel nature of our data and accounts for the distance of rural markets from capital cities. Another novel aspect of our analysis is our use of the Normalized Difference Vegetation Index (NDVI) to detect and control for variation in conditions for productivity. We find that including NDVI information significantly improves price forecasts.     

Convergence between satellite information and farmers’ perception of drought in rangelands of North-West Patagonia,Argentina

Drought is a complex natural hazard with social and environmental implications. Satellite information is increasingly used to support decision-makers in preventing or coping with the negative impacts of drought. The integration of local and scientific knowledge to support drought monitoring is still far from being the main procedure in the development of drought monitoring and early warning systems. This study aimed at assessing the degree of convergence between satellite information on the effect of droughts on rangeland vegetation, from time series analysis, and farmers’ perception of drought in North-West Patagonia, Argentina. We characterised the scientific evidence of drought in terms of duration, spatial distribution, most severe years and recovery for the period 2000–2018 by identifying inter-annual NDVI changes. Farmers’ perceptions and experiences of drought were studied with open-ending interviews, with respect to occurrence, duration and recovery for that period. Satellite information matched farmers’ perception of drought at a regional scale, emphasising the value of remote sensing tools in supporting regional policy decision-making. However, farmers’ perceptions and recall of past drought impacts were more diverse than satellite information at a local level, highlighting the need for knowledge integration at finer scales.     

基于GIS的大连地被指数研究

根据<国家人口发展功能分区技术导则>要求,在大连市人口发展功能区规划中首要进行的工作就是大连市人居环境适应性评价,而影响人居环境适宜性的诸多自然因素中,最为根本且起主导作用的则主要为能综合反映区域自然条件的土地利用及土地覆盖特征.本文基于gis手段,利用mapinfo和idris软件,以大连市乡镇街道和公里网格为评价单...     

基于山海资源的开发区 时空格局演变及其转型研究 ——以漳州招商局 国家经济技术开发区为例

40年的改革开放给中国开发区时空格局带来诸多变化.实现区域可持续发展、探寻开发区产业转型成为当下热点.本文聚焦开发区中的山海资源,以漳州招商局国家经济技术开发区为对象,定量分析其1999～2018年建成空间形态、植被指数、海岸线变迁等生态空间时空指标,用于指导开发区未来产业升级转型.结果表明,山海空间是开发区空间扩张的...     

基于资源三号卫星数据的喀什市研究区的植被信息提取

通过利用喀什市研究区2012年的资源三号卫星影像,使用ERDAS软件首先提取归一化植被指数(NDVI),再使用Arc GIS软件对研究区的植被覆盖度进行估算,最后得出研究区2012年的植被覆盖度分级图,定量地说明了研究区2012年的植被覆盖情况。     

锡林郭勒盟牧草长势监测及其与气候的关系

该文以锡林郭勒盟为研究区域，运用2002、2003年的MODISNDVI数据对牧草长势进行了动态监测；并在此基础上，以光合有效辐射、温度和降雨量作为气候指标，分析了它们与牧草长势之间的关系。结果表明：5～9月份，牧草长势呈现单峰态变化。以7月或8月MODISNDVI最高；空间上，牧草长势呈现出明显的东、中、西部差异。以7、8月份差异最为显著；影响5月份牧草长势的气候因子主要是前一年11月至当年4月的月平均气温；影响青草期中后期牧草长势的气候因子主要是降水量，尤其是7、8月份的降水量。     

The impact of exurban development on forested areas in Kurgan City,Russia

Exurban communities—a significant form of urban sprawl—can transform natural land cover. Exurban development refers to an expansion of communities located outside a city and its suburbs. One of the main reasons these settlements develop is a desire by residents to live closer to nature and developers’ recognition of the profitability of addressing this desire. Additionally, exurbs can become prosperous regions settled by people with high income. However, exurban development not only directly affects community patterns, but also species patterns, habitat reduction and disconnection, as well as land cover and land use alterations. The purpose of this paper is a quantitative analysis of the land cover transformation and forest fragmentation in Post-Soviet Russia, based on an empirical case study of the city of Kurgan. This case study also contributes to the overall research of urban sprawl in Russian provinces by adding to the discussion of homeowners’ behavior, regional environmental policies, and their role concerning the impacts of exurban settlements on the natural environment. This paper uses remote sensing imagery, census data, and primary data to analyze land cover change due to the emergence of exurban communities around Kurgan, Russia, with specific emphasis on the changes to native vegetation resulting from human behavior and stakeholder preferences.     

Detecting the impact of the “Grain for Green” program on the mean annual vegetation cover in the Shaanxi province, China using SPOT-VGT NDVI data

In order to reduce the soil erosion rate on the Chinese Loess Plateau, the Chinese government launched in 1999 the “Grain for Green” program (GfG). The objective of this program was to increase the forest cover on steep slopes in the landscape by planting trees and sowing grasses on former cropland. The program was a massive investment by the Chinese government. By the end of 2005 the GfG-program was implemented in an area of 87,000 km² in which about 400–600 million trees were planted. At present it is not known to what extent this program was successful. This paper examines the effects of the GfG-program on the mean annual vegetation cover in the Shaanxi province. A decadal time series of SPOT VEGETATION imagery from 1998 till 2005 were used to calculate NDVI-values in four counties with different rainfall regimes. By means of a regression between preceding rainfall and NDVI-values the effects of rainfall variability were filtered out. A trend analysis of the corrected NDVI time series pointed out that the GfG-program resulted in a significant increase of the vegetation cover on farmland in the northern part of Shaanxi province. In the southern part of the province, which has a more humid climate and large areas of irrigation farmland no significant increase of the vegetation cover on farmland could be detected.     

我国典型植被群落的NDVI动态变化

随着全球气候变暖,物候正在发生显著变化。植物物候变化是植物对气候与环境变化最敏感且易观测的指示计,气候变化对植物物候的影响及其响应研究成为全球变化研究的热点问题之一。传统的物候观测方法是野外观测为基础的目视观测法,遥感等新技术的发展,为物候监测、研究提供了新的手段,归一化差值植被指数(NDVI)正日益成为植被对气候响应研究的重要手段。本文基于MODIS16天合成NDVI产品,提取了全国34种典型植被群落的NDVI动态变化曲线,分析了其进行植物物候监测的能力。研究结果表明:1)自然植被群落的NDVI年内变化特征明显,大致可分为三种类型:第一种植被群落的年内NDVI波动较大,第二种植被群落的年内NDVI波动不大,但月内变化较为剧烈,第三种植被群落的年内NDVI变化曲线与第一种类型类似,但幅度较小;2)典型植被群落的NDVI动态变化曲线符合其实际生长情况。