Ecological environment quality evaluation of the Sahel region in Africa based on remote sensing ecological index

Long-term monitoring of the ecological environment changes is helpful for the protection of the ecological environment.Based on the ecological environment of the Sahel region in Africa,we established a remote sensing ecological index(RSEI)model for this region by combining dryness,moisture,greenness,and desertification indicators.Using the Moderate-resolution Imaging Spectroradiometer(MODIS)data in Google Earth Engine(GEE)platform,this study analyzed the ecological environment quality of the Sahel region during the period of 2001-2020.We used liner regression and fluctuation analysis methods to study the trend and fluctuation of RSEI,and utilized the stepwise regression approach to analyze the contribution of each indicator to the RSEI.Further,the correlation analysis was used to analyze the correlation between RSEI and precipitation,and Hurst index was applied to evaluate the change trend of RSEI in the future.The results show that RSEI of the Sahel region exhibited spatial heterogeneity.Specifically,it exhibited a decrease in gradient from south to north of the Sahel region.Moreover,RSEI in parts of the Sahel region presented non-zonal features.Different land-cover types demonstrated different RSEI values and changing trends.We found that RSEI and precipitation were positively correlated,suggesting that precipitation is the controlling factor of RSEI.The areas where RSEI values presented an increasing trend were slightly less than the areas where RSEI values presented a decreasing trend.In the Sahel region,the areas with the ecological environment characterized by continuous deterioration and continuous improvement accounted for 44.02%and 28.29%of the total study area,respectively,and the areas in which the ecological environment was changing from improvement to deterioration and from deterioration to improvement accounted for 12.42%and 15.26%of the whole area,respectively.In the face of the current ecological environment and future change trends of RSEI in the Sahel region,the research results provide a reference for the construction of the"Green Great Wall"(GGW)ecological environment project in Africa.

Effective Strategies to Encourage the Cultivation of Sorghum and Corn in the African Sahel: An Analysis of Chad

The research explores traditional sorghum and corn cropping systems in the Guera region of the Sahel, focusing on social, economic, and ecological criteria. The region faces challenges due to its tropical climate, droughts, and land characteristics, affecting sorghum and corn cultivation. A comprehensive framework, developed in collaboration with national and international organizations, is needed to improve agricultural production in infertile land. Chad’s smallholders use a low-tech, risk-averse rainfed system, but diversified techniques and new cultivation patterns can increase profits. Modern technologies and innovations can increase diversity and create new cultivation forms, involving scientific, commercial, credit, and industrial organizations. Chad faces severe water stress and crop yield issues, with up to 95% of water resources lost due to evapotranspiration. Proper water management techniques, assisted irrigation, efficient rainwater harvesting, and effective seed selection and crop management are crucial for improving agricultural production, reducing poverty, and ensuring the survival of the region’s agricultural sector. Chemical poverty complicates crop management, but fertilizers and skips can improve soil and provide good cereals. Urea can be added to legumes to increase plant growth and nitrogen fixation, while microorganisms and mycorrhizal fungi can strengthen rhizobia and enhance plant recovery. Handling tradeoffs is crucial, as environmental shocks can lead to social consequences like hunger and unemployment. The Sahel region’s sorghum and corn plant species face food production stagnation and chronic insufficiency due to increasing population and pests. Integrated pest management strategies and market access are crucial for smallholder farmers, but quality standards are weak. Public-private partnerships can improve value chains and market linkages, leading to increased farmer income, traders’ income, and consumer prices.

Combating Desertification and Improving Local Livelihoods through the GGWI in the Sahel Region: The Example of Senegal

The Great Green Wall Initiative（GGWI） has an overall objective of fighting desert encroachment through proven practices of sustainable management of land, and the reinforcement and protection of natural resources and systems of production and transformation, while also ensuring socio-economic development of local communities through multi-purpose activity platforms. The activities described in the present study are designed to accomplish several goals：（1） generate wealth,（2） strengthen access to basic social services,（3） manage the transition to a green economy as a means of creating suitable conditions for the emergence of rural production centers,（4） integrate sustainable development in order to eradicate poverty and food insecurity, and（5） strengthen adaptation and resilience capacities of local populations. The present study was undertaken on the basis of a wide variety of available publications and documentation, including articles and scientific papers, thesis, meeting summaries and reports, concerning the implementation of the Great Green Wall Initiative/GGWI in Senegal.

北非Sahel地区夏季降水异常对华北平原旱涝指示意义

利用NECP/NCAR再分析和气象站点实测降水资料,辅以分段线性回归、趋势分析及相关分析方法,分析了近54a华北平原和Sahel地区的降水变化特征,探讨了Sahel地区夏季降水异常对华北平原旱涝变化的指示意义。结果表明:(1)华北平原与Sahel地区夏季降水异常相关性存在空间差异,显著相关区域位于800mm等降水线以北的地区,淮河平原的相关性较弱;(2)华北平原与Sahel地区降水关系既有稳定性,又存在明显的年代际变化特征。20世纪70年代中期和90年代末为相关性变化的重要转折点,这与NAO,PDO和东亚季风以及青藏高原积雪突变时间一致;(3)地形因素、城市因素对降水相关性影响较弱。在省域尺度上,山东省正相关特征最为突出,表现为全区一致性;京津冀平原区表现为显著正相关,河南省则以负相关为主,江苏、安徽表现为不显著负相关;(4)Sahel中区对黄河下游旱涝具有正向指示意义,Sahel东区对海河平原旱涝具有负向指示意义。

Modelling of Sorghum (<i>Sorghum bicolor</i>) Growing Areas under Current and Future Climate in the Sudanian and Sahelian Zones of Mali

Climatic variability is one of the main constraints of agriculture in Mali, which will certainly affect long-term sorghum yields. The objective of the present study was to assess the effect of climate variability on sorghum production areas by 2050 in the Sudanian and Sahelian zones of Mali considering three climate scenarios: current scenarios (RCP 2.5), optimistic scenarios (RCP 4.5) and pessimistic scenarios (RCP 8.5). Therefore, 11,010 occurrence points of sorghum (Sorghum bicolor) were collected and associated with the environmental variables of the three climatic scenarios according to the maximum entropy approach (Maxent). Sorghum environmental data and points of occurrence were obtained from AfriClim and GBIF databases, respectively. The correlations carried out and the Jackknife test allowed us to identify variables that contributed more to the performance of the model. Overall, in the Sudanian zone, the suitable area for sorghum production which currently represents 37% of the area of the district of Koulikoro will increase up to 51% by 2050 considering the optimistic scenario (RCP 4.5). Furthermore, considering the pessimistic scenario (RCP 8.5), the suitable zones for sorghum production will experience a decrease of 10%. In the Sahelian zone, the suitable zones for sorghum production that represent 55% of San district area considering the RCP 2.5 scenario will experience a decline of 24% by 2050 considering both the optimistic (RCP 4.5) and pessimistic (RCP 8.5) scenarios. It is suggested to carry out investigations on potential sorghum yield prediction in both study areas in order to identify suitable production areas of the crop in the near future (2050) and long term (2100) as adaptation strategies and resilience of farmers to climate change.

Appraisal of Groundwater Potential of Fadama Areas within Northern Nigeria: A Review

Nigeria is a country endowed with alluvial aquifers that occur along major river valleys, in low lying areas which are frequent to flooding during the rainy season. They are scattered across the ecological zones of Guinea savannah, Sudan savannah and the Sahel Savannah and are the thickest along the river Niger and river Benue. The irrigated flood plains (Fadama) are formed by the deposition of transported weathered exogenic terrigenous materials derived from the surrounding basement rocks. These shallow aquifers are mostly unconfined and are recharged through flash flooding events which make them hold great groundwater resources for dry season farming. The fertility of the soils with their residual moisture content makes them attractive for dry season farming. The potential and importance of Fadama agriculture for food production and economic development are crucial, given the recent rising food prices, climatic changes, environmental risks associated with “modern” agriculture, modelled farming systems and population growth. Fadama areas are therefore of critical importance to the survival and economic development of millions of rural dwellers. This paper reviews the groundwater potential of the Floodplains of Fadama for dry farming systems in semi-arid northern Nigeria.

萨赫勒地区蝗灾起因和防治途径

本文在分析国内、外大量的蝗虫猖獗地区的地理、地貌和有关影响因素资料的基础上,结合我国蝗虫防治研究的成果,得出了萨赫勒地区蝗虫猖獗是在其自然地理因素主导下产生的结论,而提出焚烧灭蝗的防治新途径。

“后伊斯兰国”时代萨赫勒重点地区恐怖活动变化及对中国的影响

随着国际恐怖浪潮的演进,全球反恐进入“后伊斯兰国”时代,萨赫勒地区的恐怖主义形势也因此受到波及与影响,且愈演愈烈。萨赫勒地区的反恐作为国际反恐链条的薄弱环节,引起国际社会广泛关注。通过对相关案例、数据的梳理、研究发现,“后伊斯兰国时代”非洲萨赫勒重点地区恐怖形势呈现出老牌恐怖组织弱化、分裂,新兴恐怖组织联盟出现,以及遭受恐怖主义外溢威胁的发展现状;恐怖袭击爆发式增长、恐怖组织借助种族矛盾发展壮大以及彼此之间合作与冲突相交织等特点比较明显。因此,当前中国在萨赫勒地区国家进行投资合作时,应积极发挥中国的建设性作用,支持其自主建设,加大国际、区域性反恐援助,增强中国在萨赫勒地区人员的保护。

萨赫勒五国集团与地区反恐问题探析

目前,非洲萨赫勒地区受到恐怖主义的严重威胁,成为全球安全局势急剧恶化的地区之一。为此,萨赫勒五国组建了“萨赫勒五国集团”,采取多项举措积极打击恐怖主义,成为维护萨赫勒地区稳定的中坚力量。萨赫勒五国集团成立后受到了国际社会的广泛支持,法国是该组织最坚定的支持者。在法国的帮助下,萨赫勒五国集团也不断发展成为一个更具综合性的组织。但是,因自身的局限以及复杂的客观安全环境,该组织在未来的发展仍将面临巨大的挑战。

Spatiotemporal Drought Assessment over Sahelian Countries from 1985 to 2015

Due to infrequent rainfall, high temperatures, and degraded land, the Sahel region often suffers from droughts. The Sahel region is considered as one of the world’s driest and extreme environmental conditions. In order to assess spatiotemporal vulnerability of potential drought impacts, we used remote sensing and ground station data to evaluate drought conditions in the Sahel region from 1985 to 2015. The standard precipitation index(SPI), standard precipitation evapotranspiration index(SPEI), vegetation condition index(VCI) anomaly, along with socioeconomic indicators were performed. In addition, Pearson correlation coefficient(PCC) was computed between drought indices and three main crops(sorghum, millet, and maize) in the region to estimate the effects. The analysis showed that temperature increased by 0.78°C from 1985 to 2015, which had a significant impact on crop yield for sorghum, maize, and millet with a statistical significance value of P > 0.05. In the decade spanning 1994 to 2005 alone, the temperature increased by 0.57°C, which resulted in extreme drought in Algeria, Sudan, Chad, Nigeria, and Mauritania. For the effect of drought on crop production, high significance was noted on the SPI and SPEI-3 timescale: sorghum with SPI-3(r = 0.71) and SPEI-3(r = 0.65), millet with SPI-3(r = 0.61) and SPEI-3(r = 0.72), and maize with SPI-3(r =0.81) and SPEI-3(r = 0.65) during the study period. In the growing season, VCI anomaly had strong correlations with sorghum and millet(r = 0.67 and 0.75, respectively). A significant agreement was also noticed between the combined drought index(CDI) and vulnerability index(VI) in Burkina Faso(r =-0.676;P < 0.00), Mali(r =-0.768;P < 0.00), Mauritania(r = 0.843;P < 0.001), Niger(r =-0.625;P < 0.001), and Nigeria(r =-0.75;P < 0.005). The results show that the above indices are effective in assessing agricultural drought and its impact on crop production in the Sahel, and in identifying areas most affected by drought.

萨赫勒地区安全治理困境探源

利比亚战争结束以来,萨赫勒地区安全态势持续恶化,地区安全治理陷入长期性和结构性困境,主要体现为两个方面:一是地区安全和发展面临严峻挑战,从冲突陷阱到贫困陷阱,从气候陷阱再到治理陷阱,使该地区演变为典型的安全复合体;二是随着地区不稳定因素的升级和扩散,各类治理行为体的纷纷涌入事实上造成了“安全拥堵”,非但没有缓解地区安全局势,反而制造了更大麻烦。萨赫勒地区安全治理困境的根本原因在于,内部自主治理和外部安全援助均严重忽视发展—安全—治理关联,其“治标不治本”的方法难以从根源上解决地区安全挑战。中国式现代化坚持发展优先、发展与安全统筹的成功经验,可为萨赫勒地区摆脱安全治理困境、迈向可持续稳定与和平提供重要启示。

萨赫勒地区面临的恐怖主义威胁及其应对

萨赫勒地区是非洲恐怖主义活动最为猖獗的地区之一。受到族群矛盾、武装冲突、贫困和自然灾害困扰,以及新冠肺炎疫情、乌克兰危机等外部因素的共同作用之下,近年来萨赫勒地区恐怖主义活动的频度和烈度明显上升,活动范围不断扩大。萨赫勒地区恐怖主义呈现出一系列新的特点:恐怖组织分化重组加速,两大极端组织集团对抗加剧;恐怖组织与本土社会融合程度加深,对本土社会控制能力增强;恐怖主义与跨国有组织犯罪、气候变化叠加效应凸显。国际及地区组织、域外大国、地区国家政府、地方自卫民兵组织等不同层级行为体介入了萨赫勒地区恐怖主义治理。由于治理主体缺乏有效协调,治理方式过度依赖军事手段,多维反恐理念未被充分重视等问题,导致恐怖主义治理成效不彰,滋生恐怖主义的土壤依旧存在。未来,在推动地区国家经济与社会快速发展、提升政府治理能力、发挥各国在反恐事务自主性的基础上,制定并实施协同有效的国际反恐合作战略,系应对萨赫勒地区恐怖主义的有效路径。

价值累加理论视角下萨赫勒恐怖主义问题探析——以尼日尔蒂拉贝里地区为例

近年来,由于萨赫勒中部地区安全局势持续恶化,位于尼日尔西北部的蒂拉贝里地区遭受恐怖主义威胁日益严重。2018年以来,蒂拉贝里地区恐怖袭击事件频发,造成大量人员伤亡和财产损失。蒂拉贝里地区恐怖主义滋生发展是政府羸弱、农牧民矛盾、族群冲突等多种因素共同作用的结果。解决该地区恐怖主义问题不仅需要国内外军事力量的联合打击,还需要尼日尔政府主动发挥治理和调节作用,从经济、政治、社会等方面缓解各种矛盾,逐步实现稳定与发展。基于价值累加理论分析蒂拉贝里地区恐怖主义问题,有助于深入分析当地复杂的安全局势,为尼日尔乃至萨赫勒地区安全治理提供有益借鉴。

泛非绿色长城倡议及其农牧林发展

泛非绿色长城倡议的总体目标是通过可持续土地管理和可持续森林管理,加强和保护自然资源,共同抗击荒漠化,同时通过各种渠道和平台促进当地社区的经济发展,消除贫困,保障食品安全,稳定人口数量,加强应对干旱的能力和复原力,最终发展绿色经济。文中介绍和分析了泛非绿色长城倡议及泛非地区农牧林发展概况,通过剖析泛非11个最初成员国在实施泛非绿色长城倡议过程中面临的问题,提出了一些发展前景展望,旨在为我国企事业单位等出境机构更好地参与当地相关产业的合作与发展,以及推进当地植树造林和防沙治沙技术'走出去'和'一带一路'绿色发展联盟建设提供参考。

马里内战前后伊斯兰马格里布基地组织的调整与转型

伊斯兰马格里布基地组织一直是北非及萨赫勒地区安全的重要威胁,对撒哈拉以南非洲的影响力也在不断增加。伊斯兰马格里布基地组织的势力与影响力不断变化,2012—2013年占领马里北部地区是该组织发展历程中的关键节点,标志着其从扩张期进入蛰伏期、从发展期进入调整期。马里为该组织推行伊斯兰教法和组织结构转型提供了重要的试验场地。在马里北部及其周边地区,该组织进行了意识形态调整、组织结构转型与招募策略升级三方面的实践,积累了发展经验,缓解了内部矛盾,将马里及周边萨赫勒地区变为旗下“撒哈拉酋长国”的主要活动区域。该组织占领马里的时间虽然不长,但对马里战后重建、地区安全及防范恐怖主义渗透等方面带来的影响将长期存在。经过蛰伏与转型,国际社会需警惕该组织隐蔽的本土化发展和犯罪集团化的资金获取途径,同时加大联合打击强度,避免出现地区跨国恐怖网络的联动。