气候变化对我国北方农牧交错带空间位移的影响

北方农牧交错带地理位置特殊,脆弱性、敏感性是其主要特点。气候变化背景下我国北方农牧交错带范围也发生了相应变化。文中参考已有的界限指标,结合北方农牧交错带及其周边地区(11个省、自治区及直辖市)208个站点1961-2010年的降水资料,确定新的界限指标划定北方农牧交错带的边界,并讨论其界限移动情况。经分析,北方农牧交错带大部分地区降水量呈减少趋势,气候变化对东部降水量影响较为明显,农牧交错带范围向东南方向移动,且南界移动幅度大于北界;北部西界向西移动约2个经度;同时我国北方农牧交错带范围增加约3.5×104Km2,这一变化趋势与实际土地利用模式下农牧交错带移动情况相反,因此当前农牧交错带地区的土地利用方式不利于该地区生态环境的可持续发展,使该地区生态环境问题更加严重。     

靖边地区全新世气候变化及植被演替

靖边地区地处季风边缘区,对气候变化响应十分敏感.为研究其全新世以来的气候变化及植被演替,文中根据靖边地区孢粉代用指标,结合AMS14C定年,重建了该地区全新世以来的气候变化及植被演替.结果表明:该地区在全新世以来的气候变化经历了温凉偏湿-温暖湿润-温暖干燥-温暖偏湿-凉爽干旱5个阶段,植被演替划分为疏林草原-典型草原-...     

气候变化对我国中西部地区城市群的影响

气候变化和城市化是使得人类更易受灾害影响的两个主要因素.这两个因素在城市群相互叠加,而且城市群作为城市分布的密集区,人口、产业、基础设施等高度集中,因此,城市群成为易遭受气候变化引起的灾害侵袭并造成重大损失的高风险区.中西部地区五大城市群是所在区域经济社会发展的重要引擎,但也是气候变化影响的脆弱敏感地区.随着城市化进程...     

气候变化背景下旱地农田生态系统生态缺水变化研究——以武川县为例

近50年以来,由于受气候变化以及高强度的农业生产活动的影响,我国北方旱农地区脆弱的生态环境日益恶化,农田生态系统出现了明显的退化趋势。生态缺水是旱地农田生态退化的主要原因。文中以我国北方旱地农业区的典型县-内蒙古自治区武川县为例,探讨了气候变化背景下旱地农田生态系统生态缺水的变化趋势。研究结果表明:武川县气候正在向干暖化趋势发展,特别是近20年以来,干暖化趋势更加明显。1991-2010年武川县农田生态缺水量呈上升趋势,上升幅度分别为马铃薯45.99mm/10a,春小麦55.40mm/10a。降水是影响生态缺水量的主要因素。在气候干暖化背景下,武川县农田生态系统生态缺水量随降水量的减小而增加,气候变化加剧了旱地农田生态系统的退化。在旱农地区,气候变化背景下旱地农田生态系统退化趋势需要引起全社会的高度关注与重视。     

基于CVOR指数的巴音布鲁克高寒草原健康评价

利用草地生态系统健康评价CVOR综合指数,对巴音布鲁克高寒草原生态系统2004—2012年健康状态进行评价与退化分级研究,并对引起CVOR变化的内在驱动力因素进行探讨。结果表明:(1)研究区高寒草原生态系统健康状况由一般病态(2004年CVOR=0.58)逐渐恢复为健康状态(2012年CVOR=0.72);退化状况由强度退化恢复为中度退化,但局部仍存在强度退化;(2)降水是高寒草原生态系统CVOR指数的主要限制因子,降水也是除基况外各分指数变化的重要驱动因素;在气候变化背景下,CVOR指数将上升;(3)放牧改变了围栏外的群落功能组分,围封可以改善高寒草原生态系统的健康状况,有利于植被的正向演替,过度放牧是影响高寒草原恢复和演替的重要因素。总体上,降水和放牧是影响研究区高寒草原健康状况的主要原因。     

一个崭新的研究视角:农业生产可持续性对气候变化响应的定量评价

气候条件及其变化是构成地理环境诸要素的最敏感、最活跃的因子,对人类农业生产的发展影响也最为明显。然而,气候变化体现在时间和空间两个尺度上。在时间尺度上,气候变化是同一个地区的不同历史时期的气候特征;在空间尺度上,气候变化是不同地区的同一个历史时期的气候特征。不同的连接区域的气候构成的气候变化序列可以替代同一个区域的历史时期的气候变化序列,因为它们的变化都是连续的。基于此思想,选择气候条件明显不同的两个区域(分别用我国南方的和北方的两个省代替),分别模拟不同的气候条件利用现代的统计数据,构建农业生产可持续性评价指标,利用主成分分析和多元回归等定量方法,并通过对数据进行处理,剔除耕地面积减少、土地利用、管理、地形特征等诸多因素的影响,以定量研究探讨气候变化(可能是渐变或跳跃性的突变转型)对农业生产可持续性的影响。研究表明:当气候条件转好时,自然环境条件对农业生产的作用减小;农业社会和农业产出状况对农业生产的作用也减小;人们会有选择地耕种农业劳动生产率水平相对较高的土地。当气候条件变差时,自然环境条件对农业生产的限制作用增强;农业产出和农业社会状况对农业生产发展的作用增大;人们更多关注农业人均产出水平和农村社会生产状况,对农业劳动生产率状况的关注严重减少。     

干旱对中国北方草原总初级生产力影响的时滞和累积效应

近年来随着全球变暖，干旱事件的增加对植被的光合作用产生更加重要的影响，同时也严重影响了陆地生态系统的平衡。本文基于标准化降水蒸散指数(SPEI base v.2.7)和总初级生产力数据集（GOSIF GPP）研究了干旱对中国北方草原GPP的累积和时滞效应，利用Sen’s斜率、Mann-Kendall(MK)趋势检验、Mann-Kendall突变检验研究了GPP和SPEI在研究期内的时空变化，利用Pearson相关分析方法探究了干旱对北方草原GPP的累积和时滞效应。结果表明：（1）2001—2020年期间北方草原多年平均GPP呈现东北地区高、西南地区低的空间分布格局，多年平均SPEI呈现东北地区低、西南地区高的空间分布格局，且SPEI和GPP的年平均值都随时间变化呈现上升趋势。（2）干旱对北方草原84.99%的区域有累积效应，最长累积时间尺度主要集中在3～4个月，覆盖北方草原的39.82%；干旱对北方草原63.11%的区域有滞后效应，且主要发生在7个月，覆盖北方草原的19.73%。（3）通过对比不同水分条件下二者的变化趋势，发现干旱对草原GPP的累积效应强于时滞效应。     

光学与雷达遥感协同的大尺度草地灌丛化监测研究

受全球变化及人类利用方式强度影响,草地灌丛化已成为干旱半干旱地区草原生态系统最为突出问题之一.准确掌握大尺度草地灌丛化信息,对草地可持续利用管理及气候变化响应分析具有重要的意义.极化合成孔径雷达在地表粗糙度、灌木生物量等估算上已经展现出了一定潜力,其与多光谱光学影像的结合从理论上来说具备开展草原灌丛化监测的可能,然而目...     

基于GIMMS NDVI数据的北方13省荒漠化趋势评价

北方13省处在干旱、半干旱和半湿润地区,植被对气候变化和人类活动最为敏感,一直是荒漠化研究的热点地区。基于GIMMS NDVI和降水数据,使用一元线性回归方法对北方13省1982年-2006年ΣNDVI和降水的年际变化趋势及其相关性进行了分析,并对ΣNDVI和降水的变化趋势差异做进一步分析。研究结果表明:从总体上来看,中国北方13省在25年间荒漠化趋势变缓,即植被覆盖度呈显著上升趋势,其中显著增加的像元数为35.3%,而显著降低的像元数仅占7.2%。从ΣNDVI与降水的斜率散点象限图来看,ΣNDVI和降水的差异主要在第二象限和第三象限,说明尽管降水在北方地区植被覆盖度变化中起到主要作用,但是降水并不能完全解释植被覆盖度的变化趋势,人类活动如植树造林等是植被覆盖度增加的重要驱动力。内蒙古自治区东北部和东北地区的三江平原呈现出荒漠化趋势,在大部分地区与降水的相关性不显著,表明在该地区降水的影响作用较弱,主要是人类活动等因素导致的。     

巴音布鲁克地区植物物候时空动态变化及其驱动分析

植物物候是反映气候变化最显著、直观的指标,对理解气候变化与植物物候的相互作用具有重要的意义。而不同的生态系统对气候变化的响应和反馈存在差异,科学分析气候变化趋势下多种生态系统植物物候变化特征及其驱动因子对理解植物物候变化机制具有重要意义。本文选取多种生态系统交错分布的巴音布鲁克为研究区域,基于MODIS NDVI时间序列,得到了研究区物候的空间格局特征、时空变化特征以及与海拔和气候因子之间的关系。结果表明:(1)研究区植被返青期主要于4月上旬至5月下旬,枯黄期主要于9月中旬至10月中旬;(2) 2001—2017年,研究区植物返青期总体上呈提前趋势,其中草原、草甸和沼泽提前显著。枯黄期在北部呈提前趋势,在南部呈推迟趋势,其中高山植被和草原枯黄期提前显著;(3)植被的返青期总体上随着海拔的升高而推迟,枯黄期总体上随着海拔的升高而提前,各生态系统植被间的物候期差异随着海拔的升高而缩短。(4)研究区植物返青期与春季气温呈显著负相关,其中高山植被受5月气温影响较大,草原和沼泽受4月气温影响较大,草甸受4月和5月气温影响较大。     

甘肃黄土高原不同海拔气候变化对马铃薯生育脆弱性的影响

利用黄土高原不同海拔高度马铃薯生长发育定位观测资料和对应平行气象观测资料,分析气候变化对马铃薯生长发育敏感性的影响,以及马铃薯生育脆弱性变化特征.结果表明,研究区域降水量年际变化呈下降趋势,降水量变化曲线线性拟合倾向率在马铃薯生长季5-10月绝对值最大,表现为高海拔区大于低海拔区的特征.气温年际变化呈上升趋势,气温变化曲线线性拟合倾向率表现为高海拔区小于低海拔区的特征.作物生长季干燥指数呈显著上升趋势,干燥指数变化曲线线性拟合倾向率也表现为高海拔区小于低海拔区的特征,20世纪90年代后干燥指数明显上升,气候趋于暖干化.影响马铃薯生长发育的主导气象因子是气温,气候变暖,气温增高,导致马铃薯生育前期的营养生长阶段缩短,而生殖生长阶段延长,全生育期延长.块茎膨大期气温增高导致马铃薯生育脆弱性增加,马铃薯对气温变化的敏感性和气温增高导致马铃薯生育脆弱性均随海拔增高而降低.开花期降水减少导致马铃薯生长发育及产量形成的脆弱性增加,此时段以干旱为主的气象灾害频率的增加使马铃薯生育脆弱性增加,马铃薯对降水量变化的敏感性和降水量减少导致马铃薯生育脆弱性却随海拔增高而降低.     

近几年我国马铃薯晚疫病流行特点分析与监测建议

马铃薯晚疫病是马铃薯上的重要病害,是影响马铃薯产业发展的主要制约因素。本文系统总结了2008-2014年我国马铃薯晚疫病的发生概况及特点,分析了其影响因素。该病害年度间、地区间、品种间发生不平衡,北方产区受气候因素影响大,西南及中原产区常年偏重发生。2012年、2013年马铃薯晚疫病在全国范围内偏重发生,局部大发生,发生范围广、流行扩展速度快、危害重。在气候、菌源量、品种抗性及防治因素中,气候是影响马铃薯晚疫病发生流行的最重要因素。     

石羊河流域生态系统的气候变化脆弱性评估

选取石羊河流域生态系统作为研究对象,简要分析影响其生态系统气候变化脆弱性的主要因子。在此基础上,选取4类共13项指标,构建了生态系统脆弱性评价指标体系。通过层次分析法确定了指标权重,最后采用综合指标分析方法,对石羊河流域生态系统气候脆弱性现状进行了定量评价;结合气候变化情景,定量分析了未来该流域的脆弱性变化趋势,并给出减缓不利影响的对策和建议。     

Spatial-temporal variations of ecological vulnerability in the Tarim River Basin,Northwest China

As the largest inland river basin of China, the Tarim River Basin (TRB), known for its various natural resources and fragile environment, has an increased risk of ecological crisis due to the intensive exploitation and utilization of water and land resources. Since the Ecological Water Diversion Project (EWDP), which was implemented in 2001 to save endangered desert vegetation, there has been growing evidence of ecological improvement in local regions, but few studies have performed a comprehensive ecological vulnerability assessment of the whole TRB. This study established an evaluation framework integrating the analytic hierarchy process (AHP) and entropy method to estimate the ecological vulnerability of the TRB covering climatic, ecological, and socioeconomic indicators during 2000-2017. Based on the geographical detector model, the importance of ten driving factors on the spatial-temporal variations of ecological vulnerability was explored. The results showed that the ecosystem of the TRB was fragile, with more than half of the area (57.27%) dominated by very heavy and heavy grades of ecological vulnerability, and 28.40% of the area had potential and light grades of ecological vulnerability. The light grade of ecological vulnerability was distributed in the northern regions (Aksu River and Weigan River catchments) and western regions (Kashgar River and Yarkant River catchments), while the heavy grade was located in the southern regions (Kunlun Mountains and Qarqan River catchments) and the Mainstream catchment. The ecosystems in the western and northern regions were less vulnerable than those in the southern and eastern regions. From 2000 to 2017, the overall improvement in ecological vulnerability in the whole TRB showed that the areas with great ecological improvement increased by 46.11%, while the areas with ecological degradation decreased by 9.64%. The vegetation cover and potential evapotranspiration (PET) were the obvious driving factors, explaining 57.56% and 21.55% of the changes in ecological vulnerability across the TRB, respectively. In terms of ecological vulnerability grade changes, obvious spatial differences were observed in the upper, middle, and lower reaches of the TRB due to the different vegetation and hydrothermal conditions. The alpine source region of the TRB showed obvious ecological improvement due to increased precipitation and temperature, but the alpine meadow of the Kaidu River catchment in the Middle Tianshan Mountains experienced degradation associated with overgrazing and local drought. The improved agricultural management technologies had positive effects on farmland ecological improvement, while the desert vegetation in oasis-desert ecotones showed a decreasing trend as a result of cropland reclamation and intensive drought. The desert riparian vegetation in the lower reaches of the Tarim River was greatly improved due to the implementation of the EWDP, which has been active for tens of years. These results provide comprehensive knowledge about ecological processes and mechanisms in the whole TRB and help to develop environmental restoration measures based on different ecological vulnerability grades in each sub-catchment.     

Assessing ecological vulnerability in western China based on Time-Integrated NDVI data

Arid and semi-arid areas are the most vulnerable regions to climate change.Clear understanding of the effects of climate change on ecosystems in arid and semi-arid regions and the ecosystem vulnerability is important for ecosystem management under the background of climate change.In this study,we conducted a vulnerability assessment on various ecosystems from 1982 to 2013 in western China with large areas of arid and semi-arid lands based on the Time-Integrated Normalized Difference Vegetation Index(TINDVI)data and climate data.The results indicated that grasslands were the most vulnerable ecosystem to climate change in western China,especially for those in Tibetan Plateau.Croplands in oases were not vulnerable to climate change compared to rain-fed croplands in semi-arid regions(e.g.Gansu and Inner Mongolia),which was attributed to the well-developed drip irrigation technology in oases.Desert and Gobi ecosystems were slightly vulnerable to climate change during the past several decades.The assessment results,as revealed in this study,can provide a reference for taking appropriate actions to protect the ecosystems in western China.     

西北干旱区白刺属植物适生环境的模拟分析

白刺属(Nitraria L.)植物是古地中海第三纪孑遗植物,对我国西北干旱、半干旱地区具有极高的生态效益.本研究基于MaxEnt模型和ArcGIS软件及其SDM工具箱预测了过去到未来不同时期下白刺属6个物种在我国的潜在适生区及其迁移路线,以期为该属植物的保护及资源利用方面提供一定的理论依据.结果表明:白刺属植物当代在...     

Relative importance of climate factors and human activities in impacting vegetation dynamics during 2000–2015 in the Otindag Sandy Land,northern China

In recent years, there has been increasing research interests in differentiating the relative importance of climate factors and human activities in impacting vegetation dynamics. In this study, based on residual trend method, we used MOD13A3(MODIS vegetation index product), MCD12Q1(MODIS land cover product) and meteorological datasets to differentiate the relative importance of climate factors and human activities in impacting vegetation dynamics during 2000–2015 in the Otindag Sandy Land, northern China. Results show that during the study period(2000–2015), the overall vegetation condition had improved in the Otindag Sandy Land. The driving forces of vegetation dynamics differed spatially in the whole study area over the study period. The area with vegetation degradation solely resulted from human activities accounted for 8.23% of the study area, while the area with vegetation degradation resulted from others(including climate factors and combination of climate factors and human activities) occupied 1.53%. The area with vegetation recovery benefitted from human activities occurred over 26.02% of the study area; the area benefitted from climate factors accounted for 23.69%; and the area benefitted from both climate factors and human activities occupied 37.74%. All in all, impacts of climate factors and human activities on vegetation dynamics varied at the county/city/banner scales and locality-specific measures should be adopted to protect the environments.     

基于灰色关联度分析气候因素对江西省松材线虫病的影响

为分析不同气候因素对松材线虫Bursaphelenchus xylophilus引起的松材线虫病的影响程度,本文以江西省全南县(代表赣南,松墨天牛一年2代)和德兴市(代表赣北,松墨天牛一年1代)遭受松材线虫病危害的马尾松林生态系统为研究对象,获取2018年-2021年松材线虫病普查数据和1990年-2021年的主要气象因子数据,结合滑动平均法和灰色关联度分析法比较分析两地的气候差异和疫情年间气候变化对松材线虫病发病面积的影响。结果显示:除德兴市的年均相对湿度和年降水量与历年平均值相比有所降低外,两地其他气象因子均呈上升趋势;灰色关联度分析表明,年均最高气温和年均风速是影响赣南松材线虫疫情的重要气象因子,年均最高气温和年降水量是影响赣北松材线虫疫情的重要气象因子;气温升高促进松材线虫和其媒介昆虫的生长繁殖与活动,风速升高可使媒介昆虫远距离传播松材线虫,降水量减少可降低松材线虫和媒介昆虫染病死亡几率。赣南赣北气候的整体变化趋势都有利于松材线虫病的扩散蔓延。     

Potential impacts of climate change on Welwitschia mirabilis populations in the Namib Desert,southern Africa

Climate change is threatening natural ecosystems in the Earth, and arid regions of southern Africa are particularly exposed to further drying. Welwitschia mirabilis Hook.(Welwitschiaceae) is an unusual gymnosperm tree that is recognized as an icon of the Namib Desert, southern Africa. Many aspects of its biology were investigated in the past, with a special emphasis for its physiology and adaptations, but nothing is known about its potential sensitivity to current climate changes. In this study, we adopted an approach based on distribution data for W. mirabilis and ecological niche models for clarifying the species-climate interactions and for predicting the potential impacts of climate change on W. mirabilis populations in three well-separated sub-ranges(northern, southern and central) in northwestern Namibia, southern Africa. We evidenced that the populations occurring in the northern sub-range have peculiar climatic exigencies compared with those in the central and southern sub-ranges and are particularly exposed to the impact of climate change, which will consist of a substantial increase in temperature across the region. These impacts could be represented by demographic changes that should be detected and monitored detailedly to plan efficient measures for managing populations of this important species on the long-term scale.     

Assessment of drought hazard,vulnerability and risk in Iran using GIS techniques

The drought has enormous adverse effects on agriculture, water resources and environment, and causes damages around the world. Drought risk assessment and prioritization of drought management can help decision makers and planners to manage the adverse effects of drought. This paper aims to determine the risk of drought in Iran. At the first stage, standardized precipitation index (SPI) was calculated for the period 1981-2016. Then the probability map of different drought classes or drought hazard probability map were prepared. After that the indicator-based vulnerability assessment method was used to determine the drought vulnerability index. Five indices including climate, topography, waterway density, land use and groundwater resources were chosen as the most critical factors of drought in Iran and followed by the analytical hierarchy process questionnaire, the weights of each index were obtained based on expert opinions. Fuzzy membership maps of each index and sub-index were prepared using ArcGIS software. The drought vulnerability map of Iran was plotted using these weights and maps of each indicator. Finally, the drought risk map of Iran was provided by multiplying drought hazard and vulnerability maps. According to the 43-completed questionnaires by experts, climate index has the highest vulnerability to drought. Climate does not have an important role in drought hazard index, but it is the most crucial factor to classified drought vulnerability index. The results showed that central, northeast, southeast and west parts of Iran are at high risks of drought. There are regions with different risks in Iran due to unusual weather and climatic conditions. We realized that the climate and the groundwater situation is almost the same in the central, east and south parts of Iran, because the land use plays a crucial role in the drought vulnerability and risk in these areas. The drought risk decreases from the center of Iran to the southwest and northwest.