青藏高原东北部共和盆地末次冰消期以来古植被和环境演变(英文)

Paleoenvironmental history in the monsoonal margin in the northeast Tibetan Pla-teau provides important clue to the regional climate. Previous researches have been limited by either poor chronology or low resolution. Here we present a high-resolution pollen record from a 40.92-m-long sediment core (DLH) taken from Dalianhai, a terminal lake situated in the Gonghe Basin, the northeast Tibetan Plateau for reconstructing the vegetation and climate history since the last deglacial on the basis of a chronology controlled by 10 AMS 14C dates on plant remains preserved in the core sediments. The pollen assemblages in DLH core can be partitioned into 6 pollen zones and each zone is mainly characterized by the growth and decline of tree or herb pollen percentage. During the periods of 14.8-12.9 ka and 9.4-3.9 ka, the subalpine arboreal and local herbaceous pollen increased, indicating the subalpine forest developed in the surrounding mountains and a desert steppe or typical steppe developed in Gonghe Basin under a relatively moister climate. During the periods of 15.8-14.8 ka, 12.9-9.4 ka and 3.9-1.4 ka, the forest shrank or disappeared according to different degrees of aridity, and the desert steppe degraded to a more arid steppe desert in the basin, indicating a dry climate. After 1.4 ka, vegetation type around Dalianhai was mainly dominated by steppe suggested by increased Artemisia. Our results suggested the climate history in this region was dry from 15.8-14.8 ka, humid from 14.8-12.9 ka and dry from 12.9-9.4 ka, after which the climate was humid during 9.4-3.9 ka, followed by dry conditions during 3.9-1.4 ka and humid conditions in the last 1.4 ka. The change of pollen percentage and the evolution of palaeovegetation in Dalianhai since the last deglacial were similar to those recorded in Qinghai Lake. The forest expanded in the mountains around Dalianhai during the B?l-ling-Aller?d period, shrank during the Younger Dryas and the early Holocene, then it devel-oped and reached its maximum in the mid-Holocene. During the late Holocene, the vegetation began to shrink till disappearance. However, the timing of forest expansion in the Holocene lagged behind that of Qinghai Lake, and this spatial heterogeneity was probably caused by the different forest species between these two places. The maximum of forest development in the mid-Holocene was inconsistent with the period of stronger summer monsoon in the early Holocene indicated by stalagmite records, the reason might be related to the complexity of vegetation response to a large-scale climatic change.     

13 ka BP 以来黄土高原西部的植被与环境演化

通过对黄土高原西部三个剖面的孢粉记录分析, 重建了该区13 ka BP 以来详细的植被 与气候演化序列。结果表明, 12.1 ka BP 以前, 研究区植被以干草原为主, 气候寒冷干燥。 12.1~9.8 ka BP 植被变化显著。期间出现两次显著的湿润期, 分别为12.1~11.4 ka BP、 11.2~11.0 ka BP, 可与博令暖期和阿勒罗得暖期对比; 两次持续时间和强度明显不同的干旱 期出现在11.4~11.2 ka BP 和11.0~9.8 ka BP, 可分别与中仙女木事件和新仙女木事件对比。 经过短暂的快速变湿后, 9.6~7.6 ka BP 研究区植被以疏林草原为主, 气候波动频繁但总体温 和偏干。7.6~4.0 ka BP 森林和森林草原植被出现, 气候温暖湿润。其中6.6~5.8 ka BP 温带落 叶阔叶林发育, 为研究区全新世最适宜期。自4.0 ka BP 以来研究区草原和荒漠草原交替出 现, 气候在总体干冷的环境下存在次一级的干湿波动。     

共和盆地末次冰消期以来的植被和环境演变

在青藏高原共和盆地中的内陆湖泊--达连海获取40.92 m长的湖泊岩芯(DLH钻孔),选用植物残体作为测年材料,利用AMS14C测年技术建立可靠的地层年代序列,对岩芯进行孢粉分析,重建该地末次冰消期以来的古植被和古环境。末次冰消期以来达连海周围山地在14.8～12.9Cal ka BP和9.4～3.9 Cal ka BP时段曾发育森林,气候较湿润,达连海附近盆地发育的荒漠草原盖度增加或演化为草原;在15.8～14.8 Cal ka BP、12.9～9.4 Cal ka BP 和3.9～1.4 Cal ka BP 时段该地气候比较干旱,依据干旱的程度周围山地森林退化或消失,盆地内发育盖度较低的荒漠草原或草原化荒漠。1.4 Cal ka BP以来湿度有所增加,发育草原植被类型。依据植被的演替历史推断该地气候的变化历程是15.8～14.8 Cal ka BP 干旱,14.8～12.9 Cal ka BP 湿润,12.9～9.4 Cal ka BP干旱,9.4～3.9 Cal ka BP湿润,3.9～1.4 Cal ka BP干旱,1.4～0 Cal ka BP湿润。达连海的孢粉记录与附近青海湖的孢粉结果对比,发现两地植被发育基本一致。末次冰消期Bølling-Allerød 时期,山地森林发育;新仙女木事件发生时森林萎缩;全新世中期两地针叶林发育达到鼎盛,之后逐渐减少至消失。早全新世达连海森林扩张的时间滞后于青海湖,主要与两地森林树种的不同和植被演替的时间差异有关。该区森林发育的全盛时期在中全新世,这与石笋记录到的亚洲季风强盛时期在早全新世不相一致,可能与植被复杂的响应机制有关。     

Vegetation and environmental changes in western Chinese Loess Plateau since 13.0 ka BP

Pollen records from the Chinese Loess Plateau revealed a detailed history of vegetation variation and associated climate changes during the last 13.0 ka BP. Before 12.1 ka BP, steppe or desert-steppe vegetation dominated landscape then was replaced by a coniferous forest under a generally wet climate (12.1–11.0 ka BP). The vegetation was deteriorated into steppe landscape and further into a desert-steppe landscape between 11.0 and 9.8 ka BP. After a brief episode of a cool and wet climate (9.8–9.6 ka BP), a relatively mild and dry condition prevailed during the early Holocene (9.6–7.6 ka BP). The most favourable climate of warm and humid period occurred during mid-Holocene (7.6–~4.0 ka BP) marked by forest-steppe landscape and vegetation alternatively changed between steppe and desert- steppe from ~4.0 to ~1.0 ka BP.     

13kaBP以来黄土高原西部的植被与环境演化(英文)

Pollen records from the Chinese Loess Plateau revealed a detailed history of vegetation variation and associated climate changes during the last 13.0 ka BP.Before 12.1 ka BP,steppe or desert-steppe vegetation dominated landscape then was replaced by a coniferous forest under a generally wet climate(12.1-11.0 ka BP).The vegetation was deteriorated into steppe landscape and further into a desert-steppe landscape between 11.0 and 9.8 ka BP.After a brief episode of a cool and wet climate(9.8-9.6 ka BP),a relati...     

青藏高原植被垂直带与气候因子的空间关系

集成了青藏高原气候区149个山地植被垂直带数据,利用国家基本气象台站自建站以来到2001年的地面观测日气象数据,计算了地面的温暖(WI)、寒冷(CI)、湿润(MI)、吉良龙夫(Kira)干湿指数、干燥度(Idm)等水热指数,运用GIS的空间分析模块,模拟了青藏高原水热条件的空间分布形势,探讨山地植被垂直带谱分布规律与制约因子的定量指标.结果表明:在高原的东北部、西北边缘,以荒漠、荒漠草原、山地森林、山地草原、灌丛、草甸为组合的半干旱、干旱结构向高原腹地以高寒草原、高山草甸、荒漠带组合的高寒干旱带谱结构的变化;东南、南部边缘,以温暖湿润为特征的以森林带为优势带谱组合结构逐渐向寒冷的高原中心变化;高原的地势效应,致使的水热形势旱现从中央向边缘变化的趋势是致使青藏高原植被垂直带谱分布的重要原因.     

神农架大九湖四万年以来的植被与气候变化

通过对大九湖6 m长连续沉积岩芯剖面(DJH-1 孔) 7 个样品的AMS¹⁴C年龄测定和151 块孢粉样品的鉴定分析, 揭示了神农架区域4 万以年来植被和气候演变。末次冰期阶段大九湖附近发育森林草地或草地-草甸植被。MIS 3 晚期, ~42-39 cal ka BP之间, 气候相对干冷, 发育森林草地;~39-31 cal ka BP 之间, 气候较为湿润, 草甸扩张并伴随低海拔阔叶树种的发育。MIS 2 阶段, 草甸组分中蒿属显著增加, 高海拔可能分布有荒漠草地, 气候极端干冷;该时期植被带垂直下降达到1000 余m, 按垂直温度递减率推算, 冰盛期阶段该区域温度下降约7℃左右。从冰消期开始, 森林植被开始扩张, 北温带、暖温带和亚热带乔木组分依次增加。约在9.4-4 cal ka BP之间, 演变为亚热带常绿阔叶落叶林, 属全新世适宜期;从约4 cal ka BP以来, 北温带阔叶和针叶树开始增加, 气候趋于凉干。通过对比区域高分辨率的洞穴石笋及高纬冰芯氧同位素记录, 表明神农架区域植被环境变化对气候变化敏感, 并记录了H1, YD气候突变事件;进一步体现出该区域气候环境演变主要与北半球太阳辐射控制的东亚夏季风强度变化有关, 且与北半球高纬气候变化一致。     

Persistence of Artemisia steppe in the Tangra Yumco Basin,west-central Tibet,China: despite or in consequence of Holocene lake-level changes?

The closed Tangra Yumco Basin underwent the strongest Quaternary lake-level changes so far recorded on the Tibetan Plateau. It was hitherto unknown what effect this had on local Holocene vegetation development. A 3.6-m sediment core from a recessional lake terrace at 4,700 m a.s.l., 160 m above the present lake level of Tangra Yumco, was studied to reconstruct Holocene flooding phases (sedimentology and ostracod analyses), vegetation dynamics and human influence (palynology, charcoal and coprophilous fungi analyses). Peat at the base of the profile proves lake level was below 4,700 m a.s.l. during the Pleistocene/Holocene transition. A deep-lake phase started after 11 cal ka BP, but the ostracod record indicates the level was not higher than ~4,720 m a.s.l. (180 m above present) and decreased gradually after the early Holocene maximum. Additional sediment ages from the basin suggest recession of Tangra Yumco from the coring site after 2.6 cal ka BP, with a shallow local lake persisting at the site until ~1 cal ka BP. The final peat formation indicates drier conditions thereafter. Persistence of Artemisia steppe during the Holocene lake high-stand resembles palynological records from west Tibet that indicate early Holocene aridity, in spite of high lake levels that may have resulted from meltwater input. Yet pollen assemblages indicate humidity closer to that of present potential forest areas near Lhasa, with 500–600 mm annual precipitation. Thus, the early mid-Holocene humidity was sufficient to sustain at least juniper forest, but Artemisia dominance persisted as a consequence of a combination of environmental disturbances such as (1) strong early Holocene climate fluctuations, (2) inundation of habitats suitable for forest, (3) extensive water surfaces that served as barriers to terrestrial diaspore transport from refuge areas, (4) strong erosion that denuded the non-flooded upper slopes and (5) increasing human influence since the late glacial.     

青藏高原全新世降水序列的集成重建

青藏高原全新世降水变化对于过去全球变化研究有重要意义。在过去全球变化研究中, 大尺度区域降水序列重建缺乏可行、有效的方法, 本文以青藏高原作为研究区, 构建了分区古降水空间模拟－多区面积加权的集成方法, 重建全新世青藏高原降水序列。本研究以孢粉为环境证据, 选取有空间代表性的10 条由孢粉重建的高原样点降水序列, 获得716 条具有年代的定量降水记录, 建立全新世古降水记录数据集。借助GIS分析, 基于现代高原降水空间分布的地理因子模拟, 并与古降水记录相集成, 定量重建了高原全新世200 年分辨率的降水序列。结果显示:早全新世高原降水迅速增多, 并在9.0 kaBP达到极大值500 mm, 较现代高170 mm;9.0~5.6 kaBP是旺盛的湿润期, 降水总体比现代高出80 mm, 但呈现明显的下降趋势;5.6 kaBP以来降水减少, 降水与现代相当, 但波动幅度较小;集成序列与其他高低分辨率环境记录有很好的可比性, 说明集成序列有很好的代表性和一定的准确性。     

青藏高原植被覆盖对水热条件年内变化的响应及其空间特征

利用1982-2000年NOAA/AVHRR卫星的NDVI数据(时间分辨率旬,空间分辨率8 km×8 km),结合同时期的气温和降水资料,基于时滞互相关方法和GIS工具,分析了青藏高原植被覆盖对水、热条件年内变化的时滞响应及其空间特征。结果如下:①除高寒荒漠、森林外,青藏高原植被NDVI与同期旬均温和旬降水相关性均呈高度正相关。其中,中等覆盖度的植被受水、热影响表现更为强烈。②青藏高原植被NDVI对气温和降水有滞后效应,且滞后水平存在空间差异,高原北部(柴达木盆地、昆仑山北冀)和高原南部植被对降水、和温度的响应比较迟缓,而高原中、东部地区植被对温度和降水的响应比较敏感。③不同植被类型对水热条件的响应程度也存在差异,由高到低依次是草甸、草原、灌丛、高寒垫状植被、荒漠,最后是森林。     

史前人类探索、适应和定居青藏高原的历程及其阶段性讨论

系统梳理了近年来的考古发现与研究成果,总结出人类向青藏高原扩散直至定居的5个阶段性发展过程：古老型智人自中更新世晚期就开始了对高原的适应;现代智人于40~30 ka前已经开启了对高原腹地的探索;末次冰消期以来的气候转暖时段,细石器人群向高原大范围扩散,并在全新世早中期的活动更为频繁;粟作农业人群至少在5.2 ka前进入高原东部低海拔的河谷地带,在4.8 ka以后开始定居在高原东部3 000 m以上海拔的区域;3.5 ka以来麦作的传入和牧业经济的发展助力人群大规模定居高海拔区域。人类在向高原扩散和定居的过程中经历了漫长的生理与文化适应,但受限于当前考古发现与研究材料,史前狩猎采集、农业和牧业等人群在高原的时空分布、对高海拔环境的生理与行为适应﹑与低海拔人群和以藏族为主的现代高原人群之间的联系,以及高寒地区河谷农业和山地高原面游牧双重经济活动对高寒文明形成的支撑作用和高寒文明的普适性等问题仍需要深入研究,期待未来多学科交叉融合共同推动对这些问题的理解。     

Late Pleistocene Vegetation and Climate in the Southern Cascade Range and the Modoc Plateau Region

Pollen and sediment from Grass Lake, California provide a history of vegetation and climate in the southern Cascade Range from 36 to 19 cal ka, revealing climate changes that led to the glacial advances recorded at Upper Klamath Lake (Rosenbaum and Reynolds 2004a – this issue). Variations in the percentages of conifer and Artemisia (sagebrush) pollen at Grass Lake recorded shifts in vegetation that reflect changes in precipitation. Between 36 and 34 cal ka, a progression from steppe to open pine forest to dense pine forest indicates that precipitation increased. After 32 cal ka, the forest became more open and by 30 cal ka sagebrush steppe surrounded the lake, implying that precipitation decreased. The area was arid for most of the interval between 30 and 19 cal ka. Increases in conifer pollen recorded increases in precipitation from 21 through 19 cal ka, when open pine forest colonized the lake area. Throughout the period from 36 to 19 cal ka, centennial- to millennial-scale intervals with increased conifer pollen imply that the arid interval was interrupted by periods of increased precipitation. Pollen data also provide evidence that the major fluctuations in sand concentration in the Grass Lake core reflect temperature shifts. Changes in sediment particle size are closely related to variations in pollen concentration and accumulation rate, which in turn reflect changes in plant cover, implying that sand was deposited in the lake due to deflation of clay- and silt-sized particles from sparsely-vegetated alpine areas of the watershed. Sand deposition increased as climatic cooling led to reductions in the elevation of upper treeline and alpine conditions affected a larger part of the watershed. There is no evidence of glaciation in the basin, but pollen data show the area was above upper treeline during Cold Period III (34–32 cal ka), one of several very cold intervals. Vegetation decreased at about 28 cal ka and remained sparse for at least 9000 years, implying that the climate became cooler and remained cool until after 19 cal ka. Cold Period II developed at about 25 cal ka and terminated by 23 cal ka. The Grass Lake watershed was again above upper treeline with the onset of Cold Period I, soon after 19 cal ka. Comparison of the Grass Lake record with those from Upper Klamath Lake, Oregon and Tulelake, California suggests a persistent pattern of environmental changes in this time interval throughout the Modoc Plateau region.     

甘青地区末次冰消期以来植被与气候演化的孢粉记录对比分析

选用甘青地区达连海、青海湖、苏家湾、大地湾4个典型高分辨率的钻孔资料进行对比分析,阐明了该地区末次冰消期以来气候变化规律与主要气候事件,初步探讨了该地区植被纬向时空演化规律。结果显示末次冰消期大致开始于15.2~14.6 ka BP之间,冰消期期间该地区气候表现为冷暖波动频繁,气候不稳定,植被类型由东向西为草原-荒漠化草原。全新世早期阶段10.4~8.2 ka BP气候表现为温干,植被类型由东向西为疏林草原-草原。全新世中期8.2~4.3 ka BP气候温暖湿润,植被发育良好,由东向西出现森林-森林草原植被。4.3 ka BP以后该地区气候总体向凉干方向发展,3.9~3.4 ka BP期间陇中地区气候波动较显著,植被类型草原-森林草原交替出现。晚全新世后期2.3~0 ka BP气候冷干,从东到西发育草原-荒漠化草原植被。     

基于植被盖度和高度的不同退化程度高寒草地地上生物量估算

由于气候变化和不合理的人类活动，20世纪80年代以来青藏高原高寒草地发生严重退化。地上生物量是评价草地退化的直观指标。通常采用植被盖度和高度来估算草地地上生物量，但草地退化后，植被盖度和高度与地上生物量之间的关系是否会发生变化目前还不清楚，这影响着退化草地生物量估算的精度。通过多元回归分析研究了青藏高原中部和东北部高寒草甸、高寒草原在不同退化程度下植被盖度和高度与地上生物量的关系。结果表明：（1）高寒草甸与高寒草原地上生物量整体上及不同退化阶段都没有显著差异（P>0.05）。（2）随着退化程度的加剧植被盖度和高度对地上生物量的影响也发生改变，体现在未退化阶段地上生物量主要受植被高度影响，退化后主要受植被盖度影响。（3）无论是高寒草甸还是高寒草原分退化程度的回归模型估算结果都较不分退化程度模型估算的生物量更接近实测值。我们建议在退化高寒草地研究中采用盖度和高度估算生物量时，根据退化阶段采用不同的估算模型。     

试论西藏全新世古地理的演变

本文从冰后期以来湖泊的退缩、泥炭沼泽的发育、冰川与冻土的变化、生物的演替以及人类活动范围的扩大与缩小等方面论述西藏全新世古地理环境特征和演变过程,并结合C¹⁴的年龄数据,认为全新世时期西藏自然环境的演变可分为早全新世（10,000-7,500年）环境好转阶段、中全新世（7,500-3,000年）环境最宜阶段以及晚全新世（3,000年至现在）环境恶化阶段.而且全新世不同时期古地理环境具有明显的地域差异.现时西藏地区仍在继续上升,高原内部仍将继续向干冷的自然环境变化.     

孢粉指示鄂陵湖地区晚全新世以来植被与环境演化

通过对黄河源地区鄂陵湖地层剖面的研究,综合分析同一地区不同植被带孢粉代用指标,获得了晚全新世以来鄂陵湖流域植被及气候演变记录。1)1.90~1.60 ka BP,植被类型以高寒草原为主,区域气候干旱寒冷;2)1.60~0.80 ka BP,为高寒草甸景观,孢粉组合反映出次生植被具有垂直地带性,湖滨地区次生植被为十字花科及紫菀属,而阴坡和山顶区则为紫菀属及蒲公英属,干旱程度有所缓解;3)0.80 ka BP~,整体景观为莎草、十字花科、蒿属为主的高寒草甸景观,气候转向暖湿,但整体仍较为干旱。其中,0.66~0.84 ka BP出现一次湿润时期,植被丰富。     

NPP vulnerability of the potential vegetation of China to climate change in the past and future

Using the Integrated Biosphere Simulator, a dynamic vegetation model, this study initially simulated the net primary productivity (NPP) dynamics of China’s potential vegetation in the past 55 years (1961–2015) and in the future 35 years (2016–2050). Then, taking the NPP of the potential vegetation in average climate conditions during 1986–2005 as the basis for evaluation, this study examined whether the potential vegetation adapts to climate change or not. Meanwhile, the degree of inadaptability was evaluated. Finally, the NPP vulnerability of the potential vegetation was evaluated by synthesizing the frequency and degrees of inadaptability to climate change. In the past 55 years, the NPP of desert ecosystems in the south of the Tianshan Mountains and grassland ecosystems in the north of China and in western Tibetan Plateau was prone to the effect of climate change. The NPP of most forest ecosystems was not prone to the influence of climate change. The low NPP vulnerability to climate change of the evergreen broad-leaved and coniferous forests was observed. Furthermore, the NPP of the desert ecosystems in the north of the Tianshan Mountains and grassland ecosystems in the central and eastern Tibetan Plateau also had low vulnerability to climate change. In the next 35 years, the NPP vulnerability to climate change would reduce the forest–steppe in the Songliao Plain, the deciduous broad-leaved forests in the warm temperate zone, and the alpine steppe in the central and western Tibetan Plateau. The NPP vulnerability would significantly increase of the temperate desert in the Junggar Basin and the alpine desert in the Kunlun Mountains. The NPP vulnerability of the subtropical evergreen broad-leaved forests would also increase. The area of the regions with increased vulnerability would account for 27.5% of China.     

藏北高原高寒草地围栏禁牧和生长季降水对物种丰富度和多样性的影响(英文)

2009和2010年夏天沿藏北高原高寒草地样带调查了高寒草地生态系统(高寒草甸、高寒草原和荒漠草原)在围栏禁牧和自由放牧管理下的物种丰富度和多样性(Shannon-Wiener指数,Simpson优势度指数和Pielou均匀度指数)。研究结果显示:自2006年起藏北高原围栏禁牧在植被类型和区域尺度上没有显著改变物种丰富度和多样性。物种丰富度和多样性主要受生长季降水驱动,超过87%的变异可由生长季降水来解释。物种丰富度和多样性在自由放牧和围栏禁牧2类样地对生长季降水的响应方式一致。物种丰富度随降水呈指数型增长关系,多样性指数则呈现正线性关系。研究结果预示藏北高原地区生长季降水的变化对于物种丰富度和多样性管理至关重要,在未来高寒草地保护研究中应予以重视。     

青藏高原东北缘全新世人类活动与环境变化——以青海湖江西沟2号遗迹为例

青海湖江西沟遗迹是青藏高原东北缘一处有连续地层的重要细石器文化遗存,对其人类活动指标(石器、动物碎骨、陶片等) 与环境指标(磁化率、色度、孢粉及集成结果) 对比分析表明：细石器文化与环境变化关系密切,在全新世JXG2 细石器狩猎者一直生活在以蒿为主的草原环境.在9 ka BP以前的早全新世,环境状况不断好转,人类已经在湖区活动,并逐渐增强;9 ka BP后最佳的水热组合,较高的草原覆盖,为细石器狩猎者提供充足的食物来源,推动文化进入鼎盛期;6 ka BP后随着环境干冷化,细石器文化也开始衰弱.孢粉分析发现9~6 ka BP高的禾本科含量及种类丰富的杂草花粉,与人类活动有关;尤其是禾本科含量在6.7~4 ka BP保持较高水平,此时段恰是陶片开始出现并普遍使用的时期,推测与JXG2 先民尝试种植农作物有关.高原东北缘在6 ka BP之前为细石器文化,6 ka BP之后高原史前文化开始发生分化,细石器狩猎者活跃在海拔较高的高原上,农业种植者占据了较低的河谷地带,在二者交接地带,形成了兼具细石器文化与农业种植文化特征土著新石器文化.     

青藏高原植被NDVI对气候因子响应的格兰杰效应分析

多变的气候和复杂的地理环境使得青藏高原植被对气候变化响应敏感,因此分析高原植被与气候因子之间的动态关系对气候变化研究和生态系统管理具有重要意义。论文基于1982—2012年青藏高原气象数据(气温、降水)以及GIMMS NDVI3g遥感数据,在像素级别上运用格兰杰因果关系检验方法,在月尺度和季节尺度上分析了高原植被NDVI(主要是草原)与平均气温、降水量之间的响应情况及因果关系。研究表明：① 月尺度上NDVI与平均气温之间、NDVI与降水量之间的时序平稳性比例高于季节尺度,月尺度下达到平稳性的植被区域分别占99.13%和98.68%,季节尺度下分别占64.01%和71.97%;② 月尺度下高原平均气温和降水量对NDVI影响的滞后期都集中在第12~13个月,荒漠草原、典型草原和草甸3种植被类型的滞后期一致,季节尺度下平均气温和降水量对NDVI影响的滞后期主要分布在第3~4和第6个季度,3种植被类型的滞后期差异性较大;③ 月尺度下,青藏高原约98.95%的植被覆被区的平均气温是引起NDVI变化的格兰杰原因,反之,大部分地区(约89.05%,除高原东南区域)内NDVI也是引起平均气温变化的格兰杰原因;季节尺度下,青藏高原中部以外植被区域(约92.03%)内的平均气温是引起NDVI变化的格兰杰原因,而在东部和西部部分地区(约50.55%)中NDVI也是引起平均气温变化的格兰杰原因;④ 月尺度下,高原东北和西北地区(约72.05%)内的降水量是引起NDVI变化的格兰杰原因,大部分地区(约94.86%,除东南部少量区域)中NDVI是引起降水量变化的格兰杰原因;季节尺度下,高原东南部(约61.43%)地区内的降水量是引起NDVI变化的格兰杰原因,高原中东部地区(约48.98%)中NDVI是引起降水量变化的格兰杰原因。总之,高原植被NDVI与气温、降水的相互作用显著,彼此均可构成格兰杰因果效应,但总体上气候因子的影响程度大于植被的反馈作用,月尺度的效应区域大于季节尺度的效应区域。