Phenology is a critical feature of vegetation, and it could reflect the effects of climate variability and change on vegetation growth. There are complex feedbacks between vegetation phenology and climate change, therefore, researches on the driving mechanism of the change of vegetation phenology would provide a better understanding of the interactions between climate change and phonology. In this study, we selected Qinghai Lake watershed located in the northeastern of the Qinghai-Tibet Plateau as study area and used MODIS 16 days Enhanced Vegetation Index(EVI)composite data to analyze the spatiotemporal pattern and trend of grassland phenology (the start of the growing season, the end of growing season and days of growing season) under the different variations of EVI max of grassland. The results of the study were concluded as: (1) The changes in EVI max of grassland showed a diverse trend under the influence of climate change and human activities, an increasing, unchanged and a decreasing trend of EVI max coexisted at the same time in the whole watershed. (2) Temperature and precipitation increased significantly from 1990 to 2012. Air temperature increased at the rate of 0.42-0.83℃/10a, and precipitation increased at rate of 43.20-44.68 mm/10a. The date of the start of the growing season showed a delay trend around both Gangcha and Tianjun weather station, the date of the end of growing season showed no obvious change but the days of the growing seasons showed a shortening trend between 2001 and 2012. (3) The date of the start of the growing season lasted from April 20 to June 10 and the date of the end of growing season from Mid-August to September 10 in the Qinghai Lake watershed. The places have early dates of the start of the growing season include the eastern and southern lakesides of the Qinghai lake, Buha River estuary, hillslope and flat area of the valley in the western of the watershed. The date of the start of the growing season extended from lakeshore to the high-altitude areas, but vice verse for the date of the end of growing season. (4) Vegetation phenology showed different trend under the different variation of EVI max . When the EVI max decreased, the date of the start of the growing season advanced, the date of the end of growing season delayed and the days of the growing season increased. In contrast, the date of the start of the growing season delayed, the date of the end of growing season showed no obvious change and the days of the growing season shorten when theEVI max increased. The farmland and the places without change in EVI max had no obvious changes in the date of the start of the growing season and of the end of growing season, however, days of the growing season shorten for farmland. (5) The result suggests that the vegetation phenology change was a complex process, probably affected by multiple factors, such as grassland degradation caused by over-grazing, vegetationEVI max increased under the climate change, enclosed grassland with unreasonable management, the vegetation ecosystem of succession and so on. Therefore, using of remote sensing data for vegetation phenology studies must distinguish dynamic changes of the vegetation of the different experimental samples firstly. Otherwise, it would affect the phenology study results.

植被物候不仅直接受气候变化的影响，还反作用于气候变化。因此，明确植被物候变化的驱动机制对于进一步研究气候变化与物候的相互作用具有重要的意义。选取位于青藏高原东北部的青海湖流域，利用MODIS 16d增强植被指数（EVI）合成数据，来分析草地物候时空格局特征以及不同EVI max 变化趋势下草地物候期（返青期、枯黄期及生长季）的变化趋势。研究得到以下结果：（1）在气候变化和人类活动等因素的共同作用下，青海湖流域的EVI max 变化呈现多元化趋势，EVI max 增加、不变、降低趋势并存；（2）1990-2012年期间，流域内温度上升、降水量增加趋势显著，温度上升速率为0.42-0.83℃/10a，降水量增加速率为43.20-44.68 mm/10a。刚察、天峻气象站草地返青期在2001-2012年期间呈现延迟趋势，枯黄期变化趋势不显著，生长季呈现缩短趋势；（3）流域内草地返青从4月下旬持续到6月上旬，枯黄期从8月中旬持续到10月上旬，青海湖东岸、南岸、布哈河入湖口区域以及流域西部山坡和平坦的谷底地区牧草最早进入返青期，返青空间格局呈现由湖岸向四周高海拔地区延伸趋势，草地枯黄空间格局与返青期相反；（4）不同EVI max 变化趋势下，草地返青期、枯黄期、生长季变化趋势表现出差异。草地EVI max 降低趋势下，牧草返青期呈现提前趋势，枯黄期延迟，生长季延长；EVI max 增加趋势下，牧草返青期延迟，枯黄期变化不明显，生长季缩短；EVI max 不变区、农田的返青与枯黄期变化趋势并不明显，但是农田生长季缩短趋势较明显。

Using the meteorological data and MODIS data, the CASA model and Geographic Information System were applied to analyze the NPP change in the Qinghai Lake Basin during 2000-2012. The results showed that the annual NPP was 4.77×10 12 gC·a -1 , and spatially, NPP distribution from low to high in a ring-shaped around the Qinghai lake, and showed a decrease trend from southeast to northwest, the highest NPP was 374.19 gC·m -2 ·a -1 in the middle region of the Qinghai Lake north river. The inner-annual variation of NPP was obvious and an periodicity increasing tendency with a mean change rate of 4.81×10 10 gC·a -1 could be seen from 2000 to 2012; The NPP changed significantly in a year, July had the highest NPP account 28.77%. Most parts of Qinghai Lake Basin had an increase in total NPP , the significant increase area mainly distributed around the Gong He county in Jiang Xi-gou town, Shi Nai-hai town and Tian Jun county, expect the upstream of the Ha Er-gai river and the midstream of the Sha Liu river were the mainly decrease region. Multiple regression analysis showed that NDVI and precipitation were the main factors influenced the NPP in the Qinghai Lake Basin.

利用青海湖流域及周边地区气象资料和MODIS遥感影像等数据,结合地理信息系统技术和植被净初级生产力(NPP)估算模型(CASA模型),确定了2000-2012年青海湖流域NPP值,并评价了其时空分布特征。结果表明:2000-2012年青海湖流域年均NPP为4.77×10 12 g,空间分布以青海湖为中心,由低到高呈环带状,并呈由东南向西北递减趋势,在青海湖北侧河流中游地区年均NPP达到最高,为374.19 g·m -2 。2000-2012年NPP呈波动中逐渐增长趋势,年均增加4.81×10 10 g;NPP年内变化显著,7月NPP达到全年最高值,占全年的28.77%。13年间流域内大部分地区NPP呈增长趋势,显著增长区主要分布在共和县江西沟乡、石乃亥乡和天峻县周围;青海湖北侧哈尔盖河上游、沙柳河中游地区则是主要减少区。多元回归分析表明归一化植被指数(NDVI)和降水是青海湖流域NPP的主要影响因素。

Based on the main data source of Landsat TM remote sensing in 1987, 2000 and 2010 years, This paper studied the dynamic characteristics of alpine wetland ecosystem service values in Qinghai Lake basin through revising the ecosystem service value per unit area in China by means of biomass method. Results showed that the alpine wetland ecosystem service values from 1987 to 2010 years in Qinghai Lake basin increased to 232.34×10 8 Yuan RMB, with the annual mean rate of 0.18×10 8 Yuan RMB. Among them, the lakes, alpine meadow, alpine swamp and warm steppe ecosystem services value is the main part. Human activities and climate change drove its ecological service value dynamically. Ecological service function in the study area was mainly composed of hydrology regulation, waste management, climate regulation, and maintenance of biodiversity functions. Their service values accounted for more than 70% of the total value. Nearly 24 years, other ecosystem services' values were to some extent increased, except to the production function of the raw material. The most volatile in ecological service value were hydrology regulation, waste disposal and climate regulation functions.

以1987、2000、2010年3个时期的TM影像为主要数据源，基于对中国生态系统单位面积服务价值的生物量修订，研究了青海湖湿地生态系统服务价值的动态特征。结果表明：1987-2010年青海湖高寒湿地总生态系统服务价值增加到了232.34亿元，年均增加0.18亿元，其中，湖泊、高寒草甸、高寒沼泽和温性草原生态系统服务价值是其主要构成部分。人类活动行为和气候变化驱动着其生态服务价值动态。研究区生态服务功能以水文调节、废物处理、气候调节、维持生物多样性功能为主，此4种功能的价值占到了总价值的70%以上。近24年里除原材料生产功能外，其他各项生态系统服务功能均在不同程度地增加，生态服务价值波动最大的是水文调节、废物处理和气候调节功能。

In this study, the area around Qinghai Lake was taken as the study area. According to the main reason of the formation of eco-environment and its result, eight evaluation indexes (including vegetation index, soil luminance and soil moisture, DEM and slope, temperature, precipitation and land use) were set up based on RS and GIS technology. The weight for every evaluation index was calculated with AHP method. The study area can be marked as four degree with qualitative and quantitative analysis: tiny vulnerability, little vulnerability, middle vulnerability and heavy vulnerability. The results showed that the areas in little vulnerability and middle vulnerability account for 35.2% and 40.7% respectively. It was concluded that the current status of the integral eco-environment quality of the research area are affirmative. It could provide theoretics for the governance to protect and formulate regional management by this research.

以青海湖环湖地区为研究区,从生态环境脆弱性的影响因子和脆弱性形成的结果表现入手,通过遥感与GIS技术提取出8项生态因子包括植被指数、土壤亮度和土壤湿度指数、高程和坡度以及气温降水和土地利用作为评价指标,利用层次分析法（AHP）计算各评价指标的权重,然后计算研究区综合脆弱度,并根据统计结果将脆弱度的大小划分为微度脆弱、轻度脆弱、中度脆弱和重度脆弱4个不同等级。结果表明：研究区轻度脆弱和中度脆弱所占面积比例较大,分别占到研究区陆地面积的35.2%和40.7%,说明该区总体环境质量较好。

On basis of characteristics of physical environment and ecological system in the Qinghai Lake Watershed, and with the vegetation distribution image in 2009 in the Qinghai Lake Watershed as working map, combing with DEM altitude data, grassland type in the Qinghai Lake Watershed, administrative map, we considered synthetically factors of altitude, vegetation distribution and social economy and so on, and did three-level partition on Qinghai Lake Watershed. Based on the partition, we put forward the basic ideas of managing the ecological and environmental problems in every partition, and ways and countermeasures of ecological and environmental problems for comprehensively managing desertification, wetland shrinkage and grassland degradation. Primary partition was divided into three level areas, which were lake plain, hilly area and high mountains; Secondary partition on the basis of the primary partition, divided into grassland, river valley area and sandy area; Three-level partition was mainly to partition the areas around Qinghai Lake, the area of arable land, the grassland, the wetland and the desertification land. In this research, the natural characteristics of each region were described. On the basis of the division we proposed the existing main problems and reasons, and put forward the comprehensive control methods to solve the ecological and environmental problems which were land desertification, grassland degradation and wetland shrinking. The comprehensive control methods were following: 1) We should strengthen the rational allocation water resources of Qinghai lake basin and ecological environment management to solve the problem of the water surface decline of the Qinghai lake; 2) For the shrinking of wetlands, vegetation degradation and other issues, should strengthen vegetation protection and recovery on the banks of the river wetland; 3) For excessive reclamation and lagging irrigation, should return farmland to forest and grass and vegetation restoration should be strengthened; 4) For the problems caused by some poisonous weeds on the grassland area, should grasp the characteristics of the poisonous weeds, avoid the poisonous weeds growing season, or choose non-sensitive livestock grazing; 5) In the sand area, moderate and light desertification area would need to management, should adopt mechanical and biological measures, the potential desertification areas need to be timely prevention, tall sand hill need not control, should keep natural desert landscape.

根据青海湖流域自然环境和生态系统特征,以2009年青海湖流域植被分布图为底图,结合DEM高程数据、青海湖流域草场类型图以及青海湖流域行政区划图,综合考虑青海湖流域海拔、植被分布以及社会经济等因素,采用ArcGIS 软件对青海湖流域进行3 级划分,在分区的基础上提出各类型区生态与环境治理的基本思路与方向,提出各类型区综合治理土地沙漠化、湿地萎缩和草地退化等生态与环境问题的途径与对策。

Climate indicators suggest a warming of the Earth.Since vegetation elicits seasonal dynamics and annual changes,the monitoring of vegetation change is an important activity to study global climatic change.The daily temporal resolution and global coverage of some satellite sensors make it possible to monitor vegetation at different spatial and temporal scales globally.The pre-processing of remote sensing(RS) data affects monitoring results directly,so a lot of international organizations perform global satellite data acquisition to receive,process,and create data sets,which strongly supports this work.Indications exist as well that an increase in global and specifically boreal vegetation activity occurs.The middle and high latitude region of the Northern Hemisphere show a widely increasing vegetation activity while arid and semi-arid regions elicit a decrease in vegetation photosynthesis in the Southern Hemisphere.It is suggested that precipitation and temperature are the primary drivers for inter-annual vegetation changes.Vegetation cover changes are also highly related to ecosystems susceptible to global climate change.

植被具有明显的年际变化和季节变化特点,对植被的动态监测可以从一定程度上反映气候变化的趋势,因此监测植被动态变化以及分析这种变化与气候的关系已经成为全球变化研究的一个重要领域.随着遥感卫星获得长时间系列逐日观测数据,许多国际组织和机构制定了全球卫星数据接收、处理和生成数据集计划,所产生的标准数据集则极大地促进了该项研究.大量研究在全球尺度、洲际尺度（北美洲和欧亚大陆）以及区域尺度上广泛开展.在阅读国内外大量文献的基础上,比较分析了常用于植被监测的卫星传感器和主要数据集,汇总了植被年际变化及其与气候关系研究的主要研究方法和研究结果.结果表明近20年来全球植被活动明显增强,表现为北半球普遍存在增加的趋势,南半球干旱半干旱区出现降低的植被光合作用,但这些变化因空间位置不同和研究尺度不一样体现出不同的动态变化特征.气温和降水是影响植被变化的最主要的因素.

Qinghai Lake Basin (QLB) belongs to the alpine grassland ecosystem. The grassland degradation is an effective detector to reflect the ecological environment condition in QLB. In this study, the spatial distribution and change information of the degraded grassland in QLB were firstly mapped and extracted using remote sensing techniques. Then the spatial-temporal changes of the degraded grassland between the year 2000 and 2010 were analyzed in different perspectives using Markov model, index of dynamic variation degree, landscape pattern index and grassland change index. Results show that the grassland in QLB was in good condition in 2010, and the non-degraded meadow and non-degraded grassland dominated QLB and covered about 38% of this region. The grassland has little variation during these 11 years, and the index of dynamic variation degree is -0.0384. The grassland was improved after the first degradation, but still had slight degradation in the overall trend. The spatial landscape pattern of the degraded grassland was stable in this study. The non-degraded meadow is dominantly distributed in the central region of QLB. The spatial-temporal changes of this land cover type were stable during these 11 years, and its dynamic variation degree was 1.82%. The change of moderate-degraded meadow was the most significant. During the period of 2006-2010, even the grassland in QLB was obviously improved; there was almost 7.4 ten thousand hectare of heavy-degraded meadow from moderate-degraded meadow, covering 65% area of land cover types from moderate-degraded meadow. Light-degraded meadow, moderate-degraded meadow and heavy-degraded grassland were dominantly located in northwest region of QLB, north and surrounding area of Qinghai Lake. The spatial changes of these three land cover types evolved from and into other types were the most significant, and their dynamic variation degree floated between 15% and 20% from the year 2006 to 2010.

青海湖流域属于高寒草地生态系统,草地退化状况是反映该流域生态环境状况的有效指标。在对青海湖流域退化草地分类的基础上,利用遥感手段获得流域退化草地的空间分布和变化信息。采用Markov模型、退化草地动态变化度、转类指数和景观指数对青海湖流域草地退化状况时空变化进行多角度分析。研究表明2010年青海湖流域草地状况良好,未退化草甸与未退化草原在整个流域占绝对优势,是流域面积的38%。2000-2010年期间,流域草地变化不大,退化草地转类指数为-0.0384;草地变化整体上呈极轻微退化趋势,在这11a期间呈现先退化、后改善的状况。流域内不同退化草地类别的空间景观格局表现比较稳定。青海湖流域的优势草地类别是未退化草甸,主要分布在流域中部,2000-2010年期间该类别的动态变化度为1.82%,没有发生大幅度变化,时空变化都比较稳定。中度退化草甸是退化最明显的类别,即使在流域草地呈改善状况的2006-2010年期间,有近7.4万hm 2 退化为重度退化草甸,占中度退化草甸转变为其他类别的65%。流域中与其他类别相互转换频繁,面积变化幅度最大的类型是轻度、中度退化草甸,及重度退化草原,在流域草地退化发生改善的2006-2010年期间,这3个类别的动态变化度达到15%-21%之间;空间上它们主要分布在流域西北部、青海湖北部以及环青海湖区域。

In this paper, an indicator system based on the Pressure-State-Response (PSR) model proposed by the OECD and UNEP is developed to evaluate ecosystem health for River basin. The indicator system of the ecosystem health for the River basin is composed of the pressures from nature and humans, the status of the ecosystem and the responses of human society. Located in the coastal zone of southeast China, the economy of Dongxi River basin is relatively developed, the population density there is relatively higher, and natural resources is correspondingly indigent. The ecosystem health in the River basin is very important for sustainable development of the local social-economy. In a healthy River basin, ecosystem provides such services for human being as water resources supply, fish resources, flood diversion and storage, hydro-power, recreation, culture and scientific research, environmental purification, wildlife habitat, CO 2 fixation, nutrient cycling etc. In this paper, such indicators as population density, annual GDP growth, water resource per capita, annual precipitation, rate of forestland coverage, the rate of industrial waste water treatment were selected to reflect the pressure, the state and the response of the River basin firstly. Secondly, the weight of the indicators was confirmed by experts, and the assessment criteria were based on related national standard. Thirdly, the integrated assessment method for the healthy assessment of the River basin was proposed and the status of ecosystem health in Dongxi River basin was evaluated through this model. Lastly, five grades of ecosystem health status were classified, which are very good, good, moderate, low and very low. The status of ecosystem health in Dongxi River basin was evaluated. The results show that the ecological health index of Dongxi River basin is 0.5898, which is in the moderate condition. Some strategies for improving ecological environment of Dongxi River basin were put forward: Firstly, the control of population growth and environmental regulations enforcement should be enhanced. Secondly, use of pesticides and fertilizers should be reduced. Thirdly, wastes treatment and ecological restoration project should be conducted particularly in the upper and middle streams of the River basin.

本文根据联合国OECD和UNEP提出的“压力-状态-响应”(PSR)框架模型和流域生态系统的特点，通过建立流域生态系统健康评价的指标体系和评价模型，对福建省诏安东溪流域的生态系统健康状态进行评价。研究的基本思路是：首先，选取人口密度、GDP年增长率、人均拥有水资源量、年降雨量、森林覆盖率、工业废水达标处理率等能够充分反映流域压力、状态和响应的指标构建评价指标体系；其次，通过专家打分的方法对各评价指标进行权重分配，参考湿地的生态系统健康评价方法和相关标准对流域生态系统健康评价的各个指标进行标准化赋值；再次，提出了流域生态系统健康综合评价模型，得出流域生态系统健康综合指数；最后，把流域生态系统健康状态分为5个等级，分别是:良好状态、较好状态、警戒状态、较差状态和极差状态。根据流域生态系统健康综合指数，确定流域生态系统健康状况。研究结果表明，东溪流域生态系统健康评价指数(E)为0.5898，东溪流域生态系统健康处于警戒状态。

Evaluation on cultivated land ecological security is a significant foundation for improving the security of farmland ecosystems and the sustainable use of cultivated land. To solve the problem of asymmetric information and subjectivity in most integrated evaluations, the authors define the cultivated land ecological security, construct an evaluation index system based on the Pressure-State-Response (PSR) model, and then conduct an evaluation of the ecological security of cultivated land in China by the matter element analysis and the improved entropy method. The results show: (1) The ecological security of cultivated land in China was gradually improved from critically safe to safer from 1996 to 2010, but the correlation of "safer" was extremely weak in 2010; (2) Crucial constraints on the improvement of cultivated land ecological security include fertilizer load per unit of cultivated land, per capita cultivated land, pesticide load per unit of cultivated land, land reclamation rate, and soil erosion. For the cultivated land ecological security to be continuously improved, the economic development pattern should be transformed, land use supervision and management strengthened, and excessive consumption of land resources for economic growth reduced; green agriculture should be vigorously developed, pesticides and fertilizers applied only as needed; rural land consolidation and high-standard basic farmland construction should be strengthened, environmental protection intensified, and soil erosion effectively controlled. The evaluation index system based on the PSR model can accurately reflect the relationship between various elements of the farmland ecosystems, while the matter element analysis can reveal differentiation information of every single indicator and intermediate information of comprehensive evaluation, discovering specific problems in cultivated land ecological security. Therefore, the evaluation index system and the matter element analysis are suitable to assess the cultivated land ecological security.

耕地生态安全评价是改善农田生态系统安全状况、促进耕地可持续利用的重要基础。针对多数综合评价研究中存在信息屏蔽和主观性的问题,在界定耕地生态安全内涵的基础上,构建了基于压力-状态-响应(PSR)模型的评价指标体系,采用物元分析方法和改进的熵值法对我国耕地生态安全进行评价。研究结果表明:(1)1996-2010年我国耕地生态安全水平不断提高,安全等级经历了"临界安全-较安全"的演变历程,但2010年"较安全"等级关联度很弱;(2)单位耕地化肥负荷、人均耕地面积、单位耕地农药负荷、土地垦殖率、水土流失程度等是耕地生态安全等级提升的关键制约因素。为了促进耕地生态安全等级不断提升,需要进一步转变经济发展方式,加强土地利用监督管理,降低经济增长对土地资源的过度消耗;大力发展绿色农业,合理施用农药、化肥;积极开展农村土地整治,加强高标准基本农田建设;加大环境治理力度,有效控制水土流失程度。基于PSR模型的评价指标体系能更准确地反映农田生态系统各要素之间的关系,物元分析方法可以揭示单个评价指标的分异信息和综合评价结果的中间信息、挖掘耕地生态安全存在的具体问题,适合用于耕地生态安全的评价。

草地退化是在过牧、开垦等人为活动及不利自然因素影响下草地生态系统逆行演替的一种过程，是土地荒漠化的主要形式之一。本文在讨论了草地退化指标及其等级划分的基础上，编制了中国北方退化草地分布图。据此图计算，北方草地退化面积达137.77万km#+2，占该草地总面积的50.24%，近15年来以每年1.9%的速度在扩大退化。为此提出了防治对策及草地畜牧业可持续发展战略。