Eco-environment has been disturbed severely in the Yellow River source by global climatic change and human activity. Currently, it had been gotten people’s close concern on impact of climate change on eco-environment in source region of Yellow River. Based on the analysis and systematic summary of the research results at home and abroad in recent years, authors concluded the climate change characteristics and key problem of the eco-environmental, and gave a comprehensive analysis of the main problems from runoff, soil erosion, wetlands, permafrost and vegetation in the Yellow River source, and discussed the characters of the effect of climatic change on eco-environment. Above all, authors had provided the main strategy of the eco-environment protection in the Yellow River source. The results were as follows: The precipitation was slightly increased, but the temperature was significantly increased in the Yellow River source region; It was great variation that the inter-annual variation and inter-decadal variation for runoff in the Yellow River source region. The runoff was in ample flow period from the middle of 1960s to the late of 1970s and in low water period from the early 1990s to 2008, and the good correlativity was between the annual runoff anomaly and annual precipitation anomaly, and the precipitation intensity was another important cause for runoff volume; The Yellow River source was the region with severe soil erosion, and the wetland was seriously damaged with an obvious decreasing area and dominance and increasing the number of patch, fragmentation degree and fractal dimension; The source region of permafrost had been thinned or disappeared, and there were formed inconsistently frozen ground and residual thawed layers in the vertical profile in the fringe, and raised 50~70 m in the lower limit of permafrost distribution; In general the vegetation cover was preserved previous condition or partially degraded in the Yellow River source. Therefore, we should consummate ecological compensation mechanism, strengthen the construction of a legal system and social environmental awareness, improve the quality of the law enforcement contingent, strengthen the joint of different departments, implement the ecological immigration, and advocate improving the ecotourism toprotect the ecological environment of the Yellow River source.

在全球气候变暖和人类活动的共同作用下，黄河源区的生态环境受到严重干扰。目前，气候变化对黄河源生态环境的影响已经得到了很多学者的关注。本文在系统总结国内外已有研究成果的基础上，归纳了黄河源区的气候变化特征和已存在的生态环境问题，从径流量、土壤侵蚀、湿地、冻土和植被5个方面综合分析了黄河源区生态环境所面临的主要问题，讨论了气候变化对黄河源区生态环境的影响特点，并在此基础上提出了黄河源生态环境保护的治理对策。结果显示，黄河源区降水略有增加,气温显著升高。黄河源区径流有很大的年际和年代际变化，20世纪60年代中期至80年代后期相对偏丰，90年代初至2008年相对偏枯；源区年径流量距平的年际变化与年降水量距平的年际变化有很好的相关性；降水强度也是影响径流量的原因。黄河源区土壤侵蚀现象严重。湿地面积减少，沼泽和水域的斑块数、破碎度和分维数增加，优势度降低。源区多年冻土已经减薄或消失，多年冻土的边缘地带，垂直方向上形成不衔接冻土和融化夹层，多年冻土分布下界升高50～70 m。源区植被覆盖总体上保持原状，局部出现退化。在黄河源区生态环境保护方面应形成完善的生态补偿机制，加强法制建设，强化社会环保意识，提高执法队伍素质，加强部门联合，实施生态移民，大力发展生态旅游。

The research on the phenology of the grassland community could help cognize the function of the grassland community, and provide the background data for the ecosystem assessment. In this study, the factors that affect the flowering phenology of alpine meadow in Gannan were discussed in four aspects: geographical environment, functional traits, pollination modes and phylogeny. The results showed that, at the community level, the flowering period covered the whole growing season, but there was still a peak flowering period in the whole species. The first flowering date, peak flowering date and duration of flowering time were different. Each species has unique pattern in flowering phenology; Plants height( P <0.001) and seed size( P =0.034) could significantly predict flowering time; Wind-pollinated species flowered earlier than insect-pollinated species( P =0.008);There was a negative correlation between flowering phenology overlaps and phylogenetic distances.

对草地群落物候的研究,不仅有助于对草地群落功能认知,更重要的是为生态系统评估提供背景资料。本研究从地理环境因素、功能性状、传粉者竞争以及系统发育4个方面讨论影响甘南高寒草甸植物花期物候的因素。结果表明,在群落水平上,开花期涵盖了整个生长季,但在整体上有一个高峰期,群落中各物种的始花期、开花峰值期及开花持续期不同,每一物种均有其独特的花期格局;植株高度( P< 0 . 001)和种子大小( P =0.034)能够显著地预测开花,而比叶面积(SLA)则不显著(GLM, P> 0 . 05);风媒物种开花期早于虫媒物种( P =0.008);花期物候重叠与系统发育距离之间存在着负相关关系。

The response of vegetation phenology to climate warming has attracted increasing attention during the last few decades under the background of global change. In this paper, we summarized the response of vegetation phenology to meteorological factors (temperature, moisture, light), and their research methods were also introduced. In addition, the research progress on vegetation phonological changes in China over the past several decades were overviewed. With the global climate warming, the start of season is generally advanced in most regions of China, while this trend is not remarkable in some arid regions of Xinjiang. It is noteworthy that different observation methods at different research scales complicated the intercomparison or synthesis of phonological data at regional and global scale. Therefore, we recommended that a unified phenological observation network should be established based on the ChinaFLUX network and the widely distributed Chinese Ecological Research Network. Moreover, the method of deriving plant phenology information from the eddy covariance data should be improved. A uniform judging criterion for phenological change could standardize the research on the response of vegetation phenology to climate warming.

全球变化背景下，植物物候对气候变暖的响应已经成为研究热点。本文就植物物候对温度、水分、光照等气象因子的响应做了总结，并对国内外物候研究方法进行概述，特别是综合了近年来国内物候变化研究的文献，对我国植物春季物候变化情况作了统计：全球变化对我国大部分地区植被的影响主要是生长季提前，但新疆干旱区植被生长季开始日期在区域尺度上没有显著提前或者延迟趋势。由于物候研究方法的差异以及研究尺度的不同，在一定程度上弱化了研究结果的可比性，建议我国应基于目前的中国通量观测网以及各级生态监测网络，建立统一的物候监测平台，同时完善通量数据提取植物物候信息的方法，特别是阈值判定标准，为分析植物物候响应气候变化提供参考。  

Aims Our objective was to determine the impacts of climate change (mainly temperature and precipitation) on the phenology of tropical evergreen forests at the community and species level. Methods Two phenophases—the onset of leaf unfolding and the onset of first flowering—had been monitored in 12 evergreen broadleaf tree species in the tropical arboretum in Jianfengling, Hainan Island, since 2003. Observations were made on three mature and healthy individuals for each species once every two days in the same sunny direction in the afternoon by the same person. After the phenological data were collected, they transformed into the number of days from the first day of a calendar year (DOY, i.e. from 1th January). The outliers were excluded used the Grubbs principle. Meteorological data for the corresponding time period were derived from the National Climate Centre. Ultimately, the phenological and meteorological data were combined with the integrate regression method and used to identify the impacts of changing climate on the onset of leaf unfolding and the onset of first flowering in the 12 tree species and to determine their responses in the two phenophases to climate change. Important findings Both the onset of leaf unfolding and the onset of first flowering in the tree species were affected by climate change; the starting dates of the two phenophases in nearly all the tree species were closely related to changes in monthly temperature and precipitation. The onset of leaf unfolding was affected by the monthly mean temperature of the preceding winter and spring, and the impacts became more apparent with the time approaching the occurrence of specific phenophases. Monthly precipitation in the preceding autumn had more effects on the onset of the first flowering than any other time period, in support of the hypothesis that the effect of precipitation on phenology had a hysteretic nature. Furthermore, the onset of leaf unfolding was more susceptible to climate change than the onset of first flowering in the native tree species, whereas the introduced tree species showed reversed responses. Generally, if the monthly mean temperature increases by 0.1 °C and the monthly precipitation increases by 10 mm in the month with the strongest effects, and given that the conditions of other 11 months preceding the occurrence of the specific phenophases remains unchanged, then most of the species would advance or delay the phenophases by about one to three days. Ultimately, the Integrate Regression method provides an effective and operational approach to understanding the dynamic and complex relationships between climate change and the phenology in tropical plants, as demonstrated by the high values of the coefficient of determination ( R 2 ≥ 0.943) for the integrate temperature and precipitation regression models for phenological predictions based on climatic factors. These models can well be used for predicting the trend of phenological changes in tropical evergreen broadleaf tree species in response to changing climate.

为了探讨我国热带地区植物物候与气候变化的关系, 利用海南岛尖峰岭热带树木园12种热带常绿阔叶乔木植物2003–2011年物候观测资料结合同期月平均气温和降水数据, 运用积分回归分析方法, 筛选出影响海南岛12种乔木(8种本地种、4种引入种)展叶始期与开花始期的气象因素以及不同气象因素月值变化(月平均气温和月降水量)综合作用对这些树种物候期的动态影响, 最终建立积分回归-物候预测模型, 对气候变化背景下我国热带地区植物物候变化趋势进行了预测。结果表明: 海南岛12种热带常绿阔叶乔木展叶始期与开花始期均对气候变化做出较明显的响应, 几乎所有的树种展叶始期与开花始期的发生都受到气温和降水的共同影响。多数树种展叶始期受展叶前冬季及春季气温影响显著, 且在临近展叶始期的月份, 气温的影响更显著。上一年秋季月降水量对各树种开花始期的影响比其他时段显著, 这验证了降水的滞后性假说。本地种展叶始期对气候变化的响应比其开花始期对气候变化的响应更敏感, 引入种则相反。各树种展叶和开花在受气温和降水综合影响最明显的月份(假设其余11个月份月平均气温和月降水量不变), 月平均气温升高0.1 ℃、月降水量增加10 mm可使展叶始期和开花始期提前或推迟1–3天。积分回归分析方法为解释海南岛热带常绿阔叶乔木物候与气温和降水的动态关系提供了有效的途径, 基于气温和降水与物候资料建立的积分回归-物候预测模型具有对气温和降水变化影响下物候响应的解释率和预测精度高( R 2 ≥ 0.943)的优点, 对于预测气候变化影响下的植物物候变化趋势有一定的适用性。

Vegetation is the most active component of natural ecosystems and is highly responsive to many factors such as atmospheric conditions, water availability, and soil factors; thus, vegetation is a sensitive indicator of environmental change in terrestrial ecosystems. With growing concerns on global change and global warming, more and more scholars are focusing their research on understanding how plants respond to environmental change.Based on climate data collected from 1951 to 2000, NOAA/AVHRR NDVI data from 1982 to 2000 and flowering phenophase data for Prunus davidiana collected from 1951 to 2000 in Beijing, relationships between climatic factors and vegetation at different time scales were investigated. The purpose of the study was to assess the impacts of climate change on vegetation and feedbacks between land cover changes and climate to better understand the effects of global change. Time lag cross-correlation analyses were used to examine time lags in climatic factors and NDVI, and P． davidiana flowering phenophase.Our statistical analyses indicated that at different temporal scales different relationships between climate factors and growing conditions of plants were found. On an annual scale, there were no differences between actual temperature or effective temperature and actual precipitation or effective precipitation and their relationship to vegetation. Relationships between effective temperature, effective precipitation and vegetation were the highest when examined at the scale of a month. The highest correlation between NDVI and temperature occurred when the time lag was zero. At the scale of a year, the influencing threshold was about one year while at the scale of a month it was about one month. Land surface temperature in Beijing had a statistically more meaningful relationship with NDVI and the flowering phenophase than with precipitation. At the scale of a year, the influencing threshold between climate factors and plant phenophase was two years, whereas at the scale of a month, the influencing threshold between actual temperature and plant phenophase was about one month.

气候变化对陆地生态系统的影响及其反馈是全球变化研究的焦点之一。本文利用1951～2000年的气温、降水等气候资料、1982～2000年的NOAA/AVHRR遥感数据和1951～2000年北京春季物候的代表性指标——山桃（Prunus davidiana）始花的物候数据，分析了在年际和年内时间尺度上北京地区各气候参量与植被变化之间的关系。结果显示：植物生长与温度之间的关系远比其与降水之间的关系密切；各气候参量和植被生长状况之间的关系因时间尺度而不同。1)月际水平上，具有显著生态学意义的气候指标对植被生长状况的影响更明显。2)温度与NDVI指标的相互作用最大为零时滞：年际水平上，影响时效约为1年；月际水平上，约为1个月。3)植物物候期与温度之间的关系远比其与降水之间的关系密切。年际尺度上，气候参量和植物物候期的相互作用是同时的，其中气温的影响时效为2年；月际尺度上，实际温度和植物物候期的相互作用时效约为1个月。