植物物候模型研究

植物物候模型是基于植物对环境因子的响应机理而建立的可模拟植物生长发育的数学方程。本文介绍了树木物候模型和作物物候模型,根据对植物休眠解除过程的不同理解,树木物候模型主要有7种不同的类型;根据作物发育规律而建立的作物物候模型也大体相同。同时,还阐述和探讨了研究植物物候模型的意义、研究中存在的问题及其发展趋势。     

2001-2020年南盘江流域植被物候时空变化及其对气候的响应

植被物候对气候敏感易观测,是观测生态变化与全球气候变化的重要指标,研究植被物候变化及其对气候的响应对于了解全球气候变化与植被之间的复杂关系具有重要意义。为揭示近20年来南盘江流域植被物候时空变化及其对气候的响应特征,基于2001—2020年增强型植被指数(MOD13Q1-EVI),运用S-G滤波、动态阈值法、Sen斜率分析法、相关性分析法等方法,获取了南盘江流域植被物候参数,分析其时空分布特征,利用偏相关系数分析了气候变化对SOS,EOS的影响。结果表明:(1)2001—2020年,南盘江流域物候特征变化较大,SOS(Start of the growing season)呈提前趋势,EOS(End of the growing season)和LOS(Length of the growing season)呈推迟延长趋势,物候变化具有空间异质性,不同子流域植被物候存在较大差异。(2)植被物候变化受到地形的影响,EOS随海拔升高,结束时间提前; SOS随海拔变化的规律与LOS的规律相反,都存在1 000 m,2 000 m和2 600 m分界线。(3)南盘江流域SOS变化与气温、降水呈正相关关系,EOS与气温呈正相关关系、与降水呈负相关关系。该研究可为南盘江流域的生态环境保护与植被资源可持续发展提供科学依据。     

草地牧草物候发育模型的应用研究——以锡林郭勒草原为例

天然草地牧草生长发育受环境条件影响很大,牧草的发育期年际间和年内有很大变化。利用多年牧草物候观测资料,分析了影响草地牧草生长发育的主要气象要素并建立了锡林郭勒草原主要牧草物候发育模型。     

北京植被净初级生产力对物候变化的响应

植被净初级生产力（Net Primary Productivity,NPP）对物候的响应是全球气候变化背景下的重要研究内容,气候变化对植物物候与NPP的影响仍需明了,物候的时空变异规律更需深入探讨。该研究基于2001-2020年MODIS归一化植被指数（Normalized Difference Vegetation Index,NDVI）数据提取北京植被物候信息,利用CASA（Carnegie-Ames-Stanford-Approach）模型模拟NPP,通过线性回归、趋势分析和结构方程模型等方法,阐明NPP与物候时空变化特征,探究气象因素和物候变化对NPP的影响。结果显示：1）2001-2020年超过70 %的区域出现生长季开始（Start of Growing Season,SOS）逐渐提前,平均每年提前0.53 d。超过90%的区域生长结束期（End of Growing Season,EOS）逐渐推迟,平均每年推迟0.51 d。2）SOS提前和生长季（Length of Growing Season,LOS）延长均对NPP增长产生显著影响（P<0.05）。SOS每提前1 d,NPP增长3.74 g/m2;LOS每延长1 d,NPP增长2.56 g/m2 。秋季EOS推迟对NPP变化影响不显著。3）春季和秋季,气候通过改变物候（SOS、EOS）对NPP的间接影响大于直接影响,而夏季温度和降雨对NPP的直接影响更大。该研究表明春季物候变化是NPP年际变异的重要驱动因子,春季物候提前导致NPP年总量增加。研究结果是都市区植被生产力如何响应气候变化认识的重要补充。     

过去30年气候变化对华北平原冬小麦物候的影响研究

全球变暖已成为全球共同关注的问题。作物物候对气候变化的响应是研究气候变化对农业生产影响的重要内容。本文选用1981—2009年华北平原16个农业气象观测站的冬小麦物候资料,利用统计方法分析了冬小麦物候的变化趋势。结果表明,过去30年华北平原冬小麦播种期、出苗期和越冬开始期推迟,而返青期、开花期和成熟期呈提前趋势。物候期的提前或推迟促使小麦不同生长发育阶段历时发生变化,出苗—越冬开始、越冬开始—返青、返青—开花等阶段呈缩短趋势,但开花—成熟阶段生育期却延长0.9 d.10a 1,整个生育期历时呈减少趋势,平均减少3.4 d.10a 1。本文采用作物模型(CERES-Wheat)模拟固定小麦品种在气候变化背景下的物候变化趋势,以探讨冬小麦物候变化的主要驱动因子。模拟结果表明,过去30年小麦开花期和成熟期提前的主要驱动因素为气候变化,品种变换在一定程度上可减缓气候变化对物候的影响。     

2001-2020年青藏高原草地物候变化遥感监测

[目的]探究青藏高原草地物候时空变化规律,对于理解高寒生态系统与区域气候之间的相互作用和生态安全屏障保护与建设具有重要的科学意义。[方法]基于2001—2020年MODIS归一化植被指数(NDVI)时序产品,采用非对称高斯函数拟合法和动态阈值法,提取了青藏高原草地NDVI峰值、NDVI峰值期、返青期(SOS)、枯黄期(EOS)和生长季长度(LOS)参数。[结果](1)研究区草地物候的空间分布规律明显,自西向东,草地NDVI峰值增加、峰值期提前、SOS提前、EOS推迟、LOS延长。(2) 20年间,青藏高原草地物候年际变化主要表现为SOS呈提前趋势(12.11%的区域显著提前),EOS呈推迟趋势(18.49%的区域显著推迟),LOS呈延长趋势(18.87%的区域显著延长)。(3)青藏高原气温、降水对SOS有1～2个月的滞后效应;气温对EOS有1～2个月的滞后效应,而降水对EOS的滞后效应不明显。考虑滞后效应的条件下,气温是影响草地SOS,EOS年际变化的主导因子。[结论]青藏高原草地物候具有空间异质性,且气温是影响草地物候时空变化的主要因素。     

基于SPOT-VGT NDVI时间序列的农牧交错带植被物候监测

为了分析中国农牧交错带植被典型物候期(生长开始日期,生长结束日期和生长季长度)的变化趋势,利用2001-2010年SPOT-VGT NDVI(SPOT-VEGETATION normalized differential vegetation index)数据,基于Savitzky—Golay滤波和动态阈值法,提取了中国北方农牧交错带植被物候期,探讨研究区植被物候期的空间差异和时间变化。研究表明,农牧交错带植被的生长季一般从4月中旬到5月下旬开始,9月下旬至10月下旬结束;从西南部到东北部,植被物候表现出明显的空间差异;农田植被物候期与自然植被略有不同;对研究区10a物候期线性拟合,得出研究区大部分植被覆盖区域生长季开始日期呈现提前趋势,提前日期大约为1～10d左右;除部分地区外,2001-2010年农牧交错带植被生长季结束日期没有明显变化趋势;10a间研究区大部分草地生长季延长,也有一部分地区的生长季出现缩短趋势。研究提取结果与已有的相关研究结果较为一致,可为农牧交错带生态环境评价和保护提供一定的参考。     

基于遥感的黄土高原植被物候监测及其对气候变化的响应

为了分析黄土高原地区植被物候特征,该文基于AVHRR传感器获取的陆地长期数据记录(land long term data record,LTDR)V4 NDVI数据,对黄土高原1982-2011年间植被物候的时空变化进行分析,并借助偏相关分析方法对物候与气温和降雨的关系进行量化分析。结果表明:黄土高原近30 a间春季物候提前显著(0.54 d/a,P0.001),主要集中在北部草地和灌木植被;秋季物候推迟显著(0.74 d/a,P0.001),主要分布在甘肃、陕北、内蒙古和山西北部等地。不同植被的春秋物候稍有差异,稀疏灌木林春季物候提前趋势最多(1.31 d/a),常绿针叶林最小(0.19 d/a);秋季物候推迟最多的为乔木园地(1.18 d/a),最少的是水田(0.17 d/a)。黄土高原植被物候主要受气温影响,降雨的变化也会对物候产生一定影响。冬季和前年秋季气温上升是春季物候提前的主要驱动因子;夏季和秋季降雨则对秋季物候休眠期延迟起着重要作用。该研究可为黄土高原生态环境评价及气候变化预测模型提供一定依据。     

模拟降水变化下黄土丘陵区草地群落特征及其物候期响应

在全球气候变化背景下,黄土高原降水格局呈现出季节波动增强和极端降水事件增加趋势,降水格局变化势必会引起草地群落特征和物候期发生重要改变。为研究黄土丘陵区草地生态系统对降水改变的响应,选取黄土丘陵区退耕草地为研究对象,连续定位观测自然恢复小区不同降雨梯度下(0,±20%,±40%,±60%)物候动态变化,探究了物候期和群落结构对降水变化的响应状况。结果表明:(1)不同降水条件下群落物种组成及丰度存在明显差异,与对照组相比,增雨与减雨均提高了物种的种类。增雨60%群落种类最多,为18种。(2)降水梯度递增处理下,群落盖度呈先增加后降低趋势,地上生物量随呈单峰趋势。增雨20%处理和减雨20%处理均能够显著提高群落植被盖度和地上生物量,地上生物量在增雨处理下明显高于减雨处理。(3)丰富度和Shannon-Wiener指数总体上都呈增加趋势,减雨20%,40%,60%均使Pielou均匀度指数降低。(4)不同降水条件对物种物候期的影响显著(p<0.05),群落返青期、繁殖期和和枯黄期在减雨处理下显著提前,而增雨处理则使其繁殖期和枯黄期发生推迟。综上,群落物种组成、植被盖度和地上生物量在不同降水处理下表现出显著差异,而物种多样性对降水变化响应不敏感。     

克里雅河流域植被物候时空变化及影响因素

[目的] 探究克里雅河流域2000—2015年植被物候期时空变化规律，在气候变化背景下为该流域植被演变过程研究提供参考。[方法] 以MODIS MOD₀₉Q₁产品和当地气象站点数据为数据源，利用植被指数动态阈值法提取流域植被物候信息并进行空间趋势分析，以偏最小二乘回归方法分析克里雅河流域植被物候期与不同月份气象因子的相关性。[结果] ①研究期内植被生长期开始时间主要在第60—180 d之间，结束时间在第180—322 d之间，植被生长期长度在70~250 d之间。中游的人工绿洲植被生长期开始时间最早，结束时间最晚，植被生长时间最长。②2000—2015年克里雅河流域植被返青期整体呈提前趋势，变化速率均值为-1.3 d/10 a，植被枯黄期呈推迟趋势，生长期延长，其中以中游的变化趋势最为明显。③春季气温和降水量的升高促进植被返青期提前，秋季气温和降水量的升高会对植被枯黄期起到推迟作用。[结论] 克里雅河流域植被物候期在不同的海拔梯度上有明显的分布变化规律，中游人工绿洲植被的物候变化规律远异于自然植被物候变化规律，并且可能影响到了下游。     

Bayesian analysis of temperature sensitivity of plant phenology in Germany

The temperature sensitivity of 43 phenological phases was analysed in Germany within the period 1951–2006 with the help of a Bayesian approach. First a Bayesian model comparison of monthly temperatures and phenological phases throughout the year was conducted. We analysed the data as constant (mean onset date), as linear (constant trend over time) and as change point model (time varying change). The change point model involves the selection of two linear segments which match at a particular time. The matching point is estimated by an examination of all possible breaks weighted by their respective change point probability. Secondly a Bayesian coherence analysis was applied to investigate the relationship between phenological onset dates and an effective temperature generated as a weighted average of monthly means. Temperature weight coefficients were obtained from an optimization of a coherence factor by simulated annealing.Results reveal that late spring, summer and early autumn temperature months exhibit a clear preference for the change point model (>50%) indicating nonlinear change. The temperature development of April and August shows exceptionally high nonlinearities compared to the other months with change point model probabilities of 78% and 81% over the last five decades.For all phenophases a strong dependence of phenology on temperature is determined. We can classify two main temperature response patterns of the studied phenological phases: on the one hand spring phenophases are particularly sensitive to temperatures in April, exhibiting a prompt response. On the other hand summer phenophases are less influenced by temperature during or right before the month of the onset. They reveal a delayed response to nonlinear temperature changes mainly of April. Especially abrupt changes during the temperature sensitive stage of species cause a pronounced change in plant phenology regardless of the time of onset.     

Correlation between temperature and phenology prediction error in rice (Oryza sativa L.)

For rice (Oryza sativa L.), simulation models like ORYZA2000 and CERES-Rice have been used to explore adaptation options to climate change and weather-related stresses (drought, heat). Output of these models is very sensitive to accurate modelling of crop development, i.e. phenology. What has to date received little attention in phenology calibration is the temperature range within which phenological models are accurate. Particularly the possible correlation between temperature and phenology prediction error has received little attention, although there are indications that such correlation exists, in particular in the study by Zhang et al. (2008). The implication of such correlation is that a phenology model that is accurate within the calibration temperature range can be less accurate at higher temperatures where it can systematically overestimate or underestimate the duration of the phase from emergence to flowering. We have developed a new rice phenology calibration program that is consistent with ORYZA2000 concepts and coding. The existing calibration program DRATES of ORYZA2000 requires an assumption of default cardinal temperatures (8, 30 and 42 °C) and then calculates cultivar specific temperature sums and development rates. Our new program estimates all phenological parameters simultaneously, including the cardinal temperatures. Applied to nine large datasets from around the world we show that the use of default cardinal temperatures can lead to correlation between temperature and phenology prediction error and temperature and RMSE values in the order of 4-18 days for the period from emergence to flowering. Our new program avoids such correlation and reduces phenology prediction errors to 3-7 days (RMSE). Our results show that the often made assumption of a rapid decrease in development rate above the optimal temperature can lead to poorer predictions and systematic errors. We therefore caution against using default phenological parameters for studies where temperatures may fall outside the range for which the phenological models have been calibrated. In particular, this applies to climate change studies, were this could lead to highly erroneous conclusions. More phenological research with average growing season temperatures above the optimum, in the range of 32-40 °C, is needed to establish which phenological model best describes phenology in this temperature range.     

西安植物园木本植物近十余年物候变化的特征分析

通过对1988-2002年西安市植物园20种木本植物物侯资料的分析。结果表明：近十余年西安市植物园20种木本植物物侯变化趋势明显表现为所有植物春季物侯逐年提前、大多数植物秋季物侯逐年推迟的趋势；春季物侯对气侯变化的响应程度显著大于秋季物侯。大多植物生殖生长期的物侯变化幅度大于营养生长期。因此，春季物侯和生殖生长期物侯更加适宜作为气侯变化的物侯指标。该研究对于评价物侯及物侯不同指标对气侯变化的响应有一定的参考价值。     

Validation of winter chill models using historic records of walnut phenology

Many fruit and nut species require cold temperatures during the dormancy season to initiate flowering and bear fruit. Quantifying these chilling requirements is crucial for identifying appropriate cultivars for a given site, for timing applications of rest-breaking chemicals and for predicting consequences of climate change. We present a new method to test temperature models describing chilling and heat requirements of perennial plants, and use this method to compare the ability of four chilling models (Chilling Hours, Utah Model, Positive Utah Model and Dynamic Model) to explain walnut phenology in California.When plotting remaining heat before a phenological stage is reached against accumulated winter chill, observational curves for all years should intersect in one common point, assuming fixed chilling and heat requirements and a sequential fulfillment of these requirements. This point defines the chilling and forcing requirements of the plant, and the quality of the chilling/heat model combination is indicated by how well defined the intersection point is.We used this method on a total of 1297 phenological observations, including four walnut cultivars, seven phenological stages and eight locations in California. Using an hourly temperature record, winter chill was quantified by the four chilling models and remaining heat was estimated using the Growing Degree Hour concept.The theoretical intersection point was more clearly defined for the Dynamic and Positive Utah Models than for the Chilling Hours and Utah Models in almost all cases, indicating that these are superior in explaining walnut phenology. It was also apparent that chilling models were not equivalent and that chilling requirements determined under constant temperature conditions, when quantified in Chilling Hours, were not representative of chilling requirements in orchards.     

气候变暖对山西南部典型植物物候的影响

选取山西省运城市、临汾市、晋城市和长治县农业气象试验站典型木本和草本植物1982-2004年物候观测资料及各地1970-2004年气温资料,运用距平、线性趋势等方法分析各地气温和植物物候期的变化特征,以及气温对植物物候期的影响。结果表明,(1)春季物候期普遍呈提前趋势,生长季呈延长趋势;木本植物秋季物候期呈推迟趋势,大部分地区草本植物黄枯始期表现为略提前趋势,黄枯末期表现为推迟趋势。(2)随着年平均气温的不断升高,植物春季物候期呈提前趋势;木本植物秋季物候期呈推迟趋势,草本植物黄枯末期大多呈提前趋势。气温每升高1℃,植物展叶始期提前1～18d。     

Spatial and interspecific variability in phenological responses to warming temperatures

A comprehensive understanding of species phenological responses to global warming will require observations that are both long-term and spatially extensive. Here we present an analysis of the spring phenological response to climate variation of twelve taxa: six plants, three birds, a frog, and two insects. Phenology was monitored using standardized protocols at 176 meteorological stations in Japan and South Korea from 1953 to 2005, and in some cases even longer. We developed a hierarchical Bayesian model to examine the complex interactions of temperature, site effects, and latitude on phenology. Results show species-specific variation in the magnitude and even in the direction of their responses to increasing temperature, which also differ from site-to-site. At most sites the differences in phenology among species are forecast to become greater with warmer temperatures. Our results challenge the assertion that trends in one geographic region can be extrapolated to others, and emphasize the idiosyncratic nature of the species response to global warming. Field studies are needed to determine how these patterns of variation in species response to climate change affect species interactions and the ability to persist in a changing climate.     

气候变暖对陆地生态系统的影响

人类活动引起的温室效应导致全球气候变暖,气候变暖对全球生态环境的影响越来越受到人们的关注.作为人类赖以生存的环境主体,陆地生态系统对气候变暖将做出何种响应,更是人们关注的重点.植物物候的变化可以直观地反映某些气候变化,尤其是气候变暖.气候变暖影响植物的生长节律,进而引起植物与环境关系的改变及生态系统物质循环(如水和碳的循环)的改变.不同种类植物对气候变化的差异响应,会使植物间和动植物间的竞争与依赖关系发生深刻的变化,如北半球中高纬度地区植被生长季延长、植物提早开花、昆虫提早出现、鸟类提早产蛋以及冰川退缩、永冻土带融化、江河湖泊结冰推迟而融化提早等.本文主要从陆地生态系统的分布和演替两方面着眼,以植物和动物作为考察对象,系统论述了森林、草原、荒漠、湿地及农田等陆地生态系统在气候变暖背景下产生的变化,并从微观和宏观尺度上提出陆地生态系统变化的生态学机制,最后在技术和政策层面给出若干对策.     

民勤荒漠区物候与四季划分

利用民勤荒漠区30a以上的气温和植物物候观测资料对比分析以气温划分的四季和以物候划分的四季间的区别。结果表明：在民勤荒漠区,气温四季的春季来临过迟,冬季来临过早,以物候划分的四季更适合当地季节变化;如果以气温划分四季,在低纬度地区就会没有冬季,而在高寒地区就会没有夏季,因而,物候四季较气温四季的适用范围广泛,且与农业生产具有更为直接的联系。但是,以物候现象观测四季时,应同时观测多种指示性物候;在选择指示性物候时,应注意选择在当地有代表性的、生长健康的植物。     

近40年中国植物物候对气候变化的响应研究

根据中国科学院物候观测网络中26个观测网络中26个观测站点的物候资料，分析了近40年我国木本植物物候变化及其对气候变化的响应关系。并建立了不同年代物候期与地理位置之间的关系模式。分析了当前气候增暖背景下物候期地理分布规律变化对气候变化的响应关系。结果表明：温度上升，我国的木本植物春季物候期提前，20世纪80年代以后，东北，华北及长江下游等地区的物候期提前，西南东部，长江中游等地区的物候期推迟，同时物候期随纬度变化的幅度减小。