Effect of climate change over the past half century on the distribution,extent and NPP of ecosystems of Inner Mongolia

The response of natural vegetation to climate change is of global concern. In this research, changes in the spatial pattern of major terrestrial ecosystems from 1956 to 2006 in Inner Mongolia of China were analyzed with the Holdridge Life Zone (HLZ) model in a GIS environment, and net primary production (NPP) of natural vegetation was evaluated with the Synthetic model, to determine the effect of climate change on the ecosystem. The results showed that climate warming and drying strongly influenced ecosystems. Decreased precipitation and the subsequent increase in temperature and potential evapotranspiration caused a severe water deficiency, and hence decreased ecosystem productivity. Climate change also influenced the spatial distribution of HLZs. In particular, new HLZs began to appear, such as Warm temperate desert scrub in 1981 and Warm temperate thorn steppe in 2001. The relative area of desert (Cool temperate desert scrub, Warm temperate thorn steppe, Warm temperate desert scrub, Cool temperate desert and Warm temperate desert) increased by 50.2% over the last half century, whereas the relative area of forest (Boreal moist forest and Cool moist forest) decreased by 36.5%. Furthermore, the area of Cool temperate steppe has continuously decreased at a rate of 5.7% per decade; if the current rate of decrease continues, this HLZ could disappear in 173 years. The HLZs had a large shift range with the mean center of the relative life zones of desert shifting northeast, resulting a decrease in the steppe and forest area and an increase in the desert area. In general, a strong effect of climate change on ecosystems was indicated. Therefore, the important role of climate change must be integrated into rehabilitation strategies of ecosystem degradation of Inner Mongolia.     

气候变暖背景下秦岭陕西段植被潜在分布区格局变化

植被分布在一定程度上受控于气候因子,在气候变化背景下,利用生物气候指标研究地带性植被的潜在分布区格局变化对于区域生态系统应对气候变化具有有益的参考价值。从生态气候学角度出发,利用植被热量指标——有效温暖指数(EWI),研究1959—2020年以及未来气候模式下秦岭山地陕西段植被潜在分布格局的变化。结果表明：(1)气候变暖导致植被热量指标发生变化,近62年来,秦岭山地陕西段EWI总体呈上升趋势,并于2001年发生上升突变。(2)基于EWI对秦岭陕西段植被类型的潜在分布区划分发现,2001年以前秦岭北坡无暖温带落阔常绿混交林的分布区,2001年后秦岭北坡渭河东部出现了该植被类型的潜在分布区。(3)随着气候变暖,秦岭陕西段暖温带植被潜在分布区不断扩张,而温带、寒温带以及高寒植被分布区持续缩减,同时各植被类型分布区的平均海拔高度均呈上移趋势。从面积及海拔变化幅度来看,秦岭南坡较北坡植被对气候变化更为敏感,高海拔区较低海拔区植被对气候变化更为敏感。(4)在代表性浓度路径4.5及8.5(RCP4.5及RCP8.5)情景下,未来50年,秦岭南北坡均将可能出现亚热带常绿阔叶林潜在分布区,亚热带常绿阔叶...     

Global patterns in the vulnerability of ecosystems to vegetation shifts due to climate change

Aim Climate change threatens to shift vegetation, disrupting ecosystems and damaging human well‐being. Field observations in boreal, temperate and tropical ecosystems have detected biome changes in the 20th century, yet a lack of spatial data on vulnerability hinders organizations that manage natural resources from identifying priority areas for adaptation measures. We explore potential methods to identify areas vulnerable to vegetation shifts and potential refugia. Location Global vegetation biomes. Methods We examined nine combinations of three sets of potential indicators of the vulnerability of ecosystems to biome change: (1) observed changes of 20th‐century climate, (2) projected 21st‐century vegetation changes using the MC1 dynamic global vegetation model under three Intergovernmental Panel on Climate Change (IPCC) emissions scenarios, and (3) overlap of results from (1) and (2). Estimating probability density functions for climate observations and confidence levels for vegetation projections, we classified areas into vulnerability classes based on IPCC treatment of uncertainty. Results One‐tenth to one‐half of global land may be highly (confidence 0.80–0.95) to very highly (confidence ≥ 0.95) vulnerable. Temperate mixed forest, boreal conifer and tundra and alpine biomes show the highest vulnerability, often due to potential changes in wildfire. Tropical evergreen broadleaf forest and desert biomes show the lowest vulnerability. Main conclusions Spatial analyses of observed climate and projected vegetation indicate widespread vulnerability of ecosystems to biome change. A mismatch between vulnerability patterns and the geographic priorities of natural resource organizations suggests the need to adapt management plans. Approximately a billion people live in the areas classified as vulnerable.     

Climate-induced changes in the vegetation pattern of China in the 21st century

Quantifying climate-induced changes in vegetation patterns is essential to understanding land–climate interactions and ecosystem changes. In the present study, we estimated various distributional changes of vegetation under different climate-change scenarios in the 21st century. Both hypothetical scenarios and Hedley RCM scenarios show that the transitional vegetation types, such as shrubland and grassland, have higher sensitivity to climatic change compared to vegetation under extreme climatic conditions, such as the evergreen broadleaf forest or desert, barren lands. Mainly, the sensitive areas in China lie in the Tibetan Plateau, Yunnan-Guizhou Plateau, northeastern plain of China and eco-zones between different vegetations. As the temperature increases, mixed forests and deciduous broadleaf forests will shift towards northern China. Grassland, shrubland and wooded grassland will extend to southeastern China. The RCM-project climate changes generally have caused positive vegetation changes; vegetation cover will probably improve 19% relative to baseline, and the forest will expand to 8% relative to baseline, while the desert and bare ground will reduce by about 13%.     

Modelling the vegetation of China using the process-based equilibrium terrestrial biosphere model BIOME3

1 We model the potential vegetation and annual net primary production (NPP) of China on a 10′ grid under the present climate using the processed‐based equilibrium terrestrial biosphere model BIOME3. The simulated distribution of the vegetation was in general in good agreement with the potential natural vegetation based on a numerical comparison between the two maps using the ΔV statistic (ΔV = 0.23). Predicted and measured NPP were also similar, especially in terms of biome‐averages. 2 A coupled ocean–atmosphere general circulation model including sulphate aerosols was used to drive a double greenhouse gas scenario for 2070–2099. Simulated vegetation maps from two different CO₂ scenarios (340 and 500 p.p.m.v.) were compared to the baseline biome map using ΔV. Climate change alone produced a large reduction in desert, alpine tundra and ice/polar desert, and a general pole‐ward shift of the boreal, temperate deciduous, warm–temperate evergreen and tropical forest belts, a decline in boreal deciduous forest and the appearance of tropical deciduous forest. The inclusion of CO₂ physiological effects led to a marked decrease in moist savannas and desert, a general decrease for grasslands and steppe, and disappearance of xeric woodland/scrub. Temperate deciduous broadleaved forest, however, shifted north to occupy nearly half the area of previously temperate mixed forest. 3 The impact of climate change and increasing CO₂ is not only on biogeography, but also on potential NPP. The NPP values for most of the biomes in the scenarios with CO₂ set at 340 p.p.m.v. and 500 p.p.m.v. are greater than those under the current climate, except for the temperate deciduous forest, temperate evergreen broadleaved forest, tropical rain forest, tropical seasonal forest, and xeric woodland/scrub biomes. Total vegetation and total carbon is simulated to increase significantly in the future climate scenario, both with and without the CO₂ direct physiological effect. 4 Our results show that the global process‐based equilibrium terrestrial biosphere model BIOME3 can be used successfully at a regional scale.     

Assessing the Spatiotemporal Variation in Distribution,Extent and NPP of Terrestrial Ecosystems in Response to Climate Change from 1911 to 2000

To assess the variation in distribution, extent, and NPP of global natural vegetation in response to climate change in the period 1911–2000 and to provide a feasible method for climate change research in regions where historical data is difficult to obtain. In this research, variations in spatiotemporal distributions of global potential natural vegetation (PNV) from 1911 to 2000 were analyzed with the comprehensive sequential classification system (CSCS) and net primary production (NPP) of different ecosystems was evaluated with the synthetic model to determine the effect of climate change on the terrestrial ecosystems. The results showed that consistently rising global temperature and altered precipitation patterns had exerted strong influence on spatiotemporal distribution and productivities of terrestrial ecosystems, especially in the mid/high latitudes. Ecosystems in temperate zones expanded and desert area decreased as a consequence of climate variations. The vegetation that decreased the most was cold desert (18.79%), while the maximum increase (10.31%) was recorded in savanna. Additionally, the area of tundra and alpine steppe reduced significantly (5.43%) and were forced northward due to significant ascending temperature in the northern hemisphere. The global terrestrial ecosystems productivities increased by 2.09%, most of which was attributed to savanna (6.04%), tropical forest (0.99%), and temperate forest (5.49%). Most NPP losses were found in cold desert (27.33%). NPP increases displayed a latitudinal distribution. The NPP of tropical zones amounted to more than a half of total NPP, with an estimated increase of 1.32%. The increase in northern temperate zone was the second highest with 3.55%. Global NPP showed a significant positive correlation with mean annual precipitation in comparison with mean annual temperature and biological temperature. In general, effects of climate change on terrestrial ecosystems were deep and profound in 1911–2000, especially in the latter half of the period.     

欧亚大陆植被生态系统平均中心时空偏移的情景模拟

欧亚大陆复杂多样的植被生态系统在全球气候变化的驱动下,其时空分布格局将发生系列的偏移变化,进而对欧亚大陆"一带一路"沿线国家和地区的生态环境产生重要影响。如何从全球气候变化驱动的角度来实现欧亚大陆植被生态系统时空偏移趋势的模拟分析,已成为"一带一路"沿线国家和地区生态环境研究的热点科学问题之一。在对HLZ生态系统模型进行改进和构建植被生态系统平均中心时空偏移分析模型的基础上,基于欧亚大陆的气候观测数据(1981—2010年)和CMIP5 RCP2.6、RCP4.5和RCP8.5三种情景数据(2011—2100年),实现欧亚大陆植被生态系统平均中心时空偏移趋势的模拟分析。结果表明:欧亚大陆植被生态系统平均中心主要分布在欧亚大陆的中部和南部地区;3种气候情景下,欧亚大陆的亚热带干旱森林、暖温带湿润森林、亚热带有刺疏林、亚热带潮湿森林、冷温带潮湿森林、寒温带湿润森林、冷温带湿润森林、亚热带湿润森林、暖温带干旱森林、亚极地/高山湿润苔原和极地/冰原等植被生态系统的平均中心偏移幅度大于其他植被生态系统类型;欧亚大陆植被生态系统在RCP8.5情景下的植被生态系统平均中心偏移幅度大于其他两种情景;在2011—2100年期间,3种气候变化情景下,欧亚大陆植被生态系统平均中心整体上将呈向北偏移的变化趋势。     

Simulated distribution of vegetation types in response to climate change on the Tibetan Plateau

Abstract. Questions: What is the relationship between alpine vegetation patterns and climate? And how do alpine vegetation patterns respond to climate changes? Location: Tibetan Plateau, southwestern China. The total area is 2500000 km² with an average altitude over 4000 m. Methods: The geographic distribution of vegetation types on the Tibetan Plateau was simulated based on climatology using a small set of plant functional types (PFTs) embedded in the biogeochemistry‐biography model BIOME4. The paleoclimate for the early Holocene was used to explore the possibility of simulating past vegetation patterns. Changes in vegetation patterns were simulated assuming continuous exponential increase in atmospheric CO concentration, based on a transient ocean‐atmosphere simulation including sulfate aerosol effects during the 21st century. Results: Forest, shrub steppe, alpine steppe and alpine meadow extended while no desert vegetation developed under the warmer and humid climate of the early Holocene. In the future climate scenario, the simulated tree line is farther north in most sectors than at present. There are also major northward shifts of alpine meadows and a reduction in shrub‐dominated montane steppe. The boundary between montane desert and alpine desert will be farther to the south than today. The area of alpine desert would decrease, that of montane desert would increase. Conclusions: The outline of changes in vegetation distribution was captured with the simulation. Increased CO2 concentration would potentially lead to big changes in alpine ecosystems.     

青藏高原植被生态系统垂直分布变化的情景模拟

如何模拟和揭示青藏高原植被生态系统垂直分布在全球气候变化驱动下的时空变化情景,对定量解析青藏高原陆地生态系统对气候变化响应效应具有重要意义。该论文基于Holdridge life zone （HLZ）模型,结合数字高程模型（DEM）数据,改变模型输入参数模式,发展了改进型HLZ生态系统模型。结合1981-2010（T0）时段的气候观测数据和IPCC CMIP5 RCP2.6、RCP4.5、RCP8.5三种情景2011-2040（T1）、2041-2070（T2）、2071-2100（T3）三个时段气候情景数据,实现了青藏高原植被生态系统垂直分布的时空变化情景模拟。引入生态系统平均中心时空偏移趋势模型和生态多样性指数模型,定量揭示了青藏高原植被生态系统在不同垂直带上的时空变化情景。结果显示：青藏高原共有16种植被生态系统类型;冰雪/冰原、高山潮湿苔原和亚高山湿润森林为青藏高原主要的植被生态系统类型,其面积之和占到了青藏高原总面积的56.26%;高山干苔原、亚高山潮湿森林、山地灌丛、山地湿润森林和荒漠等对气候变化的敏感性总体上高于其它类型;在T0-T3期间,青藏高原的高山湿润苔原、高山干苔原、荒漠呈持续减少趋势,平均每10年将分别减少1.96×10⁴km²、0.15×10⁴km²和1.58×10⁴km²;亚高山潮湿森林、山地湿润森林和山地灌丛呈持续增加趋势,平均每10年将分别增加3.42×10⁴km²、2.98×10⁴km²和1.19×10⁴km²;RCP8.5情景下青藏高原的植被生态系统平均中心的偏移幅度最大,RCP4.5情景下的偏移幅度次之,而RCP2.6情景下的偏移幅度最小。另外,在三种气候变化情景驱动下,青藏高原植被生态系统的生态多样性呈减少趋势。总之,未来不同情景的气候变化将直接影响青藏高原植被生态系统的时空分布格局及其生态多样性,气候变化强度越高,影响就越大,而且气候变化对青藏高原植被生态系统的影响呈现出从低海拔到高海拔递增的影响效应。     

An Ecogeographical Regionalization for Biodiversity in China

Ecogeographical regionalization is the basis for spatial differentiation of biodiversity research. In view of the principle of international ecogeographical regionalization, this study has applied multivariate analysis and GIS method and based on some ecogeographical attributes limited to the distribution of plant and vegetation, including climatic factors, such as minimum temperature, mean temperature of the coldest month, mean temperature of the wannest month, annual average temperature, precipitation of the coldest month, precipitation of the wannest month, annual precipitation, CV of annual precipitation, biological factors such as vegetation types, vegetation division types, NPP, fiorisitic types, fauna types, abundance of plant species, genus and endemic genus; soil factors such as soil types, soil pH;topographical factors as longitude, latitude and altitude etc. The ecogeographical regionalization for biodiversity in China was made synthetically by using fuzzy cluster method. Four classes of division were used, viz., biodomain, subbiodomain, biome and bioregion. Five biodomains, seven subbiodomains and eighteen biomes were divided in China as follows: Ⅰ Boreal forest biodomain. Ⅰ A Eurasian boreal forest subbiodomain. Ⅰ A1 Southern Taiga mountain cold-temperate coniferous forest biome; Ⅰ A2 North Asian mixed coniferous-broad-leaved forest biome. Ⅱ Northern steppe and desert biodomain. Ⅱ B Eurasian steppe subbiodomain. Ⅱ BI Inner Asian temperate grass steppe biome; Ⅱ B2 Loess Plateau warm-temperate forest/shmb steppe biome. Ⅱ C Asia-Mrica desert subbiodomain. Ⅱ C1 Mid-Asian temperate desert biome; Ⅱ C2 Mongolian/Inner Asian temperate desert biome. Ⅲ East Asian biodomain. Ⅲ D East Asian deciduous broad-leaved forest subbiodomain. Ⅲ D1 East Asian deciduous broad-leaved forest biome, Ⅲ E East Asian evergreen broad-leaved forest subbiodomain. Ⅲ El East Asian mixed deciduous-evergreen broad-leaved forest biome; Ⅲ E2 East Asian evergreen broad-leaved forest biome; Ⅲ E3 East Asian monsoon evergreen broad-leaved forest biome; Ⅲ FA Western East Asian mountain evergreen broadleaved forest biome. Ⅳ Palaeotropical subdomain. IV F India-Malaysian tropical forest subbiodomain.Ⅳ Fl Northern tropical rain forest/seasonal rain forest biome; Ⅳ F2 Tropical island coral reef vegetation biome. Ⅴ Asian plateau biodomain. Ⅴ G Tibet Plateau subbiodomain. Ⅴ G1 Tibet alpine highcold shrub meadow biome;Ⅴ G2 Tibet alpine high-cold steppe biome; Ⅴ G3 Tibet alpine high-cold desert biome; Ⅴ G4 Tibet alpine temperate steppe biome; Ⅴ G5 Tibet alpine temperate desert biome.     

未来气候变化情景下中国自然湿地CH4排放的时空变化

应用TRIPLEX GHG模型,模拟未来气候变化背景下2006—2100年中国自然湿地生态系统CH₄排放的时空变化.结果表明： 保持中国现有自然湿地分布不变,在3种相对浓度路径(RCP2.6、RCP4.5和RCP8.5）情境下,21世纪末,中国自然湿地CH₄排放量与当前水平相比将分别增长32.0%、55.3%和90.8%.中国大陆南方自然湿地CH₄排放高于中部和北方,且自西向东呈现上升趋势.CH₄高通量排放区域主要集中在长江中下游湿地、东北湿地和珠江沿岸湿地.RCP4.5和RCP8.5情境下全国大部分自然湿地CH₄排放通量增加,而RCP2.6情境下21世纪中后期CH₄排放上升趋势得到控制并开始下降,到世纪末部分地区（尤其是青藏高原地区）CH₄排放通量与当前水平相比有所降低.     

不同气候变化情景下2070-2099年中国潜在植被及其敏感性

潜在植被作为当前气候条件、无人类干扰下,所能发育演替形成的最稳定、最成熟的一种顶极植被类型,能够反映立地植被发展的趋势。潜在植被的研究有助于人类了解植被与气候系统的作用机制,可为区域植被恢复工程和生态建设提供参考依据。基于综合顺序分类系统,利用A1B、A2及B1情景下2070-2099年气象数据对中国潜在植被进行了模拟,在不同气候变化情景下分析了未来中国潜在植被的空间分布和潜在植被对不同气候变化的敏感性。结果表明:(1)不同气候变化背景下中国潜在植被分布的规律具有相似性,但潜在植被类在总数和各情景下分布的面积存在差异性;(2)比较发现,中国的气候条件在20世纪和21世纪均不适宜炎热极干热带荒漠类(ⅦA)的发育;(3)中国潜在植被在3种气候变化情景下表现为敏感性的区域占到国土总面积的64.10%,在西北地区、北方地区、南方地区及青藏地区不同自然区敏感性地区所占各区的比例不同,分别为68.20%、70.82%、49.94%及66.59%。     

未来气候变化情景下中国自然湿地CH4排放的时空变化

应用TRIPLEX GHG模型,模拟未来气候变化背景下2006—2100年中国自然湿地生态系统CH₄排放的时空变化.结果表明： 保持中国现有自然湿地分布不变,在3种相对浓度路径(RCP2.6、RCP4.5和RCP8.5）情境下,21世纪末,中国自然湿地CH₄排放量与当前水平相比将分别增长32.0%、55.3%和90.8%.中国大陆南方自然湿地CH₄排放高于中部和北方,且自西向东呈现上升趋势.CH₄高通量排放区域主要集中在长江中下游湿地、东北湿地和珠江沿岸湿地.RCP4.5和RCP8.5情境下全国大部分自然湿地CH₄排放通量增加,而RCP2.6情境下21世纪中后期CH₄排放上升趋势得到控制并开始下降,到世纪末部分地区（尤其是青藏高原地区）CH₄排放通量与当前水平相比有所降低.     

Climate change‐induced vegetation shifts lead to more ecological droughts despite projected rainfall increases in many global temperate drylands

Drylands occur worldwide and are particularly vulnerable to climate change because dryland ecosystems depend directly on soil water availability that may become increasingly limited as temperatures rise. Climate change will both directly impact soil water availability and change plant biomass, with resulting indirect feedbacks on soil moisture. Thus, the net impact of direct and indirect climate change effects on soil moisture requires better understanding. We used the ecohydrological simulation model SOILWAT at sites from temperate dryland ecosystems around the globe to disentangle the contributions of direct climate change effects and of additional indirect, climate change‐induced changes in vegetation on soil water availability. We simulated current and future climate conditions projected by 16 GCMs under RCP 4.5 and RCP 8.5 for the end of the century. We determined shifts in water availability due to climate change alone and due to combined changes of climate and the growth form and biomass of vegetation. Vegetation change will mostly exacerbate low soil water availability in regions already expected to suffer from negative direct impacts of climate change (with the two RCP scenarios giving us qualitatively similar effects). By contrast, in regions that will likely experience increased water availability due to climate change alone, vegetation changes will counteract these increases due to increased water losses by interception. In only a small minority of locations, climate change‐induced vegetation changes may lead to a net increase in water availability. These results suggest that changes in vegetation in response to climate change may exacerbate drought conditions and may dampen the effects of increased precipitation, that is, leading to more ecological droughts despite higher precipitation in some regions. Our results underscore the value of considering indirect effects of climate change on vegetation when assessing future soil moisture conditions in water‐limited ecosystems.     

再论中国植被分区的原则和方案

 本文首先提出中国植被分区的原则和依据以及高级分区单位的标志,将全国划分为八大植被区,其中有五个区包括两个亚区,因作者主张亚区与区作为同一级的辅助单位看待,所以实际上把全国分为13个高级植被分区单位。除少数例外,每一植被区或亚区都分为一过渡带和典型带。全文以植被区或亚区、植被地带或亚地带为单位,论述其植被特点。     

Climatic thresholds shape northern high‐latitude fire regimes and imply vulnerability to future climate change

Boreal forests and arctic tundra cover 33% of global land area and store an estimated 50% of total soil carbon. Because wildfire is a key driver of terrestrial carbon cycling, increasing fire activity in these ecosystems would likely have global implications. To anticipate potential spatiotemporal variability in fire‐regime shifts, we modeled the spatially explicit 30‐yr probability of fire occurrence as a function of climate and landscape features (i.e. vegetation and topography) across Alaska. Boosted regression tree (BRT) models captured the spatial distribution of fire across boreal forest and tundra ecoregions (AUC from 0.63–0.78 and Pearson correlations between predicted and observed data from 0.54–0.71), highlighting summer temperature and annual moisture availability as the most influential controls of historical fire regimes. Modeled fire–climate relationships revealed distinct thresholds to fire occurrence, with a nonlinear increase in the probability of fire above an average July temperature of 13.4°C and below an annual moisture availability (i.e. P‐PET) of approximately 150 mm. To anticipate potential fire‐regime responses to 21st‐century climate change, we informed our BRTs with Coupled Model Intercomparison Project Phase 5 climate projections under the RCP 6.0 scenario. Based on these projected climatic changes alone (i.e. not accounting for potential changes in vegetation), our results suggest an increasing probability of wildfire in Alaskan boreal forest and tundra ecosystems, but of varying magnitude across space and throughout the 21st century. Regions with historically low flammability, including tundra and the forest–tundra boundary, are particularly vulnerable to climatically induced changes in fire activity, with up to a fourfold increase in the 30‐yr probability of fire occurrence by 2100. Our results underscore the climatic potential for novel fire regimes to develop in these ecosystems, relative to the past 6000–35 000 yr, and spatial variability in the vulnerability of wildfire regimes and associated ecological processes to 21st‐century climate change.     

水热积指数的估算及其在中国植被与气候关系研究中的应用

试图利用大气年平均气温、年降水量、可能蒸散和土壤水分平衡之间的关系建立一个水热积指数,并应用年平均气温、年土壤水分盈亏值和水热积指数三个气候变量来限定植物群落组合,构成一个圆形的生命-气候图式。根据全国689个标准气象台站的气候资料,计算了中国8个植被地带和26个亚地带的年平均气温、年土壤水分盈亏和水热积指数,绘制了各气候指标在中国的分布图及散点图,较好表现了中国各植被类型与气候指标的关系和格局,包括寒温带针叶林、冷温带针阔叶混交林、暖温带落叶阔叶林、亚热带常绿阔叶林、热带雨林和季雨林、温带草原、温带荒漠、青藏高原高寒植被,并得到了中国各植被地带的气候指标范围及界限。通过分析可以看出,年平均气温的等值线较好地反映了中国大陆的热量梯度,经度和纬度方向的区分均较明显;年土壤水分盈亏曲线的等值线则比较零乱;综合了热量和水分差异的水热积指数等值线与热量梯度和水分梯度均有一定的对应性,与植被类型的对应也较好。这是在宏观尺度上进行的植被与气候关系研究的一种尝试。     

植被气候关系与我国的植被分区

气候制约着植被的地理分布,植被是区域气候特征的反映和指示,两者之间存在密不可分的联系.揭示植被与气候之间的关系是正确认识植被分布的前提,是进行植被区划的理论基础.植被区划是植被研究的归纳和总结,是其他自然地理区划和农林业区划的基础.本文在简要回顾中国植被气候关系及植被分区的研究历史的基础上,对我国以往的主要植被分区原则、依据和方案进行了评述,对有争议的主要植被界线进行了讨论.我们认为,在当今我国大部分地区的原生植被已遭到破坏的现实情况下,根据原生植被及其衍生植被类型的分布,确定其分布与限制性气候因子的关系,以此来进行植被带(区)的划分,不仅反映植被气候间密不可分的关系,在实践上也便于操作.尽管在一些植被带的命名、具体界线的划定上有分歧,但最近的中国植被分区方案大都认为我国基本的植被区有8至9个,即针叶林、针阔叶混交林、落叶阔叶林、常绿落叶阔叶混交林、常绿阔叶林以及雨林季雨林、草原、荒漠以及高寒植被.通过分析主要植被带附近的植被、气候等特征,本文认为,1)秦岭淮河线是一条重要的水分气候带,而不是温度带,不是亚热带植被的北界;2)我国亚热带植被的北界基本上沿长江北岸,从杭州湾经太湖、安徽宣城、铜陵经大别山南坡到武汉往西,与WI值130-140 ℃·月一致;3)我国热带区域的面积极小,仅分布在海南岛的东南部和台湾南端及其以南地区; 4) 我国东部地区暖温带的水热条件南北差异甚大,建议以秦岭淮河为界,将暖温带划分为两个植被带,即落叶阔叶疏林带和落叶常绿阔叶混交林带;华北地区的地带性植被为落叶阔叶疏林.最后,本文还强调了对应于气候变化进行动态植被分区的重要性.     

气候变化对我国南方人工林地上生物量影响的模拟研究——以会同生态站磨哨实验林场为例

全球气候变暖对陆地生态系统尤其是森林生态系统有着重要的影响,气温升高、辐射强迫的增强将显著改变森林生态系统的结构和功能.南方人工林作为我国森林的重要组成部分,对气候变化的响应日益强烈.为了探究未来气候情景下我国南方人工林对气候变化的响应,降低未来气候变化对人工林可能带来的损失,本研究采用3种最新的气候情景—典型浓度排放路径情景(RCP2.6情景、RCP4.5情景、RCP8.5情景)预估数据,应用生态系统过程模型PnET-Ⅱ和空间直观景观模型LANDIS-Ⅱ模拟2014—2094年间湖南省会同森林生态实验站磨哨实验林场森林的地表净初级生产力(ANPP)、物种建立可能性(SEP)和地上生物量的变化.结果表明: 不同森林类型的SEP和ANPP对气候变化的响应有明显的差异,各森林类型对气候变化的响应程度表现为: 对于SEP,在RCP2.6和RCP4.5情景下,人工针叶林＞天然阔叶林＞人工阔叶林;在RCP8.5情景下,天然阔叶林＞人工阔叶林＞人工针叶林.对于ANPP,在RCP2.6情景下,人工阔叶林＞天然阔叶林＞人工针叶林;在RCP4.5和RCP8.5情景下,天然阔叶林＞人工阔叶林＞人工针叶林.人工针叶林的地上生物量在2050年左右开始下降,天然阔叶林和人工阔叶林整体呈现上升趋势.2014—2094年,研究区地上总生物量在不同气候情景下增加幅度不同,RCP2.6情景下增加了68.2%,RCP4.5情景下增加了79.3%,RCP8.5情景下增加了72.6%.3种情景下的总地上生物量大小排序为: RCP4.5> RCP8.5> RCP2.6.我们认为,适当的增温将有助于未来研究区森林总地上生物量的积累,但过度的增温也可能会阻碍森林的生产和生态功能的持续发展.     

4个常用的气候-植被分类模型对中国植被分布模拟的比较研究

 应用KAPPA一致性检验方法,比较研究了4个常用的气候植被分类模型：Penman模型、Holdridge生命地带系统、Kira模型和Thornthwaite模型对中国植被分布模拟的一致性和适用性。结果表明：这4个常用的气候 植被分类模型对中国植被区划一级分类的植被地理分布模拟效果较好。其中,Holdridge生命地带系统的KAPPA值达到0.57,模拟效果优于其它三者。但对特定地区,如青藏高原的植被地理分布,所有模型均需改进或引入新的影响因子才能较好地模拟二级植被区划的植被地理分布。1)Penman模型对温带草原和青藏高原的植被地理分布模拟的KAPPA值超过0.50,是4个模型中对青藏高原植被地理分布模拟效果最好的。2)Thornthwaite模型对热带雨林、季雨林植被地理分布模拟的KAPPA值达到0.40,可以弥补Holdridge生命地带系统对热带植被地理分布模拟精度的不足。3) Holdridge生命地带系统对中国植被地理分布模拟的效果最佳,但对西部季雨林、雨林区域(52)、西部草原亚区域(63)、青藏高原温性荒漠地带(86)和温性草原地带(84)的模拟程度不理想。4)Kira模型对亚热带常绿阔叶林植被地理分布的模拟效果可与Holdridge生命地带系统相媲美;对低海拔和湿润、湿润地区植被地理分布的模拟效果尚可,但在温带荒漠区与青藏高原区植被地理分布的模拟效果与实际相差较远。