我国森林植被的生物量和净生产量

利用森林蓄积量推算森林生物量和净生产量的方法,系统研究了我国森林植被的生物生产力。结果表明,我国森林生物生产力的地理分布规律与世界总趋势一致,但量上有差异,具体表现在：我国森林生物量的平均值小于世界平均水平,而净生产量却显得较高;我国森林的总生物量是９１０２．８７×１０６ｔ,其中,林分为８５９２．１３×１０６ｔ,经济林３２５．７２×１０６ｔ;竹林１８５．０２×１０６ｔ,疏林、灌木林７９０．５４×１０６ｔ;森林和疏林（含灌木林）的总生产力分别是１１７７．３１×１０６ｔ／ａ和４５８．１６×１０６ｔ／ａ。研究结果还显示,用材积推算的生物量（材积源生物量）比用平均生物量计算的结果更符合实际。分析中国森林在中国及全球陆地碳库中的作用发现,与其他区域和世界平均水平相比较,中国森林在中国陆地植被中所起的主导作用较弱,它的生物量不足全球森林总生物量的１％,然而,它在保护中国土壤碳库功能方面起着其他植被类型所无法替代的作用。     

青藏高原各主要植被类型特征及环境差异

青藏高原高海拔引起的地形、气候和土壤空间差异造就了其独特的植被类型及其空间变化,当前研究缺乏针对青藏高原全域范围内各植被类型特征和环境差异的定量与系统性分析。针对青藏高原特殊的地理环境和植被类型,选用植被、地形、土壤、气候4个维度共计58个空间化指标,采用频数分布统计方法对这些指标开展了定量分析,系统揭示了青藏高原全域范围内各主要植被类型的特征及环境差异。通过定量分析发现,大部分的环境及植被特征指标对青藏高原各主要植被类型的区分度较高,其中,遥感归一化植被指数、植被净初级生产力、裸地覆盖度、海拔、土壤温度、年最低温度、年总蒸散发7个指标对青藏高原各主要植被类型的区分度较高。揭示的青藏高原各主要植被类型的特征及环境差异,可提高灌丛和草地之间、各草地类型之间、高山苔原-垫状-稀疏植被与其他植被类型之间的可区分性,有助于解决青藏高原植被精细分类中广泛存在的灌丛和草地区分、草地类型细分、高山苔原-垫状-稀疏植被识别和山地垂直地带植被识别四个难点问题。研究结果一方面可服务于青藏高原的植被精细分类,另一方面也可服务于青藏高原的自然地带划分、生物多样性和生态系统功能评估、地表物质循环研究等。     

雾灵山蒙古栎林生物生产量的研究

雾灵山蒙古栎林生物生产量的研究王德艺蔡万波李东义冯学全（河北农业大学林学院,保定０７１０００）（雾灵山国家级自然保护区,兴隆县０６７３００）冯天杰李永宁（河北农业大学林学院,保定０７１０００）ＳｔｕｄｙｏｆＢｉｏｍａｓａｎｄＰｒｏｄｕｃｔｉｏｎｏｆ...     

青藏高原高山植被的初步研究

青藏高原是我国高山植被类型最丰富、独特和分布最广泛的区域,发育有大面积的高山灌丛、高寒草甸、高寒草原,高寒荒漠、高山流石坡稀疏植被及零散分布的高山垫状植被。它们占据着森林上线至永久雪线之间的高山带和广阔的高原面,从高原东南部至西北部有水平方向的地域分异。联系高山带以下各垂直带的植被特征及各地的气候条件分析,初步认为高原东南部的山地植被垂直带谱属于湿润型山地垂直带结构类型,高原腹地及西北部的山地植被垂直带谱属于干旱型山地垂直带结构类型。此外,还对青藏高原高山植被类型的丰富性及高山垫状植被的生态地理分布特点进行了初步探讨。     

泰国森林植被的主要类型

泰国的主要森林植被大致可分为常绿林和落叶林两大类（森林植被型组）和热带雨林、山地常绿林、半常绿林、针叶林、红树林、干旱龙脑香林及落叶混交林等七亚类（森林植被型）．本文简要阐述了各类森林的地理分布、层次结构和主要树种组成．     

百山祖自然保护区主要植被类型概述

对近20年来多次调查的资料进行系统整理,将百山祖植被主要划分成6个植被类型：常绿阔叶林、常绿落叶阔叶混交林、针阔叶混交林、针叶林、山地矮林和山地灌草丛,其下可分为22个群系：同时对群落的种类组成、结构和演替趋势作了概述。。     

贡嘎山地区主要植被类型的分布

贡嘎山位于青藏高原东南缘横断山系大雪山脉中段,主峰海拔高7556m。该地区有维管束植物185科,869属,约2500种。其植物区系特点为：区系成分起源古老;物种分化显著,特有种丰富;成分复杂,地理替代明显。贡嘎山主要植被类型有：冷杉、云杉组成的亚高山针叶林;松、铁杉组成的中山针叶林;松、杉、柏、油杉组成的低山针叶林;铁杉、桦木、槭树组成的针叶,阔叶混交林;樟、楠、阔楠、石栎,青冈等组成的常绿阔叶林;栎、桦、槭、杨、桤等组成的落叶阔叶林;高山栎类组成的硬叶常绿阔叶林;杜鹃、柳、圆柏等组成的高山灌丛;仙人掌(Opuntia monacantha)、金合欢、羊蹄甲等组成的河谷灌丛;嵩草(Kobresia)、羊茅(Festuca ovina), 韭和风毛菊、绢毛菊、绵参(Eriophyton wallichii)等组成的高山草甸与高山流石滩稀疏植被。贡嘎山地区水平地带性植被为常绿阔叶林,它兼有我国亚热带东部和西部常绿阔叶林的特点。 贡嘎山东坡植被垂直带谱是：1．常绿阔叶林带,海拔1100—2200m。2．山地针叶、阔叶混交林带,2200—2500m。3．亚高山针叶林带,2500—3600m。4．高山灌丛草甸带,2600—4600m。5．高山流石滩稀疏植被带,4600—4900m。6．永久冰雪带,海拔4900m以上。贡嘎山西坡植被垂直带谱是：1．亚高山针叶林带,海拔2800一4000m。2．高山灌丛草甸带,4000—4800m。3．高山流右滩稀疏植被带,4800—5100m。4．永久冰雪带,海拔5100m以上。     

贡嘎山地区主要植被类型和分布

贡嘎山位于青藏高原东南缘横断山系大雪山脉中段,主峰海拔高7556m。该地区有维管束植物185科,869属,约2500种。其植物区系特点为:区系成分起源古老;物种分化显著,特有种丰富;成分复杂,地理替代明显。贡嘎山主要植被类型有:冷杉、云杉组成的亚高山针叶林;松、铁杉组成的中山针叶林;松、杉、柏、油杉组成的低山针叶林;铁杉、桦木、槭树组成的针叶、阔叶混交林;樟、楠、阔楠、石栎、青冈等组成的常绿阔叶林;栎、桦、槭、杨、桤等组成的落叶阔叶林;高山栎类组成的硬叶常绿阔叶林;杜鹃、柳、圆柏等组成的高山灌丛;仙人掌(Opuntia monacantha)、金合欢、羊蹄甲等组成的河谷灌丛;嵩草(Kobresia)、羊茅(Festuca ovina)、韭和风毛菊、绢毛菊、绵参(Eriophyton wallichii)等组成的高山草甸与高山流石滩稀疏植被。贡嘎山地区水平地带性植被为常绿阔叶林,它兼有我国亚热带东部和西部常绿阔叶林的特点。贡嘎山东坡植被垂直带谱是:1.常绿阔叶林带,海拔1100—2200m。2.山地针叶、阔叶混交林带,2200—2500m。3.亚高山针叶林带,2500—3600m。4.高山灌丛草甸带,3600—4600m。5.高山流石滩稀疏植被带,4600—4900m。6.永久冰雪带,海拔4900m以上。贡嘎山西坡植被垂直带谱是:1.亚高山针叶林带,海拔2800—4000m。2.高山灌丛草甸带,4000—4800m。3.高山流石滩稀疏植被带,4800—5100m。4.永久冰雪带,海拔5100m以上。     

华南南亚热带植被第一性生产量的影响因素及预测模型

讨论植被类型、降雨、湿度、土壤条件对华南南亚热带植被第一性生产量的影响。比较各种预测第一性生产量的气候模型,为更好地预测和提高华南南亚热带植被第一性生产量提供依据。     

Reassessment of Holocene vegetation change on the upper Tibetan Plateau using the pollen-based REVEALS model

Previous studies based on fossil pollen data have reported significant changes in vegetation on the alpine Tibetan Plateau during the Holocene. However, since the relative proportions of fossil pollen taxa are largely influenced by individual pollen productivities and the dispersal characteristics, such inferences on vegetation have the potential to be considerably biased. We therefore examined the modern pollen–vegetation relationships for four common pollen species on the Tibetan Plateau, using Extended R-value (ERV) models. Assuming an average radius of 100 m for the sampled lakes, we estimated the relevant source area of pollen (RSAP) to be 2200 m (which represents the distance from the lake). Using Poaceae as the reference taxa (Pollen Productivity Estimate, PPE = 1), ERV Submodel 2 derived relative high PPEs for the steppe and desert taxa: 2.079 ± 0.432 for Artemisia and 5.379 ± 1.077 for Chenopodiaceae. Low PPEs were estimated for the Cyperaceae (1.036 ± 0.012), whose plants are characteristic of the alpine Kobresia meadows. Applying these PPEs to four fossil pollen sequences since the Late Glacial, the plant abundances on the central and north-eastern Tibetan Plateau were quantified using the “Regional Estimates of Vegetation Abundance from Large Sites” (REVEALS) model. The proportions of Artemisia and Chenopodiaceae were greatly reduced compared to their original pollen percentages in the reconstructed vegetation, owing to their high productivities and their dispersal characteristics, while Cyperaceae showed a relative increase in the vegetation reconstruction. The reconstructed vegetation assemblages of the four pollen sequence sites always yielded smaller compositional species turnovers than suggested by the pollen spectra, as revealed by Detrended Canonical Correspondence Analyses (DCCA) of the Holocene sections. The strength of the previously reported vegetation changes may therefore have been overestimated, which indicates the importance of taking into account pollen–vegetation relationships when discussing the potential drivers (such as climate, land use, atmospheric CO₂ concentrations) and implications (such as for land surface–climate feedbacks, carbon storage, and biodiversity) of vegetation change.     

Precipitation impacts on vegetation spring phenology on the Tibetan Plateau

The ongoing changes in vegetation spring phenology in temperate/cold regions are widely attributed to temperature. However, in arid/semiarid ecosystems, the correlation between spring temperature and phenology is much less clear. We test the hypothesis that precipitation plays an important role in the temperature dependency of phenology in arid/semiarid regions. We therefore investigated the influence of preseason precipitation on satellite‐derived estimates of starting date of vegetation growing season (SOS) across the Tibetan Plateau (TP). We observed two clear patterns linking precipitation to SOS. First, SOS is more sensitive to interannual variations in preseason precipitation in more arid than in wetter areas. Spatially, an increase in long‐term averaged preseason precipitation of 10 mm corresponds to a decrease in the precipitation sensitivity of SOS by about 0.01 day mm^?1. Second, SOS is more sensitive to variations in preseason temperature in wetter than in dryer areas of the plateau. A spatial increase in precipitation of 10 mm corresponds to an increase in temperature sensitivity of SOS of 0.25 day °C^?1 (0.25 day SOS advance per 1 °C temperature increase). Those two patterns indicate both direct and indirect impacts of precipitation on SOS on TP. This study suggests a balance between maximizing benefit from the limiting climatic resource and minimizing the risk imposed by other factors. In wetter areas, the lower risk of drought allows greater temperature sensitivity of SOS to maximize the thermal benefit, which is further supported by the weaker interannual partial correlation between growing degree days and preseason precipitation. In more arid areas, maximizing the benefit of water requires greater sensitivity of SOS to precipitation, with reduced sensitivity to temperature. This study highlights the impacts of precipitation on SOS in a large cold and arid/semiarid region and suggests that influences of water should be included in SOS module of terrestrial ecosystem models for drylands.     

青藏高原植被退化对高原及周边地区大气环流的影响

利用耦合了陆面模式的大气环流模式,结合青藏高原植被退化的范围和程度,通过在模式中修改高原地区(27°—40°N,75°—100°E)的叶面积指数的方法,探讨了植被退化以后对高原及其附近地区上空大气环流的影响。结果表明,该模式对高原地表温度场具有很强的模拟能力,并且能够很好地模拟出青藏高原及附近地区夏季位势高度场的平均特征及南亚高压的位置和强度,但南亚高压中心强度偏大且略微西退。在青藏高原植被出现退化以后,高原整体地表土壤温度和地表2 m空气温度升高,感热通量增加、潜热通量减小,进而改变了高原地区的波文比。地表感热增加导致高原及附近地区500 h Pa高度场降低和200 h Pa高度场升高,并在200 h Pa上存在强大的反气旋性环流异常,导致南亚高压增强和北扩东伸。植被退化造成的青藏高原感热增加导致了高原南部上升运动增强和北部上升运动减弱,同时又引起高原以北地区下沉气流的影响范围扩大,而下沉气流的强度减弱,其结果有助于高原以北的干旱范围扩大,而干旱程度却得到缓解。     

Modern pollen samples from alpine vegetation on the Tibetan Plateau

• 1 A set of 316 modern surface pollen samples, sampling all the alpine vegetation types that occur on the Tibetan Plateau, has been compiled and analysed. Between 82 and 92% of the pollen present in these samples is derived from only 28 major taxa. These 28 taxa include examples of both tree (AP) and herb (NAP) pollen types.
• 2 Most of the modern surface pollen samples accurately reflect the composition of the modern vegetation in the sampling region. However, airborne dust‐trap pollen samples do not provide a reliable assessment of the modern vegetation. Dust‐trap samples contain much higher percentages of tree pollen than non‐dust‐trap samples, and many of the taxa present are exotic. In the extremely windy environments of the Tibetan Plateau, contamination of dust‐trap samples by long‐distance transport of exotic pollen is a serious problem.
• 3 The most characteristic vegetation types present on the Tibetan Plateau are alpine meadows, steppe and desert. Non‐arboreal pollen (NAP) therefore dominates the pollen samples in most regions. Percentages of arboreal pollen (AP) are high in samples from the southern and eastern Tibetan Plateau, where alpine forests are an important component of the vegetation. The relative importance of forest and non‐forest vegetation across the Plateau clearly follows climatic gradients: forests occur on the southern and eastern margins of the Plateau, supported by the penetration of moisture‐bearing airmasses associated with the Indian and Pacific summer monsoons; open, treeless vegetation is dominant in the interior and northern margins of the Plateau, far from these moisture sources.
• 4 The different types of non‐forest vegetation are characterized by different modern pollen assemblages. Thus, alpine deserts are characterized by high percentages of Chenopodiaceae and Artemisia, with Ephedra and Nitraria. Alpine meadows are characterized by high percentages of Cyperaceae and Artemisia, with Ranunculaceae and Polygonaceae. Alpine steppe is characterized by high abundances of Artemisia, with Compositae, Cruciferae and Chenopodiaceae. Although Artemisia is a common component of all non‐forest vegetation types on the Tibetan Plateau, the presence of other taxa makes it possible to discriminate between the different vegetation types.
• 5 The good agreement between modern vegetation and modern surface pollen samples across the Tibetan Plateau provides a measure of the reliability of using pollen data to reconstruct past vegetation patterns in non‐forested areas.

     

Agriculturally induced vegetation change, 1950–1975

Changes in worldwide grain production area are analyzed to assess the impact of major agricultural activity onglobal biomass. During the 26-year study period, nearly 1% of the earth's ice-free land surface was converted to grain production. This increase in agricultural area reduced the planetary biomass; however, it had minimal effect on net primary productivity. Geographically, the overall change caused by increased grain production has been to redistribute the planetary biomass poleward.     

陕北黄土高原植被净初级生产力的估算

基于MODIS和地面气象数据,利用改进的CASA模型,模拟分析了2005年陕北黄土高原地区的植被净初级生产力(NPP)及其时空分布.结果表明:1)根据生态生理过程模型针对不同土地覆被类型选择不同的月平均最大光能利用率,比传统CASA模型中使用固定的全球月平均最大光能利用率进行NPP估算,更符合陕北黄土高原地区的实际情况;在估算植被参数时引入植被覆盖分类,以及利用陕北黄土高原2005年时序NDVI进行土地覆被分类的同时,结合1:100万中国植被图和实地调查情况对分类结果进行修正,可提高分类的精度,从而提高模型估算的精度.2)通过不同模型之间和与陕北部分地区实际调查数据进行比较,显示改进后的CASA模型对区域陆地植被NPP的模拟效果较好,可应用于陕北黄土高原乃至周边地区NPP的计算中.3)2005年陕北黄土高原植被净第一性生产量估计值为4.76×10~(13) g C,约占全国总NPP的1.5%,植被平均NPP为447.3 g C·m~(-2)·a~(-1),高于1992-2000年全国陆地NPP平均值323.8 g C·m~(-2)·a~(-1).4)在NPP的空间分布上,总体趋势是由东南向西北递减,其中最高值出现在东南部的黄龙山次生林区(1087g C·m~(-2)·a~(-1));西北部的荒漠植被覆盖度极低,平均NPP仅为205.0 g C·m~(-2)·a~(-1).5)陕北黄土高原NPP的季节变化明显,其中4月中旬至10月中旬6个月生长季时间里的NPP可占到全年的91.5%,而7月中旬至8月中旬间该区的净初级生产力达到年内的极大值,可占全年的37.8%.

Abstract：

Based on the data from MODIS (Moderate-resolution Imaging Speetroradiometer) and meteorological observatories, and by using improved CASA (Carnegie-Ames-Stanford Approach) model, the vegetation net primary productivity (NPP) and its spatiotemporal distribution on the North Shaanxi Loess Plateau in 2005 were simulated and analyzed. Comparing with the traditional CASA model which only uses a universal mean annual maximum light use efficiency (LUE), the estimated regional NPP by the improved CASA model was more precise, because this improved model used the LUE parameters of different vegetation covers. The detailed land cover classifica-tion also contributed to the increase of the precision via introducing the time-series Normalized Different Vegetation Index (NDVI) and ground survey data to modify and adjust the original clas-sification system based on vegetation map (1: 1000000). The testing of the simulation results from different models with the ground survey data in North Shaanxi showed that the estimation by the modified CASA model was much closer to the real survey data, implying the potential practi-cal significance of this model in estimating the vegetation NPP in North Shaanxi Loess Plateau and its adjacent areas. In 2005, the NPP in North Shaanxi was estimated as 4. 76×1013 g C, ac-counting for about 1.5% of China' s terrestrial total NPP, and the mean NPP was 447.3 g C·m~(-2)·a~(-1), being much higher than that of China' s terrestrial vegetation (323.8 g C·m~(-2)·a~(-1)) in 1982-2000. The spatial distribution pattern of the vegetation NPP showed an apparently declining trend from the southeast to the northwest, with the highest value of 1087 g C·m~(-2)a~(-1) occurred in the broadleaved-and conifer-mixed forests of Huanglong Mountain in southeast part of the region. The mean NPP of desert vegetation in the whole region was the lowest, only about 205.0 g C·m~(-2) ·a~(-1). An obvious seasonal variation of the NPP was observed. The NPP in growth season (from April to October) took about 91.5% of the total in the year, and the peak occurred in mid-July to mid-August, amounting to 37.8% of the total.     

Estimation of aboveground biomass using in situ hyperspectral measurements in five major grassland ecosystems on the Tibetan Plateau

Aims There are numerous grassland ecosystem types on the Tibetan Plateau. These include the alpine meadow and steppe and degraded alpine meadow and steppe. This study aimed at developing a method to estimate aboveground biomass (AGB) for these grasslands from hyperspectral data and to explore the feasibility of applying air/satellite-borne remote sensing techniques to AGB estimation at larger scales.Methods We carried out a field survey to collect hyperspectral reflectance and AGB for five major grassland ecosystems on the Tibetan Plateau and calculated seven narrow-band vegetation indices and the vegetation index based on universal pattern decomposition (VIUPD) from the spectra to estimate AGB. First, we investigated correlations between AGB and each of these vegetation indices to identify the best estimator of AGB for each ecosystem type. Next, we estimated AGB for the five pooled ecosystem types by developing models containing dummy variables. At last, we compared the predictions of simple regression models and the models containing dummy variables to seek an ecosystem type-independent model to improve prediction of AGB for these various grassland ecosystems from hyperspectral measurements.Important findings When we considered each ecosystem type separately, all eight vegetation indices provided good estimates of AGB, with the best predictor of AGB varying among different ecosystems. When AGB of all the five ecosystems was estimated together using a simple linear model, VIUPD showed the lowest prediction error among the eight vegetation indices. The regression models containing dummy variables predicted AGB with higher accuracy than the simple models, which could be attributed to the dummy variables accounting for the effects of ecosystem type on the relationship between AGB and vegetation index (VI). These results suggest that VIUPD is the best predictor of AGB among simple regression models. Moreover, both VIUPD and the soil-adjusted VI could provide accurate estimates of AGB with dummy variables integrated in regression models. Therefore, ground-based hyperspectral measurements are useful for estimating AGB, which indicates the potential of applying satellite/airborne remote sensing techniques to AGB estimation of these grasslands on the Tibetan Plateau.     

青藏高原植被覆盖时空变化及其对气候因子的响应

研究青藏高原植被覆盖时空分布特征对加深气候变化的认识及生态环境保护具有重要的生态价值和现实意义。利用2000—2016年MODIS NDVI 1km/月分辨率数据以及气象观测数据,采用最大合成法、趋势性分析以及相关分析方法,探讨了不同时间尺度青藏高原地区NDVI的分布特征及其与降水、气温的关系。结果表明:(1)青藏高原东南部植被状况明显好于西北部,植被覆盖的分布格局与区域水热条件的时空分布保持了较好的一致性;近17年来青藏高原植被覆盖改善的地区要比退化的地区面积大,严重退化的区域主要位于青藏高原西南部;青藏高原NDVI值在2000—2016年呈幅度较小的增加趋势。(2)除夏季降水量外,研究时段内其他季节降水量均呈增加趋势;气温均呈增加趋势,尤其以春季增加最为显著,整体上青藏高原气候呈现"暖湿化"趋势。总体上年降水量与年最大合成NDVI呈较好的正相关;年平均气温与年最大合成NDVI在高原东南部呈正相关,西南部呈负相关。降水量和热量条件均是高原植被生长的影响因素,降水与植被覆盖的影响较气温密切。     

青藏高原草地生态系统对气候变化的响应

青藏高原高寒草地生态系统对气候变化高度敏感,其如何响应和反馈气候变化一直以来受到极大关注.本文系统综述了近5年来有关青藏高原草地生态系统在物候、生产力、碳循环等方面对气候变化的响应过程以及应对气候变化的适应性管理的最新研究成果,发现气候变化对高寒草地生态系统的诸多影响还存在很大的不确定性.多数研究结果表明,增温使高寒草甸的植被物候提前和初级生产力水平提高,而高寒草原有相反的影响趋势,说明不同地域、不同群落类型对不同季节温度变化的响应模式不同.而气候变化对物种多样性和碳循环有关过程的影响结果尚没有一致的结论,时空尺度和方法上的差异可能是导致不同结果的主要原因.因此,建议在增强时空异质性的响应与反馈研究的同时,更需要加强生态过程和机理的研究.     

青藏高原微生物多样性研究

正青藏高原被誉为世界屋脊,其内部除平原外还有许多山峰、冰川、高山湖泊和高山沼泽,是生态环境最为奇特、生物资源最为丰富的自然资源宝库之一。同时,青藏高原的微生物群落结构及其多样性与其他区域存在巨大差异,因而具有极高的科学研究价值,并逐渐被人们所关注。研究发现气候变化对青藏高原高寒草地生态系统草丛-地境界面微生物会产生重要的影响[1]。冰川雪藻的研究主要在南部的Yala冰川开展,