广西花坪林区资源昆虫考察初报

花坪林区位于广西东北部,属龙胜临桂县管辖,处于北纬25°31′—25°39′及东经109°48′—109°58′之间,海拔500—1850米,为广西中山山地之一。具有中亚热带南部山区的气候特点,年均温12—14℃,夏短冬长,年雨量1800—2200毫米,全年低温高湿,干湿季节交替不明显,四季均有云雾笼罩。土壤由低到高大致区分为二垂直带,海拔700—1300米的中山区为山地黄壤带,1300米以上的高中山区为山地黄棕壤带。森林保存较好,中山区分布有较典型的亚热带常绿阔叶林,高中山区为亚热带山地落叶常绿阔叶混交林。全林区生物资源比较丰富。     

广西特有杜鹃花种群特征研究

(1 )广西特有杜鹃花在水平地带性植被典型常绿阔叶林、季风常绿阔叶林和季节性雨林都有分布 ,但主要分布在典型常绿阔叶林垂直带谱上的针阔混交林、常绿落叶阔叶混交林和山顶矮林 ;(2 )从 1 2种广西特有杜鹃花样方资料统计看 ,乔木层中最常见的科是壳斗科、山茶科和樟科等 ,这些科都是我国亚热带典型常绿阔叶林代表科 ,这就同样说明了广西特有杜鹃花的主要分布区域系在亚热带山地常绿阔叶林的垂直带谱中 ;(3 )绝大多数广西特有杜鹃花种类分布的生境条件十分恶劣 ,这间接说明了广西特有杜鹃花多是一些古老的残遗种 ;(4 )广西特有杜鹃花同其他杜鹃花一样 ,均需要土壤呈酸性、气温偏低 ,相对湿度大于 80 %的环境条件。这些特点在我们引种杜鹃花时必须加以考虑。     

中国植被地理分布的规律性

二、中国山地植被垂直分布的规律性中国是多山的国家,全国各气候区都有较高的山地。虽然影响山地植被垂直带的因素包括山体高度、山脉走向、坡向、坡度、岩石、土壤等,但各气候区的山地植被垂直带谱的结构和每一植被垂直带类型组合等都反映该山所在地水平带气候的特征,即纬度位置所联系的大气温度和海陆关系位置所联系的大气水分状况相结合的气候特征。兹述各气候区的山地植被垂直分布的特点如下:     

摩天岭北坡森林植被垂直带的初步研究

本文对摩天岭北坡森林植被的垂直分布特点进行了初步研究。采用排序的方法,结合对群落生态外貌特点的分析,以及群落所处海拔高度,划分出森林植被垂直带如下：(1)山地常绿落叶阔叶林带,海拔1600m以下;(2)山地落叶阔叶林带,海拔1600—2100m;(3)山地针阔叶混交林带,海拔2100—2900m;(4)亚高山针叶林带,海拔2900—3450m;(5)高山灌丛草甸带,海拔3450m以上。     

中国东部森林植被带划分之我见

简要回顾了中国东部森林植被带划分研究的历史及当前存在的争论。提出了中国东部植被带划分应以植被本身的特征，特别是地带性的生物群落集为主要依据，同时参照它们的区系组成和气候指标。根据上述原则将中国东部划分为６个植被带∶北方针叶林带、凉温带针阔混交林带、温带落叶阔叶林带、暖温带常绿落叶阔叶混交林带、亚热带常绿阔叶林带和热带雨林、季雨林带，并对各植被带的特征作了简要的描述。阐述了对一些植被带名称、界线改动的原因，特别讨论了我国常绿落叶阔叶混交林以及常绿阔叶林生物气候带的归属问题，认为前者归属于暖温带植被，后者归属于亚热带植被为宜。     

中国东部森林植被带划分之我见

简要回顾了中国东部森林植被带划分研究的历史及当前存在的争论。提出了中国东部植被带划分应以植被本身的特征,特别是地带性的生物群落集为主要依据,同时参照它们的区系组成和气候指标。根据上述原则将中国东部划分为6个植被带∶北方针叶林带、凉温带针阔混交林带、温带落叶阔叶林带、暖温带常绿落叶阔叶混交林带、亚热带常绿阔叶林带和热带雨林、季雨林带,并对各植被带的特征作了简要的描述。阐述了对一些植被带名称、界线改动的原因,特别讨论了我国常绿落叶阔叶混交林以及常绿阔叶林生物气候带的归属问题,认为前者归属于暖温带植被,后者归属于亚热带植被为宜。     

白水江自然保护区的蛇类资源

白水江自然保护区位于东经104°18′—105°25′,北纬32°35′—33°50′;总面积198488公顷(核心区90358公顷,实验区108310公顷)。全境为南秦岭山地,区内山峦重迭,山间河谷深陷。区内水系为长江水系。气候除河谷属亚热带湿润气候外,大部分为暖温带湿润气候,年平均温度15.9℃,最高37.5℃,最低—7.4℃。无霜期262天左右,年均降水量442毫米。植被呈明显垂直分布,可分下列四个植被带:一、低山常绿、落叶林带:海拔1600米以下,有大面积农耕区和居民点,植被以次生阔叶林为主。常见有麻栎、山楠、马桑、蔷薇等。二、中山阔叶林和混交林带:海拔1600—…     

广西花坪国家级自然保护区大型真菌资源及生态分布

报道了广西国家级花坪自然保护区的大型真菌201种,隶属105属45科;其中食用菌50种,药用菌38种,毒菌13种,菌根菌59种和木腐菌48种.保护区的大型真菌按植被类型分为5种群落类型:常绿阔叶林型、亚热带落叶阔叶林型、亚热带中山落叶常绿阔叶混交林型、灌丛型和竹林型;按垂直分布带分为3种林带型:低山林带型、中山林带型和山顶林带型.     

神农架自然遗产地植被垂直带谱的特点和代表性

充分认识并掌握我国自然遗产地山地植被垂直带谱代表性,对正确评估自然遗产地的价值进而制定相关保护管理政策具有重要的科学意义和现实意义。该研究基于群落调查数据、全球1 km~2土地利用数据,通过对比分析、空间分析等方法,从植被垂直带谱的地带性、完整性及不同垂直带群落物种更替等角度,分析论证了神农架自然遗产地植被垂直带谱的代表性。结果显示:神农架自然遗产地从低海拔到高海拔依次发育有常绿阔叶林带(遗产地南坡)、常绿落叶阔叶混交林带、落叶阔叶林带、针阔混交林带、针叶林带及亚高山灌丛和草甸带,其北坡保存的地带性常绿落叶阔叶混交林是北半球常绿落叶阔叶混交林生态系统的最典型代表。神农架自然遗产地拥有的植被垂直带谱是"全球生物地理区划"中东方落叶林生物地理省最完整的植被垂直带谱,在东方落叶林生物地理省具有唯一性和代表性,在较小的水平距离范围内浓缩了中亚热带、北亚热带、暖温带、温带和寒温带等生态系统特征,成为研究全球气候变化下山地生态系统垂直分异规律及其生态学过程的杰出范例,具有突出的世界自然遗产价值。     

神农架南坡植物群落多样性的海拔梯度格局

神农架南坡在我国植被区划中具有十分重要的意义。在神农架南坡沿海拔梯度设置50个样方进行植物物种多样性调查,通过对样方的数量分类和DCA排序,结合物种丰富度、区系分化强度、区系成分和生活型构成等方面的分析,研究神农架南坡植物物种多样性的垂直格局。结果表明：(1)神农架南坡的植被垂直带谱为：海拔900—1000m以下为常绿阔叶林;1000-1700m为常绿落叶阔叶混交林;1600—2100m为落叶阔叶林;海拔2000—2400m为针阔叶混交林;海拔2300m以上为暗针叶林。(2)植被基带群落中,在物种数量、区系成分和重要值方面,常绿和落叶阔叶树种所占的比例都相差无几。(3)植物多样性的垂直格局基本符合“单峰”模式。峰值出现在海拔1400—1500m;但混交林类型的多样性和区系分化强度较高。(4)在植物区系中,温带成分处于主导地位;世界广布属的比例随海拔上升而增加;而中国特有属仅见于海拔2000m以下。亚热带成分和东亚区域性区系成分都随海拔上升而减少,峰值都位于山地常绿落叶阔叶混交林。(5)蕨类植物丰富度随海拔上升而减小;草本植物丰富度与海拔高度之间没有呈现显著的相关关系;木本植物丰富度总体沿海拔梯度减少,但峰椎处于常绿落叶阔叶林带。针阔混交林样方的平均木本物种数也超过落叶阔叶林带。     

Wide Dynamic Range Vegetation Index for remote quantification of biophysical characteristics of vegetation

The Normalized Difference Vegetation Index (NDVI) is widely used for monitoring, analyzing, and mapping temporal and spatial distributions of physiological and biophysical characteristics of vegetation. It is well documented that the NDVI approaches saturation asymptotically under conditions of moderate-to-high aboveground biomass. While reflectance in the red region (rho(red)) exhibits a nearly flat response once the leaf area index (LAI) exceeds 2, the near infrared (NIR) reflectance (PNIR) continue to respond significantly to changes in moderate-to-high vegetation density (LAI from 2 to 6) in crops. However, this higher sensitivity of the rho(NIR) has little effect on NDVI values once the rho(NIR) exceeds 30%. In this paper a simple modification of the NDVI was proposed. The Wide Dynamic Range Vegetation Index, WDRVI = (a * rho(NIR-rho(red))/(a * rho(NIR) + rho(red)), where the weighting coefficient a has a value of 0.1-0.2, increases correlation with vegetation fraction by linearizing the relationship for typical wheat, soybean, and maize canopies. The sensitivity of the WDRVI to moderate-to-high LAI (between 2 and 6) was at least three times greater than that of the NDVI. By enhancing the dynamic range while using the same bands as the NDVI, the WDRVI enables a more robust characterization of crop physiological and phenological characteristics. Although this index needs further evaluation, the linear relationship with vegetation fraction and much higher sensitivity to change in LAI will be especially valuable for precision agriculture and monitoring vegetation status under conditions of moderate-to-high density. It is anticipated that the new index will complement the NDVI and other vegetation indices that are based on the red and NIR spectral bands.     

新疆植被生产力与叶面积指数的变化及其对气候的响应

利用美国探路者卫星遥感资料AVHRR LAI和全球生态模式CASA给出的植被净初级生产力资料(NPP)对新疆地区1982~2000年的植被时空变化进行了定量分析,结果表明新疆地区的LAI和NPP的空间分布严格受水分的制约,与气温呈负相关,表现出干旱内陆地区植被受降水控制的地带特征。相对于20世纪80年代,90年代整个新疆出现了变暖的趋势,降水基本也呈现增加的趋势,在42°N以北地区暖湿转型尤其明显,与这种气候型相对应,植被出现了明显的增加趋势,NPP最大增幅可达45gCm-2a-1。但植被对气温和降水的年际变化响应不一样,降水主要是影响植被峰值的起落,而植被在总体演变趋势上却主要受气温控制,3个分区1984~2000年的气温明显上升,而降水变化趋势不明显,植被受气温控制出现了显著的上升趋势(P<0.01)。     

鄂尔多斯植被盖度分布与环境因素的关系

 从植被指数分布与气象因素、地质地层和地质水文的关系入手, 利用遥感解译和地理信息系统的空间分析功能, 分析了不同尺度下, 气候因素、地质水文因素、基质和地貌等对鄂尔多斯高原植被盖度分布的影响。指出: 在区域尺度上, 研究区植被盖度分布主要受降水影响, 植被盖度呈从东南到西北逐渐减少的趋势; 高盖度植被主要分布在冲洪积地貌和丘陵地貌区。局部分析, 库布齐沙漠东向延伸的存在与发展与区域型断层的存在有密切的联系; 毛乌素沙地中的高盖度植被分布受地形和基质岩性组合的综合影响, 主要分布在第四系湖积物和第四系冲积物等渗水性差的基质上, 尤其集中分布于凹陷的湖相沉积。     

Synergy between small- and large-scale feedbacks of vegetation on the water cycle

Predictions of the effects of climate change on the extent of forests, savannas and deserts are usually based on simple response models derived from actual vegetation distributions. In this review, we show two major problems with the implicitly assumed straightforward cause–effect relationship. Firstly, several studies suggest that vegetation itself may have considerable effects on regional climate implying a positive feedback, which can potentially lead to large‐scale hysteresis. Secondly, vegetation ecologists have found that effects of plants on microclimate and soils can cause a microscale positive feedback, implying that critical precipitation conditions for colonization of a site may differ from those for disappearance from that site. We argue that it is important to integrate these nonlinearities at disparate scales in models to produce more realistic predictions of potential effects of climate change and deforestation.     

Increase in light interception cost and metabolic mass component of leaves are coupled for efficient resource use in the high altitude vegetation

Global syntheses of leaf trait scaling relationships report an increase in light interception costs or ‘diminishing returns’ with increase in leaf area. However, variation in light interception costs across ecological gradients and plant strategies to cope up with these costs are not adequately understood. We analyzed leaf area (A) – leaf dry mass (M), leaf water mass (W) – M and W – A scaling relationships in plants occurring in a high altitude region of western Himalaya across environmental gradients to understand changes in light interception cost and metabolic mass component. M represents light interception cost, whereas, W is considered as a proxy of metabolic mass component for liquid phase being the ultimate source of metabolic activity. Trait values were measured from 9278 leaves belonging to 136 dominant species occurring at different sites, slope aspects, elevations and habitat types. Overall, light interception cost increased with increasing A (scaling exponent (α) < 1 in A–M relationship) and metabolic mass component increased disproportionately high with increasing M and A. We found significant differences in scaling exponents of leaf trait relationship between sites, elevations, slope aspects and habitat types, indicating that increase in light interception cost was more evident at higher elevations, southern slopes and open habitats. Further, with increase in light interception cost, metabolic mass component also increased (α > 1 in W–M and W–A relationships). The changes in scaling exponents of various leaf trait relationships across ecological gradients indicated that vegetation of different regions have differences in light interception cost and metabolic mass component. Moreover, increasing light interception cost (increase in mechanical and hydraulic tissues) with increasing A and increasing metabolic mass (leaf thickness) with increasing A and M are favored in high altitude vegetation. This could be a key strategy of high altitude plants for efficient resource capture and use in harsh environments.     

Vegetation and climate reconstructions on different time scales in China: a review of Chinese palynological research

This paper reviews vegetation and climate reconstructions for different time scales based on palynological studies in China. It discusses examples of significant developments in palynological research topics within China: (1) Modern pollen—a modern pollen database (East Asia Surface Pollen Database) has been established through the collaboration of Chinese palynologists. Based on these data, modern pollen distributions and their quantitative relationship with vegetation and climate have been thoroughly studied. (2) Pre-Quaternary vegetation and climate dynamics—scientists have mapped pollen and palaeobotanical data from the Palaeogene. The vegetation distributions confirm a north–south zonal pattern during the Palaeogene that changed to an east–west monsoonal pattern during the Miocene and Pliocene. These results provide key evidence for understanding monsoon evolution. (3) Late-Quaternary vegetation—biome reconstructions based on fossil pollen data show spatial and temporal changes in vegetation since the Last Glacial Maximum, permitting a better understanding of climate change across China. (4) Quantitative climate reconstructions—some reconstructions have successfully detected Holocene climate variability thereby providing insights into monsoon history. At present, there are no comprehensive spatial reconstructions. Major possible future developments should focus on: (1) long-term vegetation reconstructions from lakes to study Asian monsoon dynamics at orbital scales; (2) quantitative reconstructions of vegetation and climate change to help stronger integration with palaeoclimate models and dynamic vegetation models; (3) land-cover and land-use change across China over the last 6,000 years to understand human impacts and provide empirical data for climate modellers; and (4) integration of pollen data with vegetation and climate modelling to understand the CO₂-vegetation relationship and climate dynamics.     

Patterns in specific leaf area and the structure of a temperate heath community

Relationships between the distribution and specific leaf area (SLA: leaf area per unit dry mass) of six heath (Ericaceae) species were investigated along an environmental gradient between peat bogs and conifer forest in British Columbia, Canada. I asked whether patterns in SLA could help to identify the processes shaping plant distributional patterns. Specifically, I assessed whether (i) species’ distributions across the environmental gradient are correlated with SLA (ii) relationships between plant distributional patterns and SLA are similar among bogs with different shrub species (iii) intraspecific patterns in SLA parallel interspecific relationships between distributions and SLA, and (iv) intraspecific patterns are environmentally determined. Results showed that distributional patterns were often correlated with SLA; species with lower SLA were more abundant towards the centre of bogs, while species with higher SLA were more abundant in forest. Intraspecific patterns in SLA paralleled distributional patterns across the gradient; individuals located towards the centre of bogs had lower SLA than those growing in forest. A transplantation experiment showed that plants typically altered their SLA according to local environmental conditions. However, one bog showed no relationship between species’ distributions and SLA. This bog lacked the two species with lowest SLA, which typically occurred at the centre of other bogs. In their absence, species with higher SLA that typically occurred in forest increased in abundance towards the centre of the bog, where they obtained lower values of SLA. Therefore, while distributional patterns were often closely associated with SLA, plasticity in SLA was associated with increased breadth of species’ distributions across the gradient. Overall results indicate SLA may serve as a useful proxy for a range of life history traits to help elucidate the processes structuring plant communities.     

The photosynthesis – leaf nitrogen relationship at ambient and elevated atmospheric carbon dioxide: a meta-analysis

Estimation of leaf photosynthetic rate (A) from leaf nitrogen content (N) is both conceptually and numerically important in models of plant, ecosystem, and biosphere responses to global change. The relationship between A and N has been studied extensively at ambient CO₂ but much less at elevated CO₂. This study was designed to (i) assess whether the A–N relationship was more similar for species within than between community and vegetation types, and (ii) examine how growth at elevated CO₂ affects the A–N relationship. Data were obtained for 39 C3 species grown at ambient CO₂ and 10 C3 species grown at ambient and elevated CO₂. A regression model was applied to each species as well as to species pooled within different community and vegetation types. Cluster analysis of the regression coefficients indicated that species measured at ambient CO₂ did not separate into distinct groups matching community or vegetation type. Instead, most community and vegetation types shared the same general parameter space for regression coefficients. Growth at elevated CO₂ increased photosynthetic nitrogen use efficiency for pines and deciduous trees. When species were pooled by vegetation type, the A–N relationship for deciduous trees expressed on a leaf-mass basis was not altered by elevated CO₂, while the intercept increased for pines. When regression coefficients were averaged to give mean responses for different vegetation types, elevated CO₂ increased the intercept and the slope for deciduous trees but increased only the intercept for pines. There were no statistical differences between the pines and deciduous trees for the effect of CO₂. Generalizations about the effect of elevated CO₂ on the A–N relationship, and differences between pines and deciduous trees will be enhanced as more data become available.     

Spatial pattern of riparian vegetation in desert of the lower Tarim River basin

AimsRevealing the spatial pattern of riparian vegetation in hyper-arid regions can improve our understanding on the water relations of riparian vegetation in the desert watershed ecosystem, and also can provide valuable scientific guidance for desertification control and water resources management of watershed of the arid region in northwestern China. This research objective is to show the spatial distribution and structures of typical riparian vegetation in hyper-arid desert watershed from regional and overall perspective.Methods Based on Landsat-8 OLI remote sensing images and a large number of field vegetation surveys, the supervised classification method was used to distinguish three main vegetation categories in the lower Tarim River basin: Tamarix thicket, Populus euphratica woodland, and Phragmites australis grassland. The leaf area index (LAI) of Tamarix thickets and Populus euphratica woodlands were inverted by using the remote-sensed LAI inversion empirical model that we developed.Important findings Supervised classification supporting abundant information of ground objects by remote sensing was an effective method to determine desert riparian vegetation categories in arid desert regions. The area was 336.4 km² for the Populus euphratica woodlands and 405.3 km² for the Tamarix thickets, respectively. The Tamarix thickets had a wider distribution range while the Populus euphratica woodlands grew near the river channel. The overall LAI of the riparian vegetation was low. The average LAI value was 0.253 for the Tamarix thickets and 0.252 for the Populus euphratica woodlands. The areas of vegetation with the LAI value of less than 0.5 accounted for 92.4% and 90.1% of the total area of the Tamarix thickets and the Populus euphratica woodlands, respectively. The statistic results showed that large spatial variability of the riparian vegetation LAI existed. The spatial variability of the Populus euphratica woodlands was larger than that of the Tamarix thickets. The LAI values of the riparian vegetation had a significant negative exponential relationship with the distances away from the river channel. The LAI values declined rapidly within the distance of 1 km from the river channel and they were generally lower than 0.1 when the distances beyond 1 km, which indicated that the riparian vegetation was mainly distributed within 1 km from both side of the river. This research indicated three basic characteristics of the spatial pattern in riparian vegetation from hyper-arid desert regions, including overall sparse spatial distribution, high spatial variability and negative exponential relationship between LAI and distance away from the river channel.     

塔里木河下游河岸带植被的空间结构特征

揭示我国内陆河流域下游河岸带植被的空间结构特征, 对于了解我国西北干旱区荒漠河岸带植被的空间分布规律、指导荒漠化治理和内陆河水资源管理具有重要意义。该研究基于野外大范围植被调查数据支持下的遥感监督分类方法, 利用Landsat-8 OLI遥感数字图像, 辨识了塔里木河下游柽柳(Tamarix spp.)灌丛、胡杨(Populus euphratica)疏林和芦苇(Phragmites australis)草地3类主要的河岸带植被, 并利用建立的叶面积指数(LAI)遥感反演经验模型反演了研究区柽柳灌丛和胡杨疏林的叶面积指数, 旨在从区域尺度和总体趋势上分析荒漠河岸带植被的空间结构和分布特征。结果表明: 在有详细地物资料的基础上, 遥感监督分类可以作为一种干旱区荒漠河岸带植被分类的有效方法; 遥感分类结果显示塔里木河下游胡杨疏林分布面积约336.4 km², 柽柳灌丛约为405.3 km², 胡杨疏林总体更靠近河道, 柽柳灌丛分布范围更广; 河岸带植被LAI整体很低, 柽柳灌丛和胡杨疏林平均LAI值分别为0.253和0.252, LAI小于0.5的植被对应面积分别占柽柳灌丛和胡杨疏林总面积的92.4%和90.1%, 表明了塔里木河下游荒漠河岸植被空间上稀疏分布的特征; 统计结果显示, 河岸带植被结构存在巨大的空间变异性, 其中胡杨疏林比柽柳灌丛的空间变异性更大; 河岸带植被LAI随距河道距离呈现显著负指数分布规律, 在离河道1 km范围内LAI随离河道距离快速下降, 而1 km外区域叶面积指数普遍低于0.1, 表明植被主要分布在河道两侧1 km范围内。整体稀疏的空间分布、显著的空间变异性, 以及由LAI体现的植被盖度随距河道距离的负指数下降规律是荒漠河岸带植被空间结构的3个基本特征。