鄂西南两个自然保护区亚热带常绿落叶阔叶混交林类型及其常绿和落叶物种组成结构分析

为深入研究亚热带常绿落叶阔叶混交林的生物多样性维持机制, 合理保护与利用此类森林植被, 以鄂西南两个自然保护区——星斗山和木林子典型的亚热带常绿落叶阔叶混交林为研究对象, 在野外样方调查的基础上进行了群落数量分类和排序, 分析了常绿和落叶物种比例随群落类型及环境因子变化的规律。研究结果表明: (1)将鄂西南两个自然保护区的亚热带常绿落叶阔叶混交林划分为5个群落类型: 即青冈-翅柃+尖连蕊茶(Cyclobalanopsis glauca-Eurya alata + Camellia cuspidata)群落(I)、川陕鹅耳枥+青冈-翅柃(Carpinus fargesiana + Cyclobalanopsis glauca-Eurya alata)群落(II)、川陕鹅耳枥+青冈-水马桑(Carpinus fargesiana + Cyclobalanopsis glauca-Weigela japonica)群落(III)、光叶水青冈+多脉青冈-翅柃(Fagus lucida + Cyclobalanopsis multinervis-Eurya alata)群落(IV)和川陕鹅耳枥+交让木+包果柯-翅柃(Carpinus fargesiana + Daphniphyllum macropodum + Lithocarpus cleistocarpus-Eurya alata)群落(V); (2)常绿和落叶物种的丰富度、多度、胸高断面积及重要值等指标随群落类型而变化。在群落II、III和V中落叶物种占优势, 而在群落I和IV中二者无显著差异; (3)各类型群落在小径级(1-5 cm)内落叶物种的丰富度大于常绿物种, 但多度、胸高断面积和重要值大都小于常绿物种。在中径级(5-10 cm)内, 群落I和群落IV的各项指标都表现为常绿物种大于落叶物种, 而群落II、群落III和群落V的则相反。在大径级(≥ 10 cm)内, 各群落类型的落叶物种都占显著优势, 其各项指标大于常绿物种; (4)海拔、坡度、坡向、土壤氮含量和土壤磷含量是影响各群落类型内常绿和落叶物种比例变化的主导因子。     

Soil organic matter quantity and quality shape microbial community compositions of subtropical broadleaved forests

As two major forest types in the subtropics, broadleaved evergreen and broadleaved deciduous forests have long interested ecologists. However, little is known about their belowground ecosystems despite their ecological importance in driving biogeochemical cycling. Here, we used Illumina MiSeq sequencing targeting 16S rRNA gene and a microarray named GeoChip targeting functional genes to analyse microbial communities in broadleaved evergreen and deciduous forest soils of Shennongjia Mountain of Central China, a region known as ‘The Oriental Botanic Garden’ for its extraordinarily rich biodiversity. We observed higher plant diversity and relatively richer nutrients in the broadleaved evergreen forest than the deciduous forest. In odds to our expectation that plant communities shaped soil microbial communities, we found that soil organic matter quantity and quality, but not plant community parameters, were the best predictors of microbial communities. Actinobacteria, a copiotrophic phylum, was more abundant in the broadleaved evergreen forest, while Verrucomicrobia, an oligotrophic phylum, was more abundant in the broadleaved deciduous forest. The density of the correlation network of microbial OTUs was higher in the broadleaved deciduous forest but its modularity was smaller, reflecting lower resistance to environment changes. In addition, keystone OTUs of the broadleaved deciduous forest were mainly oligotrophic. Microbial functional genes associated with recalcitrant carbon degradation were also more abundant in the broadleaved deciduous forests, resulting in low accumulation of organic matters. Collectively, these findings revealed the important role of soil organic matter in shaping microbial taxonomic and functional traits.     

中国成熟天然林土壤有机碳垂直分异特征

以分布在中国不同气候区的131个成熟天然林土壤为研究对象,测定不同土层(0～10、10～20、20～30、30～50和50～100 cm)土壤有机碳(SOC)密度,分析其与气象因子、土壤性质的关系,研究天然林SOC垂直分布特征及其影响机理。结果表明: 温带针叶林、温带落叶阔叶林、亚热带落叶阔叶林和亚热带常绿阔叶林0～30 cm土层SOC密度均随土壤深度增加而降低。在0～100 cm土层,SOC密度地带性分异明显,温带针叶林SOC密度显著高于温带落叶阔叶林,亚热带常绿阔叶林SOC密度显著高于亚热带落叶阔叶林。SOC密度与土壤黏粒、年降水量以及地上净初级生产力呈显著正相关,与土壤pH和年均温呈显著负相关。年降水量与年均温调节天然林SOC输入与输出,土壤pH与黏粒影响天然林SOC积累,对成熟的天然针叶林与常绿阔叶林进行有效保护,有利于增加我国森林土壤碳库。     

贵州施秉喀斯特地区林地土壤甲螨的群落组成及多样性（英文）

【目的】为了解施秉喀斯特地区林地土壤甲螨的分布和群落组成特点,明确中国西南喀斯特地区林地类型对土壤甲螨群落密度、组成和物种多样性的影响,对该区林地土壤甲螨的群落结构及多样性进行了的调查和分析。【方法】2012年8月选取了中国西南施秉喀斯特地区典型生境中的8个样地,每个样地9个取样点,用Berlese-Tullgren装置分离土样24 h。多样性分析采用常见的多样性指数;群落相似性分析采用Jaccard相似性系数(C_J);群落聚类分析分别采用Marczewski Steinhaus 距离(C_ms)和Bray-Curtis距离,应用R 2.11程序进行类平均法聚类。【结果】结果显示,中国西南喀斯特8个样地中土壤甲螨由少数的优势属和数量众多的稀有属组成。其中全菌甲螨属 Perscheloribates (22.48%)和长单翼甲螨属 Protoribates (11.45%)个体数量最为丰富。长单翼甲螨属 Protoribate、上罗甲螨属Epilohmannia、小奥甲螨属 Oppiella、小盾珠甲螨属 Suctobelbella 和盖头甲螨属 Tectocepheus 分布广泛。本区的甲螨组成（属级水平）表现出明显热带和亚热带地区特点。在天然常绿落叶阔叶林中,甲螨的个体数量和种类数较多,但多样性不高,而在人工针叶林中甲螨多样性最高。甲螨群落组成和分布特征多样,异质性高,特别是在天然常绿落叶阔叶林中突出。【结论】研究表明,施秉喀斯特生态系统的不同林分影响甲螨的物种多样性和群落稳定性,天然常绿落叶阔叶混交林是甲螨的“避难所”。     

中国中亚热带东部常绿阔叶林主要类型的群落多样性特征

 本文通过10个地区61个样地资料分析,研究了中亚热带东部常绿阔叶林群落多样性特征及其随纬度、海拔梯度的变化。结果表明,中亚热带东部常绿阔叶林群落丰富度为49±17种(样地面积400m2),各层次的多样性表现为灌木层(包括幼树与幼苗)>乔木层>草本层。常绿阔叶林各类型间的差异远比落叶阔叶林与多样性较低的常绿阔叶林之间的差异大。各层次中变化幅度从大到小的顺序为：草本层>乔木层>灌木层。在所研究地区常绿阔叶林的群落多样性没有表现出明显的随纬度梯度和海拔梯度的变化规律。     

Community Dynamics of Seed Rain in Mixed Evergreen Broad-leaved and Deciduous Forests in a Subtropical Mountain of Central China

Seed dispersal is a key process within community dynamics. The spatial and temporal variations of seed dispersal and the interspecific differences are crucial for understanding species coexistence and community dynamics. This might also hold for the mixed evergreen broadleaved and deciduous forests in the mountains of subtropical China, but until now little existing knowledge is available for this question. In 2001, we chose to monitor the seed rain process of our mixed evergreen broad-leaved and deciduous forest communities in Mount Dalaoling National Forest Park, Yichang, Hubei Province, China. The preliminary analyses show obvious variations in seed rain density, species compositions and timing of seed rain among four communities. The average seed rain densities of the four communities are 2.43 ± 5.15, 54.13 ±182.75, 10.05 ±19.30 and 24.91 ± 58.86 inds/m^2, respectively; about one tenth the values in other studies in subtropical forests of China. in each community, the seed production is dominated by a limited number of species, and the contributions from the others are generally minor. Fecundity of evergreen broadleaved tree species is weaker than deciduous species. The seed rain of four communities begins earlier than September, and stops before December, peaking from early September to late October. The beginning date, ending date and peak times of seed rain are extensively varied among the species, indicating different types of dispersal strategies. According to the existing data, the timing of seed rain is not determined by the climate conditions in the same period, while the density of seed rain may be affected by the disturbances of weather variations at a finer temporal resolution.     

神农架常绿落叶阔叶混交林碳氮磷化学计量比

生态化学计量学是研究生态过程中化学元素平衡的科学, 碳(C)、氮(N)、磷(P)化学计量比是生态系统过程及其功能的重要特征。该研究测定了神农架常绿落叶阔叶混交林植物器官、凋落物及土壤的C、N、P含量, 利用生物量加权法计算其化学计量比, 并分析该生态系统不同组分间及不同器官间化学计量比的差异。研究结果发现: 在不同组分之间, C含量、C:N及C:P表现为植物>凋落物>土壤; N、P含量及N:P表现为凋落物>植物>土壤。在不同植物器官间, C含量的差异较小, 其变异系数相对N、P含量较低且保持稳定; N、P含量为叶片最高且变异系数最低; N:P为树皮最高, 而枝的变异系数最低。常绿与落叶树种的叶片N、P含量差异显著。与不同森林类型的化学计量比相比, 该常绿落叶阔叶混交林植物群落的C:P及N:P较低, 凋落物的C:P及N:P较高, 土壤的C、N、P化学计量比与亚热带常绿阔叶林基本一致, 生态系统的C:N相对较低。利用生物量加权法计算得到的该森林生态系统不同组分的C、N、P化学计量比的大小关系与前人利用枝叶取样算术平均的结果存在较大差异。C、N、P含量及其化学计量比在不同器官的分配及内稳性与器官的生理功能关系密切。     

Effects of natural and artificial disturbance on landscape and forest structure in Tiantong National Forest Park,East China

This paper aims to understand the ecological effects of disturbance on broadleaved evergreen forest in East China. We used a manipulative field experiment approximating the common natural and artificial disturbance types in this area to investigate the community physiognomy, floristic composition, and 5-year recovery dynamics of the post-disturbance forest community. The results indicated that the landscape and forest structure have degraded into shrub communities, structure-damaged evergreen broadleaved communities, and so on. The post-disturbance communities presented different means of plant recruitment and vegetation recovery patterns at an early successional stage. The recovery of disturbed forests primarily depended on external seed sources and re-sprouting from stumps, rather than on soil seed banks, as few buried seeds were found. Re-sprouting thus appears to be key in allowing rapid vegetation recovery in evergreen broadleaved forest. Disturbances seem to be one of the most important factors that can contribute to regional species coexistence across temporal and spatial scales in evergreen broadleaved forests.     

金沙江干旱河谷植物群落的数量分类及其结构分异的环境解释

植物群落的空间分异格局是异质生境条件下物种性状、种间相互作用等生态学过程共同作用的结果, 对其分析有助于深入理解群落构建进程。本文基于金沙江流域干旱河谷116个样点562个样方的植物群落调查数据, 采用自适应仿射传播聚类的方法进行群落数量分类, 运用莫兰特征向量地图, 和方差分解的方法对影响群落结构的空间和环境因子进行分析。结果表明: (1)自适应仿射传播聚类将金沙江干旱河谷的植物群落分为30组, 可归为7个植被型, 23个群系, 以稀树草原(30.0%)、暖性落叶阔叶灌丛(55.7%)为最主要的植被类型。(2)年均温和干燥指数是限制金沙江干旱河谷植物群落分布的主要环境因子。稀树草原、肉质灌丛、常绿阔叶灌丛是典型的干热河谷植被类型; 暖性落叶阔叶灌丛、常绿硬叶林是干暖河谷植被的优势类型; 暖性针叶林、落叶阔叶林则主要在干温河谷环境占优势。(3)纯环境因子可以解释群落物种组成变化的5.5%, 纯空间因子可以解释的物种组成变化为22.5%, 有空间结构的环境因子部分为6.6%, 未解释的部分为65.4%。在诸多环境因子中, 年均温及干燥指数的不同显示了不同群落生境的重要差异, 并显著影响到群落的分布格局。大尺度的空间因子则主要通过地理隔离对群落结构的差异产生影响。     

The effects of vegetation types and microhabitats on carabid beetle community composition in cool temperate Japan

The effects of vegetation types and environmental factors on carabid beetle (Coleoptera: Carabidae) communities were studied. Carabid beetles were collected using pitfall traps (total 2844 trapping days) and seven microenvironmental factors were measured in four vegetation types: grassland, natural evergreen coniferous forest (Pinus densiflora), deciduous broad-leaved natural forest (Quercus crispula, Betula platyphylla, Alnus japonica, or Fagus crenata), and deciduous coniferous plantation (Larix kaempferi) in cool temperate Japan. These four vegetation types provided a novel comparison between natural forests and plantations because the vast majority of related studies have investigated only deciduous broad-leaved natural forests and evergreen coniferous plantations. PERMANOVA indicated that vegetation types affected carabid community composition. Ordination plots showed that community composition differed greatly between grassland and forest vegetation types, but that community composition in the plantation forest overlapped with that of natural forest types. Characteristics differentiating the grassland included a high proportion of winged species and a low mean carabid body weight. Among the examined environmental factors, litter depth, soil water content, and depth of the soil A-horizon had large effects on carabid communities. These results suggest that the effect of afforestation on carabid communities in cool temperate Japan might be insignificant compared with the effects of cover types (deciduous vs. evergreen) and microenvironmental factors.     

长江中游(以湖北湖南为主)的植物生物多样性及其保护对策

在对植物调查研究的基础上,对长江中游(湖北、湖南为主)的植物区系、植被、生物多样性保护及保护对策进行了系统的论述。根据两省土著种子植物名录统计,本区共有202科1476属7037种(包括种下等级),其中裸子植物7科30属64种;被子植物196科1445属6973种。以鄂湘为代表的华中区分布类型复杂、物种丰富、起源古老,而且特有的科、属、种多,特有度高。北温带木本植物属高度集中,体现了长江中游具有古第三纪．泛北极植物区系的代表性。拥有众多的东亚特有属、东亚．北美间断分布属和中国特有属,它们既是本地植物区系的特色,也代表了中国植物区系的核心。本地中山以亮叶水青冈(Fagus lucida)为主的阔叶林系第三纪．泛北中生落叶阔叶林的后裔。在植被区划上,本区属于常绿阔叶林区域,包括北亚热带常绿阔叶．落叶阔叶混交林地带及中亚热带常绿阔叶林两个植被地带。后者分为北部典型常绿阔叶林亚地带,南部含华南植物区系成分的常绿阔叶林亚地带。本区主要的自然植被类型(以原生类型为主)有171个类型(相当于群系formations)。从生物多样性保护的三个层次上(物种、群落、景观)对保护现状、特点、保护方针和策略等进行了探讨并提出了建议。     

中国东部海岛森林和灌丛土壤碳氮磷养分库的纬度变化

虽然海岛结构相对简单,但在生物多样性和生态功能维持方面起重要作用.以中国东部暖温带、北亚热带、中亚热带和南亚热带的14个海岛为对象,研究森林土壤碳和氮磷养分库的纬度变化特征,并分析其与气候因子和植物多样性的关系.结果表明:土壤碳和氮磷养分库在温度带间差异显著,土壤碳库与氮库在暖温带最低,分别为49.35和1.08 t·hm^-2,在北亚热带最高,为137.25和4.63 t·hm^-2;磷库在南亚热带海岛最低,为1.3 t·hm^-2,在北亚热带最高,为5.19 t·hm^-2.各植被类型土壤碳氮磷库在不同温度带间存在显著差异,落叶林土壤碳氮磷库在亚热带高于暖温带;常绿阔叶林土壤碳和氮库不受温度带影响,磷库在北亚热带和中亚热带显著高于南亚热带.年均温、年降水量、土壤含水量和植物物种多样性间的交互作用对土壤碳氮磷库有显著正向影响;植物物种多样性对土壤氮库变化有正向影响,但对磷库具有负向影响.海岛森林土壤碳库的纬度变化趋势与大陆相反,土壤氮磷养分库变化格局与大陆相似;其中,水热和植物物种多样性是驱动中国东部海岛森林土壤碳氮磷库变化的主要非生物和生物因素.     

浙江天童国家森林公园常绿阔叶林凋落叶养分含量的时空分布特征

植物凋落叶养分含量的时空分布格局在森林生态系统的物质循环和能量流动中发挥着关键作用,尤其是对森林土壤养分情况有重要的影响,而在群落结构复杂的亚热带森林中基于群落整体水平的凋落叶养分含量特征研究相对匮乏。在位于浙江天童国家森林公园中的20 hm²动态监测样地进行,收集凋落叶并测定其碳、氮、磷含量,结合不同生活型物种的凋落高峰,春季和初夏为常绿树种凋落高峰;秋季为落叶树种凋落高峰,以及地形特征对凋落叶养分含量的时空分布特征进行探究。结果表明：在时间尺度上,凋落叶养分含量表现为不同凋落高峰之间的差异,碳含量表现为秋季高峰 < 春季高峰 < 初夏季高峰,氮、磷含量为秋季高峰大于春季和初夏季高峰;在空间尺度上,凋落叶养分含量则表现为沟谷地形和山脊地形之间的差异性,在秋季凋落高峰时碳含量在沟谷地形显著低于山脊地形,氮、磷含量在山脊地形显著低于其他地形。研究结果表明群落物种组成及其生活型差异是造成森林群落水平凋落叶养分含量时空差异的主要原因。     

不同植被恢复类型的土壤肥力质量评价

科学确定森林土壤肥力指标并进行肥力质量的评价,对立地生产力和多目标森林经营的研究有着重要意义。以采伐(径级12 cm择伐)迹地上发育来的稀树灌丛、针叶林、针阔混交林和常绿阔叶林为研究对象,进行每木调查与群落分析,并比较各群落土壤因子间的差异,用典范对应分析(CCA)和因子分析对土壤肥力质量进行定量评价。结果表明,CCA可以有效地筛选土壤肥力质量指标,有助于质量指标的科学确定;土壤肥力质量综合评价分值为稀树灌丛(0.438)常绿阔叶林(0.414)针阔混交林(-0.170)针叶林(-0.331);演替初期(19 a)的植被恢复并未使土壤结构发生明显变化,土壤肥力质量是下降的;无人为干扰的3种群落类型,针叶林表现为更高的生物量积累,而天然更新的常绿阔叶林则更有利于生物多样性的增加与土壤养分的保蓄。     

中国东部南北样带森林优势植物叶片的水分利用效率和氮素利用效率

通过测定中国东部南北样带主要森林生态系统中10种优势植物(兴安落叶松、蒙古栎、水曲柳、紫椴、色木槭、红松、杉木、木荷、马尾松、锥栗)叶片的碳氮含量(Cmass、Nmass)、同位素丰度(δ13C、δ15N)以及光合响应曲线,分析了不同优势植物叶片的水分利用效率和氮素利用效率之间的差异及其相互关系.结果表明： 不同生活型植物叶片的Nmass和δ15N差异显著,表现为阔叶植物>针叶植物,落叶植物>常绿植物;最大光合速率(Pn max)表现为针叶植物>阔叶植物,落叶植物>常绿植物;植物叶片的瞬时水分利用效率(WUEi)和长期水分利用效率(WUE)均表现为阔叶植物>针叶植物,常绿植物>落叶植物;植物叶片的瞬时氮素利用效率(NUEi)和长期氮素利用效率(NUE)则表现出相反的规律,且常绿植物和落叶植物叶片的NUE差异显著;WUEi和WUE之间相关性不显著,而NUEi和NUE之间呈显著正相关.植物叶片的水分利用效率与氮素利用效率显著负相关.两种资源利用效率均受植物生活型的影响,并且存在一定的制约关系.     

A meta‐analysis on growth,physiological, and biochemical responses of woody species to ground‐level ozone highlights the role of plant functional types

The carbon‐sink strength of temperate and boreal forests at midlatitudes of the northern hemisphere is decreased by ozone pollution, but knowledge on subtropical evergreen broadleaved forests is missing. Taking the dataset from Chinese studies covering temperate and subtropical regions, effects of elevated ozone concentration ([O₃]) on growth, biomass, and functional leaf traits of different types of woody plants were quantitatively evaluated by meta‐analysis. Elevated mean [O₃] of 116 ppb reduced total biomass of woody plants by 14% compared with control (mean [O₃] of 21 ppb). Temperate species from China were more sensitive to O₃ than those from Europe and North America in terms of photosynthesis and transpiration. Significant reductions in chlorophyll content, chlorophyll fluorescence parameters, and ascorbate peroxidase induced significant injury to photosynthesis and growth (height and diameter). Importantly, subtropical species were significantly less sensitive to O₃ than temperate ones, whereas deciduous broadleaf species were significantly more sensitive than evergreen broadleaf and needle‐leaf species. These findings suggest that carbon‐sink strength of Chinese forests is reduced by present and future [O₃] relative to control (20–40 ppb). Given that (sub)‐tropical evergreen broadleaved species dominate in Chinese forests, estimation of the global carbon‐sink constraints due to [O₃] should be re‐evaluated.     

Soil N forms and gross transformation rates in Chinese subtropical forests dominated by different tree species

Background and aims

Knowledge related to extent of differing soil N forms and N transformation rates in subtropical southern China is severely limited. Accordingly, the purpose of this study was to investigate if and how tree species of different foliage types (coniferous, deciduous, and evergreen broadleaved) influence N forms and microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) content as well as gross N transformation rates in the organic and mineral soils of three distinct subtropical forests in China.

Methods

Chloroform fumigation extraction was used to determine MBC and MBN content while ¹⁵N-isotope dilution techniques were used to measure gross N transformation rates. Canonical correspondence analysis (CCA) was used to quantify relationships between soil chemical characteristics and changes in soil N transformation rates.

Results

Soil N forms, MBC and MBN content, and N transformation rates were found to be significantly different between tree species. Deciduous forest soil exhibited the highest N transformation rates. Soil N transformation rates were closely associated with total soil C and N and MBC and MBN content.

Conclusions

Soil substrate quantity and soil microbial activity play a more important role in soil N transformation processes than does soil quality in China’s subtropical forests. Tree species type should therefore be taken into account when trying to determine ecosystem N cycling.     

中国西南干旱河谷植物群落的数量分类和排序分析

中国西南干旱河谷植被是我国西南横断山区特有的植被类型, 目前关于西南干旱河谷植被还没有整体性的群落类型划分研究。根据对甘肃、四川、云南三省九条主要河流的干旱河谷段野外调查和文献来源的1,339个植物群落样方数据, 采用自适应仿射传播聚类方法, 对我国西南干旱河谷的植物群落进行数量分类, 并采用典范对应分析方法进行排序分析。结果表明: (1)调查样方的植物群落分为7个植被型(稀树草原、肉质灌丛、常绿阔叶灌丛、暖性落叶阔叶灌丛、常绿硬叶林、落叶阔叶林和暖性针叶林), 24个群系, 31个群丛类型。暖性落叶阔叶灌丛是本植被区的代表性植被类型; 分布最广的群系为鞍叶羊蹄甲灌丛(Form. Bauhinia brachycarpa, 样方比例50.9%)、黄茅灌草丛(Form. Heteropogon contortus, 样方比例11.9%)、孔颖草灌草丛(Form. Bothriochloa pertusa, 样方比例5.6%)、黄荆灌丛(Form. Vitex negundo, 样方比例4.2%)、知风草灌草丛(Form. Eragrostis ferruginea, 样方比例3.8%)、车桑子灌丛(Form. Dodonaea viscosa, 样方比例3.4%)、云南松疏林(Form. Pinus yunnanensis, 样方比例3.3%)。(2)冬季低温和降水的季节性是限制干旱河谷植物群落分布的主要气候因子。稀树草原、肉质灌丛是典型的干热河谷植被类型; 暖性落叶阔叶灌丛、常绿硬叶林、常绿阔叶灌丛是干暖河谷植被的优势类型; 暖性针叶林、落叶阔叶林则主要在干温河谷环境占优势。     

A Study on the Classification of the Plant Functional Types Based on the Topographical Pattern of Plant Distribution

An idea of plant functional types (PFTs) classification is brought forward based on the topographical pattern of plants, and a case study at Daloling region, lying in the northern part of Chinese subtropical zone, is presented. By means of extensive field study of the mountain forests, the quantitative attributes of the major 55 evergreen broadleaved tree species in the communities located at various topographical positions were acquired. The detrended canerical corre spondence analysis (DCCA) method was used to analyze: 1) The correlationships among the habitat temperature, moisture and illumination conditions and the 6 topographical attributes as elevation, mountain aspect, slope shape, slope position, slope direction and slope gradient of the habitat. 2) The diverse patterns of 55 species on the multidimensional topographical gradients. The scores of ordination were then used for a two way indicator species analysis (TWINSPAN) to the species. According to the results of previous analyses, the 55 evergreen broadleaved tree species at Dalaoling were classified into 10 PFTs. A discussion about the validity and limits of this PFTs accessing approach were given in the end.      

亚热带常绿阔叶林和暖温带落叶阔叶林叶片热值比较研究

植物干重热值(GCV)是衡量植物生命活动及组成成分的重要指标之一,反映了植物光合作用中固定太阳辐射的能力。利用氧弹量热仪测定了亚热带和暖温带两个典型森林生态系统常见的276种常见植物叶片的干重热值,探讨了亚热带和暖温带植物热值分布特征,以及不同生活型、乔木类型间植物热值的变化规律。实验结果发现:亚热带常绿阔叶林和暖温带落叶阔叶林叶片热值的平均值分别为17.83 k J/g(n=191)和17.21k J/g(n=85),整体表现为亚热带植物暖温带植物。不同地带性植被的植物叶片热值在不同生活型间表现出相似的规律,其中亚热带常绿阔叶林表现为:乔木(19.09 k J/g)灌木(17.87 k J/g)草本(16.65 k J/g);暖温带落叶阔叶林表现为:乔木(18.41 k J/g)灌木(17.94 k J/g)草本(16.53 k J/g);不同乔木类型间均呈现常绿乔木落叶乔木、针叶乔木阔叶乔木的趋势。落叶阔叶乔木表现为亚热带暖温带,而常绿针叶乔木则呈现亚热带暖温带的趋势。此外,我们对于两个分布区域内的4种针叶树种叶片热值进行了比较,发现华北落叶松(19.32 k J/g,暖温带)杉木(19.40 k J/g,亚热带)马尾松(19.82 k J/g,亚热带)油松(20.95 k J/g,暖温带)。亚热带常绿阔叶林和暖温带落叶阔叶林植物热值的特征及其变化规律,为森林生态系统的能量流动提供了理论基础。