兴安落叶松种群格局的分形特征信息维数

种群格局信息维数能够刻划格局强度的尺度变化程度,揭示出种群个体分布的非均匀性状况。采用信息维数对大兴安岭兴安落叶松种群格局的研究显示,各类兴安落叶松林中兴安落叶松种群格局的信息维数大小依次为越桔－兴安落叶松林（１．４８０）＞杜香－兴安落叶松林（１．３７３）＞杜鹃－兴安落叶松林（１．３２１）＞草类－兴安落叶松林（１．０９３）。虽为群落建群种,兴安落叶松种群格局的信息维数较低（＜１．５,远离２）,格局     

兴安落叶松种群格局的分形特征——关联维数

种群格局关联维数揭示出个体空间关联的尺度变化规律,表明种群个体的空间相关程度。采用关联维数对大兴安岭兴安落叶松种群格局的研究表明,各类兴安落叶松林中兴安落叶松种群格局具有较高的关联维数（接近２）,个体空间关联程度较高,其次序为杜鹃－兴安落叶松林（１．７４６）＞草类－兴安落叶松林（１．７４０）＞越桔－兴安落叶松林（１．５５０）＞杜香－兴安落叶松林（１．４６８）。兴安落叶松－白桦林中兴安落叶松种群格局的关联维数较小（＜１．５１２,远离２）,个体间关联较弱,处于劣势伴生地位。通过将各天然森林类型与兴安落叶松人工林比较显示,个体空间相关程度由高至低的次序为兴安落叶松人工林（１．７６２）＞兴安落叶松天然林（１．６２６）＞兴安落叶松－白桦林（１．４３４）,揭示出兴安落叶松种群在不同森林类型中个体空间关联的尺度变化的差异。文中还对综合运用各种分形维数揭示种群格局尺度变化特征的问题进行了讨论。     

北京东灵山地区植物群落多样性研究

友样带法研究了北京东灵山地区落叶阔叶林物种组成随海拔梯度表现出的变化格局。通过变换分割样带的尺度,考察了环境的中变化对群落主要组成物种的分布及优势程度的影响。东灵山落叶阔叶林优势各辽东五角枫几乎遍布整个样带,其它伴生乔木对种表现出明显的分布替代格局,以占据率和单种率考察了尺度地群落特征分析的影响。本区落叶阔叶林１ｍ样带了佳分割尺度为：乔木层４０ｍ,更新层８０ｍ、灌木层２０ｍ。样带法在研究植物群落随     

北京东灵山地区植物群落多样性研究Ⅷ.群落组成随海拔梯度的变化

以样带法研究了北京东灵山地区落叶阔叶林物种组成随海拔梯度表现出的变化格局。通过变换分割样带的尺度,考察了环境的局部变化对群落主要组成物种的分布及其优势程度的影响。东灵山落叶阔叶林优势种辽东栎和五角枫几乎遍布整个样带,其它伴生乔木树种表现出明显的分布替代格局。以占据率和单种率考察了尺度对群落特征分析的影响。本区落叶阔叶林１ｍ样带最佳分割尺度为：乔木层４０ｍ,更新层８０ｍ、灌木层２０ｍ。样带法在研究植物群落随环境梯度变化格局中具有重要价值。     

中国东北地区阔叶红松林与兴安落叶松林的碳通量特征及其影响因子比较

北半球中高纬度的森林生态系统在全球碳循环过程中扮演着非常重要的角色。基于中国东北地区阔叶红松林与兴安落叶松林2007年和2008年2a生长季的涡度相关通量资料及气象观测资料,比较分析了两类生态系统的碳通量特征及其环境控制因子。结果表明:研究期间,阔叶红松林与兴安落叶松林都表现为碳吸收,强度分别为199gCm-2(阔叶红松林2a生长季平均值)与49gCm-2(兴安落叶松林2008年生长季);阔叶红松林碳吸收强度在生长季的大部分时段都大于兴安落叶松林。半小时尺度上,两类生态系统的呼吸作用均与10cm土壤温度呈显著的指数相关,兴安落叶松林生态系统呼吸的温度敏感性(Q10=3.44)显著大于阔叶红松林(Q10=1.90);日尺度上,阔叶红松林与兴安落叶松林碳释放/吸收的转变临界温度为10℃左右。研究期间,兴安落叶松林生态系统的水分利用效率高于阔叶红松林生态系统。     

大兴安岭林区兴安落叶松人工林土壤有机碳贮量

通过样地调查,研究了大兴安岭林区10、15、26和61年生兴安落叶松人工林0～ 40cm土壤有机碳(SOC)贮量,以及原始兴安落叶松林皆伐后营造人工林过程中SOC碳源/汇的变化.结果表明:随林龄的增加,兴安落叶松人工林SOC贮量呈现先减少后增加的趋势,转折点在林龄15 ～26 a.与原始落叶松林相比,兴安落叶松人工林土壤碳库初期(10 ～26 a)表现为碳源,之后逐渐转变为碳汇,林龄61 a时SOC贮量达158.91· hm-2.兴安落叶松人工林土壤碳库的垂直分布表现为初期下层SOC贮量高于上层,26 a后上层高于下层,说明人为干扰对该地区森林土壤碳库垂直分布产生了强烈的影响.大兴安岭林区兴安落叶松人工林的主伐年龄以＞60 a为宜.     

兴安落叶松种群格局的分形特征

种群格局关联维数揭示出个体空间关联的尺度变化规律,表明种群个体的空间相关程度。采用关联维数对大兴安岭兴安落叶松种群格局的研究表明,各类兴安落叶松林中兴安落叶松种群格局具有较高的关联维数(接近2),个体空间关联程度较高,其次序为杜鹃-兴安落叶松林(1.746)＞草类-兴安落叶松林(1.740)＞越桔-兴安落叶松林(1.550)＞杜香-兴安落叶松林(1.468)。兴安落叶松-白桦林中兴安落叶松种群格局的关联维数较小(＜1.512,远离2),个体间关联较弱,处于劣势伴生地位。通过将各天然森林类型与兴安落叶松人工林比较显示,个体空间相关程度由高至低的次序为兴安落叶松人工林(1.762)＞兴安落叶松天然林(1.626)＞兴安落叶松-白桦林(1.434),揭示出兴安落叶松种群在不同森林类型中个体空间关联的尺度变化的差异。文中还对综合运用各种分形维数揭示种群格局尺度变化特征的问题进行了讨论。     

兴安落叶松种群格局的分形特征:计盒维数

分形维数是分形体填充空间程度的度量,种群格局计盒维数能够揭示出种群格局的空间占据程度及其尺度变化规律,拐点尺度指示出个体聚集尺度。本文应用计盒维数对大兴安岭主要森林类型中兴安落叶松种群空间格局进行的研究表明,兴安落叶松种群格局均具有统计自相似性。各类兴安落叶松林中兴安落叶松种群格局具有较高的计盒维数(> 1.5,接近2),对空间占据程度较高,建群和优势地位明显,空间占据程度的强弱次序为越桔-兴安落叶松(1.829) > 草类-兴安落叶松林(1.720) > 杜鹃-兴安落叶松(1.705)杜香-兴安落叶松林(1.513)。兴安落叶松-白桦林中,兴安落叶松处于劣势伴生地位,种群格局的计盒维数较低(1.371,远离2),空间占据程度低。通过对天然森林类型中兴安落叶松种群格局的计盒维数与兴安落叶松人工林的比较发现,兴安落叶松种群空间占据程度由高至低的次序为兴安落叶松人工林(1.868) > 兴安落叶松天然林(1.692) > 兴安落叶松-白桦林(1.371),揭示出兴安落叶松种群在不同森林类型中地位和作用的差异。     

中国东北落叶松属植物亲缘关系的研究

本文用RAPD方法对中国东北落叶松属植物的亲缘关系进行了研究。从100个引物中筛选出41个引物,检测出120个多态位点。应用UPGMA法计算了种群内和种群间的遗传距离,并构建了系统树。实验结果表明,分布在长白山的落叶松与分布在大、小兴安岭的落叶松之间的差异,在遗传距离上还不能达到种间分化水平。分布在长白山的落叶松应视为兴安落叶松种下的变种,分布在东京城的落叶松可能是兴安落叶松与长白山落叶松的杂交种。     

兴安落叶松种格局的分形特征：计盒维数

分形维数是分形体填充空间程度的度量,种群格局计盒维数能够揭示出种群格局的空间占据程度及其尺度变化规律,拐点尺度指示出个体聚集尺度。本应用计盒维数对大兴安岭主要森林类型中兴安落叶松种群空间格局进行的研究表明,兴安落叶松种群格局均具有统计自相似性。各类兴安落叶松林中兴安落叶松种群格局具有较高的计盒维数（＞１．５,接近２）,对空间占据程度较高,建群和优势地位明显,空间占据程度的强弱次序为越桔－兴空落叶     

贵州野钟保护区黑叶猴种群数量、分布及夜宿洞穴调查

正黑叶猴(Trachypithecus francoisi)是国家一级重点保护野生动物,也是少数仅分布在喀斯特石山地区的灵长类动物(Rowe,1996),曾在我国南部分布广泛,数量较多,在20世纪以前,野生种群数量约有3 500只(张荣祖等,2002),其中广西的种群数量约为2 200-2 500只(刘万福和韦振逸,1995),贵州数量估计为946-1 094只(李明     

Between-forest variation in vertical stratification of drosophilid populations

Abstract 1. The spatial distribution pattern of forest‐dwelling drosophilid flies was compared among species and among four forests with markedly different vertical foliage structures, including secondary and primary forests, with special reference to vertical stratification. 2. All 20 drosophilid species analysed showed vertically stratified distribution patterns, which were detected statistically in at least one forest site during the 2‐year study period. As a whole, the vertical distribution patterns were stable, with or without stratification, over the 2 years. 3. The ratio of species with stratified distribution to the total number of species changed in a similar trend with the vertical foliage complexity of forests, both showing a large gap between secondary and primary forests, even for species common to all four forests. 4. Many species, most of which were tree‐sap feeders, showed highly predictable patterns of vertical stratification across forests and years. This was associated strongly with regular preference for microhabitat, mostly for the canopy, suggesting that the unvarying nature of canopy environments in any forest is very important in producing, maintaining, and promoting the vertical stratification in organism abundance, and contributes to the ubiquity of the pattern. 5. Some species with a wider range of food resources than other species, most of which showed no clear preference for the canopy, were characterised by large between‐forest differences in vertical distribution patterns and tended to show non‐stratified patterns in secondary forests, contributing to the lower ratio of species with stratified distribution in the two secondary forests than in the primary forests. 6. The role of forest structure in organising the environment is discussed; it is suggested that vertical complexity of foliage structure affects the prevalence of vertical stratification in animal communities indirectly through the vertical heterogeneity of environmental conditions.     

On Dispersal Efficiency of Picea Pollen

To learn the dispersal efficiency of picea pollen, surface samples was collected from four Picea forests and adjacent areas in Nei Monggol and Xinjiang Autonomous regions. In the Picea forests at least half and up to 80% of the pollen are of Picea, whereas it is 30% 30 meters away from the forests. In a distance of 500 meters from the margin of the Picea forest it could be as low as 1%. However it also scatters within a radius at least 150Km. Only when the Picea pollen content is higher than 15%, can ir indicate the growth of Picea within an area of dozens of kilometers. Wind velocity and direction as well as the topographic conditions are also important factors affecting dispersal efficiency of Picca pollen. The dispersal pattern for Pious, Abies and Picea are different.     

Gap disturbances in northern old‐growth forests of British Columbia,Canada

Abstract. We characterized the abundance, size and spatial patterning of canopy gaps, as well as gap‐forming processes and light availability in boreal, sub‐boreal, northern temperate and subalpine old‐growth forests of northwestern British Columbia. The proportion of area in canopy gaps ranged from 32% in northern temperate forests to 73% in subalpine forests. Evenly distributed developmental gaps were dominant but permanent openings created by edaphic components and by shrub communities were also common, particularly in subboreal forests. Abundant gaps, large gap sizes, high numbers of gap makers per gap and frequent gap expansion events suggest that gaps have long tenure in these forests. Snapped stems and standing dead mortality were the most common modes of mortality in all forest types resulting in little forest floor disturbance, creating few germination sites for seedling establishment. We found high mean light levels (16–27% full sun) and little difference between non‐gap and gap light environments. Our results suggest that gap dynamics in these forests differ fundamentally from those in temperate and tropical forest ecosystems.     

Variation in the population structure between a natural and a human‐modified forest for a pioneer tropical tree species not restricted to large gaps

The distribution of tree species in tropical forests is generally related to the occurrence of disturbances and shifts in the local environmental conditions such as light, temperature, and biotic factors. Thus, the distribution of pioneer tree species is expected to vary according to the gap characteristics and with human disturbances. We asked whether there was variation in the distribution of a pioneer species under different environmental conditions generated by natural disturbances, and between two forests with contrasting levels of human disturbance. To answer this question, we studied the distribution patterns and population persistence of the pioneer tree species Croton floribundus in the size and age gap range of a primary Brazilian forest. Additionally, we compared the plant density of two size‐classes between a primary and an early successional human‐disturbed forest. Croton floribundus was found to be widespread and equally distributed along the gap‐size gradient in the primary forest. Overall density did not vary with gap size or age (F‐ratio = 0.062, P = 0.941), and while juveniles were found to have a higher density in the early successional forest (P = 0.021), tree density was found to be similar between forests (P = 0.058). Our results indicate that the population structure of a pioneer tree species with long life span and a broad gap‐size niche preference varied between natural and human‐disturbed forests, but not with the level of natural disturbance. We believe this can be explained by the extreme environmental changes that occur after human disturbance. The ecological processes that affect the distribution of pioneer species in natural and human‐modified forests may be similar, but our results suggest they act differently under the contrasting environmental conditions generated by natural and human disturbances.     

The diversity and distribution of lianas in the Afromontane rain forests of Ethiopia

The diversity and distribution of lianas were studied in five Afromontane rain forests of Ethiopia. Quadrats of 20 × 20 m were laid down along transects in the Bonga, Berhane‐Kontir, Harenna, Yayu and Maji forests. In all forests, 30,917 liana individuals belonging to 123 species in 87 genera and 40 plant families were recorded. The most species‐rich families were Asclepiadaceae (14), Fabaceae (9), Annonaceae (7) and Cucurbitaceae (7). The top 10 dominant families represented 56% of the total number of species. Over 400 other plant species representing different life forms were recorded growing together with lianas. The lianas accounted for over 30% of the total woody plant diversity and over 20% of the total floral diversity in the study areas. The analysis of floristic composition of the forests indicates that the Berhane‐Kontir Forest had the highest Fisher's diversity index α, and Yayu the lowest. Generally, there were low similarities between the forests in terms of species composition. Although lianas were abundant in almost all forests, there was a considerable variation among the forests in terms of density and spatial distribution. The major dispersal modes of lianas were anemochory (30%), mammaliochory (30%), ornithochory and autochory, and the four mechanisms of climbing of lianas were twining (54%), hooking (24%), rooting and use of tendrils. Altitude and human disturbance were found to be important factors affecting liana distribution. The need for sustainable management and use of lianas in the Afromontane rain forests is emphasized.     

Modelling Direct Radiation and Canopy Gap Regimes in Tropical Forests

Spatial and temporal variation in the below‐canopy light environment of tropical forests is not well known and its measurement is technically challenging. Distributions of gap and understory areas in forests are likewise little known because of the resource requirements of forest structural censuses and a lack of consensus over how gaps should be defined. A basic model of forest structure, based on tree allometries from the 50 ha Forest Dynamics Plot on Barro Colorado Island (BCI), Panama, and a solar positioning algorithm were used to predict spatial and temporal variation in the distribution of direct light at the forest floor. Predicted duration of direct sunlight was then compared with the distribution of gap and understory areas, delimited according to four standard gap definitions, giving predictions for the correspondence between direct light regimes and forest structure. At least 36 percent of the areas of gaps of all sizes was predicted to receive < 1 h of direct sunlight per day, and the understory to receive direct sunlight for ≥ 1 h per day in up to 15 percent of its area, even when not in proximity to gaps. The predicted distribution of light changed over the course of the year with the greatest spread of light throughout the forest floor coinciding with the months when maximum daily solar elevation peaked. These predictions suggest a partial decoupling of light regimes from canopy structure, with implications for gap definitions, patch models of forest development and current understanding of tree seedling recruitment patterns.     

木质藤本及其在热带森林中的生态学功能

木质藤本是热带森林的一个重要组分,直接或间接地影响着森林中树木的生长和更新,改变森林树木的种类组成,并且可以通过改变森林碳固定量等方式在生态系统水平上发挥作用。全球气候的变化,以及热带森林片断化程度的加剧,将很大程度上影响着木质藤本的多样性和丰富度,其特殊的生物学特性将在森林动态中发挥更加重要的作用。本文结合国内外目前木质藤本研究现状,概述了木质藤本的一般知识（包括木质藤本的定义和生物学特性等）,介绍了木质藤本全球分布格局、其多样性维持机理以及木质藤本在森林生态系统中的功能与作用,并就存在的一些问题以及需进一步开展的工作展开了讨论。     

木质藤本及其在热带森林中的生态学功能

木质藤本是热带森林的一个重要组分, 直接或间接地影响着森林中树木的生长和更新, 改变森林树木的种类组成, 并且可以通过改变森林碳固定量等方式在生态系统水平上发挥作用。全球气候的变化, 以及热带森林片断化程度的加剧, 将很大程度上影响着木质藤本的多样性和丰富度, 其特殊的生物学特性将在森林动态中发挥更加重要的作用。本文结合国内外目前木质藤本研究现状, 概述了木质藤本的一般知识(包括木质藤本的定义和生物学特性等), 介绍了木质藤本全球分布格局、其多样性维持机理以及木质藤本在森林生态系统中的功能与作用, 并就存在的一些问题以及需进一步开展的工作展开了讨论。