新疆阿尔泰山小东沟林区木本植物群落数量分类、排序及其环境解适

在野外样方调查和主要环境因子测定的基础上,利用聚类分析和DCCA排序技术对新疆阿尔泰山小东沟林区的森林植被进行类型划分,并定量分析植被与环境因子的关系。结果表明:利用聚类分析可将阿尔泰小东沟林区的木本植物群落划分为6个类型(灌丛、欧洲山杨林、苦杨林、疣枝桦林、新疆落叶松林和新疆落叶松与新疆冷杉、新疆云杉的针叶混交林)。DCCA排序分析表明,海拔和坡向等地形因子以及土壤类型、土壤全氮、土壤全磷、土壤水分含量和大石砾含量等土壤因子是影响阿尔泰林区植物分布的主要因子,林区不同群落类型的分布格局主要是由地形和土壤因子的共同作用所控制的。     

Relationships between <Emphasis Type="Italic">Artemisia ordosica</Emphasis> communities and environmental factors following sand-dune stabilization in the Mu Us desert,northwest China

Artemisia ordosica is an excellent sand-fixing shrub for sand stabilization in northwestern China. Sand dune stabilization, a critically important process, leads changes in abiotic factors, such as soil structure and nutrient contents. However, the effects of factors on an A. ordosica community following sand stabilization remain unclear. In this study, we used canonical correspondence analysis (CCA) to examine the relationships between A. ordosica communities and environmental factors at three habitats: semi-fixed dune (SF), fixed dune with low-coverage biological soil crust (F), and fixed dune with high-coverage biological soil crust (FC) in Mu Us desert. The mean height and coverage of plants increased with sand stabilization, while species diversity and richness increased initially and then reduced significantly. Correlation analysis and CCA revealed that slope, soil organic carbon, and nutrient contents, proportion of fine soil particles, soil moisture, and thickness of biological soil crust were all highly correlated with vegetation characteristics. These environmental factors could explain 40.42 % of the vegetation–environment relationships at the three habitats. The distribution of plant species was positively related to soil moisture in the SF dune. Soil moisture, soil nutrient, and fine-particle contents mainly affected plants distribution in the F dune. In the FC dune, distribution of plant species was positively and negatively correlated with the thickness of biological soil crust and soil moisture at a depth 0–20 cm, respectively. The dominance value of typical steppe species increased significantly following sand-dune stabilization and relations between species and samples in CCA ordination bi-plots showed that perennial grasses could invade the A. ordosica community on FC, indicating A. ordosica communities had a tendency to change into typical steppe vegetation with the further fixation. We conclude that the significant differentiation not only occurred in community characteristics, but also in the relationships between vegetation and environmental factors among the three stages of dune fixation. So, restoration of degraded dune ecosystems should be based on habitat conditions and ecological needs.     

Vegetation-environment relationships in the forests of Chitral district Hindukush range of Pakistan

We investigated the composition of plant communities to quantify their relationships with environmental parameters in the Chitral Hindukush range of Pakistan. We sampled tree vegetation using the Point Centered Quarter (PCQ) method while understory vegetation was sampled in 1.5-m circular quadrats. Cedrus deodara is the national symbol of Pakistan and was dominant in the sampled communities. Because environmental variables determine vegetation types, we analyzed and evaluated edaphic and topographic factors. DCA-Ordination showed the major gradient as an amalgam of elevation (p<0.05) and slope (p<0.01) as the topographic factors correlated with species distribution. Soil variables were the factors of environmental significance along DCA axes. However, among these factors, Mg2+ , K + and N2+ contributed not more than 0.054% 0.20% and 0.073%, respectively, to variation along the first ordination axis. We conclude that the principal reason for weak or no correlation with many edaphic variables was the anthropogenic disturbance of vegetation. The understory vegetation was composed of perennial herbs in most communities and was most dense under the tree canopy. The understory vegetation strongly regulates tree seedling growth and regeneration patterns. We recommend further study of the understory vegetation using permanent plots to aid development of forest regeneration strategies.     

Spatial pattern of a plant community in a wetland ecosystem in a semi-arid region in northwestern China

The spatial distribution characteristics of plant communities in a wetland-dry grassland ecosystem in arid and semi-arid regions in northwestern China and the main factors affecting the distribution pattern were studied. The Siertan wetland in the Haba Lake Nature Reserve was the study area. Four transect lines, each about 1 km long, were set up in the growing season along the biotope gradient in four directions: east, northeast, west and northwest. Attributes measured include frequency of occurrence, height, density, coverage, biomass and environmental soil factors. The data were analyzed using a two-way indicative species analysis (TWINSPAN), detrended correspondence analysis (DCA) and Spearman correlation coefficients. On this basis, the vegetation in the Siertan wetland was classified into three types and 14 associations. The first vegetation type was halophytic marsh vegetation, mainly distributed in the wetland zone. This type largely contains halophyte and hygric plants and its representative association is Phragmites communis + Kalidium foliatum. The second type was meadow vegetation, distributed in the ecotone. The meadow vegetation species are mainly mesophytic and their representative association is Nitraria tangutorum + Pennisetum flaccidum. The third vegetation type is grassland vegetation, which mainly consists of mesophytic and xerophytes, distributed in the arid grassland zone. The representative association of the third vegetation type is the association of Anaeurolepidium secalium + Saussurea runcinata. Correlation analysis between the axes of DCA and environmental soil factors shows that soil moisture content, organic matter, soil salt content and total nitrogen are the main environmental factors affecting the pattern of vegetation distribution along the biotope gradients from wetland to arid grassland. Other factors affecting the vegetation are microtopography and grazing pressure. Additionally, we have reported modifications and improvements to the importance value methodology. __________ Translated from Journal of Beijing Forestry University, 2008, 30(1): 6–13 [译自: 北京林业大学学报]     

埃塞俄比亚东南部Dello Menna森林植被的植物区系和结构分析(英文)

描述了埃塞俄比亚东南部Dello Menna森林植被的植物区系组成和植被结构。鉴定和描述了50个20m×20m的样方的植物群落类型、物种多样性、丰富度和均匀性,分析了已鉴定植物群落类型与环境因子的相关性,还描述了木本植物种群结构。每个样方内,均记录木本植物的物种、丰富度、高度和胸径以及海拔、坡度。利用PC-ORD软件对植被进行分类。用Sorensen相似性系数探测群落之间的差异性。计算Shannon-Wiener多样性指数、物种丰富度、Shannon均匀性来描述各种植物群落的物种多样性。共记录了53个科的171个维管植物种。豆科植物是主要的优势植物科系,包括13个属26种(1 5%),其次依次是菊科、唇形科和槭树科,各包括8个物种(4.6%)。根据植物分类结果,识别并描述了3个植物群落(Dalbergia microphylla群落、Grewia bicolar-Acaciabrevispica群落、Combretum molle-Combretum collinum群落)。植物区系之间的物种丰富度、多样性和均匀性存在差异。物种丰富度和多样性随海拔变化呈现出贝尔型分布。群落间植物随海拔梯度有一定的变化,表明海拔是决定植物群落分布的重要因素之一。Dalbergia microphylla群落物种丰富度和多样性均最高。优势种群落结构呈现出各种模型。植被可持续利用是今后的研究方向。     

白石砬子自然保护区森林植被和主要树种分布的环境解释

应用典范对应分析（CCA）对辽宁东部白石砬子国家级自然保护区56个样地中的森林植被和44种主要树种与8个环境因子间的关系进行了研究。结果表明，海拔高度、样地坡度、土壤有机质、林冠都闭度和土壤酸度是影响白石砬子森林树种和植被分布的主要因素。结合双向指示种分析（TWINSPAN），在CC样地一环境因子双序图上区分出8个样地组，分析了8个样地组的植被成员组成及其分布与环境因子间的关系。     

The role of graveyards in species conservation and beta diversity:a vegetation appraisal of sacred habitats from Bannu,Pakistan

Graveyards or sacred groves are often places of natural vegetation protected by spiritual believers because of their sacred beliefs and indigenous culture.A study of graveyards was conducted to determine their role in species conservation,community formation,and associated indicators and species composition using multivariate statistical approaches.It was hypothesized that variations in the age of graveyards would give rise to diverse plant communities under the impact of various edaphic and climatic factors.Quantitative ecological techniques were applied to determine various phytosociological attributes.All the data were put in MS Excel for analysis in PCORD and CANOCO softwares for cluster analysis(CA),two-way cluster analysis(TWCA),indicator species analysis and canonical correspondence analysis.CA and TWCA through Sorenson distance measurements identified five major graveyard plant communities:(1) FicusBougainvillea-Chenopodium;(2) Acacia-Datura-Convolvulus;(3) Ziziphus-Vitex-Abutilon;(4) Acacia-Lantana-Salsola;and(5) Melia-Rhazya-Peganum.Species such as Capparis decidua,Herniaria hirsuta,Salvadora oliedes and Populus euphratica were only present inside graveyards rather than outside and advocate the role of graveyards in species conservation.The impact of different environmental and climatic variables plus the age of the graveyards were also assessed for comparison of plant communities and their respective indicator species.The results indicate that higher chlorine concentration,age of graveyards,low soil electrical conductivity,lower anthropogenic activities,higher nitrogen,calcium and magnesium concentrations in the soil,and sandy soils were the strong environmental variables playing a significant role in the formation of graveyard plant communities,their associated indicators and species distribution patterns.These results could further be utilized to evaluate the role of edaphic and climatic factors,indicator species and conservation management practices at a greater scale.     

房干村石灰岩山地植物群落数量分类与排序研究

在群落样方调查基础上,采用双向指示种分析法(TWINSPAN)和除趋势对应分析(DCA)对莱芜房干村植物群落进行了数量分类和排序。TWINSPAN将20个样方分为7组,根据植被分类的原则划分为7个群落,论述了各群落的群落学特征。20个样方的DCA排序结果反映了植物群落类型与环境梯度之间的关系,表明影响群落分布格局的主要生态因子为海拔高度和坡向。     

Characteristics of soil seed bank in plantation forest in the rocky mountain region of Beijing, China

We investigated characteristics (scales and composition) of soil seed banks at eight study sites in the rocky mountain region of Beijing by seed identification and germination monitoring. We also surveyed the vegetation communities at the eight study sites to explore the role of soil seed banks in vegetation restoration. The storage capacity of soil seed banks at the eight sites ranked from 766.26 to 2461.92 seeds·m -2 . A total of 23 plant species were found in soil seed banks, of which 63 80% of seeds were herbs in various soil layers and 60% of seeds were located in the soil layer at 0 5cm depth. Biodiversity indices indicated clear differences in species diversity of soil seed banks among different plant communities. The species composition of aboveground vegetation showed low similarity with that based on soil seed banks. In the above- ground plant community, the afforestation tree species showed high importance values. The plant species originating from soil seed banks represented natural regeneration, which also showed relatively high importance values. This study suggests that in the rocky mountain region of Beijing the soil seed banks played a key role in the transformation from pure plantation forest to near-natural forest, promoting natural ecological processes, and the role of the seed banks in vegetation restoration was important to the improvement of ecological restoration methods.