Vegetation-environment Relationships Between Northern Slope of Karlik Mountain and Naomaohu Basin,East Tianshan Mountains

Based on data from 22 sample plots and applying the Canonical Correspondence Analysis （CCA）, this paper discusses the vegetation-environment relationships between the northern slope of Karlik Mountain and Naomaohu Ba- sin, which is situated in the easternmost end of the Tianshan Mountains, Xinjiang Uygur Autonomous Region, China. For the zonal vegetation, community diversity of mountain vegetation is higher than that of the desert vegetation due to environmental factors. The CCA ordination diagram revealed that the composition and distribution of vegetation types are mainly determined by altitude, soil pH and soil salt content. With increasing elevation, the soil pH and total salt content decrease but the contents of soil organic matter, soil water, total nitrogen and total phosphorus increase gradu- ally. In the CCA ordination diagrams, the sample plots and main species can be divided into five types according to their adaptations to the environmental factors. Type Ⅰ is composed of desert vegetation distributed on the low moun- tains, hills, plains and deserts below an elevation of 1900 m; type Ⅱ is distributed in the mountain and desert ecotone with an elevation of 1900-2300 m, and includes steppe desert, desert steppe and wetland meadow; type Ⅲ is very sim- ply composed of only salinized meadow; type Ⅳ is distributed above an elevation of 2300 m, containing mountain steppe, meadow steppe, subalpine meadow and alpine meadow; type Ⅴ only contains salinized meadow. The results show that with increasing elevation, species combination changes from the xerophytic shrubs, semi-shrubs and herbs distributed in the low altitude zone with arid climate to the cold-tolerant perennial herbs growing in the high altitudinal zone with cold climate.

Root Sprouts of Domesticated Phaseolus coccineus L. Overwinter Plants and the Environment at Its Collection Sites

Buds emerge from the roots of domesticated runner bean plants (Phaseolus coccineus L.) as sprouts and give the crop its persistence. This particularity of the species seems to be associated with the environment where the species was cultivated during long time. Data on regrowth traits were recorded on 70 accessions of domesticated P. coccineus after overwintering at a site in the central highlands of Mexico. The characteristics recorded included fresh weight of vegetative regrowth, root length, root crown diameter, and diameter of the main root. Most accessions that sprout the following spring, after the grain harvest of the previous year, come from temperate and semi-cold sites with cambisol and andosol soils in mixed Quercus pine forest and high mountain fir trees. Those that do not sprout are from sites of semiarid temperate climate, haplic phaeozem soil in shrub grasslands with deciduous broadleaved trees, and semiwarm subhumid climate, eutrophic regosol soil in deciduous broadleaved forest. Two types of roots were differentiated: branched and thickened taproots, also associated with a different climate, and the type of soil of the collection sites.

中国东北地区潜在自然植被模型模拟研究(英文)

以我国东北部地区为研究对象,针对区域自然植被分布特点,利用多元分析和GIS技术,建立了基于8个环境变量(气候、地形和土壤)的东北地区区域“植被-环境”模型,对当前环境条件下,东北地区潜在自然植被类型及其地理分布进行了模拟分析.经检验,“植被-环境”模型取得了较好的模拟效果,总体精度为66.91%,Kappa统计量值为0.61.在此基础上,获得我国东北地区“潜在自然植被图”.该模型可进一步用于全球变化条件下,潜在自然植被类型及其变化的预测.

Distribution of shrublands in relation to soil and climate in mid-subtropical China

Aims Understanding relationships between vegetation and environments is of importance for ecosystem restoration and management.However,information on how environments influence the floristic patterns of shrublands is lack,especially in the subtropical China.In this study,we explored how environments regulate species composition of shrublands at landscape scale in mid-subtropical China.Methods We investigated species composition and measured the climate and soil environments for 207 shrubland plots in mid-subtropical China(24°39′-30°08′N,108°47′-114°15′E).We applied a hierarchical cluster analysis and indicator species analysis based on the Bray-Curtis similarity index to identify the main shrubland types and employed principal coordinate analysis(PCoA)to explore the relationship between floristic composition and environment.Important Findings We identified four shrubland types occurring in different environmental conditions.Montane shrubland,dominated by species suitable for cool climates(e.g.Rhododendron simsii),were distributed in steep areas at comparatively high altitudes;foothill shrubland,dominated by mesophilous species(e.g.Loropetalum chinense),were distributed in low mountains and hills;pioneer shrubland,dominated by fast grow and short-life cycles species(e.g.Rhus chinensis),were distributed at low altitudes with dense population;and finally,limestone shrubland,dominated by calcicole plants(e.g.Coriaria nepalensis),were distributed in the extensive karst areas.Communities occurring in high pH soils were completely separated from those in low pH soils according to the hierarchical cluster analysis.PCoA ordination associated the four types with distinct edaphic and climatic gradients.Soil pH explained 63.3%of variation in PCoA,followed by soil depth and soil bulk density.