云南高黎贡山北段植物物种多样性的垂直分布格局

Vertical distribution patterns of plant species diversity in northern Mt.Gaoligong,Yunan Province

在高黎贡山北段沿海拔梯度设置17个样地,采用数量分类,对高黎贡山北段植物群落类型、物种组成和多样性的垂直格局进行了研究。结果表明:(1)随着海拔的升高,森林群落类型由常绿阔叶林(2000～2300m)依次过渡为以阔叶树为主的针阔混交林(2300～2600m)、以针叶树为主的针阔混交林(2600～3000m)和针叶林(3000～3100m);(2)木本植物的物种丰富度随着海拔高度的增加显著下降,而草本植物的物种丰富度则随着海拔高度的增加先下降,然后在林线以上显著上升;(3)木本植物β多样性随着海拔的上升呈单调下降趋势,而草本植物β多样性在中海拔附近区域较低;(4)在植物区系方面,热带亚热带成分所占比例随海拔上升而下降,温带成分、世界分布成分则随着海拔的升高而增加。中国特有分布成分所占比重较小,主要分布在中海拔区域。总体上,温带成分占主导地位。区系平衡点在海拔2100～2200m。

Seventeen sampling plots were established along an altitudinal gradient in northern Mt. Gaoligong, and the vertical distribution patterns of plant community, species composition, and species diversity were studied by using quantitative classification. The results showed that with the increase of altitude, the forest community had a transit of evergreen broad-leaved forest （2 000-2 300 m） to mixed coniferous and broad-leaved forest mainly composed by broad-leaved trees （2 300-2 600 m）, mixed coniferous and broad-leaved forest mainly composed by coniferous-leaved trees （2 600-3 000 m）, and coniferous forest （3 000-3 100 m）. The species richness and 13 diversity of woody plants decreased obviously with increasing altitude, while the species richness of herbaceous plants had an increase after an initial decrease with increasing altitude, and increased obviously over timberline. The lowest 13 diversity of herbaceous plants was found in mid-altitude region. With the increase of altitude, the proportion of tropical and subtrop- ical components decreased, while that of temperate and cosmopolitan Components increased. China endemic elements were limited in mid-altitude region. As a whole, temperate plants domina- ted the fora, and the floral balance point existed at 2 100-2 200 m.