秦岭牛背梁植物物种多样性垂直分布格局  

Altitudinal patterns of plant species diversity in Mt. Niubeiliang, Qinling Mountains

作　　者：唐志尧[1] 柯金虎[1] 

机构地区：[1]北京大学环境学院生态学系

出　　处：《生物多样性》2004年第1期108-114,共7页Biodiversity Science

基　　金：国家自然科学基金项目 ( 4 99710 0 2和 3 983 0 0 5 0 );国家重点基础研究发展规划资助 (G2 0 0 0 0 4680 1)

摘　　要：基于秦岭山脉中段牛背梁自然保护区南北坡垂直样带 5 1个样方的调查资料 ,利用植被数量分析方法(TWINSPAN和DCA)对牛背梁植物群落进行了分类和排序 ,并分析了植物物种多样性沿海拔梯度的分布格局。结果表明 ,牛背梁的植被群落具有明显的海拔梯度格局 ,从低海拔到高海拔依次分布有 :锐齿槲栎 (Quercusalienavar.acuteserrata)林 ,桦木 (Betulaspp .)林 ,巴山冷杉 (Abiesfargesii)林和亚高山灌丛。海拔梯度是牛背梁山区制约植物群落分布的主要因子 ,而坡向和坡度则起到次要作用。对物种多样性的分析表明 ,物种总数、木本植物物种多样性和草本植物物种多样性在南北坡具有不同的海拔梯度格局。物种总数在南坡呈现单峰分布格局 ,而在北坡分布趋势不明显 ;木本植物物种多样性在南北坡具有相似的分布格局 :在低海拔沿海拔梯度变化不明显 ,而在高海拔则随海拔上升而急剧下降 ;草本植物物种多样性在南北坡沿海拔梯度变化的规律不明显。β多样性沿海拔梯度先减少后增加 ,形成两端高中间低的格局 ,说明中海拔地区生境条件较为均一 ,低海拔地区的人为活动增加了生境的异质性 ,而高海拔地区的生态过渡特性增加了物种的更替速率以及群落的相异性。Using quantitative analysis (DCA and TWINSPAN), the vegetation and plant species diversity patterns along the elevation gradient in Mt. Niubeiliang, Qinling Mountains were studied based on 51 plots along two altitudinal transects between 1500 m and 2800 m on northern and southern slopes. Plant communities varied continuously along the elevation gradient. From low to high elevation, mountain oak forest, mountain birch forest, subalpine fir forests and subalpine shrub occurred on both slopes. Relationship between communities and topographic variables were analyzed by detrended correspondence analysis (DCA). Elevation was the primary determinant of floristic composition in Mt. Niubeiliang, and followed by exposure. In terms of species diversity, different patterns existed among total number of species, woody species richness and herbaceous species richness, and also between southern and northern slopes. The total number of species changed unimodally with elevation on the southern slope, peaking at middle elevations. No significant relationship between total number of species and elevation was detected on the northern slope. Woody species richness changed similarly on both southern and northern slopes, keeping stable at low elevations and decreasing monotonically with the increasing elevation at high elevations. In contrast, no significant pattern of herbaceous plant richness existed along the elevation gradient. β diversity was higher at lower and higher elevations than in the mid-altitudinal zone, indicating a more homogeneous habitat at middle elevation than upper and lower elevations. Human disturbance at lower elevation and the timberline ecotone at higher elevations may contribute to the increase of β diversity in these areas.

关 键 词：Β多样性 海拔梯度 物种多样性 植物 垂直分布 

分 类 号：Q948[生物学—植物学]