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【作者】唐志尧

【学号】10015817

【毕业学校】PKU

【答辩时间】2003.12.15

【培养单位】环境学院

【学位名称】理学博士

【中文题名】秦岭山脉植物多样性的分布格局

【外文题名】Patterns of plant species diversity in Qinling Mountains, Central China

【专业】自然地理学

【导师】方精云

【导师单位】环境学院

【关键词/主题词】Rapoport法则;海拔;气候;物种库;植物群落

【中文摘要】本文分析了不同尺度上秦岭山脉植物多样性的分布格局以及形成这种格局的原因。1．狭义的秦岭山脉平均海拔为1092 m；平均坡度为15.5度。南北坡的气温差异较小，而降水差异较大；2．248样方可划分为17个植物群丛和14个群丛亚型。这些群落具有明显的梯度格局：温度和海拔梯度是主要梯度，而经纬度是次要梯度；坡度和坡向主要影响群落中草本植物的组成；3．不同生活型植物的α多样性分布格局差异较大：草本植物不具有显著的海拔梯度格局；而木本植物多样性随着海拔的升高而减小。木本植物多样性与海拔呈负相关关系，与温度呈正相关关系；草本植物多样性与群落总盖度、灌木层盖度以及坡度呈负相关关系；4．β多样性受到取样面积距离的影响。相邻样方之间的β多样性随海拔升高而降低。不同群落内的种面积关系符合幂函数方程：S=c·Az。5．γ多样性随着海拔的升高而急剧减小；不同科的植物沿海拔梯度的分布格局有所不同；特有物种的多样性在中海拔最大，而特有度随着海拔的升高而增加。6．在经过充分调查的基础上，某一区域内的物种库可以通过包含了不同群落类型的种面积关系估算：S=a•ln(A)+b。

【外文摘要】Patterns of biodiversity along environmental gradients are fundamental in the study of biodiversity. Qinling Mountain Range is one of the most species rich areas in China. As patterns along environmental gradients are significantly scale dependent, in this study I explored the physical characteristics, altitudinal patterns of plant species richness and its controlling factors in Qinling Mountains at three scales, i.e., α, β, and γdiversity. Based on these studies, I estimated the regional species pools of several mountains in this area by analyzing the species area relationships (SAR). I applied Rapoport’s rule to test its ability to explain plant diversity patterns along altitudinal gradients in temperate mountains. The results are summarized as follows: 1.The Qinling Mountains range 500 km from east to west and 250 km from south to north, with an area of 71,092 km2 and an average elevation of 1092 m. The area of each elevational band varies significantly, the largest of which at about 1000 m a.s.l., then decreasing with increasing elevation. The average slope of this area is 15.5 degrees. The area of each slope band decreases with increasing inclination, with land at less than 5 degrees having the largest area. There is no significant difference of areas among various aspects. Mean annual temperatures (MAT) on southern and northern slopes of Qinling Mountains are 10.9℃ and 10.4℃, respectively; the difference is much less than we thought before. 2. 248 releves composed of 710 species were categorized to 17 associations and 14 sub-associations. The results of DCA ordination indicate that MAT and elevation gradients are the primary factors determining the distribution of plant communities, and latitudinal and longitudinal the secondary ones. Inclination and exposure play important roles in determining the distribution of herbaceous species. 3. Patterns of αdiversity vary among different layers of the communities. No significant pattern of herbaceous plant diversity appeared along the altitudinal gradient, while the number of woody plants decreased with increasing elevation. The correlations among species richness and environmental variables suggest that woody species richness negatively correlates with elevation, and thus positively to MAT. Conversely, herbaceous species richness correlates positively with elevation, and negatively to the community coverage, shrub layer coverage, and inclination. 4. ß diversity is influenced by the releve area and the distance between releve pairs, and the influences are significantly related to community type. ß diversity of continuous releves decreases with increasing elevation. There is a positive correlation between ß diversity of woody and herbaceous plants, indicating that the turnover rates of woody and herbaceous may be mutually dependent. ß diversity of woody plants surpasses that of herbs when the elevational distance of a releve pair exceeds 500 m, but is lower when the distance is less than 500 m. The SAR of each community type can be fitted to a power equation, S=c·Az. 5. No significant patterns ofγdiversity and species density are identifiable below 1500 m a.s.l., but they decrease with increasing elevation above 1500 m. Patterns of species richness for different families are inconsistent because of the different determinants. There are 162 plant species have distributions limited to this area. The number of endemic species is highest at mid-elevation, while endemism increases with increasing elevation. 6. The species pools of specific regions can be estimated by the species area relationship of inter-communities, which can be fitted as following equation: S=a•ln(A)+b.

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