宁夏贺兰山种子植物区系垂直分布格局及其气候解释

Altitudinal Patterns of Seed Plants Floristic Composition and Their Climatic Explanation in Helan Mountain Nature Reserve,Ningxia Province

根据我国种子植物区系地理划分,结合当地考察资料,探讨了宁夏贺兰山自然保护区种子植物及不同分布区类型的垂直分布格局,并利用SPSS软件对物种丰富度和气候因子进行了回归分析。结果表明,宁夏贺兰山种子植物以温带区系成分为主,约占73.9%,植物物种丰富度沿海拔梯度呈单峰分布,在2 000 m左右达到峰值,在高海拔地区(2 600 m以上)物种丰富度变化不明显。回归分析结果表明,种子植物和温带区系成分垂直分布格局主要受年均温和年潜在蒸散量影响,世界分布垂直分布格局受年均温、年潜在蒸散量、年降水量和最冷月均温影响,热带区系成分垂直分布格局受年均温、年潜在蒸散量、年降水量、最冷月均温和最冷季降水量影响。

Based on floristics of seed plants from China and documented data,we explored the patterns of seed plants richness along an altitudinal gradient in Mountain Helan Nature Reserve,Ningxia Province,China. Regression analysis of species richness and climatic factors was carried out by SPSS software. The results indicated that the main component of seed plants was temperate elements（ 73. 9%）. The species richness of seed plants and its floristic composition showed a unimodal pattern along the altitude in Mountain Helan Nature Reserve,up to peak value at about 2 000 m,species richness was not significantly changed at high altitude region（ above 2 600 m）. Annual mean temperature and annual potential evapotranspiration was the variable to explain the altitudinal pattern of seed plants and temperate elements species richness. In addition to these two climatic factors,cosmopolitan was influenced by min temperature of coldest month and annual precipitation,and tropical elements was influenced by min temperature of coldest month,annual precipitation and precipitation of coldest quarter.