地形对喀斯特山地植物物种多样性及分布格局的影响

目的]研究地形对喀斯特地区植物物种多样性与分布格局的影响,为喀斯特区生态保护与维持提供科学依据。方法]利用方差分析、典范对应分析(CCA)研究贵州省施秉县喀斯特山地不同地形下乔木、灌木和草本植物物种多样性差异及地形因子对其分布格局的影响。结果]乔木在山顶的均匀度显著低于其他坡位;优势度显著高于其他坡位。灌木在山顶的多样性显著高于下坡和河谷;丰富度为山顶显著高于中、下坡和河谷,上坡显著高于下坡和河谷;河谷的优势度显著高于山顶。草本的多样性为山顶显著低于中、下坡和河谷;丰富度为山脊和山顶显著低于中、下坡和河谷;优势度与多样性表现相反。半阴坡的草本丰富度显著大于半阳坡。坡度对乔木丰富度与多样性的影响一致,均为平坡显著大于缓坡和斜坡,陡坡显著大于斜坡;均匀度为斜坡显著低于平坡和陡坡,优势度与均匀度表现相反。CCA排序表明,海拔和坡度对3种生长型植物分布格局的影响均显著,坡位对乔木分布格局的影响显著,坡向对3种生长型植物分布格局的影响均不显著。结论]喀斯特区植物物种多样性及其分布格局受以海拔、坡度为主,坡位和坡向为辅的多个因子共同的影响。

Effects of Topography on Diversity and Distribution Pattern of Plant Species in Karst Mountains Area

Objective] The influence of topography on the diversity and distribution pattern of plant species in karst areas was studied, in order to provide scientific basis for ecological protection and maintenance in this region.Methods] Variance analysis was used to study the species diversity of trees, shrubs and herbs under different topographic in Shibing karst area of Guizhou Province, and canonical correspondence analysis(CCA) was used to study the effects of topographic factors on their distribution patterns.Results] The evenness of trees at the top of mountain was significantly lower than other slopes, while the dominance was significantly higher than other slopes. The diversity of shrubs at the top of mountain was significantly higher than that at the downhill and valley. The richness at the top of mountain was significantly higher than that at the middle slope, downhill slope and valley, and the uphill was significantly higher than that of the downhill and valley. The dominance of valley was significantly higher than that of the top of mountain. The diversity of herbs was significantly lower at the top of mountain than that at the middle slope, downhill and valley. The richness was significantly lower at the ridge and the top of mountain than that at the middle slope, downhill and valley. The dominance was opposite to the diversity. The richness of herbs in semi-shady slope was significantly higher than that in semi-sunny slope. The influence of slope on the richness and diversity of trees was consistent, the flat slope was significantly higher than those on the gentle slope and slope, and steep slope was significantly higher than those on slope. The evenness of slope was significantly lower than those on flat slope and steep slope, while the dominance was opposite to the evenness. The CCA results showed that, elevation and slope had significant influence on the distribution pattern of the three types of growing plants while slope direction had no significant influence. Slope position had significant influence only on the distribution pattern of tree species.Conclusion] The diversity and distribution pattern of plant species in karst areas are influenced by many factors, elevation and slope are the main influential factors, and slope position and slope direction are the secondary influential factors.