喀斯特生境中山麻杆种群与环境因子的关系

Relationships between Alchornea davidii Population and Environmental Factors in Karst Habitat

岩溶适生植物在喀斯特生态系统中占有重要的地位,是退化喀斯特环境恢复的关键所在.为阐明喀斯特环境因子对岩溶适生植物山麻杆Alchornea davidii种群的影响,揭示该种群对生境的独特适应机制,该文调查和分析了喀斯特生境中山麻杆种群特征,以及地形、土壤、生物、干扰等17个环境影响因子,采用主成分分析法探究了影响种群生存和发展的主要因子,并用相关分析和回归分析进一步揭示了种群特征与环境因子的关系.结果表明:①人为干扰是山麻杆种群生存和发展最主要的影响因子,适度干扰促进种群萌生更新,有利于种群发展;②群落物种多样性对山麻杆种群影响显著,物种间的竞争作用抑制了山麻杆种群的发展;③坡度、坡向和岩石裸露程度等通过限制其他物种的分布,对山麻杆种群更新有利.山麻杆种群在喀斯特生境中具有独特的适应机制,种群能够凭借较强的萌生更新能力抵抗外界干扰,且对喀斯特复杂异质的地形具有较强适应性.因此,在喀斯特地区干扰生境的初期植被恢复中,山麻杆是一种适宜的备选物种.

Karst plant populations play an important role in the ecological system and provide unique capabilities in the process of vegetation restoration.Research on the relationships between environmental factors and plant populations has an important guiding significance to ecological management of karst plants.To determine the influences of environmental factors on the population of Alchornea davidii,and clarify the adaptation mechanisms of its population to the karst habitats,this study addressed the relationships between A.davidii population characteristics and environmental factors by investigating and analyzing population characteristics and topography,soil,biology,disturbance and other total 17 environmental factors.Principal component analysis(PCA)and factors weight were used to elucidate the degree of importance of different environmental factors.Correlation analysis and regression analysis further revealed the relationships between population characteristics and environmental factors.The results showed that:(1)Human disturbance was the most important factor that impacted the survival and development of A.davidii population.Mild interference was beneficial to the development of the population through promoting the restoration and regeneration of the population.(2)There was a significant negative correlation between the Shannon-Wiener index of the shrub layer and the population dynamic index,and population density.(3)Harsh topographical factors such as steep slope,slope aspect,relative rock exposure,and others were beneficial for regeneration of A.davidii populations by limiting the distribution of other plant species with environmental stress in terms of light,temperature and moisture.The present study indicated that the population of A.davidii had a unique adaptation mechanism to the special harsh karst habitats.The population could resist to external interference with strong regeneration ability,also had a strong adaptability to the complex and heterogeneous karst terrain.Therefore,A.davidii is suitable plant for initial stage of vegetation restoration in karst areas.