摘要
地处澜沧江下游热带北缘与南亚热带过渡带的糯扎渡自然保护区,是中国南亚热带森林生态系统类型的自然保护区。本文以糯扎渡自然保护区主要森林类型为研究对象,利用相关分析和典范对应分析(CCA)研究了地形和乔木结构对该区域林下不同生长型地表植物生长与分布格局的影响。结果表明:地形和乔木结构对热带北缘与南亚热带过渡区林下3种生长型地表植物(灌木、层间植物和草本)的生长和分布格局的影响显著,其中地形和乔木结构对灌木生长的作用大于草本,除坡度和乔木密度外,其余指标对灌木盖度或灌木高度的影响达显著水平。地形和乔木结构对林下不同生长型植被种类组成和结构的影响是不同的,按影响程度大小,影响灌木层种类组成和结构的主要因素依次为胸高断面积、树高、乔木种数和香浓维纳指数,对于层间植物,则依次为胸高断面积、树高、海拔、乔木种数和乔木盖度,对于草本层,则依次为胸高断面积、乔木种数、坡向和树高。就整体而言,乔木结构对林下植被结构和种类的影响大于与地形因子,地形因子中,仅海拔和坡向分别对林下层间植物和草本分布的影响显著,说明乔木结构是小尺度研究中影响林下水热条件的主要因子,但海拔和坡向对它们也有较大的影响。
Nuozadu Nature Reserve located in the transitional area between China’s southern subtropical zone and the noruthern edge of the tropical zone is a forest ecosystems nature reserve of 216.8 km2 in south of Yunnan Province. Much of the environmental variability controlling the spatial patterns of ground cover might be attributed to topographical variations and their influence on soil-light-water distribution, and tree structure such as canopy vegetation and canopy gaps, which, affecting growth and mortality of understory plants. In this paper, Tto study the impacteffects of topography and tree structure on the understory plants in the transitional area between China’s southern subtropical zone and the noruthern edge of the tropical zone, we took the main forest types of Nuozadu nature reserve as the object of study and used correlation analysis and canonical correspondence analysis （CCA） in analyzing the effects of topographic and tree structure variations on the growth and distribution patterns of understory plants with different growth forms by regarding the main forest types of Nuozadu nature reserve as the object of study. The results show It was observed that the topographical variations and tree structure factors haved significantly integrative effects on the growth and distribution patterns of three growth forms （shrub, inter stratum plant and herb）. The shrub growth wais more sensitively to those factors than herb growth based on correlation analysis., Eexcept slope grade and tree density, others factors have there existed highly significant impacts on or very significant relationships between the others factors and shrub coverage or shrub height. The responses of understory plants of differrent growth forms to the topographic and tree structure factors on the ecological distribution waares different with differrent growth forms based on the correlation coefficients of CCA. The main factors influencing the ecological distribution of the shrub species are ranked as basal area at breast height, tree height, the number of tree species and Shannon-Weine index based on their importance;, as forthose on the inter stratum species, the ranked ias basal area at breast height, tree height, altitude, the number of tree species and tree coverage;, for and those on the herb species, the ranked ias basal area at breast height, the number of tree species, slope aspect and tree height. On the whole, theOverall, the influence degree of the stand structure parameters on the ecological distribution of understory plants iwas bigger than that of topographical variations., and aAmong the topographical factors, only altitude and slope have significant influences on ecological distribution of inter stratum plants and herb species aspect was respectively, significantly related with the ecological distribution of the interstratum plants and herb specieswhich suggestinged that in small-scale study tree structure variations are were the major factors that affecting the water and heat conditions of understory, but and elevation and slope aspect also have a greater impacts on them in small-scale study.
出处
《资源科学》
CSSCI
CSCD
北大核心
2012年第7期1232-1239,共8页
Resources Science
基金
科技部基础性工作专项(编号:2008FY110300)
国家973课题(编号:2009CB421106)
国家自然科学基金(编号:31070384)
关键词
地形
乔木结构
热带北缘
林下植被
典范对应分析
Topography
Tree structure
Transitional area
Understory plants
Canonical correspondence analysis
