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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。
Located in the Nuozhadu Nature Reserve, a tropical subtropical forest ecosystem in the lower reaches of the Lancang River and the Nuozhadu Nature Reserve in the subtropical zone. In this paper, the main forest types of Nuozhadu Nature Reserve were studied, and the effects of topography and arborist structure on the growth and distribution pattern of different growth types of understory plants were studied by correlation analysis and Canonical Correspondence Analysis (CCA). The results showed that topography and tree structure had significant effects on the growth and distribution patterns of three kinds of growth surface plants (shrubs, interlaces and herbs) under the forest in the tropical and southern subtropical transitional regions. The topography and tree structure Is greater than that of the herb. Except slope and tree density, the other indexes have significant effects on shrub cover or shrub height. The effects of topography and tree structure on the composition and structure of different growth types are different. According to the degree of influence, the main factors influencing the composition and structure of shrub layer are thoracic high area, tree height, arbor species and fragrant concentration Wiener index. For interpland plants, the area of chest height, height of tree, altitude, the number of arbor species and arbor coverage were the order of succession, followed by the area of chest height, arbor species, aspect and tree height. Overall, the effect of tree structure on the structure and type of undergrowth vegetation is greater than that on topographic factors. Among the topography factors, only the elevation and the slope direction have a significant impact on the distribution of plants and herbs in the undergrowth, indicating that the tree structure is a small scale The main factors affecting the hydrothermal conditions in the forest are studied, but the elevation and aspect also have a greater impact on them.