Rhododendron plants in Nanling mountains along an altitudinal gradient and the prospect of landscape greening.

【Objective】The objective was to determine the altitudinal pattern of Rhododendron plant distribution and the potential of using indigenous Rhododendron plant resource in landscape greening. 【Method】The continuous transect sampling method was employed and a total area of 15 600 m2was surveyed. A horizontal transect( 10 m × 120 m) was placed at an 100 m altitudinal interval from 700 m to 1 900 m a. s. l.,representing the altitudinal range of Rhododendron in Nanling mountains of north Guangdong. The contiguous grid quadrat sampling method was used for plant census in each transect,which consisted of 12 quadrats( 10 m × 10 m). Correlation analysis and two-way indicator species analysis( TWINSPAN) were used to analyze the altitudinal patterns of Rhododendron species. 【Result and conclusion】 Seven Rhododendron species were found in the 15 600 m2plot,all of which were perennial evergreen woody shrubs or small trees. These Rhododendron species were divided into three categories by TWINSPAN. The first category was R. championae,R. simiarum and R. chunii; the second was R. cavaleriei, R. kwangtungense and R. bachii,and the third was R. fortunei. These TWINSPAN results indicated that environmental factors influenced the distribution and ecological characteristics of Rhododendron species. The most widely distributed species in an altitudinal spectrum is R. cavaleriei,followed by R. bachii andR. championae. The altitudinal patterns of these native Rhododendron species reflect their bioclimatic adaptation and phenology,which have potentials for use in landscape greening.