Abstract: Transforming typical coniferous plantation to native broadleaved species plantation is a major management for plantation in subtropical China. To explore the effects of transforming coniferous to native broadleaved species plantation on the plant functional groups in understory, we investigated the diversity and community composition of understory, and analyzed the role of environmental variables on understory functional groups by multivariable statistics in southern China. The richness of understory species (woody, gramineous, vern and vine groups) in the broadleaved plantations was lower than that in the coniferous plantations, especially for xylophyta and herb groups in the Castanopsis hystrix and Mytilaria laosenis plantations (P<0.05). The first principal component axis significantly separated the understory composition of plant functional groups between the coniferous and broadleaved plantations by Principal Component Analysis (PCA). Leaf area index, average leaf angle, soil C/N, soil total phosphorus content, litterfall C/N and light transmittance well explained the variations in the understory plant functional groups by redundancy analysis (RDA), with values of  33%, 13%, 6%, 5%, 2% and 2%, respectively. These results suggest that changes of canopy structure induced by forest transformation rather than soil physicochemical properties result in the variation of the understory plant functional groups.

Key words: spatial and temporal distribution, mycorrhizal symbiosis, biodiversity, sustainable agriculture