Abstract: Through systematic location and surveys in four representative field sites in Sanming City, Fujian Province from 2001 to 2002, the diversity and stability of the arthropod communities in the pure and three different mixed types of the bamboo Phyllostachys heterocycla cv. Pubescens forests were compared and analyzed, aiming to explore the relationships between types of the bamboo forests and outbreaks of the major leaf pests such as phytophagous mites, Pantana phyllostachysae and Kuwanaspis vermiformis which heavily infested the bamboo in South China in recent years. The results showed that the arthropod richness in the bamboo forest mixed with broadleaf trees was higher than in the pure bamboo forest and in the bamboo forests mixed with Cunninghamia lanceolata or Pinus massoniana. Significantly more predatory and phytophagous arthropod species were found in the bamboo forest mixed with broadleaf trees, which mainly belong to the arthropod orders of Homoptera, Hemiptera, Coleoptera and Diptera in the lower layer of the forest and Acarina, Homoptera, Hemiptera and Coleoptera in the canopy of the forest. However, overall the species diversity, evenness and dominant concentration of the communities in the four forest types of the bamboo showed no significant differences. The common species in the predatory and phytophagous guilds between in the lower layers and the canopies of the three types of mixed forests were all more than those in the pure forest, which resulted in higher similarity of species composition between the two layers of the mixed forests. The measurements of the community stability in the four forest types showed significant differences. The stability of the canopy both in the bamboo forest mixed with broadleaf and in the pure bamboo forest was lower than in the other two mixed forests; the control effects of the natural enemies to the pests in the former two forest types were also lower, and the numbers of individuals of phytophagous mites and Kuwanaspis vermiformis on the bamboo leaves were also higher. We so suggested that in the bamboo forests hurt seriously by the two pests above, such measures as rebuilding of the bamboo forests mixed with Cunninghamia lanceolata or Pinus massoniana should be considered. 21 Refs.

Key words: Phyllostachys heterocycla cv. pubescens, arthropod communities, forest stand, mixed forest, diversity, stability