Abstract:

According to the theory of forest growth cycle, forest communities are dynamic mosaic systems composed of patches in different developmental stages. On basis of the quandrats investigation carried out in a 1 hm² tropical montane rain forest in Bawangling, Hainan Province, the community characteristics of the whole forest stand were analyzed.The population and community features were studied based on the theory of forest cycle. The result showed that the utilization of ecological resources in the horizontal and vertical directions for trees of different life forms were relatively separate. Most shrubs and small statured trees had greater niche breadth values in the horizontal direction, and had less niche breadth values in the vertical direction ,and those for the middle or tall trees were on the contrary. The niche breadth for the rare and low density species were the least in both directions. With the progress of forest cycle, the frequency of different species presented in different patch types changed accordingly. The distribution patterns for most dominant trees and shrubs in the community were clumped, those for the trees having moderate individuals were uniform, and those for the low density species were random. In the process of forest cycle, the individuals owned by each species and the space occupied by each species decreased gradually. The numbers of species in different patch types in the forest cycle decreased with the increase of numbers of individuals. The numbers of species with 1 individuals and 2 individuals were most abundant ,and the numbers of species with more than 3 individuals decreased apparently in the investigated forest. Similarity analysis showed that the dynamic changes of patches in the forest cycle were somewhat continuous and gradual, the similarities between the neighboring stages were greater than those non_neighboring stages in the forest cycle. Calculation of niche breadth for different species on basis of the theory of forest cycle showed that the utilization of ecological resources in different patches by the low density species or those confined only in certain patches were comparatively less, while those species presented in most patches and had moderate numbers of individuals or moderate basal areas had greater utilizations for the ecological resources in the forest cycle.

Key words: Forest cycle, Community, Niche, Species diversity, Tropical rain forest