Abstract:

In this study， we examined the ecological effect of palms on tree seedlings regeneration in a tropical lowland rain forest plot in Bawangling， Hainan Island. The results showed that there were 1 288 palm plants which belonged to 5 species in a 1 hm² plot， and Calamus faberii contributes 82.7% to the total palm plants. The mean individual crown area differed among 5 species and Livistona saribus was significantly larger than other 4 species. The palm number in each subplot showed a normal distribution. The palms abundance of the subplot was significantly negative correlated with the number of trees DBH<10 cm， but not with that of the large trees. The species richness of large seedlings， saplings， and small trees significantly decreased with increase of the palm abundance in each subplot， but no relationship was found between the richness of small seedlings and large trees with the palm abundance. The palm coverage reduced the seedlings density and there were only 18% seedlings recruited under the palms. Compared to the micro-sites with no palms cover， more small seedlings under palms recruited than large seedlings did. There were respectively 53% and 97% of species recruited in the micro-site with and without palms coverage. The short-lived pioneer species distributed exclusively in sites without palms cover. There was 11.6% and 19.8% of long-lived pioneer species seedlings and late species seedlings regenerated under palms cover， respectively.

Key words: tropical lowland rain forest, functional group, recruitment limitation, palm, seedling, Hainan Island