Wednesday, August 5, 2009
Exhibit Hall NE & SE, Albuquerque Convention Center
Min Cao, Liqing Sha and Luxiang Lin, Xishuangbanna Tropical Botanical Garden, CAS, Kunming, China
Background/Question/Methods Study of large forest dynamics plot has become an important approach to tackle complicated ecological questions such as mechanisms maintaining rainforest diversity and driving rainforest dynamics under the scenario of global climate changes. Following the mapping and tagging method used by the Center for Tropical Forest Science in forest dynamics plots worldwide, we established a 400 m×
500 m forest dynamics plot in a dipterocarp rainforest in Xishuangbanna, southwest China, where rainforest almost reaches northernmost margin. All free-standing trees ≥1 cm dbh in the 20-ha plot were identified and their locations mapped. Results/Conclusions A total of 95834 trees were recorded, in which 95498 trees (accounting for 99.65% of the total) were identified to 468 species or morphospecies that belong to 213 genera and 70 families. Pittosporopsis kerrii (20918 stems ≥1 cm dbh) of Icacinaceae and Parashorea chinensis (7919 stems ≥1 cm dbh) of Dipterocarpaceae were the two most abundant species dominating the emergent layer and treelet layer respectively. Only thirteen of the 468 species (2.78%) had more than 1000 individual ≥1 cm dbh, which represented 56.36% individuals of the total. On the other hand, 230 of 468 species (49.14%) had a mean density of ≤1 tree per ha, and 69 of 468 species (14.74%) were represented by singletons. The mean species richness, density and basal area per ha were 216.50 species, 4791.70 stems and 42.34 m2 respectively. The distributions of species richness and abundance varied across the plot. Most of the species exhibit a strong aggregated distribution in of small size classes but a rather random distribution in large size classes. Compared with other 50-ha plots established in equatorial regions, tree species richness per ha and tree abundance per ha of the plot were at moderate level. The flora of the plot is composed mainly by tropical families and genera. At genus level, 38% of the total genera are of tropical Asian distribution indicating a close affinity with flora of tropical Asian.