Abstract: On the basis of long-term (eight years) monitoring for the population dynamics of Thalassodes quadraria Guene and the structure changes of plant community as well as the climate factors in the monsoon evergreen broad-leaved forest in Dinghushan Biosphere Reserve, the interactions among them were studied. As the food resources and habitats, plants have strong effect on the population dynamics of the moth. As a feedback, the population dynamics of this insect species caused the structure changes of the plant community. Climate factors, especially rainfall, contributed much to the mortality and reproduction of the moth.

Key words: eddy covariance, CO₂ flux, net ecosystem exchange, carbon sink, Phyllostachys edulis forest.