Restoration Ecology On Evergreen Broad-leaved Forest: A Pilot Study

Maintenance, monitoring, conservation and restoration on biodiversity are the cores of biodiversity science (DIVERSITAS). The stability and restoration of evergreen broad-leaved forest, a kind of typical vegetation in the world and with the biggest distribution area in China, were concerned deeply because they were generally accompanied by mankind or agriculture especially when more and more fragmentation and island were presented. This pilot study focused on the biodiversity conservation and ecological restoration of evergreen broad-leaved forest. The results are as follows:1. Diagnosis approaches, diagnosis methods, and the possible indexes (system) on degradation degree of ecosystem were summarized. A conceptual model on the degradation degree of ecosystem was pictured. Which will help to carry on the study of restoration ecology and ecological restoration practice.2. Permanent plots (evergreen broad-leaved forest plot, evergreen and deciduous broad-leaved forest plot, eco-restoration plot), established for biodiversity monitoring and eco-restoration experiment, will promote deeply the study on biodiversity science and restoration ecology.3. A pilot analysis, on population structures of the two main species (Castanopsis fargesii and Camellia oleifera) in an evergreen broad-leaved forest community in Dujiangyan region, was reported. C. fargesii population showed a weak bimodal frequency distribution in different tree height (H) and breast-height girth (GBH) classes. C. oleifera population showed an inverse "J" frequency distribution in different H and GBH classes. We also discussed the classification standard effects of size class in population ecology. Which showed that different classification standard of size class should be selected for study according to the different aims and different species. The author suggested that the influences of island and habitat fragmentation on evergreen broad-leaved forest conservation should be studied more deeply.4. Seed rain and seed losses of a dominant tree, C. fargesii, were trapped 1.0 m above the ground A-traps and on the ground B-traps respectively with a regular deployment in a fenced evergreen broad-leaved forest site in Dujiangyan region, China. The duration of sound seed fall was about 3 months in 2001 and the annual seed production was 73.37 seeds/m2. Seed rain density, seed density on the ground, and seed losses are highly dynamic. But certain quantities of C. fargesii seeds were preserved on the ground for a prolonged time so that increased seed germination became possible. The natural regeneration of C.fargesii depends on the higher production of sound seeds in the mast years in response to "predator satiation". The "predator satiation" phenomenon of C. fargesii contributes to explain the dominance and stability of C. fargesii, which may contribute to the whole ecosystem stability. We present a model describing the fate of sound seeds after falling on the ground and show that different stages of seed rain and seed losses contribute to natural regeneration in different ways and to different extents. Overall, our results show a complex seed dispersal process related to the natural recruitment of C. fargesii.5. We studied that the effects of shading (100% PAR, 40% PAR and 22% PAR) on germination and early growth of Cyclobalanopsis glauca in subtropical abandoned fields. The results show that: (1) C. glauca can grow normally especially for early growth of seedling in the subtropical abandoned field; (2) the two treatments of shading (40% PAR and 22% PAR) contribute to get positive effects on germination and early growth of C. glauca in subtropical abandoned fields to certain different extents, and we can accelerate restoration or succession of the tropical abandoned field by shading treatment of 22% PAR especially; (3) the observed responses indicate different strategies to cope with shading; this study will prompt our following study on the effects of other shading rates and the comprehensive effects resulted from shade.6. Seedling growths of t...