Plant Community Structure During Degradation And Restoration

After early descriptive phase, two major debates arose in plant community ecology: the individual idea and the unitary community idea; neutral community theory and ecological assemblage rules. The later can be thought in essential a modern version of the old debate. Degenerating and restoration of plant communities is highly recognized all over the world, and is the frontier of ecology, conservation biology, and environment science. Degenerating and restoration of plant communities has immense influences on economy, politics, and international relationship. The alpine meadow in eastern Qing-Hai Tibet Plateau is the major rangeland in Tibet. Due to overgrazing and climate changing, the alpine meadow is under severe degeneration. The degeneration and restoration of plant community is a real challenge for ecologists, and a good opportunity to establish and test ecology theories. We established observational and manipulating experiments in typical alpine meadow of eastern Qing-Hai Tibet Plateau to understand the process under community degenerating, and the mechanism and methods to restore them.The results indicate that:1) Fertilizing and fencing increased the primary production and the quality of the alpine meadow.2) Fertilizing decreased α diversity, but increased β diversity. The decrease of α diversity overwhelmed the increase of β diversity. The increase of β diversity is contrary to niche theory, but agree with stochastic theory.3) In the early stage of succession, plants seed size show significantly negative correlation with density and frequency, but not with biomass or coverage. In later stage, plant species abundance shows no correlation with seed size.4) Bootstrap and Monte Carlo rarefaction indicate that density can explain 32.3% to 42.9% decrease of species richness, but still cannot explain all of the species richness change.4) Manipulation experiments show that species' change of traits can predict its change of abundance along the fertilizing gradient. Change of species average...