Research On The Neutral Model Of The Species Diversity Patterns In Community

Species coexistence mechanism is one of the cores of community ecology; the neutral theory becomes the focus of ecologists because of its good predictive ability compared with niche theory. This study foucs on two aspects based on the classical neutral model proposed by Graham Bell in 2000. On one hand, the effect of initial distribution and parameters on distribution of abundance is studied; on the other hand, the effect of disturbance of three rates on abundance and biodiversity is studied when the model is a nearly neutral model.The results shows that, (1) under different interference levels on species individuals in overall-scale and small-scale (including common species and rare species), the recovery degree of the community biodiversity is mainly determined by immigration rate, and the species composition of stable community has been changed; (2) disturbing community changes initial distribution of abundance to be non-uniform, in this context, species abundance distribution can be the lognormal distribution in different communities under different levels of interference and immigration rates; (3) the differences on immigration rate have no significant effect on the species rank-abundance, while the birth rate and death rate have significant effects on the species rank-abundance; (4) the species rank-reletive abundance curve has been changed when immigration rate, birth rate or death rate distribed; (5) the species abundance distributions follow lognormal distribution, however it does not obey the log-series distribution-in this sence, nearly neutral model and neutral model is consistent. Neutral theory provides a new theory to explain biodiversity and species abundance pattern and enriches the community assembly theory.