Abstract: Based on field survey, plant species abundance distributions under different utilization modes of the Hulunbuir meadow steppe were analyzed by mathematical models. The purpose of this study is to use mathematical models with different ecological significances to fit the true distribution of plant species under different ecological processes in meadow steppe. Chi-square (χ²), Akaike information criterion (AIC) and Bayesian information criterion (BIC) were used for verification. The results showed that the best fitting model of species abundance distribution in grazing, clipping, and enclosing grasslands was the broken stick model (BSM), with χ²=92.99, AIC=373.58, and BIC=378.49 for grazing grassland; χ²=98.51, AIC=307.76, and BIC=312.67 for clipping grassland; χ²=186.57, AIC=303.13, and BIC=307.53 for enclosing grassland. The fitting results of the niche overlap model (ONM) could also be accepted (χ²=422.69, AIC=409.25, BIC=414.16) in grazing grassland, but the effect was worse than that of BSM. Meanwhile, there were great differences in fitness among ONM, nichepredominance model (NPM) and random allocation model (RAM). Our results indicated that the application of multiple SDP models and verification methods would be beneficial to select the best model and better understand the ecological processes of grassland community under different utilization regimes.

Key words: forest fire, remote sensing, seasonality, burned area product, spatial distribution, trend analysis