不同海拔高程梯度下鄱阳湖典型草洲植物群落物种-多度分布格局的模型拟合

Modeling plant species-abundance distribution patterns with elevation in typical marshland communities of the Poyang Lake region

基于恒湖农场茶叶港草洲4个样带、19个样地(5 m×5 m)沿海拔高程(高高程-湖边、中高程-洲滩中间、低高程-洲滩边缘)调查得到的植被数据,用4种生态位模型拟合研究该区域不同海拔高程段植物种-多度分布格局。结果表明:(1)随着海拔高程下降,群落偶见种不断减少,且平均盖度均较低;常见种数目保持不变,其中优势种灰化薹草(Carex cinerascens Kukenth)平均盖度、平均高度持续升高,在群落中保持较高的优势地位;(2)3个高程段内生态位优先占领模型对群落物种-多度分布格局有较高的拟合优度(P<0.05,AIC值分别为-149.41、-61.11、-25.63),断棍模型、重叠生态位模型、优势优先模型总体上拟合效果较差(P<0.05,但AIC值均较大)。为研究区植物群落生物多样性的保护和构建机制的探索提供了一定参考。

Plants were surveyed in four sites using 19 quadrat plots （5 m x 5 m） at different elevations （high elevation-lakeside, medium elevation-center of marshland, edge of marshland） in the Chayegang marshland of Henghu farm, China. Four niche models were employed to simulate plant species-abundance distribution patterns along elevation gradients. Results showed that： （1） The number of occasional species declined gradually with decreasing elevation, with average coverage persistently becoming lower; whereas, the number of common species remained unchanged and average coverage and height of the dominant species Carex cinerascens Kukenth steadily increased, thus occupying a more dominant position in the community; （2） The species-abundance distribution patterns over the whole high elevation, medium elevation, and low elevation areas were best fitted by the niche preemption model （ P 〈 0.05） AIC values were -149.41, -61.11, and -25.63, respectively） ; whereas, the broken stick model, overlapping niche model, and dominance preemption model showed poor fitting along the elevation gradient in general （P 〈 0.05） AIC values were all larger）. These results should provide useful information for the protection of biodiversity and exploration of the constructive mechanisms of plant communities.