湿地草本植物冠层昆虫群落的中性理论验证

生物多样性中性理论（Unified Neutral Theory of Biodiversity）对群落中物种共存机制和多度分布提出不同于传统生态位理论的另一种解释：由处于同一营养级的物种构成的群落中,不同物种的个体间在生态学上是等价的;物种多度的分布主要决定于随机过程,如物种灭绝和物种迁入/新物种分化之间的动态平衡。对于中性理论模型是否可以准确预测物种多度分布一直存在不小的争论。本文对生长在天目山地区的湿地草本植物冠层的昆虫群落进行取样调查,分别采用中性理论模型和对数正态模型预测昆虫多度分布。采用置信区间、拟合优度检验和卡方检验等方法验证中性理论的预测。中性模型拟合的基本多样性指数θ=5.89,迁移率m=0.208 8。实测物种多度数据全部落入中性模型预测的95%置信区间内,说明中性模型预测的多度分布与实测数据基本吻合。Pearson相关性检验、Kolmogorov-Smirnov检验和卡方检验的结果表明,中性最优拟合曲线（200次中性模型模拟的平均值）的拟合优度与对数正态模型很接近,但中性理论模型的预测结果只在4%～14%的情况下（中性模型模拟200次）优于对数正态模型。因此,中性理论模型可以较好地预测天目山湿地草本植物冠层中的昆虫群落的多度分布情况,但其拟合优度并不优于对数正态模型。

Testing the Neutral Theory of Insect Communities in the Canopy of Wetland Herbaceous Plants

The unified neutral theory of biodiversity offers an alternative explanation to the species coexistence and abundance distribution mechanisms in a community,other than the traditional niche theory： individuals from different species within the same trophic level are ecologically equivalent;the determination of species abundance distribution is a stochastic process based on the dynamic balance of death,immigration,and/or speciation.Much debate has been focused on whether the neutral model can successfully predict the species abundance distribution.In this paper,the insect communities in the canopy of wetland herbaceous plants growing in Tianmu Moutains was investigated and insect spe- cies abundance distribution predicted using neutral model and lognormal model,respectively.The neutral model predictions was tested with confidence intervals,goodness—of—fit test,and chisquare test.Neutral model yielded the fundamental diversity numberθ=5.89,migrate rate m = 0. 2088.The result showed that the observed insect species abundance distributions completely fall into the 95%confidence interval of the neutral model predictions,indicating the match between the species abundance predictions by neutral model and the observed data.Kolmogorov—Smirnov test and chisquare test showed the best estimate curve of neutral model（average value of 200 neutral model simulations） has a goodness—of—fit close to that of the lognormal model,but with only 4%—14%of the times（among the 200 simulations） better than the lognormal model.Therefore,it was concluded that the neutral model can predict the abundance distribution of insect communities in the canopy of wetland herbaceous plants in Tianmu Moutains,however,with a goodness—of—fit not as good as the lognormal model.