节肢动物群落稳定性测度的灰色模型及其应用

证明了累加生成可增大两单调递增序列的协方差,意味着累加生成有可能提高两正相关序列的线性相关性,使之达到线性拟合的要求。在一个节肢动物群落中总个体数与种类数、天敌总个体数与害虫总个体数具有灰正相关关系。以各样本中总个体数m与种类数S及天敌总个体数mn与害虫总个体数mp为变量,利用累加生成和线性回归的方法建立节肢动物群落稳定性测度灰色模型。通过模型求出比值S/m和mn/mp作为测度群落稳定性的指标,其值愈大表明群落稳定性愈好。将该模型应用于福州、安溪、武夷山、福安等四地茶园节肢动物群落稳定性的测度,对所得结果应用灰色聚类法按“好”、“中”、“差”3类对4地茶园节肢动物群落稳定性状况进行灰色聚类评估。评估结果为:福州、安溪茶园为“好”,武夷山茶园为“中”,福安茶园为“差”。这一结果与实际基本相符,表明建立的灰色模型是可行的,并验证了生物多样性可导致群落稳定性这一假说。

A grey model for measuring the stability of arthropod community and its application

It has been proved in the present paper that the accumulative generation can enhance the covariance of two monotone incremental sequences,which implies that accumulative generation may enhance the linear dependence of two positive correlation sequences to meet the demand of linear fitting. There is a grey positive correlation between numbers of the total individuals and the total species,individual numbers of the pests and their natural enemies in a arthropod community.Based on numbers of the total individuals(m) and the total species(S),individual numbers of the pests(m_p) and their natural enemies(m_n),a grey model for measuring stability of arthropod community is developed using methods of the accumulative generation and the linear regression.The ratios of S/m and m_n/m_p are calculated,and used as stability indexes of the arthropod community.The greater ratio can better stabilize the arthropod community.The model has also been applied to measure the stability of arthropod communities in four tea plantations of Fuzhou,Anxi,Wuyishan and Fuan,Fujian Province.The stability of arthropod communities in the four tea plantations can be grouped into three grades,high-grade,middle-grade and low-grade according to measured values of the stability index using the grey clustering method.The tea plantations of Fuzhou and Anxi are in the high-grade group,the tea plantation of Wuyishan in the middle-grade group,and the tea plantation of Fuan in the low-grade group.The result is basically consistent with the targeted field situation,which well indicates that the grey model is feasible,and that the biodiversity may lead to the stability of communities.