苜蓿人工草地节肢动物群落的时间格局

调查了甘肃省庄浪县苜蓿人工草地节肢动物群落的组成及多样性变化，应用主分量分析和最优分割法对节肢动物群落的时间格局进行了研究。结果表明，苜蓿人工草地节肢动物群落的物种丰富度，多样性和均匀度指标在时间过程中的变化有明显的差异和规律性，6月下旬害虫和天敌的物种丰富度均达到最大值，但天敌的个体数量高峰明显落后于害虫，在时间变化过程中，影响节肢动物群落的主导因素和时间格局分化明显，根据研究结果，将苜蓿人工草地节肢动物群落在时间动态中的变化划分为5月上旬以前，5月中旬-6月上旬，6月中旬-7月中旬，7月中旬以后4个阶段，并结合气候，物候变化，分析了各阶段内主要害虫和天敌的发生特点，提出了害虫的治理对策。

Temporal pattern of arthropod community on cultivated alfalfa grassland

The variation of species and diversities of the arthropod community on cultivated alfalfa grassland was investigated and studied.Principal component analysis and optimal sorting method were used to study its temporal patterns.The results showed that the difference and regularity of species richness,and the diversity and evenness of the arthropod community at different time were obvious.The numbers of the species of insect pests and their natural enemies were the most in the last ten days of June,but the peak period of individual numbers of the natural enemies was later than that of insect pests.The main factors and temporal patterns of arthropod community in the course of seasons were obvious.Based on the results,the temporal patterns of arthropod community on cultivated alfalfa grassland could be divided into four stages:before the first ten days of May,the middle ten days of May to the first ten days of June,the middle ten days of June to the middle ten days of July,and after the middle ten days of July.Considering the climatic and phenological development,the characteristics of the pests and the natural enemies occurring in each stage were analyzed,and the corresponding management tactics were discussed.