Structure And Diversity Of Arthropod In Different Managed Areas In Organic Pear Orchard

To realize the community structure and biodiversity of arthropod community in the organic pear orchard, and to understand the effect on the arthropod community of different density planted areas with the managements of covering film and fertilization in this kind of pear orchard, and to offer some theory on the IPM of the orchard. Using the methods of diversity, the community structure and biodiversity of the arthropod communities were studied in three different managed areas of the organic pear orchard, in Shunyi, Beijing. The results were as follows:The number of arthropod species was considerably larger in the low planted area than the dense planted area and the fertilized planted area. The number of Homopterous Psyllidae pests was the largest in these areas and the ratio was the highest in the low planted area. The diversity indexes of Phytophagous group and Parasitic group were the most in the fertilized planted area and the least in the low planted area, but it was opposite to Predatory group. The dominant concentration indexes of Phytophagous group and Parasitic group were the most and Predatory group was the least in the low planted area.It was similar in the change of richness and evenness of the arthropod communities in the three areas in the whole season. The individual number of the arthropod communities in the low planted area was higher than in the other areas. It was different in the occurring time and quantity of dominant species: in early spring, there were more Psyllidaes in the dense planted area , but more main pests Opatrums and Scarabeidaes and their nature enemies Carabidaes and Spiders in the low planted area. After autumn, the quantity of Psyllidae was the largest in the low planted area, but the least in the dense planted area. Accordingly, author put forward some opinions on founding integrated management system for main pests.By the method of fuzzy clustering, studied the temporal dynamics of the arthropod community and sub-communities in three different managed areas of organic pear orchard. The results showed that: it was different in the change of pest sub-community and natural enemy sub-community. The pest sub-communities were affected by their major pests, but the natural enemy sub-community in the areas were steadier and took good effect on the pest integrated management in the pear orchard. There was obvious difference among the three areas in the whole community and the pest sub-community.The succession of main pests and nature enemies communities of three areas has measured by principal components analysis. The cumulating variance was above 85% when the number of the principal component was 6 or 7, and it was obvious difference in the kind of the main pests and nature enemies of the first three principal components which were made important effect in the three areas.The temporal niche breadth and overlap of main pests and nature enemies was analyzed. The result was that: the temporal niche breadth and overlap of Psyllidaes were high with many main pests and nature enemies in the three areas, and it was obvious difference in the temporal niche breadth and overlap of main pests and nature enemies in these areas.