| The moso bamboo (Phyllostachys pubescens Mazel), a sustainable forest resource, has been broadly used in keeping water and soil, modulating climate, embellishing environment as well as providing raw material for industry and agriculture, etc. Pest management is one of the most important in bamboo forest culture. In the past, the studies of the moso bamboo insect pests are limited to individual population. Traditional insecticides, which led to resistance and succession for main species with high fecundity, serious generation overlap and hided destruction, were adopted to control moso bamboo pests. Consequently, the frequency of pest outbreaks was very high. Based on the ecosystem of moso bamboo forest, the dynamics of canopy arthropod community, the biology and ecology of schiztetranychus bambusae Reck and Typhlodromus bambusae Ehara were studied in Changning Bamboo Area, Yibing, Sichuan. The research results were listed as follows:1. The composition and dynamics of the canopy arthropod community ofmoso bamboo forest1.1 Arthropod community compositionThe investigation locations were categorized as four areas listed as follows:Area I, Damp Valley with 515m elevations and good bamboo forest appearance.Area II, 630m elevations with poor bamboo appearance due to infertile soil. Area III, 755m elevations with high botanical richness and good bamboo growth.Area IV, 900m elevations with poor bamboo forest appearance as a result of man's disturbance.Survey by netting from April to October in 1999 indicated that there were 113 species (groups) of canopy insects, which belonged to 13 orders and 54 families method. All spiders were considered as one group because of similar ecological functions.Homptera and spiders constituted the dominant groups in arthropod communities in the four investigation areas. The relative abundance ranged from 30% to 51% for Homptera and from 19% to 43% for spiders, respectively. Dominant concentration index of Simpson was in the order of Area II>Area III>Area IV > Area I. Empoasca sp. (Homptera: Cicadellidae) was a dominant species in four Areas. At present, it has already become one of the most important bamboo pests in China.1.2 Arthropod community dynamicsIndices such as species richness, relative abundance, dominant concentration, diversity, and evenness were used to analyze and compare the seasonal dynamicsof arthropod community. The seasonal dynamics of species richness and the relative abundance showed two peak types in the four sampling areas. The first peak occurred between mid May and June was higher than the second one occurred in mid September. The dynamics of the dominant concentration, diversity and evenness in the four areas was almost the same. The dynamics of dominant concentration started highly, then decreased to a low level, but finally increased to a relatively high level. The change tendencies of the dynamics of diversity (H1) were from low to high, then to low, and to high again, and to low finally This trend was closely related to bionomics of arthropod and seasonal change, but there was difference in the four areas. The dynamics of the diversity in Area II was an exception as a result of the obvious dominance of Empoasca sp in May. Its change tendency was from high to low, then to high, and to low again, and to high again, and to low finally The diversity (H1) was a function of species richness, abundance and evenness. The main components affecting diversity were species richness and evenness, which accounted for 89.5%-99.55% of the variation in four areas.The seasonal pattern of bamboo canopy arthropod community within investigation period could be divided into five stages by the optimal sorting. The five stages were before early April, from mid April to early June, from mid June to early September, from mid September to mid October, and after mid October, respectively. The second stage forming the first peak was the most important and optimum time to monitor dynamics and control pests because most pests appeared... |
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