Study On Seasonal Distribution Of The Insect Community At Common Reed (Phragmites Australis) Community Of Chongming Dongtan Wetland

Coast salt marsh is one of the important wetlands in the world,which has many Ecosystem Service Functions of Nutrient cycling,purifing water and food production,especially ecological value and economic value.Dongtan wetland of Chongming Island,located at the estuary of Yangtze River to the sea,is a estuarine tidal wetland with the greatest size and the most perfect developed in the Changjiang estuary,and also is a rest place for birds migrating between Russia's Siberia and Australia,Dongtan wetland of Chongming Island is among the few wild bird clustering place in the world,with rich resource of birds.However,Insects are one of the important parts of various land ecosystems,which play the role in mass and energy transfering and maintaining stability of the ecosystems,the change of the insects communities composition is the reflection of ecosystem successtion.The insects community of Dongtan wetland of Chongming Island in Phragmites community was studied from Jun 2006 to May 2007 to reveal biodiversity of insects community and the variation rule of insects community at different stages of the successtion of marsh ecosystems,and the community diversity index of richness,abundance and dominance was analysized.The characters and seasonal changes of insect communities structure in Phragmites australis community(Ph.C) at Dongtan wetland of Chongming Island were studied,Inescts were collected from plants and ground,we surveyed insect diversity by net-sweeping and plant-harvesting methods from June 2006 to May 2007. Results showed that a total of 10588 insects were collected,belonging to 9 orders,57 families and 68 species.â‘ Diptera,Coleopterous,Hymenoptera and Homopterous are dominant species of Ph.C,especially the species richness of Diptera is the highest of all(18),then Coleopterous stands the second place(17);â‘¡With the higher temperature, species richness and abundance show a increasing trend totally,which fluctuat by wind and rain.â‘¢Shannon-Wiener index fluctuates at different seasons and is the lowest of all at Jul(1.28),highest of all at Sep(2.57);Pielou index does not vary greatly and fluctuates at 0.62;Simpson index is higher at Mar(0.13)than other seasons and the lowest of all at Jul(0.33)Insects were collected from Spartina alterniflora(Sp.C) community by plant-harvesting methods from June 2006 to May 2007 at Dongtan wetland of Chongming Island.Results showed that many Diptera insects were found in Sp.C, and the collected larva were found in the bottom of blast plants,closed to the wator, but there is no larva in the living plants.