Vertical Distribution Of Insect Species Diversity In Plateau Forest Of West Sichuan

To reveal the vertical distribution of forest insect diversity,we investigated forest insect community structure at different altitude in virgin forest and planted forest on plateau of western Sichuan.The major finding was below:1?Richness of plant species,insect species in the forest of the Western Sichuan plateau at different altitudes were analyzed for their correlation with altitude.The results showed that the herbaceous decreased while altitude increasing and there was significant correlation with elevation(r=0.97)between plant species richness decreasing and altitude increasing.And it's the same to the woody plants with high correlation(r=0.93).As the altitude increasing,the species amount of insects declined,and there was a high correlation between the two factors.In particular,the species amount of insects collected by light trap was decreased significantly with increasing altitude(r=0.96).Species richness of Lepidoptera,Coleoptera and Hymenoptera were decreased with the increase of elevation,and the Lepidopteran species richness decreased significantly(r=0.95).2?The species amount of insects and plants in virgin forest or planted forest in West Sichuan at different altitude levels were analyzed.Compared to the virgin forest the amount of plants species was relatively lower than in planted forest at different altitude.The species amount of insects in planted forest is less than that of virgin forest.In the forest area above 3100 meters above sea level,,the species amount of insects in planted forest was significantly less than that in virgin forest.Insect species amount of Lepidoptera,Coleoptera and Hymenoptera were fewer in planted forest than that in virgin forest.The species amounts of Lepidoptera in planted forest at different altitudes was significantly lower than that of the virgin forest,and when the altitude was above 3500 meters,the species amount of Lepidoptera was extremely significantly lower than that of the virgin forest.The species amount of Coleoptera was significantly lower than that of virgin forest at different altitudes while there was no significant difference for Hymenopteran species.3? The relationship between forest health and species richness of plants,and insects were analyzed.The results show that there was no correlation between the altitude and forest health,but there was a moderate correlation between the forest health and the altitudinal gradient of the forest(r=0.73).In planted forest,there was a moderate correlation between the forest health and plant species richness at different altitudes(r=0.79).There was a moderate correlation between the level of forest health and insect species richness in planted forest at different altitudes(r=0.62).However,there was no obvious correlation between forest health and species richness either for insect or plant in virgin forest.