A Study On Arthropod Diversity In Islanding Landscape Of Thousand-Island Lake

In short, the biodiversity is the diversity and variability of the life organism and the ecological complex, which exists on life organism. Exactly speaking, biodiversity is the general concept of all the biological species, inheritance variation of intraspecific and their survival environment, including all kinds of the animals, plants and microorganism, and all genes of theirs. The ecosystem, composing by these mentioned above and their survival environment, plays a very important role in the existence and development of the human being. Great pressure and threats appeared to the biodiversity due to the gradual growth of population and the increase of production practice. Many scholars attached much importance to it, which have become one of the popular issues, which many scholars have been studying in recent years.Thousand-Island Lake is one of the Islanding Landscapes developed by violent factitious interference. We mainly studied the effects of its area, perimeter and altitude to the biodiversity of the arthropod. The species and quantity of the insects and other arthropod were investigated by setting 53 samples on the island, which included the large, medium and small islands. The main research focused on the effects on the species richness, biodiversity, evenness and special arthropod groups caused by the area, perimeter and altitude of the island.â… . The results of investigationWe had investigated 53 islands including the large, medium and small islands in Thousand-Island Lake district islands from April 2006 to October, 2006. The arthropod species belong to 5 classes (Insecta, Arachnoidea, Myriapoda, Crustacea, Diplopoda), 26 orders, 174 families, 428 species, in which insect class occupies 19 orders, 154 families, 257 species.â…¡. The analysis of dominant groupIn the arthropod, Lepidoptera, Coleoptera, Diptera, Homoptera, Hymenoptera, Araneida and Orthoptera respectively contained 27, 27, 25, 21, 17, 12, 11 families, which percentage of occupied on the total arthropod group families was 15.61%, 15.61%, 14.45%, 12.14%, 9.83%, 6.94%, 6.36% respectively; and 140 families (7 orders) occupied the arthropod 174 families (26 orders) for 80.92%. This indicated that the 7 orders mentioned above were dominant groups of arthropod and each dominant order included relatively many dominant families.â…¢. The effect of islands-three-factors on species richnessIn the overall trend, species richness was increasing along with the islands' area, but also xisting the small-island-effect. The regression results indicated that the change of island species was caused by the area, nearly 78.80%; the change of island species was proportional with perimeter, the regression results indicated that the change of island species was caused by island perimeter, nearly 68.73%. The change of species number had no obvious rule with altitude below 108 meters; the species number had the obvious increase tendency along with the ascension of altitude above 110 meters. The regression results indicated that the change of islands species was caused by the altitude, nearly 51.82%. The analysis of interaction of the three factors indicated that the change of species number was caused by the mutual change of the area, perimeter and altitude, nearly 91.69%.â…£. The analysis of arthropod diversityCompared of both the Simpson index and the Shannon-Wiener index carries, we found that its Simpson index D=0.7585, Shannon-Wiener index H'=3.0828 from the whole island. This indicated that the diversity indices of the whole island arthropod were somewhat low, the individual quantity distribution of island species was not reasonable; the ecological stability of community was relatively bad. The regression analysis of the two indexes mentioned above to area, perimeter and altitude indicated that, the change of Simpson index was caused by the altitude change, nearly 90.72%; the change of Shannon-Wiener index was caused by the interaction among the area, altitude and perimeter, nearly 90.36%, but altitude plays the main role.Compared with evenness indices, we found that Pielou evenness index (J_sw) was consistent with Pielou evenness index (J_si), which respectively calculated by Shannon-Wiener index and Simpson index. The lower evenness indices of No. 4, No. 12, No. 18, No. 22, No. 25, No. 37, No. 45, No. 48, and No. 50 island, the relative concentrated species distribution, the relative distribution scope, which finally leaded to its relatively lower J_sw and the J_si; the change trend of Alatolo evenness index (E_a) was also consistent with J_sw and J_si. No.49 island and other islands datum demonstrated that they had high Pielou evenness index, for its more species, distinct dominant species. The diversity of individual quantity was evident between the dominant species and the non-dominant species, thus the E_a value was small. The regression analysis of the area, elevation, perimeter three factors, the results indicated that the J_sw change was caused by the altitude, nearly 89.35%; the E_a change was caused by altitude and area together, nearly 89.11%.â…¤. The analysis of Special group speciesThe analysis of the relationship among active species, non-active species number and area, perimeter, altitude, we found that both the active species number and the non-active species number increased along with the area, perimeter, altitude increasing. The regression analysis of the three factors and their interaction indicated that the active species number change was caused 73.73% by the area, 67.15% by the perimeter, and 50.25% by the altitude. But the non-active species change was caused 92.0% by the area, 53.71% by the perimeter, and 42.64% by the altitude.â…¥. Natural enemy, pests, intermediate formsThe analysis of natural enemies, pests and intermediate forms, indicated that the effects of interaction of area, altitude and perimeter on them were 83.22%, 83.33% and 54.47% respectively.