Community Changes of Soil Macrofauna in Native and Degenerative Wetlands of the Lhasa River
拉萨河流域健康湿地与退化湿地大型土壤动物群落比较研究

Alpine wetland in the Qinghai-Tibet Plateau is an important area of wetland distribution and a unique wetland type in China. Affected by economic activities, growth of population and increases of agriculture and livestock in the Qinghai-Tibet Plateau, great changes in area, vegetation and soil water content in alpine wetlands have taken placed, resulting in degradation of ecological functions and environmental effects on alpine wetlands. Soil macrofauna are important components in wetland ecosystems and show close relation with local plant community. In this paper, the authors investigated soil macrofauna in native and degenerative wetlands of the Lhasa River in an effort to examine the community characteristics of soil macrofauna, which can provide soil fauna data and would be helpful to monitor and protect alpine wetlands. Soil macrofauna were obtained by the hand-sorting method in every plot. The area of each plot was 25 cm × 25 cm and soil depth was 0-10 cm from the surface. A total of 6 replications were contained. At the same time, soil samples at a 0-10 cm soil depth were analyzed in laboratory, with determining soil organic matter, total nitrogen, available phosphorus, available nitrogen and soil water content. Results showed that a total of 15 groups of soil macrofauna were obtained in native wetlands. Lumbricidae was the dominant group. A total of 6 common groups were observed, involving Valloniidae, Curculionidae, Curculionidae larvae, Muscidae larvae, Tabanidae larvae and Asilidae larvae. A total of 8 rare groups were observed, including Agelenidae, Forficulina, Mesoveliidae, Selenopidae, Aphididae, Muscidae, Cicadidae and Aradidae. A total of 18 groups of soil macrofauna were obtained in degenerative wetlands. Lumbricidae and Valloniidae were the dominant groups. There were only 4 common groups in degenerative wetlands, i.e., Curculionidae, Curculionidae larvae, Succineidae and Lithobiidae. However, a total of 19 rare groups were observed in degenerative wetlands which were much more than that in native wetlands, i.e., Muscidae larvae, Tabanidae larvae, Cerapotogonidae larvae, Staphylinidae, Noctuidae larvae, Asilidae larvae, Agelenidae, Forficulina, Mesoveliidae, Lycosidae, Formicidae, Nabidae, Selenopidae, Aphididae, Muscidae, Cicadidae, Carabidae, Aradidae and Philodromidae. Results also showed that the number of group and individual in degenerative wetlands were both higher than that in native ones. Rare groups were highly rich in degenerative wetlands, which might be because they were much drier and therefore more soil fauna groups (e.g., Formicidae, Staphylinidae and Carabidae) have emerged. Differences in groups and individuals of soil macrofauna in native and degenerative wetlands were significant due to vegetation and water content in soil being the major factors influencing the community composition in native and degenerative wetlands.