退耕还茶地土壤动物群落结构及其动态变化

目的]研究退耕还茶地土壤动物群落结构和季节变化特征,旨在为深入了解退耕还茶后土壤质量变化趋势及研究区生态系统的健康评价提供科学依据。方法]以川西低山丘陵区名山区退林还茶地为对象,采用手捡法和干、湿漏斗法,并以相邻退耕还林地为对照进行研究。结果]退耕还茶地土壤动物群落以蜱螨目(A)、线虫纲和弹尾目(C)为优势类群,其类群数、密度、Shannon-Wiener指数、密度—类群指数和群落复杂性指数均低于退耕还林地,而群落A/C值较大,且差异多达显著(p0.05)或极显著水平(p0.01)。退耕还茶地土壤动物类群数、个体数、密度—类群指数均以秋季最高,呈单峰曲线变化,且季节间波动大于退耕还林地。受2008年春季的冰冻天气影响,退耕还茶地土壤动物个体数、类群数和密度类群指数明显降低,并在2009年有一定回升,而退耕还林地动物群落结构受气候影响较小。结论]退耕还茶地土壤动物群落对季节变化和低温天气等外界干扰反应较退耕还林地强烈,且对生态环境给予的负面刺激的反馈能力相对较差。与退耕还林相比,退耕还茶地生态系统可能存在更大的潜在风险。

Community Structure and Dynamic Changes of Soil Fauna in Farmland-transformed Tea Plantation

Objective] In order to investigate the change of soil quality and provide scientific basis for ecosystem health assessment, the community structure and seasonal change of soil fauna were studied in farmland-transformed tea plantation. Methods] A farmland-transformed tea plantation in Mingshan, which is located in the hilly region of Western Sichuan Province, was chosen as research plot. In which, soil macrofauna were picked up by hand; mesofauna and microfauna were separated and collected from the soil samples by Baermann and Tullgren methods. Results] Acarina(A), Nematoda and Collembola(C) were the dominant groups in the farmland-transformed tea plantation. The density, number of group, Shannon-Wiener index, index of density-group number and community complexity of soil fauna were all lower than the corresponding values observed in farmland. However, A/C value of soil fauna community of tea plantation was significantly higher that of farmland. The maximum values of group number, individual number and index of density-group number appeared in Autumn. These indices showed an unimodal curves and the variance among seasons were greater than that between farmland and plantation. The group number, individual number and density-group number of tea plantation decreased due to disastrous frozen snow in 2008 and increased in 2009. However, little influence was observed for the farmland-transformed forestry. Conclusion] Soil animal community in farmland-transformed tea plantation is interfered by season transition, cold weather''s attack, and other disturbances as well. And also, the feedback ability to negative stimulus of ecological environment is relatively poor. In comparison with farmland-transformed forestry, the ecological system of farmland-transformed tea plantation may undergo great potential risk.