猕猴桃园节肢动物群落重建及主要类群的生态位

为研究猕猴桃节肢动物群落重建过程和主要类群生态位移,本试验系统调查野生猕猴桃和人工栽植不同树龄(3年、9年、14年)猕猴桃园节肢动物群落,测定群落特征指标和主要类群的时空生态位。结果表明,群落包含3纲15目74科,约90种。不同桃园节肢动物群落的主要类群不同,各类群占群落总数的比例差异显著,野生猕猴桃园群落中各类群分布较均匀,栽植桃园群落中害虫比例较大。野生猕猴桃园和栽植猕猴桃园之间,群落的多样性指数、均匀度和优势度差异均极显著,群落稳定性表现为野生>9年>14年>3年。各类群的时空二维生态位也会随着栽植时间增长发生变化：蜘蛛和蝇类的生态位在不同树龄的猕猴桃园中都保持在较高水平；人工栽植初期,山楂叶螨和叶蝉占据的时空生态位较宽,成为优势类群,小薪甲与山楂叶螨生态位重叠较大,竞争激烈；随后,小薪甲和瘿蚊的时空二维生态位逐渐增大,到14年桃园中已经取代了山楂叶螨和叶蝉,成为主要害虫。总之,人工干扰的节肢动物群落重建是一个次级演替过程,与自然生态系统群落明显不同。

Arthropod community reestablishment and niche of the main groups in kiwifruit orchards

Previous research has shown that wild kiwifruit orchards have gradually been replaced by cultivated kiwifruit orchards. The arthropod community in cultivated kiwifruit orchard can changes over time, from the community that arises after colonization, to the climax community that establishes over the long term. In this study, we investigate the temporal changes in the arthropod community and the niche of the main groups found in kiwifruit orchards. Arthropod communities were surveyed in a wild orchard and three cultivated kiwifruit orchards of different ages (three years, nine years and 14 years), and we used the data to calculate various community indices and spatial-temporal dimensional niches of the main species groups. Approximately 90 species were identified, which belonged to three classes, 15 orders and 74 families. Main species groups in the arthropod communities were apparent in the four types of kiwifruit orchards. There was considerable variation in the number of different species groups. The proportions of different species groups in the wild kiwifruit orchard were similar; however, in cultivated orchards, species groups that are considered as pest formed a large proportion of the community. The differences in community indices (diversity index, evenness and dominance) between wild and cultivated orchards were statistically significant (P<0.01). The community stability of the wild kiwifruit orchard was the highest, followed by the nine-year and 14-year kiwifruit orchards, with the three-year kiwifruit orchard having the lowest. There were clear changes in the niches of species groups as the age of the orchard increased. The niches of spiders and flies were broad in the cultivated orchards, regardless of age. However, during early cultivation, the hawthorn spider mite and leafhoppers were the dominant groups with a wide niche. Because of high niche overlap, there was strong competition between Microgramme spp. and the hawthorn spider mite. Microgramme spp. and gall midge gradually replaced the hawthorn spider mite and leafhoppers to become the main pests with broad niches. Taken together, the results suggest that the arthropod community of the natural ecological system was more stable, with high species evenness, than the arthropod community that colonizes and becomes established in cultivated kiwifruit orchards, which have obviously been disturbed by human activities. Therefore, we find an important difference in the characteristics of community in wild and cultivated kiwifruit orchards, which may help the development of a theoretical basis of integrated pest management.