元谋干热河谷赤桉纯林与混交林昆虫群落多样性比较

Comparison of Species Diversity of Insects in Pure Forest and Mixed Forest of Eucalyptus camaldulensis in Yuanmou Dryhot Valley

应用物种多样性指数对赤桉纯林及其混交林间不同层次上的昆虫多样性进行比较,分析赤桉混交林改善昆虫多样性的影响机制。结果表明:不同树种昆虫多样性大小为银合欢>大叶相思>赤桉。与纯林草丛相比,赤桉+大叶相思、赤桉+银合欢混交林下草丛盖度提高,昆虫丰富度增加,物种组成相对复杂,但纯林草丛昆虫多样性指数与混交林相差不大。与纯林中赤桉树冠昆虫多样性相比,混交林中赤桉树冠昆虫多样性指数、丰富度指数、均匀度指数均明显提高,优势度指数降低。赤桉+大叶相思、赤桉+银合欢混交林比赤桉纯林具有更稳定的昆虫群落。

A survey was conducted to study the species diversity of insect both in herb layer and arbor layer of pure forest and mixed forest of Eucalyptus camaldulertsis in Yuanmou County, Yurman Province. Three forest types, E. camaidulertsis pure forest, mixed forests of E. camaidulensis with Leucaena leucocephala as well as E. camaidulensis with Acacia auriculiformis, were selected to analyse the influence mechanism of mixed forest on insect diversity. Results show that the insect diversity in tree canopy of L. leucocephala is the richest, and then followed by A. auriculiformis and E. camaidulertsis in order. Compared with the hassock in E. camaidulertsis pure forest, hassock coverage and insect richness in the mixed forests of E. camaidulensis with L. leucocephala and E. camaidulensis with A. auriculiformis are increased, and the species composition is more complicated. There is on obvious difference in insect diversity of the hassock between the pure forest and the mixed forest. The insect diversity, richness index and evenness index of E. camaidulensis crown in mixed forest markedly increase compared with those in the pure forest, however, the dominance index of mixed forest decreases. The insect community in the mixed forest is more stable than that in the pure forest.