关键词: 昆虫群落, 多样性, 稳定性, 小兴安岭, 凉水自然保护区

Abstract: [Objective] This research aims at providing theory and scientific evidence for the forest sustainable development, management and biodiversity conservation in Liangshui Nature Reserve, Xiaoxing'anling Mountains, by surveying the responsion of the insect community to the ecological environment of six forest types.[Method] To systematically study the diversity and structure of insect community in Liangshui Nature Reserve, the structure, characteristic indexes of diversity, temporal dynamics, stability, principal components and similarity were investigated by the sweep-net, shaking-off and observation methods from May 2013 to September 2013, in the present study. Sample locations included spruce plantations (YR), natural secondary birches forest (B), Korean pine plantation (HR), linden-Korean pine (DY), picea-Korean pine (YY) and maple birch-Korean pine forest(FY).[Result] A total of 4,599 insects belonging to 188 species, 67 families and 9 orders, were collected in the six forest types, among which Hymenoptera and Diptera were the dominant groups. The insect diversity indexes in the six forest types were relatively high. The diversity index and evenness index in YR and YY were higher, while the dominant concentration were lower than that in other forest type. In all sample locations, the diversity index (H') of the insect community had significantly consistent seasonal variation trend was with the evenness index (J) (r=0.708~0.955, P<0.05), and negatively correlated with the dominant concentration index (C) (r=-0.863~-0.983, P<0.001). The diversity index (H') of the insect community also was significantly correlated with the richness index (S), except the forest type of YR. While, the diversity index (H') of the insect community in YY, DY, and B was significantly correlated with the individual number. There was difference in the insect community stability calculated by different method. The S_t/S_i ratio showed that the community stability was in a decrease order YY> YR> B> FY> DY> HR, while, the S_n/S_p ratio showed YR=HR> FY> B> YY> DY. The above results showed that the insect community stability was higher in YR and YY, but lower in HR and DY. In forest insect communities of every forest type, defoliator insect community was always the most divers. In YR, the individual number of neutral insects was most divers. While, in YR, the individual number of phytophagous insects was the most. In other four forest types, the individual number of predatory insects was always the most. The principal components analysis indicated that the dominant factor of community in YY and YR, was species number of neutral insects. While, in DY and HR, the individual and species numbers of phytophagous insects were the dominant factors. In B and FY, the dominant affective factor of community first was the individual number of neutral insects, and then changed into individual number of phytophagous insects. Cluster analysis showed that the all insect communities were able to be divided into two major communities in the surveyed six forest types. One community contains the insect communities in B, YY and YR. The other community occurs in other three forest types (HR,DY and FY).[Conclusion] The results of this study showed that the insect community stability of HR and DY, was lowest among the all forest types. It would be useful to increase the plant diversity for increasing the individual number of insects in the first nutritional layer. In DY, the largest insect community was phytophagous, therefore, the insect community stability should be enhanced by increasing the richness of the natural enemy insects.

Key words: insect community, diversity, stability, Xiaoxing'anling Mountains, Liangshui Nature Reserve