不同林分类型对昆虫群落多样性的影响

为研究近自然森林经营下的华北落叶松人工林不同林分类型对昆虫群落多样性的影响,以塞罕坝自然保护区内的华北落叶松纯林和混交林作为研究对象,对6种不同林分类型中的昆虫群落结构进行了研究。共获得昆虫标本9542头,隶属于7目,68科,187种,以双翅目、半翅目和鞘翅目为优势类群。研究结果表明:6种林分类型中的昆虫在物种和个体数上存在差异,相似性分析显示群落结构均不相似;群落多样性指数分析表明华北落叶松纯林和其它类型的混交林均具有较高的丰富度指数和多样性指数;主成分分析表明各林分类型中捕食性类群和寄生性类群是影响昆虫群落结构的主要因素,且捕食性类群和寄生性类群对植食性类群的控制作用较强;稳定性分析显示6种林分类型昆虫群落结构均具有较高的稳定性。

Effects of different forest stand types on diversity of insect community

Close-to-nature forest management is a kind of forest management model which imitates and approaches the nature. Making full use of the natural growth and development principles of forest ecosystems, it employs planning and designing of forest management activities based on forest natural regeneration to optimize the structure and function of the forests. In addition, by combining economic needs with ecological benefits, it promotes the nearest natural state of the forest. The main tree species of a plantation in Saihanba Nature Reserve are Prince Rupprecht''s larch (Larix principis-rupprechtii Mayr) and Mongolian Scots pine (Pinus sylvestris var. mongolica). The close-to-nature forest management measures were implemented in this plantation by strictly controlling the outside interference from humans and by timely tending and improving the forest growing environment. In order to study effects of different stand types of Prince Rupprecht''s larch on the diversity of insect community in the plantation under close-to-nature forest management, the structure of the insect community was studied in six stand types of the Prince Rupprecht''s larch pure and mixed forests in Saihanba Nature Reserve. The insects were collected by the sweep net method, and the diversity index, similarity, principal component, and stability of insect communities in different forest types were analyzed. In total, 9542 insects, belonging to 7 orders, 68 families, 187 species, were collected; Diptera, Hemiptera, and Coleoptera were the dominant groups. The results indicate that there were differences in species and individual number of insects in the six stand types, and similarity analysis revealed different insect community structure. The community diversity analysis showed that the richness index and Shannon-Wiener diversity index in pure and mixed forests were both high. Principal component analysis showed that predatory and parasitic groups in each stand type were the main factors influencing the community structure; they had a stronger effect on the forest compared to the phytophagous group. Stability analysis showed that the structure of insect community in different forest stand types had high stability. Under the close-to-natural forest management in Saihanba Nature Reserve, the plantation not only showed a high biological diversity, but the forest ecosystems were more stable and showed higher effective resistance to external disturbances. Therefore, traditional forest management methods should be substituted with an approach where the relationships between different species in a forest ecosystem are maximally employed and the forests are managed by rational allocation of the spatial structure of trees and selection of appropriate tree species and planting density. The most important points include establishing a management philosophy of the close-to-natural forest management and managing the plantation appropriately. Only then can the forest ecosystem reach higher stability and play an important role in regulating the forest ecosystem itself. The ultimate goals are to achieve ecological as well as economic benefits of forest resources and to reach the sustainable use of the biodiversity and the state of healthy forest development.