四川蜂桶寨国家自然保护区地表甲虫物种多样性

Species diversity of litter-layer beetles in the Fengtongzhai National Nature Reserve, Sichuan Province

在四川雅安蜂桶寨国家自然保护区 (10 2°4 8′～ 10 3°18′E ,30°4 2′～ 30°5 4′N)及其周边地区 ,就森林片段化和生态恢复程度的不同 ,选择 4个代表地点 ,即位于保护区核心地带、以阔叶混交林为主的蜂桶寨天然林区 (海拔 16 80～ 2 0 80m) ,受到经济开发干扰但植被类型丰富的锅巴岩天然林区 (海拔 2 2 80～ 3340m)、以人工针叶林进行生态恢复的蚂蝗沟人工林区 (海拔 2 4 30～ 2 5 2 5m) ,以及森林高度片段化的双石镇农耕区 (海拔 870～ 116 5m) ,共设 2 6块样地 ,以巴氏罐诱法为主研究地表甲虫的群落组成和多样性变化。本研究共采集甲虫标本 2 338号 ,隐翅虫数量最多 ,占 39 6 % ;步甲次之 ,占2 9 3% ,拟步甲、象甲和叶甲的数量也各在 5 %以上 ,它们共同构成该地区地表甲虫的优势类群。锅巴岩物种的个体数量和丰富度 (S)以及多样性指数 (H′)较高 ;蚂蝗沟均匀度指数 (J)较高 ,丰富度较低 ;蜂桶寨天然林区个体数量较少 ;双石镇农耕区的多样性和均匀度指数较低。锅巴岩、蜂桶寨和蚂蝗沟间物种分布都有一定程度的相似性 ,但后两者相似性程度更高 ,双石镇物种分布与其他 3个地点差异较大 ,这反映了不同地点间的生境异质性和森林植被片段化程度的差异。整个鞘翅目。

The litter-layer beetle species diversity in Fengtongzhai National Nature Reserve (102°48′-103°18′ E,30°42′-30°54′ N) and adjacent areas, Sichuan, Southwest China was surveyed. Four local sites were selected to represent the degree of forest fragmentation and coverage of different vegetation. Fengtongzhai (elevation 1 680-2 080 m) is located in the core of the Nature Reserve and is covered with well-protected native, mixed, broad-leaved forests. Guobayan (elevation 2 280-3 340 m) is a site covered with various native vegetation types, but disturbed by intensive human activities. Mahuanggou (elevation 2 430-2 525 m) represents a site with a well-developed secondary coniferous plantation. Shuangshizhen (elevation 870-1 165 m) is covered with fragmented plantations surrounding by farmlands. Using mainly pitfall traps, we built up 26 plots to investigate how the species diversity of litter-layer beetles was influenced by factors such as forest fragmentation, elevation, slope aspect and habitat differentiation etc. Field collections were conducted from June 29 to July 5, 2001. During field research, a total of 2 338 beetle specimens were captured, of which the family Staphylinidae comprised 39.6%, Carabidae 29.3%, and Tenebrionidae, Curculionidae and Chrysomelidae each more than 5% of the total. These five families can be considered as common in the study area. Of the four local sites selected, Guobayan had the highest individual numbers, richness (S) and diversity (H′). Mahuanggou had the highest evenness (J) and the lowest value of richness. Shuangshizhen had the lowest values of diversity and evenness. Fengtongzhai was much more homogenous in habitat variations and thus did not show any extremes of diversity, evenness or richness. The beetle community in the fragmented forest of Shuangshizhen was very different from those at the other three sites. The community at Mahuanggou was more similar to that in Fengtongzhai than Guobayan. Four main types of vegetation were compared. Coleoptera, Staphylinidae and Carabidae were found to be more abundant in coniferous forest than in mixed broad-leaved forest. Tenebrionidae preferred shrub-land, and Chrysomelidae preferred coniferous forest. Curculionidae had the fewest individuals in bamboo. At Fengtongzhai and Guobayan, species and individuals of Coleoptera and dominant beetle families exhibited an overall tendency of increasing with elevation. In ten plots at Fengtongzhai, the north-facing plots were found to have the greater numbers of individual beetles, richness and diversity than the south-facing ones. Based on these results, we conclude that forest fragmentation, elevation, slope aspect, and vegetation variation (habitat types) influence the species diversity of the litter-layer beetle communities in Fengtongzhai National Nature Reserve. Therefore, for forest protection and restoration in this region, efforts to maintain or restore habitat heterogeneity will help to maintain or increase the species diversity of litter-layer beetles.