小兴安岭森林地表鞘翅目成虫对不同干扰梯度的响应

为探讨小兴安岭凉水自然保护区森林生态系统中地表鞘翅目成虫群落对不同人为干扰梯度的响应,于2015年7月、8月和10月分别对轻度干扰[原始阔叶红松林(KY)和谷地云冷杉林(YL)]、中度干扰[阔叶红松择伐林(ZF)和次生白桦林(BH)]及重度干扰[落叶松人工林(RL)和红松人工林(RHS)]的6个林型进行取样调查。结果表明:(1)整个采样周期共捕获地表鞘翅目成虫879只,隶属9科44物种;其中轻度干扰生境共捕获6科29种251只(KY捕获5科21种150只,YL捕获4科20种101只),中度干扰生境捕获6科27种276只(ZF捕获3科20种144只,BH捕获6科23种132只),重度干扰生境捕获6科29种352只(RL捕获4科22种232只,RHS捕获5科17种120只)。(2)7月和8月步甲科和葬甲科占据数量优势,10月步甲科和葬甲科成虫数量明显减少而隐翅虫科数量占优势;不同林型及不同干扰梯度地表鞘翅目成虫物种总数和总个体数于7、8、10月均表现为下降趋势,且群落多样性也呈不同程度下降。(3)林型和月份对地表鞘翅目成虫群落结构具有显著影响,干扰梯度对群落结构无显著影响;6个林型之间地表鞘翅目成虫个体数量具有显著差异,但在物种组成上无显著差异;不同干扰梯度间地表鞘翅目成虫个体数、物种数无显著差异,且随干扰梯度变化没有明显的梯度性规律;相似性系数和聚类分析表明,属于同一干扰梯度的两个林型没有表现出高度的相似性。本研究表明干扰梯度不是决定各林型间地表鞘翅目成虫群落多样性存在差异的主要原因,凉水森林生态系统地表鞘翅目成虫对不同干扰梯度的响应不符合中度干扰假说,林型和时间则是影响地表鞘翅目成虫群落组成的显著因素,本实验为地表生物多样性保护和森林生态系统管理提供数据支撑。

Responses of ground Coleoptera adults to different disturbance gradients in the forest ecosystem of the Xiaoxing'an Mountains

With the increase in human and natural disturbances, and one of the major tasks focused on contribution of disturbance on community compostions and distributions. Intermediate disturbance hypothesis has been suggested an important driver for community compositions and distributions, which assumes that intermediate disturbance can maintain high biodiversity. This hypothesis has been verified in some scientific studies for different communities; however, whether this hypothesis functions to soil animal communities is still unclear. Few studies have investigated the responses of soil animals to human disturbance intensity in grassland, farmland, and wetland ecosystems. However, the response characteristics of ground soil animals to different disturbance intensities is rarely reported in forest ecosystems. The Liangshui nature reserve presents a complete disturbance gradient of primary forest-secondary forest-plantation forest, which provides a good platform for identifying the response of soil animal communities to different gradients of disturbance intensity. This experiment was conducted in six forest habitats in the Liangshui nature reserve, that is a virgin mixed broadleaved-Korean pine forest (KY), valley spruce-fir forest (YL), selectively cut mixed broadleaved-Korean pine forest (ZF), secondary birch forest (BH), Dahurian larch plantation (RL), and Korean pine plantation (RHS). KY and YL are characterized as mildly disturbed habitats with primary forests more than 300-years-old. ZF and BH are characterized as intermediately disturbed habitats with 200-and 60-years-old secondary forests, respectively. RL and RHS are characterized as severely disturbed habitats with plantation forests more than 63-years-old, which were planted after clear cutting. To elucidate the responses of ground Coleoptera adults to different disturbance gradients in forest ecosystems, pitfall traps were used to collect ground Coleoptera beetles in July, August, and October 2015. One-way ANOVA, three-way ANOVA, and clustering analyses were subsequently performed for adult beetle communities. This study aimed to address (1) whether the abundance(individual number), richness(species number), and diversity indices of the ground Coleoptera beetle communities were significantly different among six forest habitats and three seasons; (2) whether the abundance, richness, and diversity indices of ground Coleoptera beetle communities changed gradually across the disturbance intensity gradients; and (3) whether the diversity of ground Coleoptera beetle communities in Liangshui forest ecosystems was consistent with the intermediate disturbance hypothesis. The results showed that (1) 879 ground Coleoptera beetles were captured in the six forest habitats in total, which belonged to nine families and 44 species; 251 beetles were collected in mildly disturbed habitats (150 beetles in KY and 101 beetles in YL), which belonged to six families and 29 species; 276 beetles were captured in intermediately disturbed habitats (144 beetles in ZF and 132 beetles in BH), which belonged to six families and 27 species; 352 beetles were trapped in severely disturbed habitats (232 beetles in RL and 120 beetles in RHS), which belonged to six families and 29 species. (2) In July and August, Carabidae and Silphidae beetles were numerically dominant. In October, the abundance of Carabidae and Silphidae beetles decreased, and the abundance of Staphylinidae beetles were dominant. A decreasing trend in the total number of ground Coleoptera adults was detected across the surveyed seasons (from July to October) in all forest habitats, and to some extent, community diversity indices also showed the same trend. (3) According to the results of three-way ANOVA, the main effects of forest habitat and month were significant on the ground Coleoptera beetle compositions; however, the disturbance gradient had no significant effect on community structure. The abundance of ground beetles showed a significant difference among the six forest habitats, but no such difference was observed in the richess of ground Coleoptera adults. Significant differences in the abundance, richness, and diversity indices of Coleoptera adults were not detected among habitats with mild, intermediate, and severe disturbance, indicating there was no gradual change across the disturbance intensity gradients. Furthermore, ground Coleoptera beetle communities classified as having the same disturbance gradient, did not show high similarity based on the results from similarity coefficients and clustering analyses. The results of this study suggest that the disturbance was not a main factor driving the composition of adult ground Coleoptera communities in six forest habitats in the Liangshui Nature Reserve, and the "intermediate interference hypothesis" was not verified in this study. Forest type and time were proposed as important factors for ground Coleoptera beetle structures in the six habitats. These results provide theoretical support for the protection of biodiversity and ecosystem management in forest ecosystems.