林业活动和森林片断化对甲虫多样性的影响及保护对策

森林片断化是造成生物多样性丧失的主要原因之一,而林业活动是导致森林片断化的重要因素,同时也在森林恢复中起重要作用。本文从小尺度、局域尺度以及生物地理尺度（大尺度）3个生态尺度分析林业活动和森林片断化对甲虫多样性的影响。在小尺度下,林业活动能够通过改变森林生境或微生境的类型和特性而影响甲虫物种分布。在局域尺度下,林业活动（尤其是森林砍伐）往往能提高许多甲虫类群（如步甲）的物种丰富度（α多样性）,这主要与来自周围环境物种扩散以及保留了若干耐受新环境能力较强的森林物种有关;然而,对森林生境依赖性很强的特有种受到了森林片断化的负面影响,面临局域种群灭绝的危险。在生物地理尺度下,林业活动（伐木或森林恢复）使森林生境单一化、异质性降低,从而导致对森林生境变化敏感的物种种群数量降低甚至灭绝。基于以上结果,可以归纳出3个基本原则用于指导林业管理,既能保证林业经济收益,又能维持森林生物多样性。首先,保留大面积的原始森林作为特有种的栖息环境基地,为这些物种在将来森林恢复后重新定居提供资源;其次,由于保护区内原始森林面积有限,且所代表的生境类型有限,所以发展依据自然干扰模式的新伐木方法十分必要;最后,依据自然规律（如火灾）进行森林恢复和天然演替,避免森林的单一化,丰富森林生境类型。

Effects of forestry practices and forest fragmentation on beetle diversity and conservation strategies

Forest fragmentation is inextricably linked to the fate of biodiversity, resulting in the decline of abundance and species richness. Forestry, a widespread and pervasive human activity, plays an important role in forest fragmentation and reforestation. In this paper we reviewed the effects of forestry practices and forest fragmentation on beetle diversity on three ecological scales. On the small scale, forestry affects species associated with micro-habitats of natural old-growth forest, for the forest management or logging usually removes or destroys the characteristic micro-habitats. On the local scale, species richness (α-diversity) for some taxa (e.g. ground beetles) may increase after the clear-cuts, as forest generalists persist and numerous open-habitat species appear; however, some old-growth forest specialists tend to disappear from these activities. On the biogeographical scale, the intensive forestry activities (e.g. logging or reforestation with plantation) tend to homogenize forest habitats and lead to decline or extinction of sensitive forest species. Based on these findings, three reasonable advices useful for developing a “new forestry" approach were proposed, with which forest biodiversity can still be maintained under the pressure of timber harvesting. Firstly, undisturbed old-growth forests must be set aside to sustain forest specialist species and to serve as sources for re-colonization. Secondly, since the above reserves might not be enough in size and representing enough habitat types, ecologically sound timber-harvesting practices must be developed in accordance with natural disturbance regime as guidelines. Thirdly, to avoid the homogeneity of reforestation, the restoration of habitats and the process of natural regeneration must be conducted according to the rule of natural disturbance (e.g. fire).