放牧对草地昆虫多样性的影响研究进展

在草地生态系统中,大型草食动物放牧是重要的管理方式之一,对草地生物多样性起着关键的驱动作用。昆虫是草地生态系统中生物多样性的重要组成成分,对生态系统的食物网结构以及其功能与稳定性起着关键作用。已有研究结果表明,大型草食动物与昆虫存在密切联系,放牧对草地昆虫多样性或有正向、或负向、或无明显作用,这依赖于放牧管理方式、昆虫类群以及草地类型。放牧必然通过直接(采食、践踏或粪尿)或间接(植物群落组成或植被结构)作用对昆虫多样性产生显著的影响。当前,关于大型草食动物放牧对草地昆虫多样性影响研究较多,但是,从研究系统性、深入性和延续性来说还存在一定问题。本文在综述国内外对放牧对草地昆虫多样性的影响研究基础上,提出了今后的研究方向,对于理解放牧管理的草地昆虫多样性变化规律,以及为积极探索维持草地昆虫多样性的长期有效的科学管理措施提供理论指导。

Effects of grazing by large herbivores on insect diversity in grasslands

In grassland ecosystems, grazing by large herbivores is an important management tool, and plays a central role in driving biodiversity. Insects are important components of biodiversity in grasslands, and strongly affect food-web structure, as well as ecosystem functioning and stability. Many studies have shown that there are close relationships between large herbivores and insects. The effects of large herbivores on grasshopper species richness and abundance in grazed grassland ecosystems are inconsistent (positive effects, negative effects, and neutral effects), and the effect strongly depend on grazing management, insect guild, and grassland type. Grazing affects insect diversity both directly (foraging, trampling, and feces and urine) and indirectly (altered vegetation structure and plant community composition). Although a growing number of studies have shown that large herbivores can strongly affect insect diversity and abundance, greater additional efforts regarding the research on the systematisms, depth, and continuity of the response of insect diversity to grazing are still needed. This paper reviews the known effects of large herbivore grazing on insect diversity, and identifies a number of issues that remain poorly understood and require further research. The results of these studies could improve our understanding of changes in insect diversity, and provide theoretical support for the planning of management strategies aimed to conserve of insect diversity in grazed grassland ecosystems.