A meta-analysis of the effects of habitat aridity, evolutionary history of grazing, and grazing intensity on bee and butterfly communities worldwide

A variety of habitat-associated factors moderate effects of grazing on insect biodiversity. Here, we examine how aridity, evolutionary history of grazing, and grazing intensity individually and interactively mediate the effect of livestock grazing on pollinator diversity (native bees and butterflies). Using a meta-analysis of 59 studies published in the primary literature we characterized the response of pollinator communities to grazing across several continents. In very humid habitats high grazing intensities generally had negative impacts on pollinator abundance and richness, but these effects were not found in semi-arid habitats, where livestock grazing intensity did not interact with aridity to impact pollinator abundance or richness. However, within semi-arid habitats livestock grazing was associated with reduced pollinator richness in areas with short evolutionary histories grazing. Pollinator life history mediated effects of livestock grazing on pollinator communities: livestock...多种栖息地相关因子可调控放牧对昆虫生物多样性的影响。本研究旨在探讨干旱度、放牧演化历史以及放牧强度分别及交互作用，如何介导家畜放牧对传粉者多样性（本土蜂类与蝶类）的影响。 我们通过对59项已发表于学术期刊的一手研究文献开展荟萃分析（meta-analysis），刻画了全球多大陆区域内传粉者群落对放牧的响应特征。 在极度湿润的生境中，高强度放牧通常会对传粉者的个体多度与物种丰富度产生负面影响，但该效应并未在半干旱生境中显现。半干旱生境中，家畜放牧强度并未与干旱度产生交互作用，进而影响传粉者的多度或丰富度。然而在半干旱生境内部，在放牧演化历史较短的区域，家畜放牧与传粉者物种丰富度降低存在显著关联。 传粉者生活史特征可介导家畜放牧对传粉者群落产生的影响：家畜……