Short-term responses of native bees to livestock and implications for managing ecosystem services in grasslands
Short-term responses of native bees to livestock and implications for managing ecosystem services in grasslands
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DOI：
10.1890/es12-00118.1
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发表时间：
2012-10-01
期刊：
影响因子：
2.7
通讯作者：
Rao, Sujaya
中科院分区：
文献类型：
--
作者：
Kimoto, Chiho;DeBano, Sandra J.;Rao, Sujaya
牧场是世界范围内农业生态系统的重要生态系统服务提供者。然而，很少有研究调查不同的牲畜放牧强度如何影响这些生态系统服务的一个重要提供者--本地蜜蜂。我们在太平洋西北牧场的16个40公顷牧场上进行了第一次大规模的操作研究，研究了牲畜放牧强度的梯度对本地蜜蜂的影响。在两年的时间里，每个牧场都接受四种放牧率中的一种，并通过测量利用率来量化放牧强度。我们测量了与花卉和筑巢资源相关的土壤和植被特征，以及蜜蜂群落的几个指标。放牧强度的增加显著降低了植被结构、土壤稳定性和草本凋落物，显著增加了土壤紧实度和裸地。当地蜜蜂的反应是丰度、丰富度、多样性和群落组成发生了变化。反应因分类群和季节不同而不同。大黄蜂在季节早期对放牧强度很敏感，随着放牧强度的增加，大黄蜂的丰度、多样性和/或丰富度降低，这可能是因为觅食行为发生了变化。相比之下，汗蜂似乎没有受到放牧的影响。这些结果表明，本地蜜蜂分类群对放牧做法的敏感性各不相同，这表明放牧可能是管理包括牧场在内的镶嵌农业生态系统中授粉服务的有用工具。
Rangelands are significant providers of ecosystem services in agroecosystems world-wide. Yet few studies have investigated how different intensities of livestock grazing impact one important provider of these ecosystem services-native bees. We conducted the first large-scale manipulative study on the effect of a gradient of livestock grazing intensities on native bees in 16 40-ha pastures in the Pacific Northwest Bunchgrass Prairie. Each pasture was exposed to one of four cattle stocking rates for two years and grazing intensity was quantified by measuring utilization. We measured soil and vegetation characteristics related to floral and nesting resources as well as several metrics of the bee community. Increased grazing intensity significantly reduced vegetation structure, soil stability, and herbaceous litter and significantly increased soil compaction and bare ground. Native bees responded with changes in abundance, richness, diversity, and community composition. Responses varied with taxa and time of season. Bumble bees were sensitive to grazing intensity early in the season, showing reduced abundance, diversity, and/or richness with increased intensity, potentially because of altered foraging behavior. In contrast, sweat bees appeared unaffected by grazing. These results show that native bee taxa vary in their sensitivity to livestock grazing practices and suggest that grazing may potentially be a useful tool for managing pollination services in mosaic agroecosystems that include rangelands.