The status of wild bees has received increased interest following recent estimates of large-scale declines in their abundances across the United States. However, basic information is limited regarding the factors affecting wild bee communities in temperate coniferous forest ecosystems. To assess the early responses of bees to bark beetle disturbance, we sampled the bee community of a Douglas-fir, Pseudotsuga menziesii (Mirb.), forest in western Idaho, United States during a Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins (Coleoptera: Curculionidae), outbreak beginning in summer 2016. We resampled the area in summer 2018 following reductions in forest canopy cover resulting from mortality of dominant and codominant Douglas-fir. Overall, results from rarefaction analyses indicated significant increases in bee diversity (Shannon's H) in 2018 compared to 2016. Results from ANOVA also showed significant increases in bee abundance and diversity in 2018 compared to 2016. Poisson regression analyses revealed percent tree mortality from Douglas-fir beetle was positively correlated with increases in total bee abundance and species richness, where community response variables displayed a cubic trend with percent tree mortality. Percent reduction in canopy cover from 2016 to 2018 was also correlated with bee species richness and diversity. These findings suggest that wild bee communities may benefit from changes in forest structure following bark beetle outbreaks.

中文翻译：

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道格拉斯冷杉林中树皮甲虫爆发后夏季野生蜜蜂群落的变化

在最近估计美国各地野生蜜蜂的丰度大规模下降之后，野生蜜蜂的地位受到了越来越多的关注。然而，关于影响温带针叶林生态系统中野生蜜蜂群落的因素的基本信息有限。为了评估蜜蜂对树皮甲虫干扰的早期反应，我们对美国爱达荷州西部森林中的花旗松的蜜蜂群落进行了采样，花旗松甲虫，Dendroctonus pseudotsugae Hopkins（鞘翅目： Curculionidae)，从 2016 年夏季开始爆发。我们在 2018 年夏季重新采样了该地区，因为主要和共显性花旗松死亡导致森林冠层覆盖减少。总体而言，稀疏分析的结果表明蜜蜂多样性显着增加（Shannon' s H) 在 2018 年与 2016 年相比。方差分析的结果还显示，与 2016 年相比，2018 年的蜜蜂丰度和多样性显着增加。泊松回归分析显示，花旗松甲虫的树木死亡率百分比与总蜜蜂丰度和物种的增加呈正相关丰富度，其中社区响应变量显示出树木死亡率百分比的三次趋势。从 2016 年到 2018 年，冠层覆盖减少的百分比也与蜜蜂物种的丰富度和多样性有关。这些发现表明，野蜂群落可能受益于树皮甲虫爆发后森林结构的变化。泊松回归分析显示，花旗松甲虫的树木死亡率百分比与总蜜蜂丰度和物种丰富度的增加呈正相关，其中群落响应变量显示出树木死亡率百分比的三次趋势。从 2016 年到 2018 年，冠层覆盖减少的百分比也与蜜蜂物种的丰富度和多样性有关。这些发现表明，野蜂群落可能受益于树皮甲虫爆发后森林结构的变化。泊松回归分析显示，花旗松甲虫的树木死亡率百分比与总蜜蜂丰度和物种丰富度的增加呈正相关，其中群落响应变量显示出树木死亡率百分比的三次趋势。从 2016 年到 2018 年，冠层覆盖减少的百分比也与蜜蜂物种的丰富度和多样性有关。这些发现表明，野蜂群落可能受益于树皮甲虫爆发后森林结构的变化。