Fire and grazing are historic ecosystem drivers of tallgrass prairie and both are used for restoration management today. The effects of these drivers on animal taxa are still incompletely resolved, especially for wild bees, a growing conservation and restoration priority. Fire and grazing could affect wild bee communities through structural changes to nest site availability via changes to soil conditions, vegetative cover, and availability of plant stems. Here, we sought to determine how different bee nesting groups are affected by the combination of fire and bison grazing management strategies. We grouped bee species by nesting substrate (ground, stem/hole, large cavity) because we expect the availability of these substrates to vary with the application of prescribed fire and grazing. We collected bees in restored and remnant high-quality tallgrass prairie and analyzed whether the proportion of each nesting group within the total bee community was predicted by fire and/or grazing. Ground-nesting bees reached their greatest proportion in bee communities immediately after prescribed fire, but declined proportionally over time since the last burn. Stem-/hole-nesting bees reached their highest proportion in the bee community with infrequent fire (6-year interval) and differed in their response to fire depending on the presence/absence of bison. Sampling year affected bee nesting groups and we found that nesting groups did not change in concert (i.e. different nesting groups had different good and bad years from each other). Our results show that spatiotemporal variation of prescribed fire and bison grazing is essential for conservation of multiple bee nesting groups.

中文翻译：

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规定的火和野牛放牧的变化支持高草草原中的多个蜜蜂筑巢群

火灾和放牧是高草草原的历史生态系统驱动因素，如今两者都用于恢复管理。这些驱动因素对动物类群的影响仍未完全解决，特别是对于野生蜜蜂而言，这是一个日益重要的保护和恢复优先事项。火灾和放牧可能通过改变土壤条件、植被覆盖和植物茎的可用性来改变巢址可用性的结构变化，从而影响野蜂群落。在这里，我们试图确定火和野牛放牧管理策略的组合如何影响不同的蜜蜂筑巢群体。我们通过筑巢基质（地面、茎/孔、大空腔）对蜜蜂物种进行分组，因为我们预计这些基质的可用性会随着规定的火和放牧的应用而变化。我们在恢复和残留的优质高草草原中收集蜜蜂，并分析是否通过火灾和/或放牧来预测整个蜜蜂群落中每个筑巢组的比例。地面筑巢的蜜蜂在规定的火灾后立即在蜜蜂群落中达到最大比例，但自上次燃烧后随着时间的推移按比例下降。茎/洞筑巢蜜蜂在蜜蜂群落中的比例最高，火灾不频繁（6 年间隔），并且根据野牛的存在/不存在，它们对火灾的反应不同。采样年份影响了蜜蜂的筑巢群体，我们发现筑巢群体没有同步变化（即不同的筑巢群体有不同的好年份和坏年份）。