Johnson Sarah A, Jackson Hanna M, Noth Hutton, M'Gonigle Leithen K
Department of Biological Sciences Simon Fraser University Burnaby British Columbia Canada.
UBC Okanagan Kelowna British Columbia Canada.
Ecol Evol. 2023 Jan 24;13(1):e9743. doi: 10.1002/ece3.9743. eCollection 2023 Jan.
Bumble bees are important pollinators in temperate forested regions where fire is a driving force for habitat change, and thus understanding how these insects respond to fire is critical. Previous work has shown bees are often positively affected by the postfire environment, with burned sites supporting greater bee abundance and diversity, and increased floral resources. The extent to which fire impacts variation in bumblebee site occupancy is not well-understood, especially in higher latitude regions with dense, primarily coniferous forests. Occupancy models are powerful tools for biodiversity analyses, as they separately estimate occupancy probability (likelihood that a species is present at a particular location) and detection probability (likelihood of observing a species when it is present). Using these models, we tested whether bumblebee site occupancy is higher in burned locations as a result of the increase in canopy openness, floral species richness, and floral abundance. We quantified the impact of fire, and associated habitat changes, on bumblebee species' occupancy in an area with high wildfire frequency in British Columbia, Canada. The burn status of a site was the only significant predictor for determining bumblebee occurrence (with burned sites having higher occupancy); floral resource availability and canopy openness only impacted detection probability (roughly, sample bias). These findings highlight the importance of controlling for the influence of habitat on species detection in pollinator studies and suggest that fire in this system changes the habitat for bumble bees in positive ways that extend beyond our measurements of differences in floral resources and canopy cover.
大黄蜂是温带森林地区重要的传粉者，在这些地区火灾是栖息地变化的驱动力，因此了解这些昆虫如何应对火灾至关重要。先前的研究表明，蜜蜂通常受到火灾后环境的积极影响，火烧迹地的蜜蜂数量和多样性更多，花卉资源也增加。火灾对大黄蜂栖息地占用率变化的影响程度尚不清楚，尤其是在高纬度地区茂密的主要针叶林中。占用模型是生物多样性分析的有力工具，因为它们分别估计占用概率（一个物种出现在特定位置的可能性）和检测概率（当一个物种存在时被观察到的可能性）。利用这些模型，我们测试了由于林冠开阔度、花卉物种丰富度和花卉数量的增加，大黄蜂在火烧地点的栖息地占用率是否更高。我们在加拿大不列颠哥伦比亚省野火频发的地区，量化了火灾及相关栖息地变化对大黄蜂物种占用率的影响。一个地点的火烧状态是决定大黄蜂出现的唯一重要预测因素（火烧地点的占用率更高）；花卉资源可用性和林冠开阔度仅影响检测概率（大致为样本偏差）。这些发现凸显了在传粉者研究中控制栖息地对物种检测影响的重要性，并表明该系统中的火灾以积极的方式改变了大黄蜂的栖息地，其影响超出了我们对花卉资源和林冠覆盖差异的测量。
