Wild bee abundance declines with urban warming, regardless of floral density
Wild bee abundance declines with urban warming, regardless of floral density
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DOI：
10.1007/s11252-018-0731-4
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发表时间：
2018-06-01
期刊：
影响因子：
2.9
通讯作者：
Frank, Steven D.
中科院分区：
文献类型：
--
作者：
Hamblin, April L.;Youngsteadt, Elsa;Frank, Steven D.
随着城市的扩张，保护有益昆虫对于维持诸如授粉等强大的城市生态系统服务至关重要。城市变暖改变昆虫的生理机能、适应性和数量，但城市变暖对传粉者群落的影响尚未得到研究。我们在美国北卡罗来纳州罗利市的18个地点进行了蜜蜂采样，这些地点涵盖了城市变暖的不同区域。我们通过测量气温、不透水表面百分比（在局部和景观尺度上）、花卉密度和花卉多样性来量化所有地点的栖息地变量。我们检验了城市蜜蜂群落结构取决于温度这一假设。我们还进行了模型选择，以确定温度是否是城市蜜蜂群落结构最重要的预测因子之一。最后，我们探究了蜜蜂对温度或不透水表面的反应是否取决于蜜蜂的功能特性。城市每变暖1摄氏度，蜜蜂数量大约减少41%，温度是蜜蜂数量和群落组成的最佳预测因子之一。局部不透水表面和花卉密度也是蜜蜂数量的重要预测因子，尽管似乎只有大型蜜蜂受益于高花卉密度。无论蜜蜂大小如何，蜜蜂物种丰富度都随花卉密度增加而增加，并且蜜蜂对城市栖息地变量的反应与其他生活史特征无关。尽管我们记录了高花卉密度的益处，但仅仅在原本炎热、不透水的地方增加花卉不太可能恢复整个城市传粉者群落，因为花卉资源对大型蜜蜂的益处大于对小型蜜蜂的益处。
As cities expand, conservation of beneficial insects is essential to maintaining robust urban ecosystem services such as pollination. Urban warming alters insect physiology, fitness, and abundance, but the effect of urban warming on pollinator communities has not been investigated. We sampled bees at 18 sites encompassing an urban warming mosaic within Raleigh, NC, USA. We quantified habitat variables at all sites by measuring air temperature, percent impervious surface (on local and landscape scales), floral density, and floral diversity. We tested the hypothesis that urban bee community structure depends on temperature. We also conducted model selection to determine whether temperature was among the most important predictors of urban bee community structure. Finally, we asked whether bee responses to temperature or impervious surface depended on bee functional traits. Bee abundance declined by about 41% per A degrees C urban warming, and temperature was among the best predictors of bee abundance and community composition. Local impervious surface and floral density were also important predictors of bee abundance, although only large bees appeared to benefit from high floral density. Bee species richness increased with floral density regardless of bee size, and bee responses to urban habitat variables were independent of other life-history traits. Although we document benefits of high floral density, simply adding flowers to otherwise hot, impervious sites is unlikely to restore the entire urban pollinator community since floral resources benefit large bees more than small bees.