Experimental small-scale flower patches increase species density but not abundance of small urban bees

1. Large flower plantings are often used to combat negative effects of habitat loss on pollinators, but whether these floral additions are effective at smaller scales remains unclear, particularly in urban settings.
2. To test the effectiveness of small-scale floral additions on enhancing urban bee populations, as well as their impact from one year to the next, different quantities of potted sweet alyssum (Lobularia maritima) flowers were placed across sites in Ann Arbor, Michigan for two consecutive years and the resulting Halictid bee visitors were monitored.
3. Overall we found the number of flowers added at the local level was significantly and positively correlated with small Halictid bee abundance and species density in an urban landscape. At smaller flower quantities dynamics were clearly linear, where incremental increases in number of flowers showed significant increases in bee abundance and species density. At larger quantities of floral additions, however, dynamics were non...

1. 大型花卉种植常被用于缓解生境丧失对传粉昆虫的负面影响，但此类花卉增补措施在小尺度范围内是否有效仍未明确，尤其在城市环境中。
2. 为探究小尺度花卉增补对城市蜂群种群的提升效果，以及其年度间的影响效应，研究团队在密歇根州安娜堡的多个样地中布设了不同数量的盆栽香雪球（Lobularia maritima），实验连续开展两个年度，并对到访的隧蜂（Halictid bee）进行监测。
3. 整体研究结果显示，城市景观中局部尺度新增的花卉数量与隧蜂个体丰度及物种密度呈显著正相关。在花卉投放量较低的区间，二者关系呈现清晰的线性特征：花卉数量的增量提升均能显著带动蜂群丰度与物种密度的增长。然而当花卉增补量处于较高水平时，其动态关系则呈非……