Grassland extensification enhances nest densities of ground-nesting wild bees

Ground-nesting wild bees provide essential pollination services in agroecosystems, but they are jeopardized by intensive agricultural management. To mitigate such negative impacts, agri-environment schemes have been implemented. While the success of enhancing floral food resources is relatively well studied, the role of agri-environmental schemes in providing suitable nesting habitat remains underexplored. We studied the effectiveness of meadow extensification according to the Swiss agri-environment scheme in promoting nesting of ground-nesting bees. Using a paired design, we quantified their nests during four rounds (March-June) in pairs of nine randomly selected extensively (i.e. no fertilizer input, postponed first mowing) and nine intensively managed meadows with similar soil properties, slope, exposure and landscape context. Nest numbers and vegetation characteristics were surveyed in areas of 250 m2. Vegetation properties were also assessed in 0.5 m × 0.5 m plots around nest loca...地面筑巢野生蜂（ground-nesting wild bees）在农业生态系统中提供至关重要的传粉服务，却因集约化农业管理模式而面临生存威胁。为缓解此类负面影响，农业环境计划（agri-environment schemes）已得到推行。尽管提升花卉食物资源的成效已得到较为充分的研究，但农业环境计划在提供适宜筑巢栖息地方面的作用仍未得到足够探索。 本研究针对瑞士农业环境计划下的草地粗放化管理模式，探究其对地面筑巢野生蜂筑巢活动的促进效果。研究采用配对设计，在3月至6月的四个调查周期中，对9组随机选取的粗放管理草地（即不施用肥料、首次刈割延迟）与9组土壤特性、坡度、坡向及景观背景均相似的集约化管理草地开展巢群数量量化工作。研究人员在250 m²的样地内调查了巢群数量与植被特征，并在巢位周边0.5 m × 0.5 m的小样方中对植被属性进行了测定...