Persson Anna S, Mazier Florence, Smith Henrik G
Centre of Environmental and Climate Research Lund University Lund Sweden.
Department of Environmental Geography Jean Jaurès University Toulouse France.
Ecol Evol. 2018 May 15;8(11):5777-5791. doi: 10.1002/ece3.4116. eCollection 2018 Jun.
Wild bees are declining in intensively farmed regions worldwide, threatening pollination services to flowering crops and wild plants. To halt bee declines, it is essential that conservation actions are based on a mechanistic understanding of how bee species utilize landscapes. We aimed at teasing apart how foraging resources in the landscape through the nesting season affected nesting and reproduction of a solitary bee in a farmland region. We investigated how availability of floral resources and potentially resource-rich habitats surrounding nests affected nest provisioning and reproduction in the solitary polylectic bee . The study was performed in 18 landscape sectors dominated by agriculture, but varying in agricultural intensity in terms of proportion of organic crop fields and seminatural permanent pastures. Pasture-rich sectors contained more oak (), which pollen analysis showed to be favored forage in early season. More oaks ≤100 m from nests led to higher proportions of oak pollen in nest provisions and increased speed of nest construction in early season, but this effect tapered off as flowering decreased. Late-season pollen foraging was dominated by buttercup ( spp.), common in various noncrop habitats. Foraging trips were longer with more oaks and increased further through the season. The opposite was found for buttercup. Oak and buttercup interacted to explain the number of offspring; buttercup had a positive effect only when the number of oaks was above the mean for the studied sectors. The results show that quality of complex and pasture-rich landscapes for depends on preserving existing and generating new oak trees. Lignose plants are key early-season forage resources in agricultural landscapes. Increasing habitat heterogeneity with trees and shrubs and promoting suitable late-flowering forbs can benefit and other wild bees active in spring and early summer, something which existing agri-environment schemes seldom target.
在全球集约化养殖地区，野生蜜蜂数量正在减少，这对开花作物和野生植物的授粉服务构成了威胁。为了阻止蜜蜂数量的减少，保护行动必须基于对蜜蜂物种如何利用景观的机制性理解。我们旨在厘清在筑巢季节期间，景观中的觅食资源如何影响农田地区独居蜜蜂的筑巢和繁殖。我们研究了花朵资源的可利用性以及巢穴周围潜在的资源丰富栖息地如何影响独居多食性蜜蜂的巢穴供给和繁殖。该研究在18个以农业为主导的景观区域进行，这些区域的农业集约化程度因有机作物田和半自然永久牧场的比例而异。牧场丰富的区域含有更多的橡树（），花粉分析表明这些橡树是早期的优质觅食对象。距离巢穴≤100米范围内的橡树越多，巢穴食物中橡树花粉的比例就越高，且早期筑巢速度加快，但随着开花减少，这种影响逐渐减弱。后期花粉觅食主要以毛茛（毛茛属植物）为主，常见于各种非作物栖息地。有更多橡树时觅食行程更长，且整个季节都会进一步增加。毛茛的情况则相反。橡树和毛茛相互作用来解释后代数量；只有当橡树数量高于研究区域的平均值时，毛茛才会产生积极影响。结果表明，复杂且牧场丰富的景观对[蜜蜂物种名称未明确]的质量取决于保护现有橡树并培育新的橡树。木本植物是农业景观中关键的早期觅食资源。增加树木和灌木的栖息地异质性并推广合适的晚花杂草，可以使[蜜蜂物种名称未明确]和其他在春季和初夏活跃的野生蜜蜂受益，而现有的农业环境计划很少针对这一点。
