Habitat fragmentation is modifying landscapes and the distribution of floral resources, possibly shaping pollinator resource acquisition, which is an issue of global concern for pollinator health and urbanization sustainability. Here, in different urban parks contrasting in terms of local features and surrounding urban matrix, we aimed to clarify how fragmentation and local flower availability shape bumblebee foraging dynamics by characterizing several components: the nutritional content and plant composition of collected pollen pellets, the trip length and the plant-nutrition association along a fragmentation gradient. We found mostly negative linear or non-linear relationships between nutritional quality and fragmentation, tight plant composition-nutrition associations interpretable as low access to alternative resources, and longer foraging time in smaller green areas, showing that urban green area fragmentation limits nutritional resource accessibility. However, flower local richness improved the collection of beneficial nutrients as proteins and polyphenols, thus potentially rescuing negative landscape effects. This study illuminates the link between landscape and local features and the nutritional ecology of pollinators, a key aspect for understanding pollinator foraging dynamics. The findings of the study can provide valuable guidelines for policy makers and stakeholders involved in the management and ecological restoration planning for urban green areas and even for outlining mitigation measures in urban contexts.

中文翻译：

---

景观破碎化限制了大黄蜂的营养生态和觅食动态

栖息地破碎化正在改变景观和花卉资源的分布，可能会影响传粉媒介资源的获取，这是全球关注传粉媒介健康和城市化可持续性的问题。在这里，在不同的城市公园中，根据当地特征和周围城市矩阵进行对比，我们的目的是通过表征几个组成部分来阐明碎片化和当地花卉可用性如何影响大黄蜂觅食动态：收集的花粉颗粒的营养成分和植物成分、行程长度以及沿着破碎梯度的植物-营养关联。我们发现营养质量和破碎化之间大多呈负线性或非线性关系，紧密的植物成分-营养关联可解释为替代资源的获取机会较少，以及较小绿地中较长的觅食时间，这表明城市绿地破碎化限制了营养资源的可及性。然而，当地花卉的丰富性改善了蛋白质和多酚等有益营养物质的收集，从而有可能挽救负面景观影响。这项研究阐明了景观和当地特征与传粉媒介的营养生态之间的联系，这是理解传粉媒介觅食动态的一个关键方面。该研究的结果可以为参与城市绿地管理和生态恢复规划的政策制定者和利益相关者提供有价值的指导，甚至可以为概述城市环境中的缓解措施提供有价值的指导。