Abstract

Bumblebees are a key pollinator group globally which have declined over time. However, while some species remain common others are rare and have declined at a sharper rate. The Great Yellow Bumblebee (Bombus distinguendus Morawitz) is classified as ‘Endangered’ on the Irish Red List, and ‘Vulnerable’ at European level. We aimed to investigate the ecology of B. distinguendus within the wider bumblebee community in its only remaining Irish population to inform conservation management. Eight true bumblebee species were recorded in total in four habitat types surveyed, with highest species richness in species-rich grassland and highest abundance in urban habitats. Highest numbers of B. distinguendus were found in two designated nature reserves. However, outside these reserves the species was only found in three of twelve sites surveyed in both species-rich and coastal grassland habitats. B. distinguendus is a late emerging species in this region with a foraging preference for Common Knapweed (Centaurea nigra). Availability of key forage species was lowest when numbers of B. distinguendus were highest, potentially limiting survival of this species. Some smaller suitable habitats in urban areas and roadside verges were not used by the species, which suggests potential issues with habitat connectivity, patch size and/or availability of nesting and hibernation sites.

Implications for insect conservation

Based on our findings, we suggest that existing species-rich and coastal grassland sites should be conserved, and other areas restored, for B. distinguendus in Ireland. Conservation management should focus on delaying cutting grasslands until late September, winter grazing of stock and reducing pesticides and fertilisers with the aim of increasing forage availability in late season, and ensuring that suitable habitats are connected in the landscape to allow adequate habitat area as well as movement and dispersal of the species to new areas.

中文翻译：

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在西北爱尔兰更广阔的大黄蜂群落中调查大黄蜂的生态

摘要

大黄蜂是全球主要的传粉媒介，但随着时间的流逝，其数量有所下降。但是，虽然有些物种仍然很常见，但其他物种却很少见，并且以更快的速度下降。大黄蜂（Bombus distinguendus  Morawitz）在爱尔兰红色名录中被列为“濒危”，在欧洲被列为“易受害”。我们旨在调查仅剩下的爱尔兰人口中更广泛的大黄蜂群落中的双歧双歧杆菌的生态，以告知保护管理。在所调查的四种栖息地类型中，总共记录了八种真正的大黄蜂物种，其中物种丰富的草地物种丰富度最高，城市栖息地的物种丰富度最高。B. distinguendus的最高数量在两个指定的自然保护区中被发现。但是，在这些保护区之外，仅在物种丰富和沿海草原生境中进行调查的十二个地点中的三个发现了该物种。B. distinguendus是该地区较晚出现的物种，对常见的Knapweed（Centaurea nigra）觅食。当双歧双歧杆菌的数量最高时，关键饲草物种的可利用性最低，这可能限制了该物种的生存。该物种没有在城市地区和路边的边缘使用一些较小的合适栖息地，这暗示了栖息地连通性，斑块大小和/或筑巢和冬眠地点的可用性等潜在问题。

对昆虫保护的意义

根据我们的发现，我们建议应保护 爱尔兰B. distinguendus的现有物种丰富和沿海草原，并恢复其他地区。保护管理应着重于将割草推迟到9月下旬，冬季放牧，减少农药和化肥，以期在后期增加草料的供应，并确保在景观中连接合适的生境以提供足够的生境面积和物种的迁移和散布到新的地区。