Data from: Urban nectarivorous bird communities in Cape Town, South Africa, are structured by ecological generalisation and resource distribution

Biological communities are increasingly faced with novel urban habitats and their response may depend on a combination of biological and habitat traits. The response of pollinator species to urban habitats are of particular importance because all species involved in the pollination mutualism may be affected. Nectarivorous bird communities worldwide show varying tolerances to urban areas, but studies from Africa are lacking. We investigated nectarivorous bird communities in a medium-sized South African city and asked which biological and garden traits best predict the community assembly of specialist and opportunistic nectarivorous birds. Information was collected on garden traits and the frequency of nine nectarivorous bird species for 193 gardens by means of a questionnaire. Information on biological traits of birds was obtained from published literature. Habitat generalism and tree nesting were identified as the most important biological traits influencing bird occurrence in gardens. A greater diversity of indigenous bird-pollinated plants and the presence of sugar water feeders increased the numbers of nectar specialist birds and species richness of nectarivorous birds. While bird baths increased the species richness of nectar specialist birds, opportunistic birds’ urban adjustment was further facilitated by large vegetated areas in gardens and limited by the distance to the nearest natural habitat. In conclusion, though some biological traits and dispersal barriers seem to limit urban adjustment, a combination of natural and artificial nectar resource provisioning could facilitate this adjustment.

生物群落正日益面临新兴城市生境，其响应模式可能取决于生物性状与栖息地性状的综合作用。传粉者类群对城市生境的响应尤为关键，因为所有参与传粉互利共生的物种均可能受到波及。全球范围内的食蜜鸟类群对城市区域的耐受程度存在差异，但目前仍缺乏来自非洲的相关研究。本研究针对南非一座中等规模城市的食蜜鸟类群展开调查，旨在明确哪些生物性状与庭院性状能够最优预测特化型与机会主义型食蜜鸟类的群落构建过程。研究人员通过问卷方式，收集了193个庭院的性状信息以及9种食蜜鸟类的出现频率数据；鸟类的生物性状信息则取自已发表的文献资料。研究发现，生境泛化性与树栖筑巢是影响鸟类在庭院中出现的最为关键的生物性状。本土鸟类传粉植物的多样性提升，以及糖水喂食器的设置，均会增加食蜜特化鸟类的种群数量与食蜜鸟类的物种丰富度。尽管鸟类洗浴池能够提升食蜜特化鸟类的物种丰富度，但庭院内大面积的植被覆盖区域进一步促进了机会主义鸟类的城市适应，而其适应过程则会受到与最近自然生境之间距离的限制。综上，尽管部分生物性状与扩散屏障似乎会限制鸟类的城市适应进程，但自然与人工花蜜资源的协同供给能够有效促进这一适应过程。