Effects of habitat structure, human disturbance, and habitat connectivity on urban forest bird communities

As urbanization accelerates, urban biodiversity conservation is becoming a great concern for the maintenance of urban ecosystem functions. In particular, forest bird communities in urban areas have been recognized as a conservation target because of their functions in food webs and ecosystem services. But our understanding of which local- and landscape-scale factors influence native bird communities within urban green spaces is still insufficient to provide managers with information for effectively planning biodiversity management programs. Here we examine how local habitat characteristics, human disturbance, and habitat connectivity influence the diversity of forest bird communities in 44 small forest patches (0.5–20.0 ha) embedded in an urbanized landscape. Patch size exerted a positive influence on the diversity of most bird functional groups, and it had the greatest effects on total abundance and species richness. The second most important factor was human disturbance. Remnant patches with lower levels of human disturbance had higher diversity than newly established patches where intense human activities occurred more frequently. In addition, vegetation complexity and habitat connectivity were positively related to total species richness and abundance, respectively, but they were less important. Management strategies for the conservation of urban forest birds, therefore, should consider not only local improvements in habitat structure – through increased patch size, reduced human disturbance, and increased vegetation complexity – but also the maintenance of habitat connectivity.