Urban wildlife gardeners successfully support native bees in their backyards

Abstract Residential gardens provide significant opportunities for biodiversity conservation. They cover substantial portions of urban landscapes, and it is well-established that wildlife species respond to specific habitat characteristics of residential gardens such as vegetation structure. However, wildlife responses to the full suite of landscaping decisions comprising the intentional creation of a garden for wildlife are less well-understood. We compared habitat and bee community structure, and importance in a site-species landscape network, between residential gardens described by their owners as wildlife gardens, nearby residential gardens not intended for wildlife (control gardens), and nearby remnant vegetation in Melbourne, Australia. We found that vegetation diversity was higher in wildlife and control gardens compared to remnants, and the proportion of native vegetation was higher in wildlife gardens and remnants compared to control gardens. Bee diversity, but not abundance was higher in wildlife gardens and remnants compared to control gardens. Wildlife gardens and remnants had similar numbers but different suites of bee species, with wildlife gardens supporting more above ground- compared to below ground-nesting species, suggesting that each is missing key habitat elements. Landscape mosaics comprising both habitat types may therefore maximise bee diversity at the landscape scale. Analysis of the landscape network revealed that wildlife gardens and remnants supported more habitat specialist bee species (i.e. higher node strength) compared to control gardens and contributed more to network robustness. Residents that created wildlife gardens achieved their aims of supporting more wildlife compared to control gardens. They created small habitat patches that nonetheless complemented existing urban remnants, supported habitat specialists, and enhanced the robustness of the landscape network. Local governments can achieve biodiversity conservation goals at the landscape scale by supporting residents to create and maintain wildlife gardens.