Bioretention swales as multifunctional landscapes and their influence on Australian urban biodiversity: Hymenoptera as biodiversity indicators.

摘要

For many years, urban natural landscapes have been damaged or destroyed through unplanned or poorly implemented developments. New efforts in urban landscape development encourage professionals to propose practices and multi-functional landscape features to satisfy social requirements as well as to save and enhance urban ecosystems. Using Hymenoptera as biodiversity indicators, this study examined how implementation of Water Sensitive Urban Design (WSUD) using bioretention swales in place of conventional urban greenspaces can influence urban biodiversity. The study investigated the biodiversity and habitat values of nine bioretention swales and nine corresponding greenspaces in the Melbourne area in a summer survey. The relationship between habitat factors and species assemblages of these landscapes was also examined. The results showed a decreasing trend of biodiversity from bioretention swales to gardenbed-type to lawn-type greenspaces. This result may imply similar patterns of decreasing favourable habitat features for species in these landscapes. More structural and compositional heterogeneity of planting in bioretention swales, indicated by a higher number of plant taxa and higher coverage of mid-stratum vegetation, and optimal soil pH ranges were the main habitat factors attracting Hymenopteras to these landscapes. The outcomes of this research has practical implementations for landscape professionals who are designing and managing ecologically sustainable urban landscapes using a combination of bioretention swales and conventional filter strip greenspaces in urban streetscapes.