Factors affecting terrestrial invertebrate diversity in bioretention basins in an Australian urban environment

Abstract

Biodiversity conservation is a significant challenge for urban planning and management. When new urban development strategies are introduced, their effects on urban biodiversity are often unknown and may have serious consequences for conservation. A relatively new urban development strategy for sustainable urban water cycle management is Water Sensitive Urban Design (WSUD). While this strategy has been implemented in Australia over the past decade, little is known about the impacts on biodiversity from its application. A field investigation was conducted on 12 bioretention basins, which are a type of vegetated WSUD system. The study used invertebrates captured through pitfall trapping as biodiversity indicators and was conducted in the Melbourne area during the summer of 2006–2007. It investigated the effect of ten habitat factors separately and as group factors on biodiversity of the systems. It also examined how invertebrates were distributed within these WSUD systems. The results suggested that greater leaf/plant litter depth or a combination of greater leaf/plant litter depth and larger number of plant taxa is a significant contributor to biodiversity in bioretention basins. Therefore, the design and management of bioretention basins should consider increasing these habitat factors as key elements to promote biodiversity. The distribution pattern of invertebrates within the systems increased from the edges towards the centre suggesting that designing the sites should consider shape and size to create larger interior habitats for enhancing biodiversity. The results of this study are important for the design and management of bioretention basins to improve biodiversity conservation in urban environments.