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ItemInsect diversity on extensive green roofs in Melbourne( 2013)In cities around the world, increasing human populations and expanding built environments are accompanied by decreases in vegetation. This has led to a variety of environmental problems that have driven the development of novel vegetated habitats such as green roofs to provide ecosystem services. However, there are relatively few studies that have examined green roof insect diversity and none have been conducted in Australia. This research characterised and compared the insect diversity on six extensive green roofs. Each roof was paired with two ground level sites for meaningful comparison. Companion sites were of similar size, surrounding landscape and vegetation type to the green roof, while nearby sites were vegetation close to the green roof. Two main vegetation types were comparatively investigated: one was a grassland green roof, and consisted of a range of indigenous Victorian grassland species; the other was a succulent green roof, which generally consisted of a variety of Sedum species. Three of each type were used. Seven habitat factors thought to influence insect diversity were measured either in the field or via remote sensing. These factors were age, vegetation type, surrounding percentage of vegetation, height (green roofs only), size of the vegetated area, percentage of vegetation cover and substrate depth (green roofs only). Sites were examined using combinations of pan and pitfall insect sampling techniques, to collect a range of invertebrates and provide a better picture of diurnal and nocturnal species on green roofs and ground level sites. Insect abundance, richness and evenness data (based on counts of individuals) were used to calculate Simpson's diversity index (D) and the Shannon- Wiener index (H) to compare insect diversity between green roof, companion and nearby sites, and between green roof and companion vegetation types. A mixed model procedure was employed to test whether evenness and the diversity indices differed significantly between green roof, companion and nearby sites, and between grassland green roof and companion sites and succulent green roof and companion sites. A generalised linear mixed model was employed to test whether the richness of different Orders differed significantly between green roofs, nearby and companion sites, and to evaluate the effect of habitat factors on abundance. In total 32,542 insects were collected from eleven Orders and four Classes. Green roofs had a significantly more even distribution of invertebrate orders compared to nearby and companion sites. The diversity of grassland compared to succulent sites revealed that succulent sites had a significantly more even distribution of invertebrate orders compared to grassland sites. The effect of habitat factors on Ordinal abundance from all sites revealed that Araneae (spiders), Coleoptera (beetles), Diptera (flies), Acarina (mites), Collembola (springtails) and Hemiptera (true bugs), are all affected by different habitat factors. This study revealed that 70% of Orders found on companion and nearby sites were also found on green roofs. This research has demonstrated that a variety of medium, large and even flightless, insects are able to colonise on green roofs. Furthermore, it shows that green roofs can act as habitats for a variety of invertebrates within the urban environment.