Wildlife habitat degradation is a leading cause of biodiversity loss, and largely attributed to urbanization. Green roofs (vegetated roofs) have been identified as a technology having potential to provide wildlife habitat in urban areas by creating vegetation types. Vegetation structure and composition and green space cover were quantified for 12 green roofs and their surrounding landscapes in Michigan and Illinois in 2010 and 2011. Most vegetation variables, including vegetation height and herbaceous cover, were significantly different between intensive green roofs (0-15cm planting media depth) and extensive green roofs (>15cm planting media depth). Herbaceous cover was the dominant cover type on all green roofs. Shrub cover was present on extensive and intensive roofs, and tree and turf cover were only present on some intensive roofs. Green space analysis showed future green roof installations could increase green space area >300% in landscapes immediately surrounding study sites. Twenty-five noninvasive, native bird species were detected on green roofs, and the mean estimated species richness for each green roof (within the range of 36-40 species) was greater than in surrounding landscapes. Our results support the idea that green roof vegetation can contribute to wildlife habitat in urban areas and increase space for wildlife conservation. This information should encourage collaboration of green roof designers and natural resource managers to advance green roof installations towards holistic environmental sustainability that includes wildlife conservation.
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