A three year study of green roofs and biodiversity study between 2003 and 2006 has recently been published by Lambert Academic Publishing :
In urban climes, where green space is already limited, green roofs may provide the ideal and in many cases the only habitat for species conservation. Could green roofs provide an opportunity to incorporate biodiversity within the built up environments? This study investigated the biodiversity potential of green roofs in urban environments. The main objective was to collect and quantify invertebrates on green roofs over a three-year study. By quantifying invertebrates it was possible to derive fundamental principles regarding the design of green roofs with the aim of maximizing their biodiversity value.