Preserving plant diversity on extensive green roofs – theory to practice

The growing phenomenon of green roofs throughout the world mostly results in the establishment of extensive green roofs with low species diversity. However, research from the last few decades has shown that several advantages can accrue from diverse ecological systems, such as increased faunal diversity, storm water retention, thermal stability, pollution mitigation, and visual appeal. The maintenance of diversity on extensive green roofs has not been closely examined and few studies incorporate methods to ensure long-term coexistence into green roof design. Theoretical work has placed much focus on the niche and neutral theories that attempt to explain diversity as a result of the existence of different habitats or of demographic and dispersal patterns, respectively. These theories have resulted in several theoretical and practical recommendations for the maintenance of diversity in ecological systems and could suggest additional practices that would support biodiverse green roofs. We hereby review and d...