Preserving plant diversity on extensive green roofs – theory to practice

Abstract

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 discuss relevant theory and supporting research to provide suggestions regarding future research in the field as well as practical green roof construction recommendations and species selection.

Keywords:

• diversity
• niche theory
• neutral theory
• green roof

Acknowledgements

We wish to thank Jeremy Lundholm and Emily Walker for their insightful comments on the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Kadas Green Roofs Ecology Center, University of Haifa and the Israeli Council for Higher Education.