Plant selection on ecological green roofs
Green roofs are used to provide ecosystem services using shallow substrates and plants. Policy encouragements like LEED and Sustainable Sites prescribe natives for a broad range of services. Are these services really provided as promised? Do native plants really provide more services than non-natives? How does the industry define native vegetation, nationally, regionally, locally? This presentation investigates different ways these terms have been applied and interpreted in a number of greenroof designs.
Several case studies which demonstrate the need for good regional and local native plant information. A reliable and knowledgeable supply chain is also critical to achieve the intended ecosystem services. Urban areas have undergone dramatic ecological changes since native evolved in them. For example parts Washington DC were wetland and are now drained and now upslope habitat. The design and groups like LEED and Sustainable Sites need to be more specific about the primary service of the green roof.