Ecoroofs in Multnomah County: Oregon as habitat for the Oregon vesper sparrow and common nighthawk

Abstract

This project uses spatial analysis to identify existing buildings in Multnomah County, Oregon, that, if retrofitted with an ecoroof, could serve as breeding and stopover habitat for the Oregon vesper sparrow and common nighthawk. Both bird species have experienced population declines in recent years as a result of urban development, pesticide use, and predation. This project explores a new approach to habitat restoration, where suitable sites for bird habitat are identified on buildings themselves, rather than the land surrounding buildings. Through this exploration, the project deviates from more standard approaches to ecoroof design, which conceives these vegetated spaces with little consideration for the wildlife habitat they could provide, or the larger green matrix within which they exist. The over arching premise is if ecoroofs are adjacent to suitable habitat, the Oregon vesper sparrow and common nighthawk are more likely to use them for breeding and stopover habitat. The results identified a total of 49 buildings suitable for ecoroofs to support Oregon vesper sparrow breeding habit and 188 buildings suitable for ecoroofs to support common nighthawk breeding and Oregon vesper sparrow stopover habitat. With suitable buildings identified, this project presents an ecoroof design on one building in Portland that details the layout of grasses and forbs, all of which support the Oregon vesper sparrow’s breeding life history needs.