Nature-based solutions for stormwater management in urbanizing areas are an example of practices that can help connect communities and ecosystems. Green infrastructure provides direct benefits for stormwater management as well as co-benefits, such as protection of habitat, conservation of specific populations, and dispersal corridors. The objective of this study was to assess the impacts of future landscape change on vertebrate biodiversity for three designed alternative future scenarios. We used a stakeholder-guided process to develop three alternative future scenarios (circa 2060) for the Chicken Creek Watershed southwest of Portland, Oregon. The three scenarios (Current Course, Integrated Water Future, Stressed Resources) explore the effects of climate change, population growth, and different human responses in terms of incorporating nature-based stormwater management (protection of open space, riparian forest, and wetlands) into designs for watershed and neighborhood development. We used a suitability weighted species-habitat matrix developed for the Willamette River Basin to calculate relative habitat loss or gain for all non-fish vertebrate species in the watershed as an indicator of the impact of these different development scenarios on vertebrate biodiversity relative to the existing landscape circa 2010.
Results/Conclusions
Cluster analysis of the species-habitat data identified five groups based on species’ habitat affiliations; forest, water, agriculture, shrub, and development. Habitat loss and gain were compared among scenarios across taxa (birds, mammals, herptiles) and by habitat affiliation. Habitat losses in the Stressed Resources Future had the greatest impact on native biodiversity, with values of the habitat change statistic ranging from -0.46 (amphibians) to -3.64 (mammals). Native mammal species lost habitat relative to the existing landscape in all future scenarios (change statistic ranging from -1.46 to -3.64); whereas native bird species lost habitat in the Current Course and Stressed Resources Future, but showed slight gains in the Integrated Water Future (change statistic of 0.32), driven primarily by protection and afforestation of riparian areas. Introduced bird and mammal species gained habitat in all future scenarios as a result of conversion of forest and agricultural land to development. Habitat for native amphibians increased slightly in the Current Course and Integrated Water Futures, due to wetland restoration and protection in those scenarios. While urbanization will have impacts on wildlife habitat, some of those impacts can be reduced by incorporation of natural features into stormwater planning, providing important co-benefits to innovations in water management.