The legacy of redlining: Addressing current socioeconomic and ecological problems within our urban spaces using avian response

Background/Question/Methods

Growing acknowledgement of the benefits of urban nature to human well-being is pushing policy makers to incorporate nature and ecology into decision-making around development. However, US cities have a long history of racist urban policies, which have led to an inequitable distribution of greenspaces across racial or socioeconomic groups. Notable among these is redlining, where largely neighborhoods of color were designated as “hazardous” and denied loans from banks to mortgage homes. The distribution of biodiversity is impacted by investment in communities via development of greenspaces , and redlining may be linked to higher levels of biodiversity in wealthier neighborhoods. We focus on San Francisco as a case study of a historically redlined city, and use citizen science data (eBird) to answer how the legacy of redlining affects bird communities today. We overlay historical redlining data with NDVI as a measure of greenery to examine the spatial distribution of greenspaces, as well as bird biodiversity, measured as Shannon’s Diversity Index. We compare avian diversity between historically redlined and non-redlined neighborhoods to ask the following questions: 1. How is avian species diversity affected by redlining status? and 2. How are these relationships affected by current amounts of greenspace in different neighborhoods?

Results/Conclusions

We used HOLC’s redlining system to categorize our results. There were a total of 13 A-ranked (“Best”) neighborhoods, 36 B-ranked (“still desirable”) neighborhoods, 31 C-ranked (“definitely declining”) neighborhoods, and 17 total D-ranked (“Hazardous”) neighborhoods in San Francisco. We found that there was less bird diversity in D and C neighborhoods compared to A and B neighborhoods. B-ranked neighborhoods had the highest diversity with a 8% increase in Shannon’s Diversity compared to C and D ranked neighborhoods. NDVI was over 60% higher in A-ranked neighborhoods compared to D-ranked neighborhoods, with B-ranked neighborhoods having the next highest NDVI, followed by C and D. A and B ranked neighborhoods also had the highest percentage of the White population and higher median income. Our results show that contemporary urban avian ecology is shaped by historical discriminatory practices. Our study suggests that future policy should heavily consider remediation policies in greenspace placement to address redlining and provide equitable access to nature and wildlife, especially in marginalized communities.