2024 South Philadelphia Bioblitz, in association with the City Nature Challenge

By Joni Baumgarten, PhD

Previous work has shown that social factors impact the biodiversity of urban areas, especially the historical delineation in the 1930s of certain neighborhoods as hazardous to invest in home loans, a term called "redlining". Redlining has been associated with lower species biodiversity in present times, which is a cause for concern for a variety of reasons, including that it indicates there is not environmental equity for urban residents via their access to green space, which can provide significant health benefits.

Our team from Bryn Mawr College (Joni Baumgarten and two students, Marley Iralien and Sherab Lhanyitsang) investigated the available data through OpenDataPhilly and iNaturalist for a specific area of Philadelphia for which the entirety was redlined. We wanted to know if, at this local scale, redlining had a consistent legacy on species biodiversity, or if other, more recent factors, like current average annual income, were stronger indicators of higher species diversity. The boundaries of the investigation ran from Walnut Street to Washington Avenue with the dividing lines of Broad Street and South Street.

A major challenge for this investigation was that iNaturalist data are fundamentally biased, and therefore it is hard to make conclusions from these data. For iNaturalist data, there is no easy correction or controlling for the timing of what observations are made when, and there is similarly no way to ensure that the observations were collected with equal effort of sampling time. What that means is that the trends on iNaturalist could just be residual impact of one area having more people choose to observe things there, rather than indicating that the species biodiversity is actually higher.

That’s where this bioblitz comes into play! With the help of volunteers, we will survey the four quadrants with equal effort, at exactly the same time, thus correcting for some of the underlying challenges of iNaturalist data—the impact of phenology (the timing of sampling), and the impact of different individuals doing the observations for fun rather than with a specific purpose.

The bioblitz will start at the intersection of Broad Street and South Street, and at least four teams of volunteers will go survey the four quadrants for a period of two hours. Are you interested in helping out? Here are the relevant links:

Google form : Register as a volunteer

iNaturalist project: Join here to be able to contribute observations to the project