Urbanization alters species ranges and nature’s contributions to people, motivating urban conservation. Residential segregation policies have left an indelible impact on urban environments, greenspaces, and wildlife communities, creating socioeconomic heterogeneity and altering biota. However, the extent to which data sufficiently capture urban biodiversity patterns remains unclear, especially when considering historic segregation. We explore how biodiversity metrics (sampling density, estimated completeness of sampling, and expected species richness) vary by Home Owner’s Loan Corporation (HOLC) grade across taxonomic groups, leveraging nearly 60 million amphibia, aves, fungi, insecta, mammalia, plantae, and reptilia observations collected between 2000 and 2020, for 145 Metropolitan Statistical Areas in the United States. After accounting for environmental conditions, we estimate significant differences in sampling density across HOLC grade for all taxonomic groups, with the lowest values found in areas previously redlined. Estimated completeness of biodiversity inventory was low (average ~42% across all taxa) and varied significantly by HOLC grade for birds, mammals, and plants. Expected richness only varied by HOLC grade for birds. Our findings highlight how differences in biodiversity sampling may not translate to differences in expected species richness patterns, and suggest that applying insights obtained from certain taxonomic groups and extrapolating to multiple others may not be appropriate. Urban wildlife communities are not well-documented despite the explosion of digital information, and what is documented is known to be biased along a housing segregation typology for some taxon. These findings add evidence to suggest long-lasting effects of legacies of segregation on the natural world.
Legacies of social and environmental injustices can leave an imprint on the present and constrain transitions for more sustainable futures. In this article, we ask this question: What is the relationship of environmental inequality and histories of segregation? The answer for Baltimore is complex, where past practices of de jure and de facto segregation have created social and environmental legacies that persist on the landscape today. To answer this question, we examine the interactions among past and current environmental injustices in Baltimore from the late 1880s to the present using nearly twenty years of social and environmental justice research from the Baltimore Ecosystem Study (BES), a long-term social–ecological research project. Our research demonstrates that patterns and procedures in the city's early history of formal and informal segregation, followed by "redlining" in the 1930s, have left indelible patterns of social and environmental inequalities. These patterns are manifest in the distribution of environmental disamenities such as polluting industries, urban heat islands, and vulnerability to flooding, and they are also evident in the distribution of environmental amenities such as parks and trees. Further, our work shows how these legacies are complicated by changing perceptions of what counts as an environmental disamenity and amenity. Ultimately, we argue that the interactions among historical patterns, processes, and procedures over the long term are crucial for understanding environmental injustices of the past and present and for constructing sustainable cities for the future.
Redlining was a racially discriminatory housing policy established by the federal Home Owners’ Loan Corporation (HOLC) during the 1930s. For decades, redlining limited access to homeownership and wealth creation among racial minorities, contributing to a host of adverse social outcomes, including high unemployment, poverty, and residential vacancy, that persist today. While the multigenerational socioeconomic impacts of redlining are increasingly understood, the impacts on urban environments and ecosystems remains unclear. To begin to address this gap, we investigated how the HOLC policy administered 80 years ago may relate to present-day tree canopy at the neighborhood level. Urban trees provide many ecosystem services, mitigate the urban heat island effect, and may improve quality of life in cities. In our prior research in Baltimore, MD, we discovered that redlining policy influenced the location and allocation of trees and parks. Our analysis of 37 metropolitan areas here shows that areas formerly graded D, which were mostly inhabited by racial and ethnic minorities, have on average ~23% tree canopy cover today. Areas formerly graded A, characterized by U.S.-born white populations living in newer housing stock, had nearly twice as much tree canopy (~43%). Results are consistent across small and large metropolitan regions. The ranking system used by Home Owners’ Loan Corporation to assess loan risk in the 1930s parallels the rank order of average percent tree canopy cover today.
This file set accompanies this paper: Locke, D.H., Romolini, R., Galvin, M. F., O’Neil-Dunne, J. P. M., Strauss, E. G.. (2017). Tree canopy change in Coastal Los Angeles, 2009 - 2014. Cities And The Environment (CATE) http://digitalcommons.lmu.edu/cate/vol10/iss2/3 The files contain a Census block group shapefile and a parcel .*dbf (1.2 GB). The parcel polygons were not provided to keep the file size manageable. Contact me if you would like the polygons to accompany the tabular parcel data. This script replicates the analyses contained in the paper. Additional data and analyses are provided, by only those appearing in the paper are documented in the script.
