Historic residential segregation impacts biodiversity data availability disparately across the tree of life

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.