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

Historical residential segregation policies have left a lasting impact on urban environments, greenspaces, and wildlife communities, creating socioeconomic heterogeneity and altering biota. However, the extent to which these policies continue to impact urban biodiversity remains unclear, especially across taxonomic groups and spatial scales. We explore how sampling and biodiversity metrics (sampling density, estimated completeness of sampling, and expected species richness) across taxonomic groups vary across historically redlined neighborhoods and relative to broader urban areas. To explore these patterns, we leverage nearly 60 million observations of amphibia, aves, fungi, insecta, mammalia, plantae, and reptilia collected between 2000 and 2020 within 145 Metropolitan Statistical Areas in the United States. We estimate significant differences in sampling density across redlined neighborhoods 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 Home Owners' Loan Corporation (HOLC) grade for birds, mammals, and plants. Expected richness varied significantly by HOLC grade only 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 gradients of housing segregation and multiple urban scales. These findings add evidence to suggest long-lasting effects of legacies of segregation on the natural world.