Historical racial redlining and contemporary patterns of income inequality negatively affect birds, their habitat, and people in Los Angeles, California
Data files
Sep 05, 2023 version files 2.02 MB
Abstract
The Home Owners’ Loan Corporation (HOLC) was a U.S. government-sponsored program initiated in the 1930s to evaluate mortgage lending risk. The program resulted in hand-drawn ‘security risk’ maps intended to grade sections of cities where investment should be focused (greenlined areas) or limited (redlined zones). The security maps have since been widely criticized as being inherently racist and have been associated with high levels of segregation and lower levels of green amenities in cities across the country. Our goal was to explore the potential legacy effects of the HOLC grading practice on birds, their habitat, and the people who may experience them throughout a metropolis where the security risk maps were widely applied, Greater Los Angeles, California (L.A.). We used ground-collected, remotely sensed, and census data and descriptive and predictive modeling approaches to address our goal. Patterns of bird habitat and avian communities strongly aligned with the luxury-effect phenomenon, where green amenities were more robust, and bird communities were more diverse and abundant in the wealthiest parts of L.A. Our analysis also revealed potential legacy effects from the HOLC grading practice. Associations between bird habitat features and avian communities in redlined and greenlined zones were generally stronger than in areas of L.A. that did not experience the HOLC grading, in part because redlined zones, which included some of the poorest locations of L.A., had the highest levels of dense urban conditions, e.g., impervious surface cover. In contrast, greenlined zones, which included some of the city's wealthiest areas, had the highest levels of green amenities, e.g., tree canopy cover. The White population of L.A., which constitutes the highest percentage of a racial or ethnic group in greenlined areas, was aligned with a considerably greater abundance of birds affiliated with natural habitat features (e.g., trees and shrubs). Conversely, the Hispanic or Latino population, which is dominant in redlined zones, was positively related to a significantly greater abundance of synanthropic birds, which are species associated with dense urban conditions. Our results suggest that historical redlining and contemporary patterns of income inequality are associated with distinct avifaunal communities and their habitat, which potentially influence the human experience of these components of biodiversity throughout L.A. Redlined zones and low-income residential areas that were not graded by the HOLC can particularly benefit from deliberate urban greening and habitat enhancement projects, which would likely carry over to benefit birds and humans.
README: Wood, E. M., S. Esaian, C. Benitez, P.J. Ethington, T. Longcore, L.Y. Pomara. Historical racial redlining and contemporary patterns of income inequality negatively affect birds, their habitat, and people in Los Angeles, California. Ornithological Applications
Description of the Data and file structure
These data, furnished as CSV files, are related to the analyses to address the objectives of our study. We also include R Markdown files, with similar names, that has all code, plots, and statistical outputs for ease of reference. If one were inclined to redo our analyses, please use the code in the R Markdown files, and the associated CSV files (it has the same name as the R Markdown file).
- All data below are found in the associated CSV file (Wood et al. redlining and birds - Objective 1 and 2 Analysis). Data in the CSV file can be used for all analyses, including multivariate analyses for objectives 1 and 2.
Variable Name Description
- Number Number of sites
- Group Site Name
- Longitude Longitude
- Latidude Latidude
- HOLC_code HOLC code
- HOLC_code_groups HOLC code_groups for analysis
- Income_status Low, medium, high income status
- acwo_abundance_nmixture Acorn Woodpecker abundance (nmixture model estimate)
- alhu_abundance_max_count Allen's Hummingbird abundance (max count)
- amcr_abundance_max_count American Crow abundance (max count)
- amro_abundance_max_count American Robin abundance (max count)
- anhu_abundance_nmixture Anna's Hummingbird abundance (nmixture model estimate)
- bewr_abundance_nmixture Bewick's Wren abundance (nmixture model estimate)
- blph_abundance_max_count Black Phoebe abundance (max count)
- btpi_abundance_nmixture Band-tailed Pigeon abundance (nmixture model estimate)
- btyw_abundance_nmixture Black-throated Gray Warbler abundance (nmixture model estimate)
- bush_abundance_nmixture Bushtit abundance (nmixture model estimate)
- calt_abundance_nmixture California Towhee abundance (nmixture model estimate)
- casj_abundance_nmixture Acorn Woodpecker abundance (nmixture model estimate)
- cora_abundance_max_count California Scrub-Jay abundance (max count)
- deju_abundance_max_count Dark-eyed Junco abundance (max count)
- ecdo_abundance_max_count Eurasian Collared-Dove abundance (max count)
- eust_abundance_nmixture European Starling abundance (nmixture model estimate)
- hofi_abundance_max_count House Finch abundance (max count)
- hosp_abundance_max_count House Sparrow abundance (max count)
- lego_abundance_max_count Lesser Goldfinch abundance (max count)
- modo_abundance_nmixture Mourning Dove abundance (nmixture model estimate)
- nomo_abundance_max_count Northern Mockingbird abundance (max count)
- oati_abundance_nmixture Oak Titmouse abundance (nmixture model estimate)
- ocwa_abundance_max_count Orange-crowned Warbler abundance (max count)
- rcki_abundance_nmixture Ruby-crowned Kinglet abundance (nmixture model estimate)
- rcpa_abundance_nmixture Amazonia spp. abundance (nmixture model estimate)
- ropi_abundance_nmixture Rock Pigeon abundance (max count)
- rwwb_abundance_max_count Red-whiskered Bulbul abundance (max count)
- spto_abundance_nmixture Spotted Towhee abundance (nmixture model estimate)
- towa_abundance_nmixture Townsend's Warbler abundance (nmixture model estimate)
- wcsp_abundance_nmixture White-crowned Sparrow abundance (nmixture model estimate)
- webl_abundance_max_count Western Bluebird abundance (max count)
- yrwa_abundance_nmixture Yellow-rumped Warbler abundance (nmixture model estimate)
- Forest_abundance_sum Forest-bird abundance (aggregate)
- Shrub_abundance_sum Shrub-bird abundance (aggregate)
- Synanthrope_abundance_sum Synanthrope-bird abundance (aggregate)
- Natural_lands_abundance_sum Natural-lands-bird abundance (aggregate)
- Exotic_abundance_sum Exotic-bird abundance (aggregate)
- Migrant_abundance_sum Migratory-bird abundance (aggregate)
- Resident_abudance_sum Resident-bird abundance (aggregate)
- Cumulative_richness Cumulative bird richness
- Forest_richness Forest-bird abundance
- Shrub_richness Shrub-bird abundance
- Natural_lands_richness Natural-lands-bird abundance
- Synanthrope_richness Synanthrope-bird abundance
- Exotic_richness Exotic-bird abundance
- Migratory_richness Migratory-bird abundance
- Resident_richness Resident-bird abundance
- Building density Building density of parcels
- Year built Year a parcel was built
- Land value $ Land value $ of parcels
- Last sale price $ Last sale price $ of parcels
- Bedrooms & bathrooms Bedrooms & bathrooms of parcels
- Square footage Square footage of parcels
- Tree canopy cover % Tree canopy cover %
- Grass cover % Grass cover %
- Impervious cover % Impervious cover %
- Building cover % Building cover %
- Paved surface % Paved surface %
- Street-tree density Street-tree density
- Street-tree dominance Street-tree dominance
- Street-tree importance value Street-tree importance value
- Natural areas & wildlife sanctuaries Natural areas & wildlife sanctuaries - distance in m
- Ecological sites Ecological sites - distance in m
- Regional parks & gardens Regional parks & gardens - distance in m
- Golf courses Golf courses - distance in m
- Cemeteries Cemeteries - distance in m
- Beaches & marinas Beaches & marinas - distance in m
- All data below are found in the associated CSV file (Wood et al. redlining and birds - Objective 4 mixed model Analysis). Data in the csv file can be used for the mixed model, time series analysis of objective 4.
- Number Number
- TRT2000 Census tract id for 2000 (see Ethington et al. 2000, cited in paper)
- Year Decadal year identifier
- Race Race or ethnicity of dominant group in a census tract
- Proportion Proportion of the race or ethnic group in a tract
- holc_grade THE HOLC grade, intersected and applied to a given census tract
- All data below are found in the associated CSV file (Wood et al. redlining and birds - Objective 4 and 5 AnalysesWood et al. redlining and birds - Objective 4 and 5 Analyses). Data in the CSV file can be used for the mixed model, time series analysis of objective 4.
OBJECTID OBJECTID
- GEOID Identified to link with 2000 census tract outlines (see Ethington et al. 2000)
- holc_grade HOLC grade assigned to census tract
- Race Dominant race or ethnicity category of census tract
- White_percent percent White within census tract in 2015-2019 ACA database
- Asian_percent percent Asian within census tract in 2015-2019 ACA database
- Black_percent percent Black within census tract in 2015-2019 ACA database
- Hispanic_Latino_percent percent Hispanic or Latino within census tract in 2015-2019 ACA database
- RLandVmean Parcel land values (average) of census tract
- CanPmean % tree canopy cover of parcels (average) within census tract)
- prc_fit predicted forest-bird abundance (mean values)
- prc_se predicted forest-bird abundance (standard error)
- prc_u_fit predicted urban-bird abundance (mean values)
- prc_u_se predicted urban-bird abundance (standard error)
- holc_id HOLC id for individual HOLC polygon (largest) within a census tract.
Sharing/access Information
All data are available to share, use for metanalyses, etc.
For any questions, please contact:
ERIC WOOD, PH.D.Associate Professor of Avian & Urban EcologyDepartment of Biological SciencesCalifornia State University, Los Angeles5151 State University Dr.Los Angeles, CA 90032-8201www.ericmwood.orgwww.ericmwood@calstatela.edu001 323 343 2055
Research Associate
Natural History Museum of L.A County
Department of Ornithology
Methods
We used point count data to collect bird data, remote sensing, and field approaches for the predictor data. We also used Census data from existing products. Please reference our paper for the full methodology.
Usage notes
These data, furnished as CSV files, are related to the analyses to address the objectives of our study. We also include R Markdown files, that have code, plots, and statistical outputs for ease of reference for some analyses. If one were inclined to redo our analyses, please either reference our analysis section, which details which tests (most are straightforward to implement in R), or use the code in the R Markdown files, and the associated CSV files (identified by which objective the data are intended for).