Bats, Insecticide Use, and Environmental Justice in California’s Central Valley
Free-tailed bats are important ecosystem service providers, consuming large quantities of agricultural pests and potentially reducing the need for chemical insecticides. In California’s Central Valley, a region with some of the highest agricultural production and pesticide application rates in the country, pesticide exposure is a major concern for both environmental and human health, particularly for vulnerable communities identified by the CalEnviroScreen dataset. Arantza and Brian explored the relationship between bat activity, pesticide use, and environmental justice indicators to better understand whether bat-mediated pest control can contribute to reducing pesticide exposure risks for at-risk populations.
The research goals were to integrate radar-based bat occurrence data with the California Pesticide Use Reporting (PUR) dataset and CalEnviroScreen 4.0 indicators to identify geographic and crop-specific patterns linking bat activity to pesticide use and environmental vulnerability. The team started building spatially explicit models that test whether higher bat activity corresponds with lower pesticide use by first compiling and cleaning, ulti-scale datasets, conducting exploratory spatial analysis, and initiating regression modeling. This work highlighted communities where bat conservation could have co-benefits for environmental health and justice.
Arantza and Brian’s Impacts:
- Documented all project tools (Google Drive, QGIS, Python/Colab) for reproducible analysis
- Flagged ~10 key scientific papers for the literature review on bats, pesticides, and environmental justice
- Downloaded, cleaned, and summarized CalEnviroScreen 4.0 shape files and key variables by census tract
- Integrated PUR pesticide use data with crop type classifications from the USDA Cropland Data Layer
- Produced county-scale maps of pesticide use, heat maps of EJ indicators, and preliminary overlays of bat detections and pesticide application
- Conducted spatial joins between bat activity metrics, pesticide use, and EJ indicators
- Stratified datasets by crop type to identify potential high-priority focus areas
- Created initial scatterplots and spatial summaries to guide future regression analyses
