Identifying opportunities for high resolution pesticide usage data to improve the efficiency of endangered species pesticide risk assessment.

The US pesticide registration and review process requires regular re-assessment of the risk of pesticide use to species listed under the Endangered Species Act (ESA), yet current assessment methods are inefficient when applied to hundreds of pesticides potentially impacting multiple species across a continent. Thus, many pesticides remain on the market without complete review. We assessed the value of using high resolution pesticide usage data in the risk assessment process to rapidly improve process efficiency. By using data available only in California, we found that high resolution data increased the number of species deemed not likely to be adversely affected by pesticides from <5 % to nearly 50 %. Across the contiguous US, we predicted that 48 % of species would be deemed not likely to be adversely affected using high resolution data, compared to 20 % without. However, if such data were available in just 11 states, 68 % of the available gains in efficiency could be obtained. Overall, using existing high-resolution data in California and a focused collection of such information from 11 other states could reduce risk assessment burden across the contiguous U.S. by one-quarter.