Cats in a bag: state-based spending for invasive species management across the United States is haphazard, uncoordinated, and incomplete

Invasive species are an increasing source of economic loss, costing nations billions of dollars annually. Significant financial resources are spent to manage invasive species, but few comprehensive syntheses of the economic expenditures associated with this management effort exist. As a relatively affluent developed country, the United States should serve as a model of how to both manage invasive species and, more critically, understand the economic costs of doing so. To begin understanding the scale of expenditures on invasive species in the U.S., our goal was to quantify spending on invasive species management at the state level. We contacted natural resource management officials from all 50 states following a standardized protocol. While 47 of the 50 states provided expenditures for at least one of the five years requested (2017–2021), the distribution of expenditures by state varied dramatically, suggesting that actual expenditures might be much higher than those reported. While most states shared annual expenditures, they varied by an order of magnitude from $28,370 for Connecticut to $118,695,389 for Washington. Specifically, a widespread lack of careful and consistent expense tracking and coordination within and between states made clear and correct evaluation difficult. While the expenditures we obtained are almost certainly a significant underestimate, they also represent a serious lack of accounting at a state level. Hence, better tracking and coordination, within and between states, will be critical to handle the ongoing invasive species crisis.