Good (de)fences make good neighbors
Research summary written by Bethany Bradley, edited by Eve Beaury
Summary
Invasive plant regulations are commonly used across U.S. states to phase out or prohibit the sale of harmful species in the nursery trade. Optimally, regulations would be used consistently across state borders and would proactively prohibit the sale of invasive species before they are widespread (e.g., range-shifting invasive plants). Beaury et al. (2021) instead show that the regulatory landscape across the lower 48 U.S. states is a patchwork that is neither consistent in the identity of regulated species nor proactive in prohibiting trade of range-shifting species with climate change. Lack of coordination across state borders likely leads to confusion in how nurseries should manage cross-border trade and is thus a missed opportunity to slow invasions at the regional scale. As invasive species managers know well, the actions of your neighbors affect your management — Beaury et al. (2021) identify the need for more coordination of management actions at state and regional levels as well.
Take home points
553 plant taxa are regulated in the U.S. The number of species regulated per state varies from 0 to 162 invasive species (mean of 45).
State regulations are inconsistent — an average of only 16.8% of regulated species are shared between adjacent states.
State regulations are reactive — regulated species are already widespread in the state (present in an average of 47% of counties).
Management implications
Lack of regulation or low levels of regulation in some states contributes to the ongoing availability of invasive plants in the nursery trade (e.g., Beaury et al. 2021), which can exacerbate invasions in neighboring states.
Almost all states regulate one or more species proactively (i.e. have prohibited the sale of a plant not yet present in the state). This suggests that existing risk assessment protocols are not a barrier to proactive regulation, but rather that states have not evaluated risk from range-shifting invasive species.
For the Northeast, RISCC’s Do Not Sell management challenge identifies a priority set of ornamental plants that are known to be invasive in the mid-Atlantic or Southeast.
Keywords
Management, Policy, Range Shifts, Invasive Plant, Risk/Monitoring