Non-native invasive plants cause significant impacts to ecosystems worldwide. The ecological effects of plant invasions are well known but we have a poor understanding of the economic impacts of invasions. In particular, a better understanding of the costs of invasive plant management is needed to motivate proactive spending early in the invasion process and ultimately reduce overall management costs. We used a combination of data mining and personal communications to compile six years of data on spending for invasive plant management for 13 state and federal agencies in Florida, arguably the most highly invaded and invader impacted state in the US. Collectively, these agencies manage nearly 90% of the state’s conservation acres. Our specific goals were: (1) Quantify the economic costs to state and federal agencies of managing upland and aquatic non-native plant invasions in Florida’s natural areas; and (2) Analyze how patterns of spending have changed temporally, spatially, and across different invasive plant taxa.
Results/Conclusions
Between 2009 and 2014, an average of more than $43.5M was spent per year on invasive plant management in Florida. Although state and federal agencies managed approximately the same number of conservation acres (5,930,363 and 5,543,207 acres, respectively), state agencies annually spent nearly 10 times more than federal agencies. Significantly more money was spent on aquatic ($21.6M/year) than terrestrial plant species ($13.8M/year), with the most costly aquatic invaders being Hydrilla verticillata ($9.7M/year) and Eichhornia crassipes or Pistia stratiotes ($6.5M/year). Over 60% of total aquatic spending was in non-coastal central Florida counties, while nearly 60% of the terrestrial spending was allocated to counties in the southeast portion of the state. Continued spending on invasive plant management is critical for Florida, where ecotourism and recreation sectors rely on the health and function of natural areas and comprise more than $17 billion/year of the state’s economy. Management expenditures are, therefore, less than 0.3% of the value of these sectors alone. However, both ecological and economic costs in Florida would be reduced if prevention and early detection and rapid response efforts were prioritized through pre-border risk assessment and aggressive eradication efforts.