Ali Serhan Tarkan and Ismael Soto discuss recently published work, conducted with colleagues, surrounding novel biological invasions and their impacts. The study suggests that, to effectively manage invasions, decision-makers need solid information to base decisions on.
Invasive species are like unwelcome guests wreaking havoc on biodiversity, ecosystems, and human well-being. And with forecasted climate change and ever-increasing human activities moving species around, novel biological invasions and the impacts of invasive populations are a major cause for concern. However, in order to effectively prevent and control these invasions, decision-makers and land managers need solid information to base decisions/management actions on.
Identifying the invasive species with the greatest impact, both ecologically and socio-economically is, therefore, crucial. Such information is particularly valuable to inform decisions as to whether to take a proactive approach (i.e. prevention through biosecurity measures and eradication efforts) or a reactive one (i.e. controlling populations once they have already established) to manage these invasive species.
Current assessment limits
Multiple risk assessment methods have already been developed to prioritize invasive species with the most significant impacts. A major issue is that these assessments often lack basic quantitative data and instead they rely on qualitative information, like expert opinion.
The expertise of the assessor and the extent of data considered can therefore introduce biases and poorly represent the ‘true’ impacts of a species. The assessments tend to be suitable at large scales, but what managers need are local solutions. This mismatch leads to inconsistencies in assessment outcomes. Ultimately, we lack formal and reliable information for many invasive species, resulting in poor assessments.
Monetary costs in assessments
To improve assessment indicators, we propose incorporating standardized economic data into risk assessments. This means considering monetary losses, spending, and impacts on human health. Until recently, this would have been difficult to implement into risk assessments given that for most taxa, economic impacts were poorly synthesized and not reported in standardized and comparable terms.
The development of the InvaCost database fills this major gap in the invasion science toolbox by collating and harmonizing data on the monetary burden imposed by invasive species globally. Studies using the database demonstrate the extreme costs invasive species have; estimated to have cost over $2 trillion US dollars globally since the 1970s through damage and management expenses. Being able to report these costs alongside ecological impacts in risk assessments will help to produce robust data to inform conservation actions.
Incorporating costs into risk assessments
Current risk screening protocols can account for known monetary costs. However, getting this data can be challenging due to accessibility issues, research gaps and language barriers. We suggest focusing on observed monetary losses, specifically those in the InvaCost database, while excluding management investment costs for separate consideration.
This information is vital for informing policy decisions and prioritizing management efforts. InvaCost offers a standardized approach that normalizes costs, reducing confusion for decision-makers during the assessment process.
We believe that establishing a link between monetary costs and ecological impacts can improve prioritization efforts. In the absence of cost data, we can use trait profiling to estimate costs for closely related species. However, wherever possible, efforts should be made to estimate the damage and control costs of invasive species in project reporting.
We recommend structured programs by national governments to report the economic effects of biological invasions. With growing data resources, future assessments should include quantitative measures of the economic costs of invasive species, and the InvaCost database provides a reliable and transparent foundation for available cost data on hundreds of invasive species worldwide.
Read the full article “Monetary impacts should be considered in biological invasion risk assessments” in Journal of Applied Ecology