A recent article that assesses different measures to control invasive species in oceans at early stages of invasion finds the most effective measures to be raising public awareness and encouraging the commercial use of these invasive species.
Why we need to control invasive alien species
As the second most common cause of species extinctions, invasive alien species are one of the greatest challenges facing terrestrial, freshwater, and marine native biodiversity.
Their ecological impacts can filter down to the food web and affect ecosystem functioning, thereby affecting socio-economics and health.
Consequently, their management is crucial for biodiversity conservation and human well-being.
International institutions have explicitly recognised the need to control and eradicate biological invasions and have set relevant targets (e.g. the Aichi Target 9 set by the Convention on Biological Diversity).
Management options available
While some progress has been made in controlling terrestrial invasive species, the high environmental connectivity of and dispersion capacity of species in water makes it more difficult to control biological invasions in the marine environment.
Given the difficulty in eradicating established invasive populations, management efforts generally focus on reducing their populations to levels that exert lower impacts on native ecosystems and the environment.
Slow decision-making can hinder the efficient eradication and control of invasive species.
A new approach to quickly prioritise actions
The article presents an approach that allows decision-makers to quickly prioritise management actions based on the species' dispersion capacity and distribution in the area to be managed.
Experts assessed 11 actions for controlling 12 model species (distinguished on the basis of their different dispersion capacity, distribution, and taxonomic identity) using an ‘applicability’ metric based on the combination of five criteria (effectiveness, feasibility, acceptability, impacts on native communities, and cost).
Based on this metric, they found raising public awareness about the risks associated with invasive species and encouraging their commercial use to be the most effective options.
Biological control actions were considered to be the least applicable, given their lack of effectiveness and the high and socially unacceptable risks involved.
Biocides and poisoning were deemed too risky as they have a high risk of diffusion, and can jeopardise the health of entire ecosystems.
The “do nothing” approach - doing nothing and waiting for the invaders to diminish - received relatively high scores as the easiest and least expensive management solution. However, the authors warn that this approach should be treated with great caution as spontaneous population crashes are not guaranteed or may only occur after causing lasting ecological damage.
This new approach can guide rapid decision-making on prioritising management options for the control of invasive species especially at early stages of invasion, when reducing managers' response time is critical.
It can also guide decision-making in subsequent invasion stages, and help prioritise actions for more than one established invasive species that share common characteristics within a management area.
Call for greater involvement of stakeholders and citizens
As ‘public awareness and education’ was prioritised over any other action, the authors call for substantial efforts to be invested to engage stakeholders and the general public in efforts to prevent and control invasive species, for example through citizen science projects.
- Management priorities for marine invasive species
- Aichi Target 9 of the Convention on Biological Diversity
- Citizen Science projects on Invasive Alien Species (IAS)
- 8 august 2019