Management priorities for marine invasive species
Giakoumi, S., Katsanevakis, S., Albano, P. G., Azzurro, E., Cardoso, A. C., Cebrian, E., Deidun, A., Edelist, D., Francour, P., Jimenez, C., Mačić, V., Occhipinti-Ambrogi, A., Rilov, G., & Sghaier, Y. R. (2019). Management priorities for marine invasive species. Science of The Total Environment, 688, 976–982. https://doi.org/10.1016/j.scitotenv.2019.06.282
Summary
There are a wide variety of measures for managing invasive species, and rapid decision-making is vital for mitigating the damages invaders cause. Giakoumi et. al. collected expert opinions on the most effective management options for marine species with variable distributions, dispersal capabilities, and taxonomic groups. They rated 11 methods for their efficacy, feasibility, social acceptability, impacts on native communities, and costs of implementation.
While no method was considered ideal for the management of a particular species, educating people about the impacts of the invasive species was the highest-rated method of control across the most species. This rated highly in terms of feasibility, acceptability, and low costs, however, the authors note that the experts rated the efficacy of this action as "fifty-fifty." In the case of localized infestations with low dispersal ability, physical removal of the species was the highest-rated method.
Biological control options, including the promotion of predators, parasites, and diseases, were considered poorly applicable regardless of the native or alien origin of the species being introduced as a biological control agent. Poor public perception and the large potential impacts biocontrol can have on non-target species limit feasibility. This was also the case for the application of biocides, which have a much greater chance of dispersion in marine environments.
Finally, the authors also note that invasive marine populations sometimes experience "boom and bust" population dynamics, where species can rapidly multiply and later experience sharp population declines. Thus, experts rated the option of "do nothing" highly for many species due to its feasibility, acceptability, and low cost. The authors caution that steep population decline is not guaranteed, so the option must be approached with great caution.
Take home points
No single management action was considered ideal for model species, regardless of distribution and taxa.
Biocontrol and biocides have potentially hazardous impacts on non-target species and are difficult to employ well in marine environments.
In some scenarios, invasive populations will naturally decline, but relying on this can be dangerous.
Management implications
The framework emphasizes that rapid prioritizing of actions is important: based on the expert consensus, public education and physical removal may be the preferred options for rapid management of marine invaders.
Biocontrol is not considered an effective management strategy in most marine environments.
Keywords
Management Efficacy; Review; Management actions; Marine conservation; Marine invasive species; Prioritization