The InvaCost project started in 2014, after being somewhat frustrated to be able to cite only old and methodologically flawed or unsourced materials, while there was a clear need to provide cost estimates of biological invasions. This was (and still is!) important because quantification of impacts is still lacking in most cases of invasions, precluding an adequate ecological understanding of the process, and because monetization of the impacts, even if not perfect, allows more consideration by decision makers.

We therefore decided, quite candidly, to gather all the studies of economic costs due to invasive alien species worldwide in order to sum up the costs. After all, there should be that many…

Little did we know that there were hundreds of studies out there, with thousands of costs. Nor did we realize that these economic costs were all extremely heterogeneous in nature, focus and scale, and that it was just impossible to only sum them up to get a more global picture than our collection of case studies.

We therefore set up to work with economists to devise a standardization protocol so that extraction of data from each source could lead to a possibility to compile and compare costs across a multitude of descriptors (costs of a given invasive species, in a given region or on a given activity sector, for example). That is how the InvaCost project really started.