Data from: Socio-economic impact classification of alien taxa (SEICAT)

Many alien taxa are known to cause socio-economic impacts by affecting the
different constituents of human well-being (security; material and
non-material assets; health; social, spiritual and cultural relations;
freedom of choice and action). Attempts to quantify socio-economic impacts
in monetary terms are unlikely to provide a useful basis for evaluating
and comparing impacts of alien taxa because they are notoriously difficult
to measure and important aspects of human well-being are ignored. Here, we
propose a novel standardised method for classifying alien taxa in terms of
the magnitude of their impacts on human well-being, based on the
capability approach from welfare economics. The core characteristic of
this approach is that it uses changes in peoples' activities as a
common metric for evaluating impacts on well-being. Impacts are assigned
to one of five levels, from Minimal Concern to Massive, according to
semi-quantitative scenarios that describe the severity of the impacts.
Taxa are then classified according to the highest level of deleterious
impact that they have been recorded to cause on any constituent of human
well-being. The scheme also includes categories for taxa that are not
evaluated, have no alien population, or are data deficient, and a method
for assigning uncertainty to all the classifications. To demonstrate the
utility of the system, we classified impacts of amphibians globally. These
showed a variety of impacts on human well-being, with the cane toad
(Rhinella marina) scoring Major impacts. For most species, however, no
studies reporting impacts on human well-being were found, i.e. these
species were data deficient. The classification provides a consistent
procedure for translating the broad range of measures and types of impact
into ranked levels of socio-economic impact, assigns alien taxa on the
basis of the best available evidence of their documented deleterious
impacts, and is applicable across taxa and at a range of spatial scales.
The system was designed to align closely with the Environmental Impact
Classification for Alien Taxa (EICAT) and the Red List, both of which have
been adopted by the International Union of Nature Conservation (IUCN), and
could therefore be readily integrated into international practices and
policies.