Data from: Quantifying and linking mechanism scenarios to invasive species impact

Plant species invasion represents one of the major drivers of biodiversity
change globally, yet there is confusion about the nature of non-indigenous
species (NIS) impact. This stems from differing notions of what
constitutes invasive species impact and the scales at which it should be
assessed. At local scales, the mechanisms of impact on local competitors
can be classified into four scenarios: 1) minimal impact from NIS
inhabiting unique niches; 2) neutral impact spread across the community
and proportional to NIS abundance; 3) targeted impact on a small number of
competitors with overlapping niches; and 4) pervasive impact that is
disproportionate to NIS abundance and caused by modifications that filter
out other species. I developed a statistical test to distinguish these
four mechanism scenarios based on plant community rank-abundance curves
and then created a scale-independent standardized impact score. Using an
example long-term dataset, that has high native plant diversity and an
abundance gradient of the invasive vine, Vincetoxicum rossicum, I show
that impact resulted in either targeted or pervasive extirpations.
Regardless of whether NIS impact is neutral, targeted, or pervasive, the
net outcome will be the homogenization of ecosystems and reduced
biodiversity at larger scales, perhaps reducing ecosystem resilience. The
framework and statistical evaluation of impact presented in this paper
provide researchers and managers with an objective approach to quantifying
NIS impact and prioritizing species for further management actions.