Discussion
Our study summarises how simple communities respond to the combination
of three major drivers of global change: warming, eutrophication and
species invasions (IPBES 2019). While these drivers have received
considerable attention separately (Bellard et al. 2013; Binzer et al.
2016; Gallien & Carboni 2017), their combined impacts on local
communities remain poorly understood despite some recent advances
(Latombe et al. 2021; Sentis et al. 2021). We focused on two ubiquitous
interactions through which invaders affect resident
communities—predation and competition (Gallardo et al. 2016; Dueñas et
al. 2018)—to understand how invasion outcomes relate to changes in
community composition, diversity and stability (Tilman 1999). We showed
that the outcomes depend predictably on the interplay between
environmental conditions and differences in body mass and trophic
position between the invader and its local competitor or predator/prey
(Table S12). This allowed us to (i) identify combinations of
environmental conditions, invader traits and community size structure
that characterise communities prone to successful invasions, and (ii)
describe the community-level consequences of such invasions.