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.