Biological invasions are a population-level rather than a species-level phenomenon

ASICS project (ANR-20-EBI5- 0004),BiodivERsA, BiodivClim call (2019–2020). EGB is supported bythe Spanish Ministry of Science, Innovation and Universities(MCIN/AEI/10.13039/501100011033) and the European Union(NextGenerationEU/PRTR) through projects PID2019-103936GB-C21,TED2021-129889B-I00, and RED2022-134338-T. NIK is fundedbу the basic project of Sukachev Institute of Forest SB RAS, Russia(Project No. FWES-2021- 0011) and the Russian Science Foundation(project No. 22-16- 00075). SM acknowledges support of NBFC,funded by the Italian Ministry of University and Research, P.N.R.R.,Missione 4 Componente 2, “Dalla ricerca all'impresa”, Investimento1.4, Project CN00000033. RNC is funded by the Leverhulme Trust(ECF-2021- 001). Open Access funding enabled and organized by Projekt DEAL