Advancing the understanding of global plant invasions

Humans have deliberately and undeliberately introduced many species from their native regions into regions where they did not previously occur. Some of these species have become naturalized, and some of those have become invasive. However, only in the last couple of years, the global extent patterns and processes of such biological invasions have started to emerge. This has been possible through large-scale collaborative initiatives such as the Global Naturalized Alien Flora (GloNAF) database, funded by the DFG and FWF. The GloNAF database currently includes entries of 16,564 alien vascular plant species in 1388 regions. In this new follow-up proposal, we want to continue updating and expanding GloNAF. We will use the database to test how threat status and commonness in the native range relate to naturalization elsewhere. This will be done by combining GloNAF with the ThreatSearch database and with multiple datasets on changes in distributions of native species in different parts of Europe. Furthermore, by using resurveyed vegetation relevé data from the recently established ResurveyEurope initiative, we will assess small scale patterns and drivers of changes in alien and native plant species richness and composition in plant communities of Europe. By using the novel Global Alien Pathogenic Fungi database, we will analyze the interactions of plant invasions and alien pathogenic fungi. Finally, we will use species distribution modelling on all naturalized species with sufficient occurrence records in GBIF to quantify naturalization debts and the potential global ranges of alien species. These studies will further advance our understanding of local and global plant invasions and their impacts on biodiversity.

This bilateral WEAVE project, conducted jointly with the University of Konstanz (Germany), aimed to deepen scientific understanding of global plant invasions. The research addressed key questions in invasion biology, macroecology, and conservation science. The project was structured into five work packages (WPs). It investigated how non-native plants spread globally, the factors influencing their successful establishment, and the consequences for native plant diversity. A central foundation was the global database GloNAF, which was updated, expanded, and taxonomically standardized. A key focus was whether plant species that are threatened or rare in their native ranges are also less successful at establishing themselves outside their home regions. At the same time, the project examined whether species with increasing populations in their native ranges are particularly likely to colonize new areas. For Europe, the project analyzed how non-native and native plant species within plant communities change over time, specifically examining the impacts of climate change, land use, and nitrogen deposition. Using various future scenarios, the researchers estimated how plant diversity might evolve by 2050 and 2100. Another area of study focused on introduced fungal diseases that can harm plants, identifying particularly vulnerable native plant species and regions. Finally, the project investigated whether non-native plants have already fully colonized their potential distribution ranges or whether further spread is to be expected in the future. The findings are intended to help improve the understanding of changes in global plant diversity and facilitate the early detection of risks. By combining global data sources, innovative modeling, and interdisciplinary expertise, the project has improved the understanding of plant invasion dynamics and contributed to global biodiversity policy. The findings have refined theories in invasion biology, optimized strategies for early detection and management. The results have been widely disseminated through 41 scientific publications and communicated at professional scientific conferences.