Running to the sun: niche evolution of a global invasive shrub

Climatic similarities between native and invaded areas are fundamental conditions for the establishment and dissemination of invasive alien species. Preventive measures to indicate potential areas for biological invasions are crucial for managing invasion risks. This measure assumes that species maintain their environmental conditions conserved between native and invaded areas. However, some species can quickly change their fundamental niche when exposed to previously unexperienced environmental conditions. Here, we distinguish between these types of changes in the climatic niche of the Nicotiana glauca, a global invasive species, employing multivariate analyses to compare niche overlap between the native (Argentina and Bolivia) and invaded areas (North America, Mediterranean, Northeast South America, Southern Africa and Australia). We found evidence that the climatic niche occupied by N. glauca in its native area does not overlap with the invaded area in the Caatinga (Northeast Brazil) and the Mediterranean region. The niche in these invaded areas exhibits both warmer climates with lower daily and annual temperature amplitude (Caatinga) and colder, drier climates (Mediterranean). A small portion of the climatic niche in the invaded area of N. glauca in the Mediterranean region expanded compared to the climatic space of the native area, suggesting that the species occupied part of the fundamental niche restricted by dispersal barriers. However, almost the entire climatic space occupied by N. glauca in the Caatinga expanded compared to the native area, suggesting the species enlarged its climatic niche in this invaded area. Therefore, N. glauca has the capability to inhabit niches across a diverse climatic range that cannot be solely predicted based on the native distribution, owing to the evolution of niche and the occupation of a previously unknown part of the fundamental niche. Thus, we suggest that when using predictive methods to identify potential areas for invasive non-native species, both invaded and native climatic spaces should be considered.