Humans have spread plants globally for millennia, inadvertently causing ecological disruptions. Apart from their negative effects, biological invasions provide a unique opportunity to study how species modify their niche when confronted with novel environments. Focusing on the Mediterranean Basin, we assessed (1) which traits influence niche dynamics, and (2) whether niche conservatism or niche shift promotes invasion success. We selected the 80 most widespread alien vascular plant species in Mediterranean Europe and compiled data on their distributions in their native and invaded ranges. We then tested how a species' residence time, biogeographic origin, dispersal ability, functional traits, and intraspecific trait variability (ITV) influence its niche dynamics following invasion. Using already published independent data, we finally assessed whether niche dynamics can explain different dimensions of invasion success (quantified as regional spread or local abundance). We found that niche shifts were common (71% of species) and were mostly driven by species failing to occupy all suitable environments in their invaded range (unfilling), regardless of residence time. Niche unfilling and niche expansion were more important in species with high intraspecific trait variability introduced from non-Mediterranean biomes (temperate or tropical). Niche expansion was also greater in species with long-distance dispersal, a narrow native niche, and bigger seeds. Interestingly, invasion success correlated more with a species' ability to conserve its niche and residence time than with niche expansion. Niche shifts were better predicted by species traits than residence time. For example, high adaptive and acclimatization potential (inferred from high intraspecific trait variability) favored niche shifts in general, and long-distance dispersal favored niche expansion. Understanding how these traits relate to niche dynamics is important since a species' ability to conserve and fill its niche is, in turn, a good predictor of invasion success.

• Klíčová slova
• acclimatization, invasion success, invasive species, niche dynamics, niche filling, phenotypic plasticity, rapid adaptation, species traits,
• MeSH
• distribuce rostlin * MeSH
• ekosystém * MeSH
• rostliny * klasifikace   MeSH
• zavlečené druhy * MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Evropa MeSH
• Středomoří MeSH

AIM: Interspecific hybridization can promote invasiveness of alien species. In many regions of the world, public and domestic gardens contain a huge pool of non-native plants. Climate change may relax constraints on their naturalization and hence facilitate hybridization with related species in the resident flora. Here, we evaluate this possible increase in hybridization risk by predicting changes in the overlap of climatically suitable ranges between a set of garden plants and their congeners in the resident flora. LOCATION: Europe. METHODS: From the pool of alien garden plants, we selected those which (1) are not naturalized in Europe, but established outside their native range elsewhere in the world; (2) belong to a genus where interspecific hybridization has been previously reported; and (3) have congeners in the native and naturalized flora of Europe. For the resulting set of 34 alien ornamentals as well as for 173 of their European congeners, we fitted species distribution models and projected suitable ranges under the current climate and three future climate scenarios. Changes in range overlap between garden plants and congeners were then assessed by means of the true skill statistic. RESULTS: Projections suggest that under a warming climate, suitable ranges of garden plants will increase, on average, while those of their congeners will remain constant or shrink, at least under the more severe climate scenarios. The mean overlap in ranges among congeners of the two groups will decrease. Variation among genera is pronounced; however, and for some congeners, range overlap is predicted to increase significantly. MAIN CONCLUSIONS: Averaged across all modelled species, our results do not indicate that hybrids between potential future invaders and resident species will emerge more frequently in Europe when climate warms. These average trends do not preclude, however, that hybridization risk may considerably increase in particular genera.

• Klíčová slova
• alien ornamental plants, climate change, interspecific hybridization, invasion biology, range overlap, species distribution models,
• Publikační typ
• časopisecké články MeSH