In this contribution, new data concerning the distribution of vascular flora alien to Italy are presented. It includes new records, confirmations, exclusions, and status changes for Italy or for Italian administrative regions. Furthermore, three new combinations are proposed. Nomenclatural and distribution updates published elsewhere are provided as Suppl. material 1.

In this contribution, new data concerning the distribution of vascular flora alien to Italy are presented. It includes new records, confirmations, exclusions, and status changes for Italy or for Italian administrative regions. Nomenclatural and distribution updates published elsewhere are provided as Suppl. material 1.

Effects of climate change are particularly important in the Mediterranean Biodiversity hotspot where rising temperatures and drought are negatively affecting several plant taxa, including endemic species. Assisted colonisation (AC) represents a useful tool for reducing the effect of climate change on endemic plant species threatened by climate change. We combined species distribution models (SDMs) for 188 taxa endemic to Italy with the IUCN red listing range loss threshold under criterion A (30%) to define: (a) the number of AC (measured as 2 × 2 km grid cells that should be occupied by new populations, i.e. grid cells = new populations) required to fully compensate for predicted range loss and to halt the decline below the 30% of range loss; (b) The number of cells necessary to compensate for range loss was calculated as the number of currently occupied cells lost under future climate due to unsuitable conditions. We used two representative concentration pathways, +2.6 and +8.5 W/m2, optimistic and pessimistic scenarios respectively. Availability of suitable areas for AC was also assessed within the current species distribution and within protected areas. Under the optimistic scenario, no taxa would lose more than 30% of their range and AC would not be required. Under the pessimistic scenario, roughly the 90% of taxa showed a cell loss higher than 30%. Eight taxa were predicted to lose >95% of their range. For these species, AC was required from 13 to 16 new populations (=13–16 grid cells) per taxon to cap the range loss at 30%. For currently VU or EN species, an average number of 32–35 AC attempts would be necessary to fully compensate their range loss under a pessimistic scenario. Suitable recipient sites within protected areas falling in their projected range were identified, allowing for short‐distance AC. Synthesis. Combining species distribution models and red listing thresholds under Criterion A has enabled the strategic planning of multiple species assisted colonisation minimising the effort in terms of new populations to be created and maximising the conservation benefit in terms of range loss compensation.

Background Quantifying variation of genetic traits over the geographical range of species is crucial for understanding the factors driving their range dynamics. The center-periphery hypothesis postulates, and many studies support, the idea that genetic diversity decreases and genetic differentiation increases toward the geographical periphery due to population isolation. The effects of environmental marginality on genetic variation has however received much less attention. Methods We tested the concordance between geographical and environmental gradients and the genetic predictions of center-periphery hypothesis for endemic Lilium pomponium in the southern Alps. Results We found little evidence for concordance between genetic variation and both geographical and environmental gradients. Although the prediction of increased differentiation at range limits is met, genetic diversity does not decrease towards the geographical periphery. Increased differentiation among peripheral populations, that are not ecologically marginal, may be explained by a decrease in habitat availability that reduces population connectivity. In contrast, a decrease of genetic diversity along environmental but not geographical gradients may be due to the presence of low quality habitats in the different parts of the range of a species that reduce effective population size or increase environmental constraints. As a result, environmental factors may affect population dynamics irrespective of distance from the geographical center of the range. In such situations of discordance between geographical and environmental gradients, the predictions of decreasing genetic diversity and increasing differentiation toward the geographical periphery may not be respected.

Climate change seriously threatens biodiversity, particularly in mountain ecosystems. However, studies on climate change effects rarely consider endemic species and their niche properties. Using species distribution models, we assessed the impact of climate change on the endemic flora of the richest centre of endemism in the Alps: the South-Western Alps. We projected the potential distributions of 100 taxa under both an optimistic (RCP2.6) and a pessimistic (RCP8.5) climate scenario, analysing the relationships between range dynamics and several predictors (dispersal abilities, vegetation belts, niche marginality, niche breadth, altitudinal range and present range). The negative impact ranged from weak to severe according to the scenario, but the extinction risk was low. The dispersal abilities of species strongly affected these range dynamics. Colline and subalpine species were the most threatened and the relationship between range dynamics and predictors varied among vegetation belts. Our results suggest that the rough topography of the SW Alps will probably buffer the climate change effects on endemics, especially if climate will remain within the limits already experienced by species during the Holocene. The presence of the Mediterranean-mountain flora, less affected by climate change than the alpine one, may explain the lower number of species threatened by extinction in the SW Alps than in other European mountains. These results suggest that the relationship between plants’ sensitivity to climate change, and both niche properties and vegetation belts, depends on the difference between the current climate in which species grow and the future climate, and not just on their niche breadth.