Predicting the distribution of invasive plants in the Ukrainian Carpathians under climatic change and intensification of anthropogenic disturbances: implications for biodiversity conservation.

Biodiversity conservation in the Ukrainian Carpathians cannot be accomplished without a clear understanding of the factors negatively impacting habitats and species, and long-term projection of these impacts. One factor that may severely alter the ecosystems involved is the introduction and spread of invasive plant species, but the potential distribution and spatial aggregation of suitable habitats for several invaders have not been quantified. The Maxent approach was used to model the potential establishment within the entire mountain range of 11 alien invasive plant species based on stratified sampling and herbaria records and six variables representing climatic extremes, topography, and anthropogenic and natural disturbances. Predictions of habitat suitability were projected to two future change scenarios depicting increasing rates of climate warming and anthropogenic disturbances in 2050 and 2100. Under current climate and disturbance patterns, the models predicted suitable habitats for invasive species establishment to be aggregated in the southwest, east and north-east of the Ukrainian Carpathians, along major rivers and roads at altitudes of up to c. 700 m. Eight per cent of the total area within protected areas was predicted to be potentially susceptible to invasion by at least one species, with 13% of these susceptible habitats being suitable for all 11 species. Under the future change scenarios, suitable habitat ranges increased significantly in the entire study area and within regions of high conservation value. All species were projected to gain suitable habitats at higher altitudes along linear habitats and to potentially expand their ranges laterally from habitats predicted as suitable for current conditions along small rivers and roads. Under the scenario solely of increased average seasonal temperatures, suitable habitats for the establishment of at least one species within protected areas and a proposed ecological network increased by more than 15 percentage points by 2050 and by more than 30 percentage points by 2100 when compared with predictions for current conditions. Similar future patterns were discernible for the aggregation of suitable habitats for all 11 species. Incorporating increases in anthropogenic pressures into climatic-change projections led to a significantly greater projected expansion of suitable habitats for establishment as compared to scenarios considering only climatic changes. As the 11 species have already established viable populations within protected areas, further spread of at least one species is likely if conservation planning is not changed to include the management of invasive species in such areas.