Alien species pool influences habitat levels of invasion
| Autoři | |
|---|---|
| Rok publikování | 2018 |
| Druh | Konferenční abstrakty |
| Citace | |
| Popis | Habitats differ significantly in the number of alien species established, i.e. habitat levels of invasion. Numbers of alien plant species can be determined by (1) habitat invasibility and (2) propagule pressure. Here we suggest another important factor: (3) habitat-specific regional pools of alien species. Traits of alien species are influenced by adaptations to original (donor) habitats in their native range. Because individual donor habitats provide different species pools for invasion, regional species pools of aliens available for invasion to individual habitats in the invaded range will also differ. Observed levels of invasion of analogous recipient habitats should therefore depend on these differences in alien species pools. Using the Czech National Phytosociological Database and the Carolina Vegetation Survey Database, we identified native and alien vascular plant species occurring in 27 habitats in temperate regions of Central Europe and eastern North America. We calculated each habitat’s level of invasion as the proportion of alien species in a representative sample of vegetation plots from the habitat. We also calculated the contribution of each donor habitat to the regional alien species pool as the proportion of species in a habitat that are native to one continent and donated as aliens to the other. The relationship between each habitat’s levels of invasion and the size of its regional alien species pool was significant for both the invasion of European plant species to North American habitats and the invasion of North American species to European habitats. We found that the more native species a habitat contributed as aliens to the other continent, the more of them established in the analogous recipient habitat on the other continent, creating a direct species-pool effect. We also found that the proportion of alien species in a habitat increased with the proportion of its native species that same habitat donated to the other continent. Donor habitats contributing large numbers of alien species to regional species pools elsewhere are thus themselves subjected to higher levels of invasion by alien species from analogous habitats elsewhere, creating a reciprocal species-pool effect. |
| Související projekty: |