Identifying areas threatened by aquatic invasive alien plants
Aquatic habitats can be vulnerable to biological invasions due to their use for human activities and their connectivity. Aquatic invasive alien plants can have an array of negative impacts on native biodiversity and ecosystem services. They can degrade a waterbody and can be both difficult and costly to control. The study included 71 non-native aquatic plant species (31 species that are already established in the Iberian Peninsula (Table 1) and 40 non-native species that have invasive potential). The aim of the study was to produce a map of suitable areas to assess the invasion risk of these species in the Iberian Peninsula. Occurrence data was gathered for each species and the 19 bioclimatic variables from WorldClim were used in the model to predict the potential distribution of the species in the Iberian Peninsula. Additional layers were added to the model for the effect of anthropogenic influences, which may influence the occurrence of aquatic plant species. The result showed, out of the 9 039 grid cells in the regional map, that 759 grid cells contained occurrences of non-native aquatic plant species. Most of the grid cells which contain aquatic plant species occur in the western half of the Iberian Peninsula: in the coastal areas of Portugal, around the Tagus River, the Guadiana Basin and the coast of the southwestern Iberian Peninsula. Cells along the east coast of the Peninsula were also occupied by a large number of non-native aquatic plant species. This map can be used as a reference tool for management regimes and control strategies aimed at the prevention and eradication of non-native aquatic plant species.
Table 1. List of aquatic alien plant species already established in the Iberian Peninsula.
Species | Family | Origin | EPPO status |
Alternanthera philoxeroides | Amaranthaceae | South America | EPPO A2 |
Azolla filiculoides | Salviniaceae | Americas | Observation List |
Bacopa monnieri | Plantaginaceae | Widespread | - |
Crassula aquatica | Crassulaceae | Widespread | - |
Egeria densa | Hydrocharitaceae | South America | List IAP |
Pontederia crassipes | Pontederiaceae | South America | EPPO A2 |
Elodea canadensis | Hydrocharitaceae | North America | - |
Heteranthera limosa | Pontederiaceae | Americas | - |
Heteranthera reniformis | Pontederiaceae | Americas | - |
Heteranthera rotundifolia | Pontederiaceae | Americas | - |
Hydrocotyle bonariensis | Araliaceae | Americas | - |
Hydrocotyle ranunculoides | Araliaceae | Americas | EPPO A2 |
Hydrocotyle verticillata | Araliaceae | Americas/Africa | - |
Lagarosiphon major | Hydrocharitaceae | Southern Africa | List IAP |
Lemna minuta | Araceae | Americas | - |
Lemna valdiviana | Araceae | Americas | - |
Hydrocharis laevigata | Hydrocharitaceae | Central & South America | - |
Ludwigia grandiflora | Onagraceae | Americas | EPPO A2 |
Ludwigia peploides subsp. montevidensis | Onagraceae | South America | - |
Ludwigia repens | Onagraceae | Central & North America | - |
Myriophyllum aquaticum | Haloragaceae | Central & South America | List IAP |
Myriophyllum heterophyllum | Haloragaceae | Central & North America | EPPO A2 |
Najas gracillima | Hydrocharitaceae | Widespread | - |
Najas graminea | Hydrocharitaceae | Widespread | - |
Nymphaea mexicana | Nymphaeaceae | Central America | - |
Pistia stratiotes | Araceae | Widespread | EPPO A2 |
Rotala indica | Lythraceae | Asia | - |
Salvinia molesta | Salviniaceae | South America | EPPO A2 |
Spartina alterniflora | Poaceae | Americas | - |
Spartina densiflora | Poaceae | South America | - |
Spartina patens | Poaceae | Central & North America | - |
Sources
Rodríguez-Merino A (2023) Identifying and managing areas under threat in the Iberian Peninsula: An invasion risk atlas for non-native aquatic plant species as a potential tool. Plants 12, 3069. https://doi.org/10.3390/plants12173069