Alien Species
The introduction of non-native species to these islands has been a mixed blessing. Some species have not thrived while others have overwhelmed their native counterpart. The new world grey squirrel is one such example. Our rivers have also received some unwelcome visitors, some of which have thrived.
Here is the Environment Agency's list of top ten least favourite alien species:
| 1 | Japanese Knotweed | Plant | Fallopia japonica |
|---|---|---|---|
| 2 | North American signal crayfish | Crustacean | Pacifastacus leniusculus |
| 3 | Mink | Mammal | Mustela vison |
| 4 | Giant Hogweed | Plant | Heracleum mantegazzianum |
| 5 | Floating pennywort | Plant | Hydrocotyle ranunculoides |
| 6 | Himalayan Balsam | Plant | Impatiens glandulifera |
| 7 | Australian swamp stonecrop | Plant | Crassula helmsii |
| 8 | Canadian pondweed | Plant | Elodea canadensis |
| 9 | Parrots feather | Plant | Myriophyllum aquaticum |
| 10 | Topmouth gudgeon | Fish | Pseudorasbora parva |
From the list above there are five species currently doing rather well on our river banks marked in red. Projects are in hand to contain or eradicate the worst of them. Please see Projects.
