Invasion
Invasion Description
1st record: Triabunna/Tasmania/Pacific Ocean (1988, Valentine 2003)
Geographic Extent
Triabunna/Tasmania/Pacific Ocean (1988, Valentine 2003); Lords Bluff/Tasmania/Mercury Passage (1999, Valentine and Johnson 2005)
Vectors
| Level | Vector |
|---|---|
| Alternate | Hull Fouling |
| Alternate | Ballast Water |
Regional Impacts
| Ecological Impact | Competition | |
| Invasion of Undaria pinnatifida, in Tasmania, decreased diversity of native seaweeds. There was partial recovery, but with changed community composition after experimental removal of U. pinnatifida (Valentine and Johnson 2003). Experimental removal of the native seaweed canopy, simulating sea urchin herbivory, resulted in rapid increases of U. pinnatifida, rising form 7% of cover in controls to 35% in cleared blocks (Edgar et al. 2004). | ||
| Ecological Impact | Food/Prey | |
| In Tasmania, the sea urchin Heliocidaris erythrogramma grazed significantly on Undaria pinnatifida sporophytes, but did not prevent the establishment of a canopy. Experimental manipulations indicated that urchin grazing was not responsible for the dominance of Undarua over native algae (Valentine and Johnson 2005). | ||