Species

Japanese knotweed is a bamboo-like plant native to Asia that – like many other invasive species – was introduced to England and subsequently North America as a garden ornamental (State of Washington Department of Ecology, n.d.) The plant is a perennial, growing year round by seeds in the spring and rhizomes at other times of the year (Royal Horticultural Society, n.d.) In its non-native territory, the plant grows solely by its creeping rhizome network; these rhizomes can extend 13 – 18m in length. The vegetation in riparian areas has a strong influence on river and stream ecosystems, and therefore can dramatically change its structure. This greatly effects the aquatic species that reside in the creek and on its edge, as well as those that thrive off of those aquatic species. In addition to its potential for ecological damage, F. japonica poses a threat to human infrastructure – it is known to eat right through concrete! The industrious growth habits of Japanese knotweed make it a serious threat to both native ecosystems in its introduced range, and to human infrastructure. As a result, initiatives across coastal British Columbia have begun to raise awareness about the plant, including its siblings Giant knotweed and Bohemian knotweed.

The Anderson Creek Watershed has already been subject to environmental degredation due to historical logging in the Caren Range. Logging increased sediment runoff, which compacts the creek bed, decreasing the oxygen content of the water and decreasing the habitat for egg laying and spawning salmon. Anderson Creek saw decreased salmon returns, and locals became concerned. In the 1980s, extensive alteration of the ecosystem took place to create spawning ponds to promote greater returns, and considerable success was seen. However, with the arrival of Japanese knotweed, the Anderson Creek Watershed and its salmon population face yet another threat.