Invasive PlantsThe Cultus watershed has become home for many invasive plant species. They include Japanese knotweed, tansy, English ivy, morning glory, giant hogweed, yellow flag iris, broom, and many more. And there may be new ones on the way. Most disturbed soils become weed sites. The Fraser Valley Invasive Plant Council has conducted tours to highlight the invasive plants at Cultus Lake. Invasive plants cost the ecosystem, landscaping and even infrastructure.
Despite their often-attractive appearance, invasive plants are one of the five most significant causes of biodiversity loss and change to ecosystem functions, as reported by the Millennium Ecosystem Assessment. They carry potential negative impacts to the economy, environment, and society; therefore, preventative planning and careful budgeting are required. Help is available from the Fraser Valley Invasive Plant Council and the Invasive Species Council of BC.
Aquatic invasive species include Eurasian Watermilfoil, which has colonized the littoral area (shoreline) of Cultus Lake. At the same time yellow flag iris is growing in Sweltzer Creek and needs to be managed. Invasive aquatic plants have long been a concern to residents and park managers. Earlier efforts of mitigation did not reduce the Watermilfoil, and in fact made it worse. Cultivation and even hand-pulling techniques were found to be ineffective, as every fragment would float away and create new colonies. CLASS is now facilitating a pilot project to use mats to suffocate watermilfoil in key areas around the lake.
Some actions include:
- Watermilfoil assessments have been done (the last one in 2004);
- Watermilfoil growth pattern research was conducted by the class of Connie Williams at Chilliwack High-school;
- In other places, like Christina Lake, they are finding an indigenous weevil that eats Watermilfoil; so far, not found at Cultus Lake;
- Cultus Lake Park Board has a fund earmarked for Watermilfoil