Himalayan Blackberry and Knotweed Management at Alaksen National Wildlife Area and the Sea Island Conservation Area

Work Location

ANWA is located at 5421 Robertson Road in Delta, BC (V4K 3N2). ANWA is open between 9:00 – 15:30 from Monday to Friday, excluding weekends and statutory holidays.

SICA is located just north of 5940 Ferguson Road in Richmond, BC (V7B 1M6). SICA can be accessed at any time as there are no limitations to access in place

Background

The Alaksen National Wildlife Area (ANWA) is located on the northern tip of Westham Island in Delta, BC, and was established in 1976 for the conservation of important migration and overwintering habitat for various bird species. The ANWA comprises a portion of the Fraser River delta, which makes up a vital link in the hemispherically significant network of coastal habitats that span from Siberia to South America. The Fraser River delta is considered important in this network because it supports at least half a million birds each winter, and there are no comparable sites along the Pacific coast of North America.

Designated under the Species at Risk Act (SARA), there are at least 15 species at risk that reside within the ANWA. Some of these species include great blue heron (Ardea herodias), western painted turtle (Chrysemys picta bellii), barn swallow (Hirundo rustica), and Pacific water shrew (Sorex bendirii) among others. To support these species, the ANWA is comprised of a variety of habitat types, including riparian forests, wetlands, agricultural areas, pastures, estuarine marshes, ponds, sloughs, ditches, and urbanized zones.

Within many of these habitat types, Himalayan blackberry (Rubus armeniacus) is present. This particularly fast-growing and invasive species quickly colonizes disturbed substrates and often creates near monocultures of vegetation. Thus, native species diversity, richness, and associated wildlife habitat are generally negatively affected. In addition to effects to ecosystems, Himalayan blackberry also negatively affects infrastructure, as canes can overtop infrastructures and impact building foundations.

While there are ongoing mowing efforts to control Himalayan blackberry throughout ANWA, this management approach is not feasible for use around sensitive habitats and within close proximity to infrastructure and people. In addition, mowing Himalayan blackberry is not an effective long-term removal strategy, as it does not remove the rhizomes from which the canes grow from. Therefore, there is a need for a more sensitive and delicate means of Himalayan blackberry control within ANWA, which will remove both aboveground and belowground biomass.