Invasive species Spartina densiflora nearing eradication on B.C.’s coast

Now in its 22nd year, the Spartina eradication program is beginning to show what that persistence can achieve. A recent progress report stated that in 2025 alone, crews surveyed more than 190 kilometres of coastline, tracking and treating invasive populations across the Lower Mainland and Vancouver Island.  

Dramatic recovery 

One species in particular, Spartina densiflora, is in dramatic decline. At its peak in 2015, more than 14,000 plants were recorded along B.C. coastlines. In 2025, fewer than 250 known plants remained province-wide; a 98% reduction, and those plants, once identified, were manually removed. For Marriott and the team, those numbers represent years of steady and often unglamorous work, and the work itself is as varied as the coastline. 

Some days are spent walking shorelines and mapping new plants with GPS tools. Others involve carefully removing plants by hand, or applying targeted herbicide treatments designed to minimize impacts to surrounding ecosystems.

Close, but the job isn’t finished 

In 2025, some Spartina populations showed small increases, often tied to newly discovered patches or seed spread. But the broader trend remains clear: populations are shrinking, and the remaining plants are more fragmented and manageable. 

The program is now approaching a turning point, shifting from large-scale control toward the possibility of full eradication for some species, a huge milestone to achieve for many invasive species programs. 

“Our success is built on a few factors. This work was made a priority for quick response by the Province of British Columbia, and funding from the Province of B.C. as well as the Vancouver Fraser Port Authority supporting capacity to build teams and respond. Partnerships and collaboration facilitated information-sharing, and technological advances allowed for easy in-the-field tracking. Of course, none of this would be possible without the help of many hard-working individuals and groups like the British Columbia Conservation Foundation who helped get boots on the ground,” Marriott expressed.   

Taking out Spartina reintroduces space for what was there before it arrived: healthy mudflats, functioning marshes and resilient habitat that supports migratory birds, coastal species and local residents.  

Hopefully, the Spartina program may soon become a surveillance program only, with field staff acting like security guards, scanning for and quickly removing nuisance plants before they have a chance to take hold. In the meantime, native species have more room to once again stretch their roots and strengthen shorelines. 

DUC gratefully acknowledges the financial support of the Province of British Columbia through the Ministry of Forests.