The 2025 invasive Spartina treatment season is underway! Continuing a systematic phased approach for addressing heavily infested sites where access was previously restricted, this year the team will take on North Marsh in San Leandro, the largest remaining invasive Spartina infestation in San Francisco Bay with a 60-acre treatment area.
The restoration team kicked off the revegetation planting season in November with a field trip to long-time plant propagation partner, The Watershed Nursery Cooperative, to tour the facilities and to learn more about nursery best management practices.
This year, the project’s workforce development program hired and trained additional field staff to help cover the increased project scale, as well as providing vital opportunities for the emerging generation of stewardship professionals.
Invasive Spartina treatment may not be considered the most sexy restoration activity, but it is a critical action to enable the San Francisco Bay to adapt to sea level rise. Surrounded by residential and industrial development, agriculture, and infrastructure, the San Francisco Bay is the most urbanized estuary west of the Mississippi River.
The ISP has reduced the net area of invasive Spartina by more than 97%, from a peak of 805 net acres in 2005 down to 20.7 net acres as of 2022 monitoring. However, at a subset of sites, treatment has proceeded slowly in a carefully phased approach to protect the endangered California Ridgway’s rail (Rallus obsoletus obsoletus).
Thanks to the rain that pummeled the Bay in early 2023, ISP project managers expect to see an increase in tidal marsh vegetation throughout the estuary, including possibly a bump in net cover of the invasive hybrid Spartina alterniflora.
As the 2022 treatment season draws to a close, our team is gratified to see the results of many years of hard work. Many of the ten heavily infested sites that were approved for treatment since 2018 have now reached a point where they are able to be treated by just a small team of applicators in a single morning as opposed to a large mobilization effort over multiple days.
This year, the ISP enters its 18th season of monitoring and treating invasive Spartina in the San Francisco Estuary. In late June, biologists began surveys across the 221 sites within the project’s 70,000 acres, spanning the shoreline of nine counties. Inventory surveys and mapping will continue through the fall to inform treatment or to confirm absence of the invasive plant.
ISP biologists just finished this year’s rail surveys, which means we have been seeing lots of sunrises and sunsets!
Invasive Spartina treatment work is almost complete for the 2021 season! A total of 153 sites were treated, beginning in early June and slated for completion during the first week of December.