When Stinkwort Invades: SFPUC’s Early Detection and Rapid Response

It takes a team of committed professionals working together to take on the likes of an invasive, foul-smelling pest known as stinkwort.

One of several high priority species of invasive weeds on the Peninsula and Alameda County, stinkwort, along with yellow starthistle, purple starthistle and artichoke thistle, are targeted for removal and control by the SFPUC’s Integrated Pest Management (IPM) coordinators Kevin Woolen and Don Thomas.

IPM Coordinator Kevin Woolen about to handle stinkwort at Williams Gulch in the Alameda Watershed.

IPM is an environmentally-sensitive approach to pest management in our watersheds and right of way land areas.  Healthy watersheds are important for our high-quality water. IPM techniques such as hand-pulling weeds early, before they can spread into large areas, reduces the chance of these invasive weeds from becoming a threat. These control methods can be effective and present little to no risk to people or the environment.

Woolen and Thomas work closely with many SFPUC staff, Alameda County and consultant NOMAD Ecology on the mapping, early detection and rapid response method of vegetation management.

Restoration ecologist Erin McDermott, mapping invasive plant locations in GIS.

According to Woolen, “We want to find small infestations of weeds in high-value habitat areas. It is easier to manage small weed invasions in healthy ecosystems than to manage a large infestation in stressed ecosystems. The strategy is data-driven and depends on a thorough mapping of invasive plants.”

One of the first steps was to update the weed maps in the remote areas of the Alameda Watershed. A team of seasoned watershed keepers provided safe access for NOMAD Ecology staff to gather data and create maps. Watershed keepers cleared fallen trees that blocked roads, assessed fire danger, and gave guided tours into remote areas for NOMAD Ecology staff. The maps created target invasive weed data points that are extremely useful to vegetation management efforts.  

Arnesti Maio removing yellow starthistle in the Alameda Watershed.

Woolen, along with watershed worker Arnesti Maio, used the data gathered to immediately respond to small areas of stinkwort in the Alameda Watershed. According to Maio, “It was amazing to have a data point of a single stinkwort plant. That single plant can produce tens of thousands of seeds that can remain in the soil for several years, producing large areas of invasive weeds.”

According to Woolen, “The synergistic effect of Natural Resources & Land Management staff and consultants lead by Jessica Appel, Erin McDermott, Krysten Laine, and others help yield excellent results and a lot of bang for the buck in our IPM program.”

Working together on early detection and rapid response, this dedicated team are protecting our watershed lands for many generations to come.