Padilla Bay

A number of invasive species exist within the Reserve, including estuarine and upland species. We use an integrated weed management approach for those species deemed noxious, assessing each infestation and using the best method for that particular site (physical, mechanical, chemical).

There are many invasive plants and animals in Padilla Bay. Just a few of the more notable ones are listed here. Scroll down for more detailed information about these:

More information is available in the Review of Non-Native Species [PDF, 200kb] or contact the Reserve.

Cord grass (Spartina): Our total acreage of Spartina peaked in 1997 at about 17 acres. There were only 2.5 square meters remaining in 2011. We do an annual survey of shorelines and can achieve control now simply by digging the few plants and small clones that we find each year. Spartina alterniflora was planted in the 1940s on one island at the south end of the bay and was the largest part of our infestation. We did not find any S. alterniflora in 2011. Spartina anglica was originally planted about 30 miles south near Camano Island. The S. anglica seed has since spread around northern Puget Sound. The Washington State Department of Agriculture coordinates Spartina control in Washington state, with local control coordinated by the Noxious Weed Control Boards and others (such as People for Puget Sound who coordinates kayak surveys of shorelines).

Japanese eelgrass (Zostera japonica): This is a non-native seagrass, probably introduced with oyster culture. Its impact on the native seagrass, Zostera marina, is being studied (Technical Report No. 12). We do not try to control this species. However, it has been added to the state noxious weed list as a Class C weed so commercial shellfish growers can eradicate it on their lands.

Crabs: We presently do not have any invasive crabs. However, we have been montoring for invasive crabs, namely the European green crab (Carcinus maenas) since 2001. Using protocols established by the Washington Department of Fish and Wildlife, we set traps once a month April-September to catch crabs. We rotate between three sites, monitoring one site a year. We gain baseline data on native shore crab populations at the same time that we monitor for invasive crabs.

Mud snail (Batillaria attramentaria): This mud snail was introduced with oyster culture, probably in the 1930s. There are literally billions of them in the bay and their impacts are being explored by researchers (Technical Report No. 25). Native hermit crabs (Pagurus granosimanus and Pagurus hirsutiusculus) use empty Batillaria shells as homes.

Purple varnish clam (Nutallia obscurata): Commonly called the purple varnish clam, this clam is thought to have been introduced via ballast water in British Columbia. The clam has spread southward over the last ten years and arrived in Padilla Bay in about 2000. Studies are being done to determine its impact.

Canada thistle (Cirsium arvense): The plant occurs on our 64-acre upland site and on parts of the Demonstration Farm site. It is on ongoing problem.

Shiny geranium (Geranium lucidum): This plant was probably initially introduced at Bay View State Park, about a quarter mile south of the Breazeale Interpretive Center. It is a forest understory plant that outcompetes native species and is spreading northward toward Reserve property. We worked with an adjacent property owner in 2011 to create a larger buffer zone between the Reserve and the more active infestation and in Spring 2012 will be evaluating how effective our control efforts were.

Other upland non-native species we monitor and control include: Robert's geranium (Geranium robertianum), Bull thistle (Cirsium vulgare), Reed canarygrass (Phalaris arundinaceae), Himalayan blackberry (Rubus discolor), and Evergreen blackberry (Rubus laciniatus).