By Doug Johnson, Cal-IPC and Andrew Brooks, UCSB Marine Science Institute
Reprinted with permission from the Spring 2018 issue of Dispatch, the newsletter of the California Invasive Plant Council (www.cal-ipc.org).
The Carpinteria Salt Marsh is a special spot along California’s south-central coast. Migratory waterfowl stop at the marsh, and the estuary includes extensive wetland, sub-tidal channel, and emergent upland habitats that support many sensitive plant and animal species.
Several species, such as Belding’s savanna sparrow, are listed as endangered, threatened, or of special concern; and there are plans in the works to re-introduce Light-footed clapper rails. Located next to a sandy beach, subtidal rocky reef, and kelp beds, the 230-acre marsh is also an important regional nursery for California halibut, diamond turbot, and other species of marine and estuarine fish.
The predominant vegetation in the marsh is estuarine emergent wetland dominated by pickleweed (Salicornia virginica). The flora of Carpinteria Salt Marsh has been of interest to scientists for at least 90 years. Eleven species growing presently at the estuary are regionally rare plants, and two species - salt marsh bird’s-beak (Chloropyron maritimum) and Coulter’s goldfields (Lasthenia glabrata) are endangered.
One of the top invasive plant threats to the marsh is European sea lavender (Limonium duriusculum), which is one of the few plants that can displace native plant species in salt marsh habitat. (Cal-IPC is on its third year of funded work to remove invasive sea lavender from salt marshes around San Francisco Bay, where it has become a significant problem.) In August 2017, a grant from UCSB Coastal Fund enabled staff and volunteers from Channel Islands Restoration and students from UC Santa Barbara to perform a survey of the endangered salt marsh bird’s-beak and Coulter’s goldfields in the marsh. Teams of two or three individuals walked parallel lines in a systematic grid, circumventing meandering channels and deep mud as needed. The teams also mapped the distribution of European sea lavender.
Not only did they find more sea lavender than had previously been mapped, they also found extensive co-occurrence of European sea lavender and salt marsh bird’s-beak, which is a parasitic plant. They recommend that tarping and herbicide applications, though effective, not be used in areas where the two species co-occur because the methods are likely to cause too much collateral damage. In these areas, hand-pulling is recommended as the best method for removing invasive sea lavender.