Management Requirements: Control of this introduced species is necessary to protect the limited occurrences of viable natural sand dune systems along our coastlines. Continued control of existing Ammophila arenaria stands and monitoring for new introductions are needed.
Manual removal (digging) controls the spread of A. arenaria but is labor intensive. In one case, complete removal was achieved, but the site was subsequently invaded by other exotic species. In the first year, monthly treatment intervals are suggested; in subsequent years, frequency can be decreased. Monitoring should be conducted to determine if exotic species, such as Carpobrotus, are replacing A. arenaria. Ultimately, re-vegetation with native species should be a standard part of management, once control techniques are refined.
Management Programs: Management of Ammophila arenaria is being carried out by TNC at the Lanphere-Christensen Dunes Preserve, by Humboldt State University through the Menzies' Wallflower Research Project, by the California Department of Parks at McKenicher State Park, at Vandenberg Air Force Base, and by the Oregon Department of Fish and Wildlife.
Contact: Andrea Pickart Habitat Restoration Coordinator Menzies' Wallflower Research Project Lanphere-Christensen Dunes Preserve 6800 Lanphere Road Arcata, CA 95521 (707) 822-6378.
James Barry Resource Protection Division California Dept. of Parks PO Box 2390 Sacramento, CA 95811 (916) 322-8562
Charles Bruce Oregon Dept. of Fish and Wildlife Route 5, Box 325 Corvallis, OR 97330 (503) 757-4186.
Monitoring Programs: The current monitoring program involves annual photodocumentation of stands before and after control treatments, and measurement of untreated stands.
Contact: Andrea Pickart, Preserve Manager Lanphere-Christensen Dunes Preserve 6800 Lanphere Road Arcata, CA 95521 (707) 822-6378.
Management Research Programs: The Habitat Restoration Program of the Menzies' Wallflower Research Project (MWRP) at Humboldt State University, Arcata, California, is currently investigating three methods of A. arenaria control: salt application, use of herbicides, and manual removal. Previous research at LCDP indicates manual removal (digging up plants 10 cm below the surface at repeated intervals) is effective in reducing stand density. An ongoing eradication program has utilized this method with mixed results. Complete eradication has been accomplished on only one stand. The MWRP is implementing an experimental program which increases the frequency and depth of digging to remove the active rhizome bud bank.
Earlier small-scale experiments at the preserve found that a 2% solution of Roundup, applied during anthesis, resulted in 60 to 100% mortality. The MWRP is further refining methods and specifications. Timing of application may be critical.
Salt was believed to be a potential control since A. arenaria has a relatively low tolerance to soil salt (NaCl), although brief to moderate exposure to high salinity may stimulate bud emergence (Baye 1988). Unfortunately, the use of NaCl to control a weedy species is illegal as it is not registered as a pesticide in the state of California. The use of alternate salts has not been addressed.
Management Research Needs: Research is needed on the effects of potential control methods including the use of herbicides (Roundup), manual removal, and salt application.