Assessing the effectiveness of physical treatments to control non-native Spartina patens in a constructed marsh in Port Moody, British Columbia

Field trials were conducted at a constructed salt marsh in Port Moody, British Columbia to test the following physical control variations for their effectiveness at reducing non-native Spartina patens: 1) covering using polyethylene and geotextile; 2) covering for six and twelve months; 3) stressing the plant by pre-treating with steam or mowing to ground prior to covering; and, 4) applying steam.;No significant difference was observed between the various treatments after six months. After twelve months, both geotextile and polyethylene covered plots showed a significant decrease in percent cover, with polyethylene appearing to be more effective. Neither cover material, however, achieved a complete reduction in live stems. Pre-treating by applying steam or mowing had no significant effect. Steam alone without covering also showed no effect. Doubling up layers of geotextile or combining polyethylene with geotextile is recommended for future eradication efforts in British Columbia and elsewhere on the Pacific coast.