Repeated Herbicide Application for Control of Old World Climbing Fern (Lygodium microphyllum) and the Effects on Nontarget Vegetation on Everglade Tree Islands

Abstract

AbstractThe effects of annual, aerial and ground, herbicide treatments with glyphosate and metsulfuron were evaluated for control of Old World climbing fern (OWCF) and effects on native plants on tree islands in Arthur R. Marshall Loxahatchee National Wildlife Refuge during 2006 to 2009. Initial aerial herbicide treatments reduced OWCF cover by greater than 98% on metsulfuron-treated islands and greater than 88% on glyphosate-treated islands, but there was a concomitant decrease in native ground cover with both herbicides. Follow-up ground treatments, during years two and three of the study, were effective at maintaining low levels of OWCF. OWCF cover at the end of the study was 1 to 2% of pretreatment cover on metsulfuron-treated islands and 8 to 10% on glyphosate-treated islands. At the end of the study (3 yr after treatment), species richness was dominated by ruderal native species not typically found on tree islands. The survival rate of tree and shrubs was 65 to 93% on islands treated with metsulfuron and 6 to 20% on islands treated with glyphosate. Minimum effects were recorded for canopy cover on tree islands treated with metsulfuron compared with glyphosate. These data indicate that the aerial application of metsulfuron can be used for control of OWCF on tree islands. Follow-up ground treatments will be required for OWCF regrowth and new sporelings and should be conducted within 1 yr of the aerial application.