distribution of the non-indigenous invasive Old World climbing fern, Lygodium microphyllum, in southern Florida: The relationship to abiotic and biotic variables

Old World Climbing Fern, Lygodium microphyllum is an aggressive nonindigenous plant that is on the verge of becoming a major ecological threat in South Florida. Currently, specific habitat characteristics that contribute to success or failure of its establishment are unknown. I studied the pattern of distribution of the fern in Florida's Big Cypress Swamp. Two similar forested wetland sites with high incidence of L. microphyllum infestation were assessed in order to identify broad-scale hydrological and physiographic conditions that may favor high susceptibility to L. microphyllum invasion. On each site, species richness, abundance and distribution of herbs, shrubs and trees were characterized. In addition, several parameters including elevation, substrate depth, percentage substrate water content, percentage substrate organic content, substrate texture, and photosynthetically active radiation were quantified. The patterns of distribution of L. microphyfum indicated that presence of the fern was dependent on relatively low elevation, relatively deep substrate and moderately high substrate water content.