Invasion by non-native species has had significant ecological and economic impacts on a global scale. In the state of Florida, Old World climbing fern (Lygodium microphyllum) is an invasive plant listed by FLEPPC as a category one invader with significant ecological impacts that threaten native plant diversity. This species relies on existing vegetative structures for support to climb into the forest canopy and forms dense mats that cover tree crowns. This subsequently affects the resources available to other species present. Quantifying the structural changes due to the presence of this species has proved logistically difficult, especially on a large spatial scale. Airborne LiDAR (Light Detection And Ranging) technology is a form of remote sensing that measures the elevation of surfaces over a site. In this study I utilized LiDAR to calculate various forest structure metrics at Jonathan Dickinson State Park (JDSP) in Hobe Sound, Florida across various management frequencies and densities of Old World climbing fern. These data were used to quantify the degree to which this invasive species alters forest structure across these two gradients. I also recorded species composition in the field to relate how Old World climbing fern impacts native plant diversity. Structural measurements including average canopy height, height of median energy (HOME), rugosity, canopy openness, and vertical structural diversity (LHDI) were calculated for a total of three hundred 0.25ha sites stratified by invasion density and management frequency. Using a combination of univariate and multivariate statistical analyses I found that the presence of Old World Climbing fern altered the physical structure of the forest communities it invades. Higher percent cover of Old World climbing fern decreased structural diversity while increased management effort was found to mitigate those impacts. The management for Old World Climbing fern was also found to impact both species richness and diversity at JDSP. I also demonstrated that there were several species that were not found and others that were more common in the presence of Old World climbing fern and that there was a relationship between management and what species were present. The results show that both Old World climbing fern and the management practices used to control it have had significant ecological impacts on the natural communities in South Florida.

Lygodium microphyllum, native to the Old World tropics, has invaded central and southern Florida, destroying native habitats, reducing biodiversity and altering fire regimes. Prescribed fire, one of several methods used to manage L. microphyllum infestations, reduces fern biomass over large areas, but its effects on spore viability are unknown. To provide tools to evaluate whether fire-dispersed spores are viable, this research determined how heat affects spore viability. Spores were exposed to temperatures of 50°C to 300°C for durations of 5 seconds to 1 hour, then allowed to germinate on agar in petri plates. Percent germination was assayed after two weeks. Temperatures of 50°C had little effect; 300°C killed spores for all durations. Results indicate that while viability of unburnt spores decreases with increasing temperature and duration of heat exposure, spores are killed when exposed to relatively low temperatures compared to those in fires.