PARENT SESSION
Poster Session # 16: Invasive Species.
Wednesday, August 6 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.
Predicting the landscape spread of Lygodium microphyllum in South Florida.
Muss, Jordan*,1, Owen, Dianne1, Volin, John1, 1 Florida Atlantic University, Davie, FL
ABSTRACT- Invasions by non-indigenous plant species can profoundly disrupt the original composition, structure and function of native plant communities. In Florida, over 4,000 plant species have been introduced, 125 of which are listed as invasive by the Florida Exotic Pest Plant Council. Among these, Lygodium microphyllum is of major concern because of its recent rapid spread. In 1978, 14 infested sites were documented in Martin County, Florida. By 1999 it had spread throughout the ten southernmost counties of peninsular Florida, occurring at nearly 1,200 documented sites. To understand the rates and patterns that characterize the spread of L. microphyllum, we have developed a predictive, spatially explicit, cellular model of its dispersal and establishment within the South Florida landscape. Parameter values estimated from field and laboratory data on habitat susceptibility to invasion, growth habits of L. microphyllum, spore production rates and dispersal profiles were used to calibrate the model for the period from 1978 to 1993. Model validation was performed using data on documented invasion sites for the period from 1995 through 1999, and will be extended to 2001 when the data is released. Validation of model output, using a permutation procedure that is not biased by spatial autocorrelation, showed good agreement between the model and data, with correlations generally higher than 0.5 across a range of spatial grains. Model runs initialized to the documented 1999 invasion sites show that L. microphyllum will spread to most of the suitable habitats found in South Florida within the next decade.
Key words: Lygodium microphyllum, invasion, landscape