Using Matrix Analysis to Model the Spread of an Invasive Plant, Alternanthera philoxeroides

Alternanthera philoxeroides, more commonly known as alligator weed is an invasive species indigenous to South America. With its rapid invasion of south east United States water ways, understanding the invasiveness of this plant species is both important and imperative. Utilizing experimental growth data obtained over the summer of 2010, matrix analysis is used to model the growth of alligator weed. These matrices are population projection models whose eigenvalues represent the growth rate of alligator weed in its different stages of the life cycle. A high growth rate is a key feature of successful invaders. Residuals were calculated and sensitivity analysis was performed to test the accuracy and importance of the models. The result of this study indicates that in competitive aquatic conditions, which are the most realistic environment for alligator weed to reside in, the earlier life stage plants are the most sensitive to control measures.