Determinants and patterns of population growth in water hyacinth

Mathematical models of the growth of water hyacinth are developed to provide a sound basis for assessing existing and potential control options. We show that under constant experimental conditions, water hyacinth shows logistic growth (r2 of 0.69-1.00). The effects of nutrients and temperature on model parameters are explored using data from the literature. The model is verified against growth in a natural infestation. The resulting model incorporates two of the most important factors (temperature and water nutrient level) that determine whether water hyacinth is an important environmental problem at a given site. These relationships form a robust basis for further model development, and can be readily used to evaluate how the plant will respond to changes in nutrient inputs.