This study evaluated sap flow of neotropical mangrove species subjected to background nutrient loading, and well as fertilization with either nitrogen or phosphorus, at Ding Darling National Wildlife Refuge (NWR). Data collections were made seasonally to model stand water use by mangrove forests as a metric of ecosystem stress through alteration of water use potential at the stand level. Data on leaf-scale water use efficiency, and data from a partial weather station deployed near study sites, were included for enabling model development and calculation of stand water use.