Predicting a range shift and range limits in an introduced tropical marine invertebrate using species distribution models

A major goal of invasion biology is to predict range shifts and potential range limits of nonnative species. Species distribution models (SDMs) are commonly used to achieve these goals, but the predictive accuracy of these models is rarely tested using natural range shifts. The barnacle Megabalanus coccopoma is native to the eastern tropical Pacific and has been introduced to a number of locations globally including the southeastern United States. During the unusually cold winter months of 2010, the range of M. coccopoma within the USA SE retracted 825 km. The ability of the SDM MaxEnt to accurately predict the range retraction and M. coccopoma's range within the USA SE was tested using distributional data from before and after the range retraction. Three MaxEnt models were trained using data from the global range, the native range, and the USA SE introduced range. Only the model trained on data from the USA SE was able to accurately predict the entire extent of the range retraction and most known populations prior to the range retraction. Globally trained models may provide the most conservative estimates of potential distributions; however, niche shifts may limit the ability of these models to accurately predict range shifts.