Alien plants invade many ecosystems worldwide, often having substantial negative effects on ecosystem structure and functioning. The apparent complexity of invasions has impaired the development of a predictive framework of alien plant spread. Such a framework requires both a conceptual understanding of the ecology of invasions and appropriate modelling tools. We demonstrate, using a simple conceptual model and illustrative examples from the literature, that a predictive understanding of invasions can be established. Potential modelling tools are reviewed by categorizing models of plant spread as either simple-demographic, spatial-phenomenological or spatial-mechanistic, based on the model's data inputs and outputs. The assumptions, predictive potential, knowledge and data requirements of these modelling tools are discussed in the context of selecting the most appropriate alien plant spread model for a given case.
Journal articles from the Grassland Society of Southern Africa (GSSA) African Journal of Range and Forage Science as well as related articles and reports from throughout the southern African region.