Patchy distribution of weeds and some implications for modelling population dynamics: a short literature review

Summary Until recently the modelling of crop‐weed interactions has largely ignored the complexities resulting from the patchy distribution of weeds and the multi‐species nature of weed communities. Some progress has now been made in dealing with these two sources of variation. A population dynamical approach has proven to be quite helpful in this respect. In this approach the whole life‐cycle of the species is considered, divided in a step by step fashion into separate stages, thereby offering a top‐down modelling approach. Such models can easily be extended over a period of years, helping in developing long‐term control strategies: complexity can be added as the need arises. Spatial heterogeneity can be taken into account by explicitly defining a spatial scale and the dispersal process. The multi‐species nature of competition can be dealt with by using neighbourhood models of plant interference. A few recent contributions from the literature, using weeds as an example, are reviewed here against a more general background of weed demography.