Plant dispersal across multiple scales: linking models and reality

The study of dispersal has undergone a revival over the last decade. This increase in research activity has been marked by edited books (e.g. Bullock et al . 2002; Levey et al . 2002) and collections of papers devoted to the subject in ecological journals (e.g. Cain et al . 2003; Nathan 2005). This Journal of Ecology Special Feature, consisting of 12 papers, aims to examine the current state of knowledge about plant dispersal and to illustrate the major advances that have been made in this rapidly growing field over the last few years. The key features of dispersal we asked authors to address in writing for this Special Feature are summarized in its title. Plants are generally sessile, and dispersal of seeds or other diaspores links the life cycle of an immobile individual to processes at local, landscape and biogeographic scales. One of the key themes driving the renaissance in plant dispersal research is the growing recognition that easily-observed dispersal at local scales (typically a few tens of metres) cannot be simply extrapolated to yield understanding and prediction of processes at larger scales. Studying plant dispersal across multiple scales requires the development of new statistical, simulation and mathematical models to predict dispersal more precisely and to use the better data to understand ecological processes at these scales. Authors of the papers in this Special Feature were encouraged to present their own interpretation of this general premise. Thus, the papers address a wide range of questions about dispersal across multiple scales. Despite this range, three common issues can be identified.