Facilitation in plant communities: the past, the present, and the future

1 Once neglected, the role of facilitative interactions in plant communities has received considerable attention in the last two decades, and is now widely recognized. It is timely to consider the progress made by research in this field. 2 We review the development of plant facilitation research, focusing on the history of the field, the relationship between plant–plant interactions and environmental severity gradients, and attempts to integrate facilitation into mainstream ecological theory. We then consider future directions for facilitation research. 3 With respect to our fundamental understanding of plant facilitation, clarification of the relationship between interactions and environmental gradients is…