Does the seed rain limit recruitment, regeneration, and plant community dynamics?

Abstract

The role of the seed rain in affecting recruitment, regeneration, and plant community dynamics continues to be debated. Studies show that seed limitation for recruitment is more likely as ecosystems become colder and more species-poor, as in boreal forests, and for species that have large seeds and short-lived seed banks. Even if there is a limiting effect of the seed rain for recruitment, however, clumping seen for mature trees and other evidence suggests that its effect diminishes with time. I posit that the dynamics of plant communities are largely determined where the seed rain is abundant and not limiting—in local spaces close to dispersing plants. Putting all the evidence together, I conclude that it is what happens to seeds after dispersal—such as loss to predation and pathogenic attack, or germination success resulting from environmental tolerances—that has a greater effect on recruitment, regeneration and plant community dynamics. And thus the variation in the workings of seed fate mechanisms and environmental tolerances, deserve more research attention. The importance of the seed rain in affecting recruitment of individual plants, regeneration of individual plants, and plant community dynamics has been over-emphasized in plant modeling and theory.