Closing the seed dispersal loop

Seed dispersal links the end of the reproductive cycle of adult plants with the establishment of their offspring, and is widely accepted to have a profound effect on vegetation structure. Confirming and quantifying this effect, however, has proven to be a challenge. Recent research on animal-mediated seed dispersal has brought us closer to this goal: ecologists have been explicitly examining the processes that mediate seed deposition and seedling recruitment. Exciting new techniques, such as the analysis of stable isotope ratios and molecular genetic markers, are making it possible to relate dispersed seeds and seedlings back to parent plants. Meanwhile, evidence from plant demography research is revealing that seed dispersal might have an important role in determining patterns of tree diversity and distribution. The continued synergy between seed dispersal research and the study of plant demography should help researchers link seed dispersal and adult vegetation structure, closing the seed dispersal loop.