DOES SEED DORMANCY BENEFIT THE MOTHER PLANT BY REDUCING SIB COMPETITION

Seed dormancy has been considered, almost without exception, as a bet- hedging strategy in a temporally varying environment. However, in this paper we show that seed dormancy can improve the reproductive success of the mother plant when competition between sibling seedlings and ad ult plants is intense even if the environment is temporally invariable . We allow a cohort of sibling seeds to germinate simultaneously in th e same patch and assume a density dependent survival and fecundity of seedlings. In the model, the mother plant is assumed to control the ge rmination behaviour of the seeds, e.g. by enclosing the seeds in coats of different hardiness. When sib competition is intense, a postponed germination of her seeds can increase the reproductive success of the mother plant up to four times, measured in terms of the number of gran dchildren. Consequently, our results suggest that postponed germinatio n may function as a mechanism that alters local interactions in viscou s plant populations with limited dispersal.