Life history flexibility allows Sargassum polyceratium to persist in different environments subjected to stochastic disturbance events

Stochastic, stage-based matrix models were used to investigate the life history strategy of the seaweed Sargassum polyceratium in shallow intertidal and deep-water (18 m) populations. Matrix models were parameterized with 3 years of yearly transitions among four plant stages quantified from three bays on Curacao (Netherlands Antilles). There were years without a storm, with a moderate (winter) storm and with a strong storm (Hurricane Lenny). The stochastic population growth rate varied among populations (lambda(s): 0.54-1.03) but was not related to depth. The most important stages for population growth were reproductive adults (shallow) and non-reproductive adults (deep). With the occurrence of storms, vegetative growth (mainly deep) and fertility (mainly shallow) became the most important processes. Recruitment (shallow) and regeneration from holdfasts (deep) only contributed to population persistence after the hurricane. It is concluded that S. polyceratium has a flexible, depth-dependent, life history strategy that is adjusted to disturbance events.