A COMPARISON OF DISPERSAL, GERMINATION AND ESTABLISHMENT OF WOODY PLANTS SUBJECTED TO DISTINCT FLOODING REGIMES IN BRAZILIAN FLOOD•PRONE FORESTS AND ESTUARINE VEGETATION*

Fábio Rubio Scarano

Abstract


Flood-tolerance does not guarantee successful colonization of flood-prone habitats, since a given species might undergo a number of hazards during the processes of seed dispersal, germination and seedling establishment; or else, be flood-sensitive as seed and/or seedling. I compare the ecological and ecophysiological aspects of reproductive mode, seed dispersal, germination and seedling establishment in some woody Brazilian species from distinct habitats subjected to distinct flood-regimes (seasonal river flooding in the Amazon; tidal flooding in estuaries; and permanent phreatic flooding in the swamps of southeastern Brazil). Differences in regeneration strategies seem to be responses to variation in habitat seasonality and predictability. Vegetative propagation was common to many species in swamps where safe unflooded patches are unpredictable in space and time. Seed propagation success in the various habitats was often related to an efficient fruit/seed water dispersal, to a combination of pre- and post-dispersal dormancy and to cryptocopylar seedlings. Two-phase dispersal (another agent besides water itself) was often found. In the aquatic phase, both buoyant and submerged fruit/seeds were found. Buoyancy was related to heterogeneity in the duration of dormancy among seeds of a same cohort, and submergence to prolonged dormancy. Fast-growing cryptocotylar seedlings were common among the species studied.

 

*This is dedicated to the young-hearted couple Jandyra F. Scarano, on her 89th birthday, and Francisco V. Scarano, on his 93rd birthday.

 



Keywords


plant ecophysiology; habitat differences; seed dispersal; germination; seedling establishment

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