Fr. Scarano et al., PLANT ESTABLISHMENT ON FLOODED AND UNFLOODED PATCHES OF A FRESH-WATERSWAMP FOREST IN SOUTHEASTERN BRAZIL, Journal of tropical ecology, 13, 1997, pp. 793-803
Plant establishment was studied in a swamp forest in the lowland Atlan
tic rainforest in southeastern Brazil. A topographic gradient allowed
a clear distinction between a periodically flooded and a permanently f
looded site in the study area. Both sites were mosaics of patches: the
former showed soil patches of varying sizes subject to distinct flood
ing durations (from 0 to 300 d per year) and in the latter, the tank b
romeliads which densely occupied the understorey, trap litter and prov
ided 'suspended soil' patches. In the periodically flooded site, the o
ccurrence of regenerants (< 1.0 m tall) of the actively regenerating t
ree populations of Calophyllum brasiliense, Symphonia globulifera and
Tovomitopsis paniculata (all Clusiaceae), originating from seed or veg
etative organs, was recorded for 1 m(2) quadrats placed in flooded (n
= 82) and unflooded (n = 103) patches. In the permanently flooded site
, dominated by Tabebuia cassinoides (Bignoniaceae), the presence of ge
rminated seedlings was counted for 400 rosettes of the terrestrial tan
k bromeliad Nidularium procerum. The results showed that unflooded pat
ches, including tank bromeliads, favoured seedling establishment. Howe
ver, T. paniculata and T. cassinoides colonize patches where flooding
lasts longer or is permanent mostly by reproducing vegetatively, while
the seeds of C. brasiliense, which showed no form of vegetative repro
duction, and S. globulifera are successful in colonizing flooded parch
es. Germination tests and field observations indicated that, for C. br
asiliense, pre- and post-dispersal seed dormancy, a two-phase seed dis
persal (water and bats) and seedling tolerance to flooding accounted f
or this pattern.