Palavras-chave: fragmentos, chuva de sementes, ornitocoria, quiropterocoria.
Abstract
Seed dispersal is a necessary process for the persistence of plant populations,
being a fundamental mechanism for the maintenance of species richness. Birds
and bats are considered the best dispersal agents in terms of quantity of seeds
dispersed and dispersal distance. This is due to its high mobility, feeding mode
and retention time of seeds they eat. The aim of this study are (1) to describe
and compare the composition, richness and abundance of seeds dispersed by
birds and bats in “capões” in the southern Pantanal (2) to analyze if canopy
opening and the area of the “capões” influence these parameters; (3) and to
characterize the species of seeds dispersed by birds and bats according to its
successional stage. It was recorded a total of 6957 seeds belonging to 16
species and 11 botanical families, of which 5077 seeds, distributed in 16
species of plants were dispersed by birds and 1880 distributed in five species
were dispersed by bats. Species richness of seeds dispersed by birds was
higher, but there was no difference for the abundance of seeds dispersed by
both groups. The canopy opening was higher in the center of the studied
“capões”, where the bats dispersed greater species richness of seeds, relatively
to the birds. Nevertheless, the abundance of seeds dispersed by birds and bats
did not differ between center and edge, and the richness and abundance of
seeds defecated by both groups did not vary according to the area of “capões”.
Most of the species dispersed by birds and bats belong to the early stages of
succession. Based on the site of deposition of the seed rain and the light
requirements of species recorded in the collectors, seeds of all species
dispersed by both groups are being deposited in suitable sites for germination in
“capões”. According to the results of this study, birds and bats play an important
role in seed dispersal in “capões”, acting in a complementary fashion and being
fundamental for the regeneration processes and maintenance of plant
populations in these fragments.
Key-words: fragments, seed rain, ornithochory, chiropterocory.