Effects of distinct types of disturbance on seed rain in the Atlantic forest of NE Brazil |
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Authors: | Adriana Maria Zanforlin Martini Flavio Antonio Maës dos Santos |
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Institution: | (1) Departamento de Ciências Biológicas, Universidade Estadual de Santa Cruz, Rodovia Ilhéus Itabuna Km 16, Ilhéus, BA, CEP 45650-000, Brazil;(2) PPG-Ecologia-UNICAMP, Caixa Postal 6109, Campinas, SP, CEP 13083-970, Brazil;(3) Departamento de Botanica, UNICAMP, Caixa postal 6109, Campinas, SP, CEP 13083-970, Brazil;(4) Present address: Projeto Parcelas Permanentes, DCB/LERF/ESALQ-USP, Caixa Postal 9, Piracicaba, SP, CEP 13418-900, Brazil |
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Abstract: | In disturbed sites, some groups of seeds might be excluded from the seed rain due to their dispersal modes or seed size, and
some groups might be successful as a result of disturbance effects. In the present study, we examined the seed rain in natural
treefall gaps and in an area of regenerating forest following an accidental burning, which occurred 4 years before this study.
Both of these disturbed areas were compared with nearby forest understorey. The number of seeds, number of species, and proportion
of wind-dispersed seeds were compared between these disturbed and undisturbed areas. The treefall gaps have received lower
numbers of seeds and species than the nearby understorey, but the number of wind-dispersed seeds did not differ between these
areas. The lowest seed number observed in treefall gaps can be attributed to a lower number of animal-dispersed seeds, suggesting
that animals may be avoiding treefall gap areas. A higher number of seeds and a lower number of species were observed in the
burned area when compared to the adjacent understorey. The high number of small-sized seeds and of wind-dispersed seeds in
the burned area was almost surely a consequence of the local production of the pioneer plants established after the burning.
In this study, substantial differences were observed in the characteristics of the seed rain at disturbed sites, when compared
with undisturbed understorey. However, these two distinct types of disturbance showed quite differing patterns, as treefall
gaps received lower number of seeds while the burned area received a higher number of seeds, with a greater proportion of
wind-dispersed seeds. The exception was for species richness, which was quite low at both these disturbed sites. |
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Keywords: | Fire Miconia mirabilis Natural treefall gaps Seed size Understorey Wind-dispersed seeds |
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