Soil seed banks in successional stages of forest ecosystems in the Belém, Pará, Brazil, metropolitan region

Abstract

The seed bank is essential for the initiation of natural forest regeneration, especially in ecosystems in
 the early stages of development, where there have been anthropogenic or natural disturbances. The objective
 of the current study was to evaluate seed bank dynamics in three forest ecosystems, two in Utinga State Park
 (PEUt) and one on the Federal Rural University of Amazonia (UFRA) campus, both in Belém, Pará, Amazonian
 Brazil. The ecosystems were: primary forest (PF), early successional forest (ESF), and late successional forest
 (LSF). For seed bank evaluation, five plots were installed in each forest ecosystem, and in each plot 5 soil
 samples were removed at a depth of 0-0.05 m. In the three ecosystems, the most abundant species in the
 seed bank were Cecropia obtusa, Phyllanthus tenellus and Vismia guianensis. Zoochoria was the dominant
 dispersion syndrome with 1,041 (67.8%) individuals. In the PF and LST ecosystems the predominant life form
 was tree, followed by shrub, whereas in the ESF the shrub life form predominated, followed by tree. Thirtyone
 species were recorded in PF, 26 in ISF, and 32 in LSF. In general, pioneers were most frequent ecological
 group, with 289 individuals (93.2%) in PF, 288 individuals (88.7%) in LSF, and 188 (75.06%) in ESF. Thus, all
 ecosystems possessed a high potential for resilience in case of possible forest disturbances, and the PF seed
 bank was considered the most diverse in terms of arboreal species.