Soil seed bank during succession at an abandoned pasture in the upper Paraná river-floodplain, Brazil

Tatiani Elisa Chapla,João Batista Campos

doi:10.4025/actascibiolsci.v33i1.6391

Tatiani Elisa Chapla, João Batista Campos

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https://doi.org/10.4025/actascibiolsci.v33i1.6391

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Abstract

We evaluated density and species composition of the soil seed bank in active pasture and in secondary forest on a 10 year-old abandoned pasture to identify changes in density, richness, diversity and species composition during secondary succession of abandoned pastures. The implications of those changes for the forest recovery process were also considered. Soil samples were collected at Porto Rico island, state of Paraná, in 2007. The seedling emergence method was used. Data on active pasture collected in 1996, published by Campos and Souza (2003) were used for comparative analysis. No evidence was found of a pattern of changes in density of the soil seed bank during succession of abandoned pastures. We observed increases in richness and diversity, in the contribution of tree and shrub species and dominance of herb species for the seed bank during the first 10 years of abandonment of pastures in riparian forests. At the end of succession, the soil used as pasture can result in systems that are different from the original environment, due to seed bank impoverishment and presence of exotic species.

Highlights

A soil seed bank is formed by all viable seeds on or in the soil (SIMPSON et al, 1989), as a dynamic input and output system (FENNER, 1985; GARWOOD, 1989)
The study was conducted in Porto Rico Island, Porto Rico, Paraná State (Figure 1), in the upper Paraná river-floodplain, the only remaining freeflowing portion of Paraná river in Brazil (AGOSTINHO et al, 2004)
We counted between 48 and 18900 seeds m-2, which are within the expected range for pastures and secondary tropical forests according to the literature review undertaken by Garwood (1989) and Young (1985)

Summary

Introduction

A soil seed bank is formed by all viable seeds on or in the soil (SIMPSON et al, 1989), as a dynamic input and output system (FENNER, 1985; GARWOOD, 1989). The bank is a source of genetic variability for plant communities (HARPER, 1977; FENNER, 1985; SIMPSON et al, 1989). It is the main seed provider for the regeneration of natural gaps (BAIDER et al, 1999; DALLING et al, 1997; GARWOOD, 1989; SAULEI; SWAINE, 1988) and for areas in early stages of secondary succession (BAIDER et al, 1999; FENNER, 1985). Cattle raising leads to soil compaction (REINERS et al, 1994), inhibiting or rendering difficult vegetation recovery

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