Soil seed bank during succession at an abandoned pasture in the upper Paran芍 river-floodplain, Brazil = Banco de sementes do solo durante sucess o em pastagem abandonada na plan赤cie de inunda o do alto rio Paran芍, Brasil

作者：Tatiani Elisa Chapla; Joo Batista Campos

来源：Acta Scientiarum - Biological Sciences, 2011.

• riparian vegetation
• invasive exotic species
• environmental conservation areas
• Psidium guajava
• floresta riparia
• especies exoticas invasoras
• unidades de conserva o

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 Paran芍, 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. Foi avaliada a densidade e composi o de esp谷cies do banco de sementes em pastagem ativa e floresta secund芍ria sobre pastagem abandonada (dez anos), visando entender as varia es na densidade, riqueza, diversidade e composi o de esp谷cies durante sucess o de pastagens abandonadas, e as implica es dessas mudan as para o processo de recupera o da floresta. Foram coletadas amostras de solo na ilha Porto Rico, Porto Rico Estado do Paran芍, em 2007, sendo utilizado o m谷todo de emerg那ncia de plantulas. Para uma an芍lise comparativa foram utilizados dados de 1996 (condi o de pastagem ativa) publicados por Campos e Souza (2003). N o h芍 evid那ncias sobre altera es na densidade do banco de sementes do solo durante a sucess o de pastagens abandonadas. Por outro lado, ocorreu acr谷scimo na riqueza e diversidade, com o predom赤nio de esp谷cies herb芍ceas e acr谷scimo na contribui o de esp谷cies arbustivoarb車reas no banco de sementes durante os primeiros dez anos de abandono de pastagens emflorestas rip芍rias. O uso do solo como pastagem pode, portanto, resultar em ambientes distintos do original no final da sucess o, pelo empobrecimento do banco de sementes e presen a de esp谷cies ex車ticas.