Caracterização do banco de sementes e monitoramento de uma APP em restauração há sete anos às margens do Ribeirão Três Bocas, Londrina - PR

Abstract

The present study was developed in a Permanent Preservation Area (PPA) that underwent total planting aiming its restoration seven years ago, located in a rural property (Sítio Água Viva) on the banks of the river Três Bocas, in Londrina, Paraná. It was applied the monitoring protocol of restoration projects developed by the Environment Agency of the State of São Paulo (Ordinance CBRN 01/2015). The application of the Protocol was done by the arrangement in the area of three transects (T1, T2 and T3), with 23, 20 and 20 meters of extension, respectively and 4 meters wide. The indicators sampled were crown cover by native vegetation, density of native regenerating individuals, and number of native regenerating species. The individuals sampled had a height (H) greater than 50 centimeters and Chest Height Circumference (CAP) less than 15 centimeters. Plants with height less than 50 cm were also counted in 5 plots (2x2m) randomly arranged in each transect, 15 plots in total. At the same area of the protocol application, soil samples were collected for seed bank analysis in 15 points arranged systematically in 3 lines paralleled to the water course. The samples were taken to the Greenhouse at the Federal Technological University of Paraná Campus Londrina, and received water daily. The germinated plants were counted monthly, and identified when completed 120 days. The results obtained for the protocol indicators were 100% of crown cover, 10,297 natural regenerants/ha and 39 native regenerating species, values that suggest that the area is in an adequate state of restoration. All of the species were distributed into 14 botanical families and 2 artificial categories (indeterminate and grouped). The most abundant families were Solanaceae, Sapindaceae, Anacardiaceae e Lauraceae. We also obtained high density (29,500, 17,500 e 26,000 ind/ha for T1, T2 e T3) for the plants with H<50cm. Regarding the seed bank, it was found a density of 1,670.37± 480.23 germinated seed/ m2 in the first 30 days of experiment. The final density were not considered due to the mortality caused by the irrigation loss. The great majority of the germinated seeds in the bank were herbaceous. It was sampled 149 woody plants (111.1 woody tree seeds/m2), emphasizing five species: Trema micrantha, Cecropia sp, Schinus terebintifolius, Croton sp and Melia azedarach, this last one an exotic species. The great presence of shrubs and wines points out that the dispersal and the establishment of the natural regenerants in the area are being favored. The low reachness of species in the seed bank might be a consequence of the small sampled area and/or the river extravasation at the beginning of 2016.