Banco de sementes induzido como estratégia para enriquecimento de áreas em processo de recuperação

Abstract

The enrichment of areas under ecology restoration process is an important strategy in situations where the area has low species diversity and absence of progenitor supply matrices nearby. Thus, the introduction of species, especially those of advanced succession, is crucial to reach the objectives of the restoration project. The present work had as objective to evaluate the viability of the use of induced seed bank as a basis for enrichment strategy in the area under restoration process and eucalyptus plantation. Eight native tree species were selected to compose the induced seed bank. The design was randomized blocks. For each species, 3 blocks (repetitions) were installed in each area. Seed samples (4 to 6) of each species were placed in nylon mesh bags and deposited under litter in each one of the 3 blocks in both areas. For the species whose seeds have dormancy and dispersion by fruits, the treatments consisted of seeds with and without dormancy breaking treatment, as well as intact fruits. An extra sample of each species was also placed under litter outside the nylon bag to assess seedling establishment ability after one year. Percentages of germinated, predated, deteriorated, removed and remaining (intact) seeds were evaluated. Data of soil moisture, air humidity and temperature, and canopy opening were collected monthly from both areas. The results of each species were compared between the study areas and over the months using binomial GLM and LSD test at 5% significance. The results showed that the species presented different responses. Most species presented higher germination percentages in the native area, while the highest percentages of predation and removal were verified in the area with eucalyptus. Seeds of Sapindus saponaria presented higher percentage of seedlings in the treatment with scarified seeds. There was no difference between the treatments (seeds with and without dormancy breaking) in Hymenaea courbaril seedlings, but the treatment with intact seeds showed the lowest predation. The use of seed bank induced as an enrichment strategy in the native area was more feasible for the species Handroanthus serratifolius, Handroanthus impetiginosus and Hymenaea courbaril. In the area planted with Eucalyptus urograndis, the use of the induced seed bank did not present satisfactory results for the species chosen, due to the lower germination of the seeds, as well as the high percentages of predation and removal observed, demonstrating the need for further studies on better strategies and choice of species to be used for the enrichment of such areas.