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| Author(s): |
Silvana Cristina Pereira Muniz de Souza
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Piracicaba. |
| Institution: | Universidade de São Paulo (USP). Escola Superior de Agricultura Luiz de Queiroz (ESALA/BC) |
| Defense date: | 2002-06-18 |
| Examining board members: |
Ricardo Ribeiro Rodrigues;
Vera Lex Engel;
Sergius Gandolfi
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| Advisor: | Ricardo Ribeiro Rodrigues |
| Abstract | |
This work had as a goal identifying the resilience of an area, which was deforested in the past, currently used as pasture and Citrus sp crop. This resilience was evaluated through the following aspects of forest dynamics: soil seed bank analysis, seed rain and saplings. It was conducted in the Jurupará State Park in Ibiúna and Piedade (São Paulo State), in a transition area between the Ombrophil Forest and the Semideciduous Seasonal Forest. In this area, three sampling strips were allocated, each one with five 10 X 20 m plots, being one inside the Citrus sp crop and the others inside the pasture, distant 0-20 m and 80-100 m from the forest remant. For evaluating the seed rain, three circular seeds collectors of 0.52 cm in diameter were randomly set in each plot, with monthly samplings of the deposited seeds. For evaluating the seed bank, soil of three 0.25 X 0.25 m sub-plots and 0.05 m deep was collected in two different seasons: rainy season (January/2001) and dry season (August/2001). To the saplings evaluation, four 0.5 X 0.5 m sub-plots were implanted randomly, in which three evaluations of all the shrubs and trees individuals (0.30-1.30m height) were performed. At the seed rain inside the Citrus sp crop, a high density of autoctone seed of shrubs and trees species (Leandra sp. with 20,638.73 seed.m -2 and Tibouchina sp. with 12,681.85 seeds.m -2 ) was observed; inside the pasture, there were a predominance of ruderal species, while the average density of shrubs and trees species were, 335.75 seeds.m -2 in the pasture distant 0-20m from the remaining forest and 577.58 seeds.m -2 in the pasture distant 80-100m from the remaining forest. At the soil seed bank evaluation in the experimental area inside the Citrus sp crop, the ruderal species were 99.88% of the germinated species in the rainy season and 99.73% in the dry season. In the experimental area inside the pasture, for the rainy season, 100% of the germinated species were herbal species typically ruderal in both distances; in the soil collected in the dry season, this life form was predominant in 99.66% and 99.92% in both distances, respectively. In the saplings counting, a 5.8 ind.m -2 density inside was found the Citrus sp crop and 1.2 and 2.2 ind.m -2 inside the pasture in both distances. Only for the seeds rain significant differences were found between the Citrus sp crop and the pasture. No significant differences were found between the two distances within the pasture area strips, denying the hypothesis that the resilience of the study area is inversely related to the remaining forest distance. (AU) | |