Estudos sobre banco de sementes do solo, resgate de plântulas e dinâmica da paisagem para fins de restauração florestal, Carandaí, MG

• Autor(a) principal: Calegari, Leandro
• Data de Publicação: 2009
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/529
• topic: Recuperação de áreas degradadas; Restauração ecológica; Produção de mudas; Geoprocessamento; Degraded areas recovery; Ecological restoration; Seedling production; Geoprocessing; CNPQ::CIENCIAS AGRARIAS::RECURSOS FLORESTAIS E ENGENHARIA FLORESTAL::MANEJO FLORESTAL

As a consequent of the need for new methodologies that allow restored areas to be consolidated in due course, a series of ecological studies were carried out at a rural property, situated in the municipal district of Carandaí, Minas Gerais, Brazil. This dissertation is organized in terms of the following chapters: 1) characterization of the patches of a secondary Seasonal Semidecidual Forest located inside and around the rural property; 2) evaluation of the soil seed bank; and 3) rescue of shrub and tree shoots. The application of an appropriate environmental administration, one that favors the conservation and restoration of depleted areas, is favored by extant knowledge on existing forest patches in rural properties. By using the programs Spring and Fragstats, the dynamics of the landscape was characterized with emphasis on the forest patches and its evolution from the period 1984-2007. It may conclude that progressive increases in the total area of native forest occurred due to the appearance of new patches, and the individual area of each patch presented a tendency at reduction, which provided for an increase of the edge area and reduced the total percentage of each patch that made up the core area. Despite the advantage of the predominance of patches in simple geometric ways, with a reduction of the edge effect, the quality of the landscape was threatened because it was predominantly made up of small patches. The forest patches were still distant enough from each other (by more than 200 meters) that they presented a small tendency to merge (the result of the increase in the number of patches), which was, nevertheless, still insufficient. Therefore, although the covering of native forest has shown an increase in the total area in general, it lost quality during the period studied. The knowledge regarding the soil seed bank provides important information about the potential for the regeneration of a particular area, allowing one to draw some inferences about its restoration. Taking into account 20 plots, 25 x 25 cm and 5 cm deep, samples of soils from different environmental situations were gathered (clean pasture, dirty pasture, coppice, eucalyptus, and forest). The material collected was put to germinate in a vegetation shed and analyzed during eight months, with the composition and the density of the species (herbaceous, subshrubby, shrubby, and arboreal) evaluated. The environmental situations presented different manifestations of natural regeneration. The dirty pasture was the situation that presented the largest number of regenerating herbaceous trees, which makes it more problematic for forest restoration. All the environmental situations presented banks of seeds of tree and shrub shoots, which can help in the restoration process. However, the success of this activity will be tied directly to the activities of the control of competing seeds, mainly of Urochloa decumbens (Stapf) R.D. Webster, an aggressive grass that germinated in every environmental situation. Due to the absence of species in a final succession stage in the seed bank in the soil, there might have been other accompanying interventions, such as the planting of seedlings, the direct sowing of arboreal species, and/or the implantation of artificial galleries to accelerate the vegetable succession. The technique of rescuing shorts is an alternative for reducing the problem of the loss of biological diversity in the projects of restoration of depleted areas. To evaluate this technique, shoots were rescued from two forest patches with different stages of ecological succession (average and initial). Trees 60 cm in height or less were transplanted to forest nurseries and evaluated during six months. A total of 966 specimens were rescued, identified as belong to 26 families and 70 species, with a larger percentage observed in the patches with a more advanced stage of succession. The average rate of survival was 79.3%, differing statistically among patches, specimen height and species. Specimens from the initial stage patch, as well as the ones less than 40 cm in height, were characterized by the highest survival level. Some species were notable for presenting a larger growth in height, as well as others for the loss of their leaves after the transplant, with subsequent sprouting. Mainly pioneer species, in addition to some non-pioneers, demonstrated high survival rates, many commonly not found in forest nurseries and, consequently, also absent in the restoration projects. These informations are important for the formulation of strategies to promote the connectivity of the forest patches on and around the property of Cimento Tupi S.A.