Proposta metodológica de identificação dos estágios de sucessão de fragmentos florestais do bioma Mata Atlântica
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Data
2018-12-11
Autores
Amorim, Amanda Trindade
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Universidade Estadual Paulista (Unesp)
Resumo
Os estágios de sucessão dos fragmentos florestais podem ser avaliados por diferentes procedimentos e variáveis, entretanto requerem bastante tempo e esforços de trabalhos em campo, além de elevados custos e pessoal qualificado para sua avaliação. Diversas pesquisas propõem métodos alternativos, utilizando técnicas de geoprocessamento e o sensoriamento remoto, porém observa-se a necessidade de incorporar novos métodos para essa avaliação, visando aprimorar e reduzir os custos de levantamento de dados. A presente pesquisa teve por objetivo estudar fragmentos florestais de Mata Atlântica, priorizando o conhecimento dos estágios de sucessão com o intuito de propor um método de avaliação desses estágios visando contribuir com o planejamento e a gestão ambiental para preservação e conservação dos recursos florestais. A área de estudo foi a Bacia Hidrográfica do Rio Murundú-Paiol, inserida no bioma Mata Atlântica, localizada no município de Ibiúna, São Paulo. Inicialmente a metodologia consistiu na construção de uma base cartográfica de apoio a partir de cartas topográficas do município de Ibiúna/SP (escala 1:10.000), compartimentação morfométrica em três níveis de altitude (baixo, médio e alto), e no mapeamento do uso e cobertura da terra a partir de ortoimagens do sensor Vexcel Ultracam. Do mapeamento do uso e cobertura da terra, foram extraídos os fragmentos florestais para avaliação de suas métricas, bem como para a avaliação do efeito antrópico em seu entorno. Os fragmentos florestais também foram avaliados quanto às condicionantes físicas do terreno (altitude, declividade e orientação do terreno) e posteriormente quanto às suas características espectrais a partir dos índices de vegetação (SAVI - Índice de Vegetação Ajustado ao Solo e IAF - Índice de Área Foliar) obtidos por imagens do satélite RapidEye, que permitem avaliar seus parâmetros biofísicos. Foram selecionados 14 fragmentos florestais para avaliação dos seus estágios em campo, a partir de um levantamento ecológico que priorizou a descrição qualitativa de fatores indicativos dos estágios de sucessão. Por fim, foi proposto um indicador dos estágios de sucessão (IES) que integrou os parâmetros que obtiveram forte correlação entre si. Os resultados mostraram que a área da bacia hidrográfica apresenta o total de 57,9% de matas, com maior conservação do setor alto, exibindo maior fragmentação da paisagem no setor baixo da bacia hidrográfica. Dentre todos os parâmetros avaliados, a melhor correlação foi entre as classes dos índices SAVI e IAF (0,91), seguidos da correlação entre o SAVI com as classes de altitude (0,797) e de relevo (0,782), respectivamente. A construção do IES integrou então as classes do SAVI, as classes de altitude e as classes referentes ao relevo. A partir do IES observa-se que dos 72 fragmentos florestais, 16 são indicativos de estágio inicial, 31 de estágio médio e 25 de estágio avançado de sucessão e verificou-se uma acurácia de 85,7% dos fragmentos avaliados pelo IES. O indicador proposto pode ser replicado em outras áreas do bioma Mata Atlântica e mostrou ser uma alternativa científica viável e eficiente na observação e avaliação dos estágios de sucessão de fragmentos florestais deste bioma, podendo contribuir com o planejamento e gestão ambiental dos recursos florestais.
The stages of succession of the forest fragments can be evaluated by different procedures and variables, however they require a lot of time and fieldwork efforts, as well as high costs and qualified personnel for evaluation. Several researches propose alternative methods, using geoprocessing techniques and remote sensing, but it is necessary to incorporate new methods for this evaluation, in order to improve and reduce the costs of data collection. The present research had the objective to study forest fragments of Atlantic Forest, prioritizing the knowledge of succession stages with the purpose of proposing a method of evaluation of these stages in order to contribute to environmental planning and management for the preservation and conservation of forest resources. The study area was the Murundú-Paiol river watershed, inserted in the Mata Atlântica biome, located in Ibiúna, São Paulo. Initially, the methodology consisted in the composition of a cartographic base of support from topographic maps of the city of Ibiúna/SP (scale 1: 10,000), morphometric subdivision at three levels of altitude (low, medium and high), and in the mapping of land use from orthoimages of the Vexcel Ultracam sensor. From the land use mapping, the forest fragments were extracted to evaluate their metrics, as well as to evaluate the anthropic effect in their environment. The forest fragments were also evaluated for the physical conditions of the terrain (altitude, slope and aspect) and later on their spectral characteristics from the vegetation indexes (SAVI - Soil-adjusted vegetation index and LAI - Leaf area index) obtained by images from the RapidEye satellite, that allow to evaluate its biophysical parameters. A total of 14 forest fragments were selected to evaluate their stages in the field, starting with an ecological survey that prioritized the qualitative description of factors indicative of succession stages. Finally, an indicator of the stages of succession (IES) were proposed that integrated the parameters that obtained a strong correlation with each other. The results showed that the area of the watershed presents the total of 57.88% of forests, with greater conservation of the high sector, exhibiting greater fragmentation of the landscape in the low sector of the watershed. Among all the parameters evaluated, the best correlation was between the SAVI and LAI index classes (0.91), followed by the SAVI correlation with the altitude classes (0.797) and the relief class (0.782), respectively. The construction of the IES then integrated SAVI classes, altitude classes and relief classes. From the IES it can be observed that of the 72 forest fragments, 16 are indicative of the initial stage, 31 of the middle stage and 25 of the advanced stage of succession, and an accuracy of 85.7% of the fragments evaluated by the IES. The proposed indicator can be replicated in other areas of the Atlantic Forest biome and proved to be a viable and efficient scientific alternative in the observation and evaluation of the stages of succession of forest fragments of this biome, contributing to the environmental planning and management of forest resources.
The stages of succession of the forest fragments can be evaluated by different procedures and variables, however they require a lot of time and fieldwork efforts, as well as high costs and qualified personnel for evaluation. Several researches propose alternative methods, using geoprocessing techniques and remote sensing, but it is necessary to incorporate new methods for this evaluation, in order to improve and reduce the costs of data collection. The present research had the objective to study forest fragments of Atlantic Forest, prioritizing the knowledge of succession stages with the purpose of proposing a method of evaluation of these stages in order to contribute to environmental planning and management for the preservation and conservation of forest resources. The study area was the Murundú-Paiol river watershed, inserted in the Mata Atlântica biome, located in Ibiúna, São Paulo. Initially, the methodology consisted in the composition of a cartographic base of support from topographic maps of the city of Ibiúna/SP (scale 1: 10,000), morphometric subdivision at three levels of altitude (low, medium and high), and in the mapping of land use from orthoimages of the Vexcel Ultracam sensor. From the land use mapping, the forest fragments were extracted to evaluate their metrics, as well as to evaluate the anthropic effect in their environment. The forest fragments were also evaluated for the physical conditions of the terrain (altitude, slope and aspect) and later on their spectral characteristics from the vegetation indexes (SAVI - Soil-adjusted vegetation index and LAI - Leaf area index) obtained by images from the RapidEye satellite, that allow to evaluate its biophysical parameters. A total of 14 forest fragments were selected to evaluate their stages in the field, starting with an ecological survey that prioritized the qualitative description of factors indicative of succession stages. Finally, an indicator of the stages of succession (IES) were proposed that integrated the parameters that obtained a strong correlation with each other. The results showed that the area of the watershed presents the total of 57.88% of forests, with greater conservation of the high sector, exhibiting greater fragmentation of the landscape in the low sector of the watershed. Among all the parameters evaluated, the best correlation was between the SAVI and LAI index classes (0.91), followed by the SAVI correlation with the altitude classes (0.797) and the relief class (0.782), respectively. The construction of the IES then integrated SAVI classes, altitude classes and relief classes. From the IES it can be observed that of the 72 forest fragments, 16 are indicative of the initial stage, 31 of the middle stage and 25 of the advanced stage of succession, and an accuracy of 85.7% of the fragments evaluated by the IES. The proposed indicator can be replicated in other areas of the Atlantic Forest biome and proved to be a viable and efficient scientific alternative in the observation and evaluation of the stages of succession of forest fragments of this biome, contributing to the environmental planning and management of forest resources.
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Palavras-chave
Fragmentos florestais, Indicador do estágio de sucessão, Geotecnologias, Modelagem matemática, Forest fragments, Indicator of the stage of succession, Geotechnology, Mathematical modeling