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Efeito da intensidade do desbaste de Pinus pinea na estrutura e diversidade da vegetação da Mata Nacional dos Medos
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A Reserva Botânica da Mata Nacional dos Medos é um local de grande interesse para a
biodiversidade, inserida na Paisagem Protegida da Arriba Fóssil da Costa da Caparica,
constituindo desde logo um desafio no que diz respeito à gestão. Nos finais de outubro de 2021
até final de janeiro de 2022 foi realizada uma intervenção de desbaste e desrame de Pinus pinea
tornando-se fulcral perceber os seus efeitos na estrutura e biodiversidade da floresta. O desenho
experimental considerou 24 pontos de amostragem, 12 em zonas com desbaste e 12 em zonas não
desbastadas (controlo). Os pontos de amostragem foram distribuídos em 3 classes homogéneas
de 5 variáveis ambientais: a distância à costa, o Índice Topográfico de Humidade, a elevação, o
declive e a Radiação Solar Potencial. Em cada ponto de amostragem, foi avaliado o estrato
arbóreo, através da quantificação da densidade de àrvores através do método dos quadrantes, da
altura, do diâmetro à altura do peito e dos crescimentos anuais dos ramos. Para determinar a
abundância de espécies arbustivas utilizou-se o método de intersecção de linha e realizou-se um
levantamento das espécies herbáceas. Os resultados obtidos mostraram que a densidade de árvores
diminuiu em locais de desbaste enquanto que os crescimentos anuais dos ramos foram maiores
nos locais controlo. A riqueza específica de herbáceas aumentou em locais de desbaste. Contudo,
em termos de percentagem de cobertura absoluta total de espécies arbustivas, esta verificou-se
maior nos locais de controlo. Não obstante, através da análise de estudos semelhantes espera-se
que os arbustos recuperem e ocupem as zonas onde antes existiam pinheiros mansos, promovendo
as espécies autóctones. Este estudo permitiu a avaliação inicial dos efeitos de desbaste de Pinus
Pinea junto à linha de costa portuguesa, fornecendo informação para estudos futuros sobre temas
similares e contribuindo para melhorar futuras intervenções florestais.
The Botanical Reserve of Mata Nacional dos Medos is a place of great interest for biodiversity, belonging to the Protected Landscape of Arriba Fóssil da Costa da Caparica, constituting a management challenge. From the end of October 2021 until the end of January 2022, a thinning and pruning of Pinus pinea was carried out. It was crucial to understand the effects of this intervention on the structure and biodiversity of the forest. The experimental design consisted of 24 sampling points, 12 in thinned areas and 12 in unthinned areas (control). The sampling points were distributed into 3 homogeneous classes of 5 environmental variables: distance from the coast, Topographic Wetness Index, elevation, slope and Potential Solar Radiation. At each sampling point, the tree stratum was assessed by quantifying tree density using the quadrant method, height, diameter at breast height and annual branch growth. To determine the abundance of shrub species, the line intersept method was used and a survey of herbaceous species was carried out. The results showed that tree density decreased in thinning sites while annual branch growth was greater in control sites. Herbaceous species richness and total diversity increased at thinning sites. However, in terms of the percentage of total absolute coverage of shrub species, this was higher in the control sites. Nevertheless, it is expected that shrubs will recover and occupy areas where there were once Pinus pinea, promoting native species. This study provided an initial assessment of the effects of Pinus Pinea thinning along the Portuguese coastline, providing information for future studies on similar topics and contributing to improve future forestry interventions.
The Botanical Reserve of Mata Nacional dos Medos is a place of great interest for biodiversity, belonging to the Protected Landscape of Arriba Fóssil da Costa da Caparica, constituting a management challenge. From the end of October 2021 until the end of January 2022, a thinning and pruning of Pinus pinea was carried out. It was crucial to understand the effects of this intervention on the structure and biodiversity of the forest. The experimental design consisted of 24 sampling points, 12 in thinned areas and 12 in unthinned areas (control). The sampling points were distributed into 3 homogeneous classes of 5 environmental variables: distance from the coast, Topographic Wetness Index, elevation, slope and Potential Solar Radiation. At each sampling point, the tree stratum was assessed by quantifying tree density using the quadrant method, height, diameter at breast height and annual branch growth. To determine the abundance of shrub species, the line intersept method was used and a survey of herbaceous species was carried out. The results showed that tree density decreased in thinning sites while annual branch growth was greater in control sites. Herbaceous species richness and total diversity increased at thinning sites. However, in terms of the percentage of total absolute coverage of shrub species, this was higher in the control sites. Nevertheless, it is expected that shrubs will recover and occupy areas where there were once Pinus pinea, promoting native species. This study provided an initial assessment of the effects of Pinus Pinea thinning along the Portuguese coastline, providing information for future studies on similar topics and contributing to improve future forestry interventions.
Descrição
Relatório de Estágio de Mestrado, Ecologia e Gestão ambiental, 2024, Universidade de Lisboa, Faculdade de Ciências
Palavras-chave
Mata Nacional dos Medos Pinus Pinea Desbaste Diversidade Abundância Teses de mestrado - 2024