Balanço de carbono em ecossistemas mediterrânicos

• Autor(es): Correia, Alexandra Cristina Pires
• Data: 2013
• Identificador Persistente: http://hdl.handle.net/10400.5/6153
• Origem: Repositório da UTL
• Assunto(s): carbon balance; Pinus pinea; allometric models; soil respiration; Bayesian statistic; Cistus; Ulex; eddy covariance; upscaling; Mediterranean ecosystem
• Tipo de Documento: Tese de Doutoramento
• Idioma: Português
• Orientador(es): Pereira, João Santos

Descrição

Doutoramento em Engenharia Florestal e dos Recursos Naturais - Instituto Superior de Agronomia Forests play an important role in climate change mitigation as they sequester and store carbon dioxide (CO2) from the atmosphere. The aim of this thesis was to investigate forest carbon balance in its main compartments: tress, understory and soils. We present methods to estimate carbon stock in biomass of stone pine stands in south Portugal. Allometric models, as well as conversion and expansion factors were presented allowing the quantification of stand carbon stocks irrespective of the inventory base information available for the site. The undercanopy vegetation of a cork oak montado represented 20% of the total carbon assimilated by the ecosystem during summer/autumn 2011. It was proven that the vegetation mosaic that naturally colonized the understory have contrasting strategies to efficiently use the limited environmental resources available like water and light. Soil CO2 efflux, resulted from plants and microorganisms respiration, is similar between forests, shrublands and grasslands. Soil moisture, more than temperature, is determinant in this process. We present several empirical models, validated and calibrated using the Bayesian statistics, which allows estimating monthly soil respiration in grasslands for the Mediterranean region.