Recursos de colección

UTL Repository Universidade Técnica de Lisboa (35.546 recursos)

O Repositório Institucional da Universidade Técnica de Lisboa desenvolvido no âmbito do projecto RCAAP. Este repositório destina-se a recolher, preservar e disponibilizar o acesso às publicações científicas e didácticas de seis: Escolas da UTL: Faculdade de Medicina Veterinária, Instituto Superior de Agronomia, Instituto Superior de Economia e Gestão, Instituto Superior de Ciências Sociais e Políticas , Faculdade de Motricidade Humana, Faculdade de Arquitectura. O Instituto Superior Técnico, igualmente Escola Da UTL, tem repositório independente.

CEABN - Artigos de Revista

Mostrando recursos 1 - 4 de 4

  1. Are drought and wilfires turning Mediterranean cork oak forests into persistent shrublands ?

    Acácio, Vanda; Holmgren, Milena; Rego, Francisco Castro; Moreira, Francisco; Godefridus, M.J.Mohren
    In the Iberian Peninsula Mediterranean oak forests have been transformed into a mosaic landscape of four main patch-types: forests, savannas, shrublands and grasslands. We used aerial photographs over a period of 45 years (1958–2002) to quantify the persistence and rates of transitions between vegetation patch-types in southern Portugal, where cork oak is the dominant tree species. We used logistic regression to relate vegetation changes with topographical features and wildfire history. Over the 45 years, shrublands have been the most persistent patch-type (59%), and have been expanding; forests are also persistent (55%) but have been decreasing since 1985; savannas and grasslands were less persistent (33% and 15%, respectively). Shrublands persistence was significantly correlated with wildfire occurrence, particularly...
    - 05-abr-2018

  2. Extensões da função de Shannon e equilibrios de proporções - uma aplicação ao mosaico da paisagem

    Casquilho, José Pinto; Neves, Manuela; Rego, Francisco Castro
    Shannon's function is revisited and we review its application to ecological problems, including the analysis of the diversity of a land mosaic(sensu Forman). We present a generalization of Shannon's function, organized in two families (extensions)where we interpret the quantities related and analyse the extremal behaviour of the models (proofs are presented). We name the families respectively as systemic diversity index and value index of the mosaic.We suggest the concepts of intrinsic value, informative value and contributive value of each component(habitat) of the land mosaic. We exemplify the use of the models with a small case study based on ecological and...
    - 05-abr-2018

  3. Wildfires as a major driver of landscape dynamics in three fire-prone areas of Portugal

    Silva, Joaquim S.; Vaz, Pedro; Moreira, Francisco; Catry, Filipe; Rego, Francisco Castro
    Available at ScienceDirect
    - 05-abr-2018

  4. Size-dependent pattern of wilfire ignitions in Portugal: when do ignitions turn into big fires ?

    Moreira, Francisco; Catry, Filipe; Rego, Francisco Castro; Bacao, Fernando
    Not all wildfire ignitions result in burned areas of a similar size. The aim of this study was to explore whether there was a size-dependent pattern (in terms of resulting burned area) of fire ignitions in Portugal. For that purpose we characterised 71,618 fire ignitions occurring in the country in the period 2001–2003, in terms of population density in the local parish, land cover type and distance to roads. We then assigned each ignition into subsets of five classes according to the resulting burned area:[5 ha, [50 ha,[100 ha,[250 ha,[500 ha. The probability of an ignition resulting in different burned area classes was modelled using binary logistic regression, and the relative importance, strength...
    - 05-abr-2018

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