Epiphytic lichens as surrogates for biodiversity and ecosystem resilience in native oakwoods of the Baixo Tamega region (Northern Portugal)

In the last 50 years, concern about the loss of lichen diversity associated with forest management and forest fragmentation has led to many studies designed to assess patterns and monitor trends of lichen biodiversity in forests worldwide. However there are surprisingly few studies focusing on the effect of natural disturbance for epiphytic lichens in forest ecosystems and, especially, on how these changes affect the relationships between epiphytic lichens and other organisms. The major goal of this thesis was to characterize and valuate the epiphytic lichens in the Baixo Tamega region (northern Portugal) and to assess its vulnerability to several drivers of change, particularly fire. The study area is located in Aboboreira and Castelo, a mountain area with 105 km2 and a top altitude of approximately 1000 m.a.s.l. In this region, fire is one of the worst natural catastrophes not only because of its high frequency and wide extension but also because of their enormous destructive effects. This thesis has included three case studies that proved the need to develop management and conservation actions for the area. In the first study we assessed the epiphytic lichen diversity in the oak woods of the Aboboreira and Castelo mountains. Results have revealed high diversity value and presence of a lichen community that has suffered general decline throughout Europe. The second study has addressed the impact of fire over epiphytic lichens and community recovering patterns. Results observed along the fire gradient showed that the most common and abundant lichen species establish themselves early in post-fire gradient while “old-growth” associated lichens tend to recover slowly along the same gradient. The third study intended to evaluate the potential use of selected lichen species or groups as biodiversity surrogates, in a scenario of fire-controlled ecological changes. Results showed that the use of epiphytic lichens as surrogates of bryophyte and vascular plant diversity should consider not only species richeness and composition, but also occurrence of disturbing factors, such fire. among the studied groups, lichen genera is the only group that can be used as surrogate of total epiphytic lichen diversity, independently of fire induced changes

As Barragens em cabo Verde - Avaliação dos Impactes Ambientais - Socioeconómicos e Culturais - Caso de Estudo - A Barragem do Poilão Ilha Santiago

Os sucessivos anos de seca têm agravado a crónica falta de água que marca o quadro hídrico de Cabo Verde. No arquipélago verifica-se a perda de um grande volume de água que se escoa para o mar, aquando das grandes chuvadas, e que é estimado em milhões de m3/ano. Para atenuar a problemática da falta de água, principalmente no setor agrícola, o Governo Cabo-verdiano tem apostado na política de construção de barragens. No ano de 2006 com o objetivo de aumentar os recursos hídricos disponíveis e concomitantemente alargar a área irrigada e diminuir a pobreza, foi inaugurada a barragem do Poilão, a primeira do arquipélago, no interior da ilha de Santiago no concelho de São Lourenço dos Órgãos. Baseado no pressuposto que as barragens são estruturas de grande impacte ambiental e socioeconómico, antes, durante e depois da sua construção, o presente trabalho tem como objetivo principal avaliar o desempenho ambiental, socioeconómico e cultural da Barragem de Poilão. Para tal, o trabalho segue uma metodologia DPSIR1e a aplicação de inquéritos e entrevistas, procurando integrar o conhecimento e a perceção da paisagem na área de influência da albufeira por parte de diversos atores locais. Espera-se colher subsídios que sirvam de base para os estudos futuros das demais barragens projetadas e a serem construídas em Cabo Verde.