Juniperus navicularis - a study of Portuguese population structure and fitness

Juniperus navicularis Gand. is a dioecious endemic conifer that constitutes the understory of seaside pine forests in Portugal, areas currently threatened by increasing urban expansion. The aim of this study is to assess the conservation status of previously known populations of this species located on its core area of distribution. The study was performed in south-west coast of Portugal. Three populations varying in size and pine density were analyzed. Number of individuals, population density, spatial distribution and individual characteristics of junipers were estimated. Female cone, seed characteristics and seed viability were also evaluated. Results suggest that J. navicularis populations are vulnerable because seminal recruitment is scarce, what may lead to a reduction of genetic variability due solely to vegetative propagation. This vulnerability seems to be strongly determined by climatic constraints toward increasing aridity. Ratio between male and female shrubs did not differ from 1:1 in any population. Deviations from 1:1 between mature and non-mature plants were found in all populations, denoting population ageing. Very low seed viability was observed. A major part of described Juniperus navicularis populations have disappeared through direct habitat loss to urban development, loss of fitness in drier and warmer locations and low seed viability. This study is the first to address J. navicularis conservation, and represents a valuable first step toward this species preservation.

The influence of forest management on bird communities of portuguese montados

The world distribution of cork oak Quercus suber and holm oak Q. rotundifolia is basically restricted to the western Mediterranean basin. These two evergreen oaks are the base of the Portuguese montado and the Spanish dehesa. This thesis aims to analyse how bird communities of the montado are influenced by management practices. We used different approaches to study this relationship, and to evaluate which features are responsible for species distribution in different typologies of montado. First, we reviewed the concept of montado in order to better understand the system and to set thresholds on what can be considered as montado. Afterwards, we studied the elements that promote higher species diversity and individual species, or group of species, that can act as indicators of High Nature Value for montados. Finally, we evaluated how the bird communities are structured, and the influence of the main management actions (e.g. cattle and cork exploitation) on those communities; Resumo: A distribuição mundial do sobreiro Quercus suber e da azinheira Quercus rotundifolia é praticamente restrita à bacia do Mediterrâneo. Estas duas espécies de carvalhos são a base dos montados em Portugal e das dehesas em Espanha. No âmbito desta tese analisamos como as comunidades de aves do montado são influenciadas pela gestão florestal. Para este efeito usámos diferentes abordagens e avaliámos quais as características do montado responsáveis pela distribuição das espécies ao longo das suas diferentes tipologias. Fizemos uma revisão do conceito de montado e proposemos uma definição para o sistema, englobando a sua multifuncionalidade. Estudámos os elementos singulares que promovem a diversidade de aves e que podem ser simultaneamente indicadores de áreas de Alto Valor Natural (HNV). Por fim, avaliámos qual a influência da gestão (p. ex. pastoreio e descortiçamento) na estruturação das comunidades de aves.