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The influence of forest landscape composition and structure on spider communities in Mafra (Portugal) and Hamsterley forest (England, United Kingdom)
| Nome: | Descrição: | Tamanho: | Formato: | |
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| Resumo | 6.97 KB | Adobe PDF | ||
| Introduction | 69.5 KB | Adobe PDF | ||
| Cap. 1, 2 e 3 | 1.32 MB | Adobe PDF | ||
| Cap. 4, 5 e 6 | 1.07 MB | Adobe PDF | ||
| Cap. 7 | 269.76 KB | Adobe PDF |
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Orientador(es)
Resumo(s)
The present work proposed to evaluate the effects of land use and fragmentation on
spider diversity and community structure. In Portugal, Oak, Pine, Eucalyptus and
Shrubland were sampled to study the effects of habitat complexity on diversity, while
abundance and richness were analyzed across a Eucalyptus-Grassland ecotone. In
England, assemblage structure and diversity were assessed in different aged blocks of
Sitka spruce and Oak woodland. Multivariate analyses were used to classify and
ordinate data to assess the influence of measured environmental variables on spider
distribution. Estimated values of richness calculated using non-parametric estimators
confirmed that richness increased in areas with decreasing levels of disturbance.
Using CCA, both crown cover and soil pH significantly influenced spider distribution
in the forest areas. Across a Eucalyptus-Grassland ecotone, both abundance and
richness were highest in Grassland, with spider abundance greatest 10m away from
the boundary, and estimated richness highest at the Grassland-edge. A high degree of
mixing was observed between the two habitats, with no apparent edge-associated
species. Along a successional gradient in Sitka spruce, the number of species
decreased with increasing plantation age, and was linked to the concomitant loss of
vegetation complexity with increased canopy closure. Finally, 23 additions to the
Portuguese checklist are provided.
Descrição
Doutoramento em Engenharia Florestal - Instituto Superior de Agronomia
Palavras-chave
spiders biodiversity fragmentation ecotone succession forest landscape ecology multivariate analysis community structure