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Title: Biodiversity change in the Cerrado following invasive pine tree establishment
Author: Rocha Kortz, Alessandra
ISNI:       0000 0004 6499 0074
Awarding Body: University of St Andrews
Current Institution: University of St Andrews
Date of Award: 2017
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How do newly established species interact with existing assemblage members to alter local biodiversity? This question is especially topical given growing concerns about increased temporal turnover levels relative to background rates. My PhD thesis concerns young, isolated pines Pinus elliottii invading the Cerrado (Brazilian savanna) as a study system to test the hypothesis that the impact of newly established individuals varies across habitat layers. I sampled both vegetation layers (shrub and grass) of two distinct habitats, the shrub-dominated campo sujo and the grass-dominated campo úmido. My results show that the pine is changing α diversity in the dominant vegetation layer of each habitat: the shrub layer of campo sujo and the grass layer of campo úmido. The shape of the diversity v. establishment time relationship is habitat dependent; there is a hump shaped relationship between diversity and pine size in the grass layer but a linear one in the shrub layer. β diversity metrics – which take species composition into account - reveal marked differences in species composition between the habitats in the shrub layer, whereas the corresponding pair of invaded and control sites of the same habitat and layer is more similar than expected (in both vegetation layers). The degree of similarity between sites also changes as the invasion proceeds. In the campo sujo habitat, sites become more compositionally distinct, whereas in the grass layer of campo úmido sites get more similar. This suggests that the timing of changes in species composition is habitat-dependent and reinforces the need to remove the invader individuals from the area. My results show that, though complex, the consequences for local biodiversity of non-native species establishment are not haphazard. As such they contribute to the understanding of species coexistence and help explain why species invasion can lead to very different biodiversity outcomes.
Supervisor: Magurran, Anne E. Sponsor: Brazilian Science Without Borders Program/Ciência sem Fronteiras ; Coordenação de Aprimoramento de Pessoal de Nível Superior (CAPES)
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Biological diversity ; Community ecology ; Habitat structure ; Invasion impact ; Pinus elliottii ; QK263.R7 ; Biodiversity--Brazil ; Cerrados--Brazil ; Introduced organisms ; Forest ecology