Banca de DEFESA: SARAH PEREIRA BARROS

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : SARAH PEREIRA BARROS
DATA : 04/08/2021
HORA: 14:00
LOCAL: PPG Ecologia e Conservação - videoconferência
TÍTULO:

Bird community structure determinants in the Cerrado-Amazon ecotone.

PALAVRAS-CHAVES:

beta diversity, CAMI, community assembly, INLA, phylobetadiversity, phylogenetic diversity.

PÁGINAS: 69
GRANDE ÁREA: Ciências Biológicas
ÁREA: Ecologia
SUBÁREA: Ecologia Teórica
RESUMO:

The structure of ecological communities can be defined by several biotic and abiotic factors, and the relative influence of those factors on community assembly processes may operate at different spatial scales. In this project, our aim was to understand the ecological and historical processes that determined the structure and assembly of bird communities in the Cerrado-Amazon ecotone. To do so, we proposed the following question: which factors act on the beta diversity and phylobetadiversity patterns of bird communities along the Cerrado-Amazon ecotone? We proposed three distinct biological hypotheses: 1) Give the high vegetation heterogeneity of the Cerrado-Amazon ecotone, and the associated niche availability, we expect that climatic variables (as a proxy for vegetation heterogeneity) will be more important than geographic distance in determining the spatial variation of communities. Being so, we predict that there will be greater compositional dissimilarity (beta diversity and phylobetadiversity) associated with environmental variables than with geographic distance alone in the Cerrado-Amazon ecotone communities, while the opposite will be observed for both Cerrado and Amazon communities. 2) In addition, given the high niche availability, we hypothesize that there will be an accumulation of species from both biomes in ecotone communities, leading to an increase in alpha and phylogenetic diversity in these communities compared to Cerrado and Amazon communities. If that is true, we expect that the environmental predictors will estimate higher values of alpha and phylogenetic diversity in the communities closer to the ecotone. 3) On the other hand, it is possible that the interaction between species (i.e., competition) is a more important biotic filter than the biotic and abiotic filters mentioned above. If this hypothesis is true, we predict that a) the community assembly in the Cerrado-Amazon ecotone will be better explained by a mathematical model of competitive exclusion and; b) there will be smaller alpha diversity, but higher phylogenetic diversity in communities in the Cerrado-Amazon ecotone, since closely related species will tend not to co-occur locally. This study was developed using data from communities distributed in the Cerrado and Amazon biomes, including the extensive ecotone between them. For this, we compiled a database with the bird communities of each biome through a wide survey of scientific articles. To investigate beta diversity patterns we use the Generalized Dissimilarity Model (GDM), and also the phylogenetic informed version of the same model, PhyloGDM. In addition, we used a Bayesian hierarchical approach estimated using an Integrated Nested Laplace Approximation (INLA) algorithm to estimate alpha and phylogenetic diversity in terms of environmental predictors. Finally, to investigate whether the interaction between species (i.e., competitive exclusion) was an important factor determining community assmbly in the region, we used the CAMI (Community Assembly Model Inference) analysis. The results showed that environmental variables, such as seasonality, isothermality and average temperature, were the most important determinants of beta and phylobetadiversity patterns of bird communities in the Cerrado-Amazon ecotone. Environmental predictors did not estimate higher alpha and phylogenetic diversity in ecotone communities. The competitive exclusion model was not the most important in the assembly of the ecotone communities, but a neutral model of species accumulation from both biomes. Finally, we conclude that the environmental factors linked to niche diversity associated with vegetation heterogeneity are important factors sustaining bird diversity in the Cerrado-Amazon ecotone.

MEMBROS DA BANCA:
Presidente - 005.506.021-86 - FABRÍCIUS MAIA CHAVES BICALHO DOMINGOS - NENHUMA
Externo à Instituição - TARCISIO LYRA DOS SANTOS ABREU - UnB
Externo à Instituição - UBIRAJARA DE OLIVEIRA - UFMG