The role of wetlands on Amazonian tree species diversity patterns

Author(s)

Bruno Garcia Luize

• Document type: Doctoral Thesis
• Press: Rio Claro. 2020-01-30.
• Institution: Universidade Estadual Paulista (Unesp). Instituto de Biociências. Rio Claro
• Defense date: 2019-12-13
• Advisor: Clarisse Palma da Silva; Thiago Sanna Freire Silva

Abstract

Wetlands are in the interface of terrestrial and aquatic environments, where seasonally water availability may be in excess or scarcity. Geological history of Amazon basin is closely linked with a huge temporal and spatial extents of wetlands. Nowadays, floodplains (i.e., Vázea and Igapó) are the wetlands with greatest coverage in Amazon. The present thesis is focused on the role of wetlands to tree species diversity in Amazon. Wetland forests have lower tree species diversity than upland forests (i.e., Terra-Firme); most likely due to ecological and physiological limitations. Notwithstanding, in Amazonian wetland forests 3,515 tree species already were recorded, (Chapter 2), which is comparable to tree species diversity in the Atlantic Forest. Wetland tree species show greater ranges sizes and niche breadth compared to tree species do not occur in wetlands (Chapter 3). Floristic compositional turnover and phylogenetic distances between floodplain forests in Central Amazon is high (Chapter 4). The most influential driver of floristic compositional turnover was the geographic distances between localities, whereas phylogenetic distances is driven mainly by the environmental gradients between forests. Furthermore, in general, the most abundant species are those that shows greater co-occurrence associations (Chapter 5). Co-occurrence structure is influenced by biotic interactions like facilitation and competition among species, but also by niche similarities indicated in the evolutionary distance among them. Moreover, dispersal limitation suggested by species range overlap is another factor structuring species pairs co-occurrences. One of the limitations of biological diversity studies is the use of species as basic unities of evaluation. However, sometimes it is impossible distinguish tree species in tropical forests as discrete unities. The lack of diagnosis characters in botanical collections, low representativity of phenotypic variation, and cryptic character variation between close related species were factors that beset species delimitation. DNA barcode is presented as a promising technique to reduce the identification shortfall of recent diverging Lecythidaceae species occurring in várzea and terra-firme forests of Central Amazon (Chapter 6). At this thesis we studied the role of wetlands on the origin and maintenance of tree species diversity in Amazonian forests, and we conclude that wetlands promote changes in ecological features of tree species and generates biotic heterogeneity in the region. (AU)

• FAPESP's process: 15/24554-0 - The role of floodplains in the origin and maintenance of tree species diversity in the Amazon
• Grantee: Bruno Garcia Luize
• Support Opportunities: Scholarships in Brazil - Doctorate