Taxonomic, functional, and phylogenetic diversity of stream fish communities under the damming effect in the Ribeira de Iguape River Basin

• Grant number: 22/04653-8
• Support Opportunities: Regular Research Grants
• Start date: August 01, 2022
• End date: July 31, 2025
• Field of knowledge: Biological Sciences - Ecology - Applied Ecology
• Principal Investigator: Mauricio Cetra
• Grantee: Mauricio Cetra
• Host Institution: Centro de Ciências e Tecnologias para a Sustentabilidade (CCTS). Universidade Federal de São Carlos (UFSCAR). Sorocaba , SP, Brazil
• Associated researchers: George Mendes Taliaferro Mattox

Abstract

Many studies have shown that environmental and spatial factors structure the diversity patterns of fish communities in Neotropical streams. However, the role of water network connectivity has been little studied. Recently, the variation in the composition of the biological community along spatial and environmental gradients has included taxonomic, functional, and phylogenetic levels. The use of multiple facets of diversity has improved our understanding of the relative contribution of the processes that shape community assembly. Furthermore, the partitioning of beta diversity into species replacement and species richness differences components may provide additional insights into the mechanisms that shape biodiversity patterns at large spatial scales. Our objective will be to compare two contiguous sub-basins with different connectivity structures (with and without dam) and to unravel the relative importance of environmental variables measured at various levels (local, drainage area and spatial) in the variation of composition in different facets of beta diversity (taxonomic, functional, and phylogenetic) and its components (substitution and richness difference) in fish communities from streams of the Ribeira de Iguape river basin. Fish communities from 19 stream stretches will be sampled. We will analyze the variation in beta diversity's different facets and components using generalized dissimilarity modelling (GDM) and beta diversity partitioning procedures. The spatial structure will be modelled using AEM analysis (asymmetric eigenvector maps). We expect a significant effect of local and spatial variables for all streams, independently of the dam's occurrence in the system. For streams that are dammed, we expect to find, irrespective of the diversity facet, a more significant relative contribution of the richness difference, evidencing the spatial isolation promoted by the disruption of connectivity. On the other hand, we expect a more significant relative contribution of substitution to taxonomic diversity and a more negligible contribution to functional and phylogenetic diversity. We assume that species are replaced in this context, but functional and phylogenetic structures are saturated. Such expectations indicate the effect of environmental filters on the stream fish community assembly. (AU)