Fish species richness is associated with the availability of landscape components across seasons in the Amazonian floodplain

Abstract

Understanding environmental biodiversity drivers in freshwater systems continues to be a fundamental challenge in studies of their fish assemblages. The present study seeks to determine the degree to which landscape variables of Amazonian floodplain lakes influences fish assemblages in these environments. Fish species richness was estimated in 15 Amazonian floodplain lakes during the high and low-water phases and correlated with the areas of four inundated wetland classes: (i) open water, (ii) flooded herbaceous, (iii) flooded shrubs and (iv) flooded forest estimated in different radius circular areas around each sampling site. Data were analyzed using generalized linear models with fish species richness, total and guilds as the dependent variable and estimates of buffered landscape areas as explanatory variables. Our analysis identified the significance of landscape variables in determining the diversity of fish assemblages in Amazonian floodplain lakes. Spatial scale was also identified as a significant determinant of fish diversity as landscape effects were more evident at larger spatial scales. In particular, (1) total species richness was more sensitive to variations in the landscape areas than number of species within guilds and (2) the spatial extent of the wetland class of shrubs was consistently the more influential on fish species diversity.

Conservation of migratory fishes in the Amazon basin

“…Recent analyses of stable isotopes demonstrated that terrestrial plant material and arthropods were the most important items contributing to migratory fish biomass in the oligotrophic Apaporis River floodplains in Colombia, emphasizing the importance of seasonally flooded forests for sustaining fisheries in the Amazon basin (Correa & Winemiller, 2018). Adverse impacts of deforestation on fish species richness, diversity, abundance (Arantes et al, 2018;Freitas et al, 2018), biomass and functional diversity , and on fishery yield of migratory species (Castello et al, 2018) have also been shown.…”

Seasonal hydrology and fish assemblage structure in the floodplain of the lower Amazon River

“…Ropke et al, 2015;Saint-Paul et al, 2000;Sousa & Freitas, 2008), there remains a lack of detailed information on the relationships between functional assemblage structure and hydrological fluctuations, particularly in a large scale. The available information suggests that certain ecological characteristics of fish species facilitate or hinder their resilience under certain hydrological conditions (Freitas et al, 2018;Ropke et al, 2017). For example, an intense drought in a lake in the Central Amazon leads to declines in the abundance of groups of species with equilibrium life history (characterised by low fecundity and parental care) and periodic life history strategists (characterised by high fertility and no parental care).…”

Patterns of Pelagic Fish Diversity in Floodplain Lakes of Whitewater and Blackwater Drainage Systems Within the Central Amazon River Basin of Brazil

“…Components of the floodplain landscape, including terrestrial wetland shrubs that are rooted vegetation and more permanent than floating macrophyte meadows, also have been proposed as important to maintenance of floodplain fish diversity (Freitas et al, 2018). Other studies have demonstrated that the forest cover bordering Amazonian floodplain lakes is a determinant of both the taxonomic and functional diversity of fish assemblages (Arantes et al, 2017(Arantes et al, , 2019, which indicates that the overall floodplain landscape exerts an important influence on fish diversity (Lobón-Cerviá et al, 2015;Freitas et al, 2018). Another factor is connectivity among habitats, which can stabilize regional populations and preserve diversity by inter-habitat migration and metapopulation dynamics (Arrington and Winemiller, 2006;Miyazono et al, 2010;Hurd et al, 2016).…”