Abstract

Amazonian freshwaters host the most diverse ichthyofauna in the world but the ecological mechanisms that generate and regulate this diversity are poorly known. I performed the first comparison of spatial and temporal patterns of fish community diversity among the four primary aquatic habitats of the Amazon (major rivers, floodplains, lowland terra firme streams, and upland shield streams) and among the three distinct chemical water types in Amazon river-floodplain systems (low-nutrient blackwaters and clearwaters, and high-nutrient whitewaters). To minimize confounding influences of geographical variation in species ranges, my study targeted one of the few parts of Amazonia (near Santarém, Brazil) where all four habitats and all three river-floodplain water types occur in close proximity. In the first of three chapters, I compare diversity and biomass between blackwater, clearwater, and whitewater rivers and floodplains. My results provide the first support for positive species-energy and biomass-energy relationships across multiple aquatic habitat types from the same biome and region. In Chapter 2 I compare patterns of temporal beta-diversity, and beta-deviations from null model simulations, to demonstrate that species turnover is positively correlated to seasonality and hydrological connectivity among the four Amazonian habitats types but is uninfluenced by water type. In Chapter 3 I compare up-river transects from the common confluence of a blackwater, Clearwater, and whitewater river to infer that abrupt gradient of water chemistry act as major barriers to fish dispersal. My results have important implications for biodiversity monitoring and conservation planning in the increasingly threatened aquatic habitats of the Amazon basin.

Notes

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Graduation Date

2020

Semester

Summer

Advisor

Crampton, William

Degree

Doctor of Philosophy (Ph.D.)

College

College of Sciences

Department

Biology

Degree Program

Conservation Biology; Integrative Biology

Format

application/pdf

Identifier

CFE0008573

Language

English

Release Date

February 2026

Length of Campus-only Access

5 years

Access Status

Doctoral Dissertation (Campus-only Access)

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