Fish Species Composition Reflects Geomorphology in the Western Amazon, the Earth's Vertebrate Biodiversity Hotspot
ORCID
Bogotá-Gregory: https://orcid.org/0000-0001-9732-4703; DoNascimiento: https://orcid.org/0000-0002-8680-7942; Lima: https://orcid.org/0000-0001-8680-2669; Correa: https://orcid.org/0000-0003-4466-6923; Ohyama: https://orcid.org/0000-0002-1874-2972; Acosta-Santos: https://orcid.org/0000-0003-2927-9298; Córdoba : https://orcid.org/0000-0001-9318-2568; Jenkins: https://orcid.org/0000-0002-0363-2260; Albert: https://orcid.org/0000-0001-5477-1749
MSU Affiliation
College of Forest Resources; Department of Wildlife, Fisheries and Aquaculture
Creation Date
2026-03-30
Abstract
Fishes of the Western Amazon exhibit the greatest diversity of any continental vertebrate fauna on Earth. Hypotheses to explain diversity patterns have focused on various ecological and evolutionary processes, yet we have historically lacked detailed knowledge of species’ geographic distributions and habitat tolerances to test these alternative hypotheses. We compare spatial patterns in newly-compiled high-resolution fish distributions from the Colombian Amazon with those of eight geomorphologically-defined ecosystems: Andean rivers and streams, foothill alluvial rivers, major low-gradient rivers, lowland rapids, lowland floodplains, lowland small rivers and “terra firme” streams, and high-gradient shield streams. An incidence matrix containing 905 native species, based on ~16,000 museum records, was subjected to multivariate analyses (hierarchical clustering on principal components and PERMANOVA) to assess the association between species composition and geomorphology. We used variation partitioning and differences in species composition due to adjacency between ecosystems to determine spatial autocorrelation. We followed a network approach to identify ecological specializations. Our analysis found evidence of spatial autocorrelation, supports two major species assemblages in Andean and lowland settings, and four major habitat clusters: Andean systems (rivers, streams, and foothills), lowland systems (major rivers, floodplains, and small rivers and streams), rapids, and shield streams. Network analysis detected significant modularity, indicating species geomorphological specialization. We provide the first study of fish distributions in the Western Amazon using geomorphologically-defined habitat categories, finding that local fish assemblages are not randomly selected from the regional fauna. Instead, species show significant habitat specialization according to geomorphology, which might act as an environmental filter according to species phenotype.
Publication Date
1-13-2026
Publication Title
Frontiers of Biogeography
Publisher
Pensoft Publishers
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Recommended Citation
Bogotá-Gregory JD, DoNascimiento C, Lima FCT, Correa SB, Ohyama L, Acosta-Santos A, Agudelo Córdoba E, Jenkins DG, Albert JS (2026) Fish species composition reflects geomorphology in the Western Amazon, the Earth's vertebrate biodiversity hotspot. Frontiers of Biogeography 19: e173249. https://doi.org/10.21425/fob.19.173249
