Presenters-0709
From CSDMS
CSDMS 2026: Modeling Landscapes in Motion
Topographic and biological signatures of repeated river captures
Abstract
Drainage divides, the topographic boundaries of river basins, are dynamic landscape features. Asymmetric erosion rates across drainage divides can cause gradual divide migration and occasionally, the flow of water may be redirected towards a neighboring basin in via ‘river capture’. Geomorphologists often use topographic evidence to infer erosional disequilibrium across drainage divides. Similarly, freshwater biologists infer a history of river capture using biological lines of evidence including the presence of disjunct populations of freshwater organisms found on the ‘wrong’ side of the drainage divide and/or phylogenetic relationships that reflect paleo-river networks. Yet, these lines of evidence may be challenging to interpret when there is a history of multiple river capture events in the same basin that each cause transient erosional responses and repeatedly transfer freshwater organisms across the drainage divide. Here, I explore the topographic and biological signatures of repeated river captures using coupled population-genetic simulations and landscape evolution models. I also present an empirical case-study across the Eastern Continental Divide, USA. Population genetic analysis of the Saffron Shiner (Hydrophlox rubricoceus) and topographic evidence (knickpoints and windgaps) suggest that the Linville River (Atlantic-draining) has repeatedly captured area from the upper tributaries of the Tennessee River (Gulf-draining). The results highlight the challenges and promise of integrating biological and geologic datasets to investigate the history of river network reorganization.
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