Dr. Helen Willemien Dow (maiden name: Beeson)

Watch my Landscapes Live talk on this here.

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Landscapes and their associated ecosystems coevolve over geologic time. Correlative approaches have elucidated the importance of topographic diversity and tectonic history but have not identified specific causal links between tectono-geomorphic processes and biodiversity metrics. To address this issue, we coupled the numerical landscape evolution model DAC (Divide and Capture) with a mechanistic 'SEED' model for biodiversity that simulates speciation, evolution, extinction, and dispersal to develop hypothetical biological signatures of different functional groups (aquatic and terrestrial) to a variety of landscape histories. Specifically, we test how horizontal advection characteristic of mountain ranges formed as orogenic wedges influences the spatial and temporal patterns of species richness and species’ range sizes for both aquatic and terrestrial organisms. We find that horizontal advection promotes ongoing reorganization of the drainage network with stream capture occurring from small basins to large basins on the pro-wedge side of the orogenic wedge and from pro-wedge to retro-wedge basins. Advection promotes movement of terrestrial species up the pro-wedge side of the mountain range toward the main divide, and river captures promote geographic transfer of both terrestrial and aquatic species from the pro-wedge side of the mountain range to the retro-wedge side. These processes leave distinct biological signatures in diversification rates and species richness.