13 Earth Life Sciences across the Cordillera

This session showcases interdisciplinary research that bridges geological sciences with allied fields including (but not limited to) genetics, ecology, biogeography, archaeology, informatics to emphasize innovative approaches to understand the interconnectedness of Earth systems.

Wednesday, 22 April 2026
1:30 PM - 5:30 PM
LMH, Fiesta Terrace Salon

Do life-history traits explain phylogeographic discordance in the Baja California Peninsula?

Paper number: 13-6
Program: Technical Sessions
Time: 3:30 PM – 3:50 PM

Authors

Abstract

Comparative phylogeography has revealed how shared geographic and climatic histories shape genetic structure of co-distributed species. However, phylogeographic discordance is common even among taxa exposed to the same historical events and is often attributed, post hoc, to species-specific life-history differences. In this study, we explicitly assessed the role of life-history traits in generating concordant and discordant phylogeographic patterns using a spatially explicit demogenetic simulation framework.

We simulated 72 virtual species spanning a broad life-history continuum, with variation in vital rates, dispersal capacity, and population size. The species were subjected to two contrasting biogeographic scenarios in the Baja California Peninsula: (1) isolation by distance and (2) a transient vicariant barrier in the mid-peninsula. By tracking the temporal dynamics of genetic differentiation (Fst), we quantified how individual traits influence the accumulation of divergence and the persistence of genetic signatures after barrier removal.

Our results show that dispersal capacity and population size explain most of the variance in genetic differentiation. Population size impacts the divergence accumulation during vicariance and peak differentiation, whereas dispersal governs post-barrier decay rates. Vital rates contribute less, but consistently, to the explained variation. Overall, our findings highlight that phylogeographic discordance emerges from context-dependent and non-additive interactions among traits, with dispersal limitation and demographic constraints outweighing intrinsic life-history syndromes. This work provides a theoretical benchmark for interpreting (dis)concordance in comparative phylogeographic studies.

Geological Society of America Abstracts with Programs. Vol. 58, No. 3

doi: 10.1130/abs/2026CD-410803

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