Research has conclusively demonstrated the potential for dispersal
evolution in range expansions and shifts through a process termed
spatial sorting. However, the degree of dispersal evolution observed has
varied substantially among organisms. Further, it is unknown how the
factors influencing dispersal evolution might impact other ecological
processes at play. We use an individual-based model to investigate the
effects of the underlying genetics of dispersal and mode of reproduction
in range expansions and shifts. Spatial sorting behaves similarly to
natural selection in that dispersal evolution increases with sexual
selection and loci number. Contrary to our predictions, however,
increased dispersal does not always improve a population's ability to
track changing conditions. The mate finding Allee effect inherent to
sexual reproduction increases extinction risk during range shifts,
counteracting the beneficial effect of increased dispersal evolution.
Our results demonstrate the importance of considering both ecological
and evolutionary processes for understanding range expansions and
shifts.