Population dynamics in hybridizing invasive blue mussels (Mytilus spp.) in British Columbia and the Atlantic provinces.

摘要

The Mytilus species complex provides a naturally occurring opportunity to investigate hybrid zone dynamics. The purpose of this thesis was to evaluate mechanisms contributing to hybrid zone stability, and factors responsible for the maintenance of genetic integrity among sympatric populations. First, variable hybrid fitness was found on Vancouver Island (VI), BC, which suggested that the hybrid distribution should expand north. However, hybrids have remained restricted to the south region of VI for over ten years, suggesting barriers to gene flow. A second study confirms the stable southern distribution but temporally variable abundance of non-native genotypes on VI, identifying oceanographic factors and marine landscape as contributing barriers to gene flow. A third study provides a contrasting view of hybrid zone dynamics. In the Atlantic Provinces low levels of hybridization demonstrate that barriers to gene flow are not related to dispersal limitation but rather, result from selection against hybridization.