Plant density effects on genetic variation and dispersal for two co-occurring Persoonia species

[Truncated abstract] Genetic variation is spatially structured at different scales, such as population, subpopulation or among neighbouring individuals. This spatial genetic structure is typically a product of environmental influences and ecological factors affecting reproduction and dispersal are likely to be particularly important in determining genetic structure. Consequently, information about ecological factors such as plant density, pollen dispersal and seed dispersal represent important processes for conservation managers. In this thesis, molecular markers are applied to better understand patterns and processes effecting genetic variation in two co-occurring tree congeners, chosen because they have densities that are typically three orders of magnitude different, yet near identical life-history parameters. Persoonia longifolia occurs in the southwest jarrah (Eucalyptus marginata) forest of Western Australia in relatively high densities, while P. elliptica occurs largely at very low densities.

To develop molecular markers for these two broadly distributed tree species, microsatellite markers developed for the southeast Australian P. mollis were initially screened for amplification in individuals of both P. elliptica and P. longifolia. This cross amplification of primers was unsuccessful for both study species. Therefore, microsatellite enriched libraries and 454 GS-FLX shotgun sequencing were employed to identify nine microsatellite loci for P. elliptica (one 454; eight cloning) and six loci for P. longifolia (three 454; three cloning). The microsatellites identified in this study enabled the examination of spatial structuring of genetic diversity and pollen and seed dispersal characteristics in P. elliptica and P. longifolia.