title: Life history mediates mate limitation and population viability in self-incompatible plant species.
abstract: Genetically controlled self-incompatibility systems represent links between genetic diversity and plant demography with the potential to directly impact on population dynamics. We use an individual-based spatial simulation to investigate the demographic and genetic consequences of different self-incompatibility systems for plants that vary in reproductive capacity and lifespan. The results support the idea that, in the absence of inbreeding effects, populations of self-incompatible species will often be smaller and less viable than self-compatible species, particularly for shorter-lived organisms or where potential fecundity is low. At high ovule production and low mortality, self-incompatible and self-compatible species are demographically similar, thus self-incompatibility does not automatically lead to reduced mate availability or population viability. Overall, sporophytic codominant self-incompatibility was more limiting than gametophytic or sporophytic dominant systems, which generally behaved in a similar fashion. Under a narrow range of conditions, the sporophytic dominant system maintained marginally greater mate availability owing to the production of S locus homozygotes. While self-incompatibility reduces population size and persistence for a broad range of conditions, the actual number of S alleles, beyond that required for reproduction, is important for only a subset of life histories. For these situations, results suggest that addition of new S alleles may result in significant demographic rescue.
authors.affiliation: CSIRO Plant Industry GPO Box 1600, Canberra, Australian Capital Territory, 2601, Australia.
authors.forename: Peter H
authors.initials: PH
authors.lastname: Thrall
authors.affiliation: CSIRO Plant Industry GPO Box 1600, Canberra, Australian Capital Territory, 2601, Australia.
authors.forename: Francisco
authors.initials: F
authors.lastname: Encinas-Viso
authors.affiliation: Department of Botany, La Trobe University Bundoora, Victoria, 3086, Australia.
authors.forename: Susan E
authors.initials: SE
authors.lastname: Hoebee
authors.affiliation: CSIRO Plant Industry GPO Box 1600, Canberra, Australian Capital Territory, 2601, Australia.
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Young
keywords: Conservation; S alleles; demographic rescue; gametophytic; inbreeding; mate availability; mating system; simulation model; sporophytic