Data from: Tree, sex and size: ecological determinants of male versus female fecundity in three Fagus sylvatica stands

Inter-individual variation in fecundities has major consequences on
population evolutionary potential, through genetic drift and selection.
Using two spatially explicit mating models that analyze the genotypes of
seeds and seedlings, we investigated the variation of male and female
fecundities within and among three European beech (Fagus sylvatica) stands
situated along an elevational gradient. Female and male individual
fecundity distributions were both skewed in this monoecious species, and
we found a higher variance in female as compared to male fecundities. Both
female and male fecundities increased with tree size and decreased with
density and competition in the neighborhood, the details of these effects
suggesting sex-specific strategies to deal with the impact of limited
resource on fecundity. The studied populations were functionally
male-biased. Among-individual variations in functional gender were not
driven by tree size but by density and competition in the neighborhood,
consistently with the expectation of a decreasing femaleness under limited
resource availability due to higher cost of female reproduction.
Considering the variation of gene flow and genetic drift across elevation,
our results suggest that the adaptive potential could be enhanced by low
genetic drift at low elevation, and by high pollen-mediated gene flow at
high elevation. Finally, this study predicts a more efficient response to
selection for traits related to male versus female fitness, for a given
selection intensity.