Density-dependence in Salvia lyrata, a herbaceous perennial: the effects of experimental alteration of seed densities.

Number of seedlings establishing varied widely from year to year. The half-life of the seedling population was c10 months and seedling mortality rate declined with time. Correlation of seedling mortality with population density was low. Established individuals significantly reduced the proportion of seedlings emerging and surviving. Seed density had no demonstrable effect on the proportion of seedlings emerging over a range of densities (0-1440 seeds dm^-2). Seedling mortality depended strongly on seed and seedling density. Seedling growth was negatively density-dependent. Regulation of numbers of seedlings occurs primarily through the negative effects of adults. -from Authors