spatial variation in the seed ecology of a woodland herb (primula vulgaris) in relation to light environment

Abstract

1. Patches of Primula vulgaris occur across a range of light conditions within forests. To understand how light affects the stages of the life cycle involved in reproduction and recruitment, several fecundity-related variables (flower and capsule production, seed set, seed germination and seedling establishment) were studied in eight populations across a range of light conditions. 2. The mean number of seeds per plant varied greatly, from seven to 136, and the percentage of seedling establishment varied from 0.4 to 17.2%. These variables, as well as the number of flowers per plant and fecundity, were positively correlated with the light conditions. 3. Primula vulgaris populations establish in newly opened gaps. How this species colonizes new clearings was investigated by looking at seed survival in the soil and seed removal by potential dispersers, in particular rodents and ants. 4. After 14 months in the greenhouse, only three P. vulgaris seedlings were observed germinating from 200 soil samples taken from two populations. Germination of retrieved seeds from buried samples was generally lower than 10%. This suggests that only a small number of seeds remain viable in the soil for long periods of time. 5. Seed removal was high in the populations studied (more than 70% in 10 days). Rodents harvested a greater proportion of seeds than ants. Seed dispersal by ants is known to occur within short distances but rodents may be long-distance dispersers, which may be important for the long-term persistence of P. vulgaris in a site because it allows seeds to reach newly opened gaps.