COMPARATIVE-STUDY OF ESTABLISHMENT OF PLANTAGO-CORONOPUS L FROM SEEDS SOWN RANDOMLY AND IN CLUMPS

This paper reports the results of a study of the establishment of Plantago coronopus L. seeds in the field. Seeds were introduced at a range of densities into plots with intact vegetation, and plots from which the vegetation was removed. Seeds were also sown in a variety of clump sizes on to non‐vegetated plots. The aim of this experiment was to determine whether the density‐dependent germination patterns exhibited by this species in laboratory experiments could also be observed in the field. All treatments exhibited similar patterns of seedling recruitment although different conditions of planting showed quantitatively different responses. During the first 4 weeks after sowing there was rapid seedling recruitment followed by mortality which balanced this recruitment. Eight weeks after sowing, seedling densities were not significantly different from the starting densities in any of the treatments. In particular, the chance of a seed forming an established seedling was not increased when seeds were sown in clumps, thus calling into doubt the ecological benefits of density‐dependent germination responses which have been proposed in previous laboratory studies of the phenomenon. Factors influencing germination and establishment were investigated by means of an autocorrelation matrix. Recruitment of seedlings into the population appears to be limited by the number of adult and seedling plants already present in the population. Copyright © 1979, Wiley Blackwell. All rights reserved