Comparative demography of Plantago. I. Observations on eight populations of Plantago lanceolata

The demography of Plantago lanceolata was studied in eight grassland habitats ranging from open unmanaged vegetations and pasture on dry sandy soil to hayfields with a high and dense vegetation on loam or clay soils. Data on density and survival of juvenile and adult plants and on aspects of natality were collected. The first two axes of a principal component analysis of these data represented 41 % and 25%, respectively, of the total variance. Correlations of the axes with environmental factors of the respective habitats were calculated. The first axis was primarily correlated with light transmission of the vegetation in summer. Thus, survival of juvenile and adult plants during the summer, and in general their density, was highest in open vegetations, while in dense vegetations survival in a severe winter and the number of seeds per plant were higher. Supporting evidence is given for the conclusion that the survival in summer, especially of young and small plants, is positively influenced by this factor. The most important (negative) contribution to the second axis comes from the survival in the second (mild) winter. This axis is significantly correlated with the organic matter and total nitrogen content and moisture content of the soil in winter. This correlation is probably caused by mortality due to water-saturation of the soil. During the period studied no adverse influence of drought in summer was found.