The demography of Lychnis alpina L. on the Meikle Kilrannoch ultramafic site

Summary

The demography of Lychnis alpina L. on skeletal soil at the Meikle Kilrannoch (MK1) ultramafic outcrop was studied from 1991–1993. Estimates were made of seed production and the size of the seed bank at different times. The germination of seeds was investigated in a laboratory experiment. Seedling survival, numbers and sizes of rosettes per genet, flowering, and herbivory at flowering were recorded in permanent quadrats in the field. High rates of herbivory occurred at flowering and the soil seed bank was found to be small. There were differences in the annual rate of increase of the population in two areas of the outcrop; λ = 1.58 on a deeper soil, indicating an increasing population and λ = 1.05 indicating a stable population on shallow soil over outcropping bedrock. The high survival of the original cohort after two years (0.8) suggests that it is the longevity of established plants rather than enhanced recruitment that is responsible for the increase of the deeper-soil population.