Population dynamics of Euphrasia pseudokerneri, Gentianella amarella and Linum carthartlcum in an English chalk grassland community
- R. D. Papaiti, Aramoho, Wanganui, New Zealand
[Abstract of a paper read at the Ecological Society Conference, 1983.]
Over three years, the population dynamics of one annual hemiparasite (Eupharasia pseudokerneri) and two strict biennials (Gentianella amarella and Linum cartharticum) were studied in a natural English chalk grassland community. Euphrasia numbers declined in that time, while the other species' numbers fluctuated. All three species' survival was affected by the perennial species which formed the turf. Euphrasia and Linum were affected by the drought, but only Linum was affected by mollusc grazing. Density-dependent mortality was observed in two years out of three in Linum, one year of three in Euphrasia, and not observed in Gentianella. There was no measurable interference between the short-lived species at field densities.