EFFECTS OF DENSITY AND WEATHER ON TILLER DYNAMICS IN AGROSTIS-STOLONIFERA, FESTUCA-RUBRA AND POA-IRRIGATA

Tiller populations of three grass species, Agrostis stolonifera, Festuca rubra and Poa irrigata (= Poa pratensis ssp. irrigata), were studied for 5 years on a Baltic seashore meadow in Sweden. No significant relationships were found between the death rate of tillers and tiller density in any of the species. The birth rate of F. rubra tillers was negatively related to their density. An increase in death rate of F. rubra tillers lead to an increase in their birth rate. The frequency of flowering in F. rubra was negatively related to its density. Negative relationships were found between spring temperature and the death rates of F. rubra and P. irrigata tillers. The birth rates of tillers of all species were positively related to summer precipitation.