SHOOT AND LEAF DEMOGRAPHY OF CAREX-CURVULA SSP CURVULA AND CAREX-CURVULA SSP ROSAE IN THE CENTRAL ALPS

Populations of Catex curvula ssp. curvula, C. curvula ssp. rosae and t heir intermediate form were investigated in the Central Alps over a th ree-year period. The closely related taxa showed a different dominance behaviour in their respective communities. This may be caused by diff erent growth strategies and a different reproduction biology. There fo re, the main aim of the study was to compare the demography of the thr ee taxa. Shoot and leaf turnover, flower and seed production and popul ation half-lives were determined. Differences in growth dynamics were less pronounced between the two species of Carer curvula than between these taxa and their intermediate form which showed the highest shoot turnover, highest number of fertile inflorescences and highest number of seeds per inflorescence. Car ex curvula ssp. rosae showed a slightl y higher shoot and leaf production but a lower reproduction capacity t han Carer curvula ssp. curvula. Recruitment of populations of the thre e Carer-forms was only by vegetative shoots. Flowering had a striking effect on the shoot dynamics of the species grown in the grassland sit es: up to about 70% of all dead shoots could be identified as dead flo wering shoots from the previous year. The different dominance behaviou r of the three taxa could not be explained by their demographical feat ures. Interspecific interactions and the occurrence of microniches mig ht affect the growth and reproduction processes of the taxa.