VASCULAR PLANTS AS BIOINDICATORS OF REGIONAL WARMING IN ANTARCTICA

Monitoring selected populations of the only two native Antarctic vascu lar plant species (Colobanthus quitensis and Deschampsia antarctica) o ver a 27-year period has revealed a significant and relatively rapid i ncrease in numbers of individuals and populations at two widely separa ted localities in the maritime Antarctic. There is strong evidence tha t this increase is a response to a warming trend in summer air tempera tures, which has been evident throughout the region since the late 194 0s, enhancing seed maturation, germination and seedling survival. This study provides the only known long term monitoring data for any terre strial organisms in Antarc-tica. Because their response to amelioratin g conditions is more rapid than that of the dominant crypt ogamic grou ps, Antarctic phanerogams may be useful bioindicators of climate chang e in West Antarctica.