abstract
Seasonal changes in concentrations of N, K, Ca, Mg and Na in the plants at a fjaeldmark and two fernbrake communities in sub-Antarctic Marion Island (47°S, 38°E) are described. In general N, P and K concentration in the aboveground biomass decreased, and those of Ca (sometimes also Mg) increased as the season progressed. Exceptions to this pattern are discussed. Seasonal changes in nutrient concentration in reproductive organs, roots, rhizomes and in the aboveground necromass (dead plant material) differed between species. N, P and K concentrations in living leaves of dicotyledonous species (and of the fern Blechnum penna-marina, which at the island behaves ecologically like a dwarf shrub) are similar to those for dwarf-shrubs and shrubs at northern hemisphere tundra and tundra-like communities; in many instances the K concentrations are higher than for tundra species. Mg and Na levels in the island dicots are greater than those generally reported for tundra plants. Ca concentrations in all the island species considered in this study are markedly lower than for plants from tundra and tundra-like areas. There were no conspicuous seasonal variations in soil nutrient levels at the three island communities.
