Investigations of the seasonal changes in vegetation standing crop have enabled an assessment of annual net primary production (ANP) at a fjaeldmark, open fernbrake and closed fernbrake at Marion Island (46 °54'S, 37 °45'E). These communities represent a successional sequence on relatively dry ridges and slopes on the island. Together, they are representative of a large proportion of the island's lowland (c. 300 m above sea level) vegetation. Aboveground ANP's were 728 g m -2 y-1 at closed fernbrake, 502 g m -2 y-1 at open fernbrake and 226g m -2 y-1 at fjaeldmark. Total (above-plus below) ANP's were 1958gm 2 y 1 , 1578gm 2 y 1 and 685 g m -2y-1 , respectively. These values are greater than those found for most tundra and tundra-like shrub and dwarf shrub-dominated communities of the northern hemisphere. The island's oceanic climate ensures a long growing season (c. 300 days for vascular plants, 365 days for bryophytes) and aboveground productivities for the island communities (including two mire-grasslands reported on previously), based on the length of the growing season, were 0.9 to 2.9g m 2 d l , lower than for most comparable shrub and dwarf shrub sub-Arctic or alpine communities and more similar to low Artic and low alpine sedge-moss and grass-herb communities. Production efficiencies (0.7°7o to 2.1°70 of photosynthetically active radiation) were in the range reported for northern hemisphere subpolar vegetations.