ION-RICH PRECIPITATION AND VEGETATION PATTERN ON SUB-ANTARCTIC CAMPBELL ISLAND

Campbell Island, situated in the middle of the belt of southern ocean gales, experiences a mean windspeed above that at which sea spray form s. Ionic concentration and related parameters were measured in precipi tation collected throughout a year along a transect of rain gauges ext ending inland from the windward. westerly coast and up to the highest point on the island (558 m). Concentrations decreased logarithmically away from the coast and varied between seasons. Seasonal variation was correlated with the frequency of gales. The calculated annual input o f ions ranged from 2507 kg ha-1 yr-1 Na at 50 m from the windward coas t to 187 kg ha-1 yr-1 Na at 5500 m from the windward coast. The high v alues are related to the exposure of the collection points and to the latitude, and hence climate, of Campbell Island. Marked spatial variat ions in ionic input have a controlling influence on floristic structur e and productivity patterns of subantarctic vegetation. This is consis tent with the dominance of the maritime factor in explaining the prima ry axes of vegetation ordination.