A vegetation history from north-east Nelson, New Zealand

Abstract

Abstract A pollen analysis and three radiocarbon dates are reported from Dew Lakes in northern South Island, New Zealand. The results show that a mixed Nothofagus-podocarp forest has existed in the area for the last 10 500 yr B.P. The major change in forest taxa has been a continuing rise in Nothofagus which probably began before 10 500 yr B.P. and peaked at c. 4 800 yr B.P. Podocarpus ferrugineus and Dacrydium cupressinum were present in relatively constant amounts but the Nothofagus rise was accompanied by a decrease in other Podocarpus spp. and shrub taxa. A second major change was a clearance phase and the appearance of Pinus pollen coincident with the arrival of European man. Changes in local taxa show that initially a shallow swamp existed at the site but this became a lake between 8 500 yr B.P. and 100 yr B.P., suggesting a wetter climate since 8 500 yr B.P. than earher. The end of this phase is not clearly represented, because succession in the swamp has led to natural shallowing of the water as evidenced by a return of shallow swamp taxa and shrubs on the peat. The results are discussed in relation to other published pollen diagrams from New Zealand and it is noted that the results fit better with diagrams from the Ruahine Range in southern North Island than with results from South Island sites.