Modern pollen rain and Aranuian vegetation from Lady Lake, north Westland, New Zealand

Abstract

The results of pollen analysis of six moss cushions and nine lake sediment samples are presented. Pollen derived from locally growing tree taxa are the major components of modem pollen spectra analysed from the lake. Most pollen types are well represented with the exception of Weinmannia, Dacrycarpus, and Cyperceae which are under-represented and Cyathea which is over-represented. These observations confirm earlier work on pollen representation although over-representation of Cyathea is thought to result from in wash of spores from the soil and exposed stream banks. Pollen percentages of most taxa in the lake sediments are fairly constant over the entire lake basin and attributable to redeposition. Redeposition cannot account for Quintinia pollen which increases in proportion with depth and Dacrydium cupressinum which varies unsystematically throughout the samples. Nearshore sediments are enriched with Podocarpus ferrugineus pollen due to differential pollen flotation. Past pollen floras indicate that vegetation similar to that of the present day existed at Lady Lake about 5700 radiocarbon years ago. Changes are noted but most are thought to be localised and due in part to variations in the character of the lake.