Holocene pollen stratigraphy and sedimentation, Wellington Harbour, New Zealand

Abstract

Pollen and spore spectra obtained from within, and around, Wellington Harbour provide a record of climate and land‐use change from early Holocene to the present day. Samples of four cores from Wellington Harbour show that Nothofagus group pollen has increased six‐fold relative to Dacrydium cupressinum since c. 10 000 years ago.

From A.D. 1840 there is evidence of land clearance and the introduction of exotic species by European settlers. Historical records show that 80–90?% of the native forest was replaced with grassland between A.D. 1840 and 1900, a far greater land‐use change than that indicated by the pollen record.

Palynomorphs from the modern harbour floor contain assemblages similar to those obtained from contemporary forested terrestrial sites. Both are dominated by Nothofagus group, Dacrydium cupressinum pollen, and fern spores. In contrast, assemblages from non‐forested areas are dominated by the local pollen source and contain considerable grass and shrub spores. There is a uniform, mixed nature to the palynomorph spectra in Wellington Harbour. It is concluded that almost all pollen entering Wellington Harbour does so via the Hutt River from reworked forested parts of the upper river catchment.

Keywords:

• Wellington Harbour
• palynology
• Holocene
• climate
• land‐use change
• palynomorph sources
• Nothofagus group
• Dacrydium cupressinum; Hutt River