Using Pollen Records from New Zealand and Southern Chile to Reconstruct New Zealand Climate Variability over the Last 14,000 years

• Main Author: Jara Parra, Ignacio Alonso
• Format: Thesis
• Language: unknown
• Published: 2016
• Subjects: Physical Geography and Environmental Geoscience not elsewhere classified; Climate; Vegetation; New Zealand; School: School of Geography; Environment and Earth Sciences; 040699 Physical Geography and Environmental Geoscience not elsewhere classified; 970104 Expanding Knowledge in the Earth Sciences; Marsden: 269901 Physical Geography; Degree Discipline: Physical Geography; Degree Level: Doctoral; Degree Name: Doctor of Philosophy; Antarctic; Patagonia; Marsden; Alpine Lake; Antarc*
• Online Access: https://doi.org/10.26686/wgtn.17019902.v1; https://figshare.com/articles/thesis/Using_Pollen_Records_from_New_Zealand_and_Southern_Chile_to_Reconstruct_New_Zealand_Climate_Variability_over_the_Last_14_000_years/17019902

Climate variability in New Zealand (34-47°S), a long, narrow continental strip straddling the mid-latitudes of the Southern Hemisphere, results largely from the interplay between sub-tropical and sub-Antarctic atmospheric and oceanic circulation systems. Despite their importance to present-day New Zealand climate, these hemispheric-wide systems have only recently come under the spotlight of paleo-climate investigations with most attention having traditionally been centred on reconstructing climate trends. This PhD adopts a broader approach to climate reconstruction, by developing and comparing two new pollen-climate reconstructions from New Zealand (38-42°S) and one from Patagonia, Southern Chile (43°S). At each site, paleo-climate interpretations are based on the changes in climate-sensitive plant indicators. The influence of hemispheric atmospheric circulation on New Zealand climate history is assessed by: (1) comparing New Zealand climate/vegetation trends with published proxies from low- and high-latitudes, and (2) comparing New Zealand reconstructions with the Patagonian record. Finally, a multi-millennial pattern of Southern Hemisphere circulation over the last 14,000 cal yr BP (calendar years before AD 1950) is outlined. The first record presented is a 16,000-year temperature reconstruction from a small alpine lake in South Island, New Zealand (41°S), based on pollen and plant macrofossils. Climate variations are interpreted from the relative abundance of lowland and highland vegetation. The results include a lifting of the altitudinal forest limits attributed to warming pulses between 13,000-10,000 cal yr BP and between 7000-6000 cal yr BP, and a decline of lowland relative to upland forest taxa interpreted as cooling trends between 10,000-7000 cal yr BP and over the last 3000 years. The second record gives 15,000-year temperature and precipitation reconstructions from a peatbog in northern New Zealand (38°S), based on pollen and charcoal analysis. Temperature changes are assessed based on two quantitate ...