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Data from: Human occupation and ecosystem change on Upolu (Samoa) during the Holocene

Citation

Gosling, William et al. (2020), Data from: Human occupation and ecosystem change on Upolu (Samoa) during the Holocene, Dryad, Dataset, https://doi.org/10.5061/dryad.51c59zw4j

Abstract

Aim

To track the peopling of the South Pacific and assess their impact on terrestrial and aquatic ecosystems.

Location

Upolu, Samoa.

Taxon

Ancient charcoal, pollen, sprores, algae and cyanobacteria types are recorded.

Methods

A sedimentary record covering the last c. 10,500 years was recovered from the volcanic crater that contains Lake Lanoto'o near the centre of Upolu Island. Information on past ecological change was obtained from microscopic and macroscopic remains extracted from the sediments: charcoal (fire history), pollen/spores and plant remains (vegetation history), and lake status (algae/cyanobacteria). Information on the depositional environment and climate was obtained from geochemical and sedimentary analysis: loss‐on‐ignition (sediment composition), cryptotephras (volcanic eruptions) and precipitation regime (Ti/inc). The environmental history developed was compared with the archaeological record from the region.

Results

Charcoal material was found in the Lake Lanoto'o sediments at higher abundances and more frequently in samples from the period after the first archaeological evidence of people on Upolu (c. 2900–2700 years ago). No abrupt shift is recognized in the vegetation or aquatic ecosystem assemblages coincident with the arrival of people on the island.

Main conclusions

Macrocharcoal is demonstrated to be an effective proxy for detecting human occupation of Upolu around 2,800 years ago. The immediate impact of these settlers on the vegetation seems to have been minimal; however, a subsequent opening up of the landscape is suggested through the gradual increase in ferns. The absence of any significant change in the aquatic community associated with, or after, the arrival of people on the islands suggests that humans rarely visited the lake. We suggest that on Upolu a simple model of decreasing human impact away from coastal areas is applicable.

Methods

The timing and ecological impact of the peopling of the South Pacific island of Upolu (Samoa) was explored through a multi-proxy palaeoecological investigation of sediments obatined from Lake Lanoto'o. Charcoal, pollen, spores, plant remains, algae and cyanobacteria we analysed from a sediment record spanning c. 10,500 years. These data are presented here and were used in the associated manuscript to reconstruct the fire, vegetation and lake history on Upolu. We intepret these data as indicating that macrocharcoal is an effective proxy for detecting human occupation, that initial human populations had a minimal impact on the islands ecosystems, and that human impacts decreased with increasing distance from the coast.

Usage Notes

All data related to the palaeoecological investigation of Lake Lanoto'o (Upolu, Samoa) is provided in .xls and .c2 format. The data contained within the two files is identical, however, the .c2 file loads directly into the stratigraphic plotting program C2 (https://www.staff.ncl.ac.uk/stephen.juggins/software/C2Home.htm) and contains the interactive versions of the figures presented in the associated manuscript.

The datasets within the .xls file are organised into tabs based on the data type:

  • Metadata - manuscript title, authors, and data location
  • Lead210Dates - link to reference containing Lead210 chronological control data
  • RadiocarbonDates - list of radiocarbon dates obtained from the study site
  • Chronology - details of how the relationship between the depth and age of sediments was established
  • TOC+CN - Total Organic Carbon and Carbon/Nitrogen datasets
  • Magnetic - Magnetic susceptibility data
  • Ti - Titanium data
  • Microcharcoal - Charcoal fragments < 160 microns (identified on pollen slides)
  • Macrocharcoal - Charcoal fragments > 160 microns
  • PollenCounts - Pollen and spore data
  • PollenPercentages - Pollen and spore data converted to percentage abundance relative to the terrestrial pollen sum
  • MacroscopicRemains - Seed and fern sporangia data (identified in macrocharcoal samples)
  • AlgalCounts - Algal and cyanobacterial data (identified on pollen slides)
  • AlgalPercentage - Algal and cyanobacterial data converted to percentage abundance relative to the total abundance of algae and cyanobacteria

Funding

NERC Radiocarbon Facility, Award: NRCF010001, 2004.0416, 1799.0414, 1900.0415

Quaternary Research Association

Explorers Club Exploration Fund Grant

Gilchrist Expedition Grant

Royal Geographical Society (with IBG) Monica Cole Grant