A high resolution 15,600-year pollen and microcharcoal record from the Cederberg Mountains, South Africa

Verushka Valsecchi*, Brian M. Chase, Jasper A. Slingsby, Andrew S. Carr, Lynne J. Quick, Michael E. Meadows, Rachid Cheddadi, Paula J. Reimer

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

38 Citations (Scopus)

Abstract

The Cederberg Mountains (Western Cape Province, South Africa) are located within the Fynbos Biome, which exhibits some of the highest levels of species richness and endemism in the world. The region's post-glacial vegetation history, however, remains largely unknown. Presented here are high resolution pollen and microcharcoal records spanning the last 15,600 years obtained from the De Rif rock hyrax midden from the Driehoek Valley of the central Cederberg. In this region, previous pollen studies have shown muted variability in vegetation community composition during periods of globally marked climatic variability (e.g. the last glacial-interglacial transition). In our record, however, significant changes in vegetation composition are apparent. Most notably, they indicate a shift from ericaceous/restioid fynbos (present from 15,600 to 13,300 cal yr BP) to a brief, but prominent, development of proteoid fynbos at the beginning of the Holocene around 11,200 cal yr BP. This vegetation shift is associated with increased moisture at the site, and coincides with reduced fire frequency as indicated by the microcharcoal record. At 10,400 cal yr BP, there is a marked reduction in Protea-type pollen, which is replaced by thicket, characterised by Dodonaea, which became the dominant arboreal pollen type. This shift was likely the result of a long relatively fire-free period coupled with warmer and wetter climates spanning much of the early Holocene. A brief but marked decrease in water availability around 8500-8000 cal yr BP resulted in the strong decrease of Dodonaea pollen. The vegetation of the mid- to late Holocene is characterised by the increased occurrence of Asteraceae and succulent taxa, suggesting substantially drier conditions. These data give unprecedented insight into the vegetation dynamics across a period of substantial, rapid climate change, and while they confirm the presence of fynbos elements throughout the last 15,600 years, the results highlight significant fluctuations in the vegetation that were triggered by changes in both climate and fire regimes. (C) 2013 Elsevier B.V. All rights reserved.

Original languageEnglish
Pages (from-to)6-16
JournalPalaeogeography, Palaeoclimatology, Palaeoecology
Volume387
Early online date15 Jul 2013
DOIs
Publication statusPublished - 01 Oct 2013

Keywords

  • Pollen
  • Microcharcoal
  • Rock hyrax middens
  • Late Quaternary
  • Fynbos Biome
  • South Africa
  • RADIOCARBON AGE CALIBRATION
  • FECAL DEPOSITS HYRACEUM
  • CAPE FLORISTIC REGION
  • WINTER RAINFALL ZONE
  • CAL KYR BP
  • VEGETATION HISTORY
  • WESTERN-CAPE
  • FIRE MANAGEMENT
  • HYRAX MIDDENS
  • FYNBOS BIOME

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