Menu

Javascript is not activated in your browser. This website needs javascript activated to work properly.
You are here

Postglacial evolution and spatial differentiation of seasonal temperate rainforest in western Canada

Author:
  • K. J. Brown
  • Anne Birgitte Nielsen
  • R. J. Fitton
  • R. J. Hebda
Publishing year: 2008
Language: English
Pages: 715-727
Publication/Series: The Holocene
Volume: 18
Issue: 5
Document type: Journal article
Publisher: SAGE Publications
Additional info: The uploaded file is a preprint. The final version is available from the journal, but requires subscription.

Abstract english

Surface samples from Vancouver Island, Canada, were used to assess the relationship between discrete seasonal temperate rainforest (STR) plant communities and their corresponding pollen signatures. Pollen from ten sediment cores was further used to evaluate the postglacial development of these communities. Principal components analysis (PCA) of the surface data revealed the distinctiveness of the modern pollen rain, with samples from the Coastal Douglas Fir (CDF) zone, the dry Coastal Western Hemlock (CWH) zone, the wet CWH subzones and the Mountain Hemlock (MH) zone clustering distinctly. PCA of the fossil data revealed early-seral open canopy, wet rainforest, subalpine rainforest and Lateglacial plant associations and showed that the STR has changed markedly through time. Pinus woodlands with low palynological richness prevailed in the early Lateglacial period, only to be supplanted by mixed conifer forest with increased pollen richness. In the early Holocene, STR vegetation differentiated spatially as early-seral open canopy forests expanded, though a non-analogue Picea-dominated forest persisted on the moist outer coast. Generally high pollen richness is attributed to the expansion of dryland habitat coupled with the development of a fire-maintained vegetation mosaic. In the mid- and late-Holocene intervals, open canopy communities persisted in eastern areas, eventually developing into modern CDF and dry CWH forest. In contrast, moist and oceanic CWH rainforest developed on central and western Vancouver Island, whereas subalpine forest established at high elevation. Pollen richness declined in the mid Holocene concomitant with increased precipitation and a general reduction in the incidence of fire, though this trend was offset somewhat in the late Holocene by paludification.

Keywords

  • Geology
  • vegetation history
  • pollen analysis
  • temperate rainforest
  • surface samples
  • Holocene
  • British Columbia
  • Canada

Other

Published
  • ISSN: 0959-6836
Anne Birgitte Nielsen
E-mail: anne_birgitte [dot] nielsen [at] geol [dot] lu [dot] se

Senior lecturer

Quaternary Sciences

+46 46 222 39 48

315

Sölvegatan 12, Lund

16

Department of Physical Geography and Ecosystem Science
Lund University
Sölvegatan 12
S-223 62 Lund
Sweden

Processing of personal data

Accessibility statement