Modem pollen spectra from west central British Columbia

Abstract

Sixty-four moss and organic litter samples were collected from five biogeoclimatic zones distributed from sea level on the central coast of British Columbia onto the western edge of the Interior Plateau at 1000 – 1900 m and analyzed for pollen and spores. Four of the five biogeoclimatic zones produced characteristic pollen and spore spectra. The coastal western hemlock biogeoclimatic zone is characterized by Tsuga heterophylla, Alnus, and Cupressaceae. Significant levels of nonarboreal pollen (NAP), mainly Lysichiton and fern spores, occur in some sites. Interior Douglas-fir zone samples are dominated by Pseudotsuga and Tsuga heterophylla with notable Betula, Cupressaceae, and Alnus. Pinus pollen becomes the dominant type at the eastern margins of the interior Douglas-fir zone and dominates the Engelmann spruce – subalpine fir, montane spruce, and sub-boreal pine–spruce biogeoclimatic zones at high and intermediate elevations to the east. In the Engelmann spruce – subalpine fir zone, Abies pollen is characteristically more abundant than Picea, and notable percentages of NAP, especially Artemisia, occur. In the transition from Engelmann spruce – subalpine fir zone to montane spruce zone, Abies and Picea percentages are about equal or Picea predominates slightly, whereas in the montane spruce zone and sub-boreal pine spruce zones, Picea values exceed Abies values often four to five times. Percent pollen and spore versus percent taxon cover diagrams, despite widely spread values, reveal general relationships and background pollen rain values for major taxa valuable to the interpretation of fossil pollen assemblages. Pinus is greatly overrepresented with a regional background of 10–15%. At low to intermediate cover values, Tsuga heterophylla, Pseudotsuga, and Cupressaceae are represented more or less as they occur in the vegetation, with regional backgrounds up to 5%. Picea and Abies are underrepresented, with regional background value of 0–3%. Key words: pollen, surface spectra, biogeoclimatic zones, species cover, British Columbia.