Surface pollen spectra from southern Vancouver Island, British Columbia, Canada (original) (raw)
Related papers
Canadian Journal of Botany, 1997
Surticial sediment samples from 42 lakes, distributed from sea level to alpine elevations of coastal British Columbia and northwest Washington, were analyzed for pollen and spores. Pollen analysis revealed characteristic differences among the assemblages of the Coastal Western Hemlock, Mountain Hemlock, and Fngelmann Spruce -Subalpine Fir biogeoclimatic zones (the Alpine zone is less clearly identifiable). Cluster analysis and. detrended correspondence analysis (DCA) correctly group the sites according to their biogeoclimatic zones and also by geographic origin. DCA indicates a high correlation between the biogeoclimatic zones of the sample sites and annual precipitation (-0.89), January temperature (-0.77), annual temperature (-0.64), and growing-season precipitation (-0.68). Further analysis of the samples and eight environmental gradients using canonical correspondence analysis groups the pollen assemblages from the study sites into biogeoclimatic zones in relation to annual precipitation, growing-season precipitation, annual snowfall, annual temperature, and growing degree-days. These data are useful for testing whether or not postglacial pollen assemblages have modern analogues.
Géographie physique et Quaternaire, 2000
Isopoll maps based on 173 modern-pollen samples illustrate the geographical patterns of 12 pollen types within a 600,000 sq. km area centered in southern Québec. The mapped patterns reflect several scales of vegetational pattern that ranges from the major regional change between conifer-hardwood forest and boreal forest down to the minor local differences in vegetation between nearby sites. Picea and other arboreal pollen types are most representative of the regional patterns, whereas Cyperaceae and Ericaceae pollen often vary markedly between adjacent sites. Further analysis of these pollen data explored how much differences in sediment type and variations in analyst practices among the samples can affect the sensitivity of the pollen data to certain of the vegetational patterns. The set of 173 samples was divided into three subsets, two of which differ in sediment types and two of which differ in analyst practices. The distributions of pollen types are then correlated between the ...
Géographie physique et Quaternaire, 1982
At 39 sites in eastern and central northern Canada, multiple samples of surface moss and lichens have been analyzed for their pollen content. Although pollen from 20 to 30 taxa were identified in the samples from each site, 8 pollen types (Alnus, Betula, Picea. Pinus, Salix, Gramineae, Cyperaceae and Ericaceae) usually comprise 90 to 100% of the pollen rain. We present isopoll maps of these taxa based on mean percentages of multiple samples from the 39 sites. The data are further analyzed by a number of statistical methods to determine whether there are specific pollen assemblages within this region and to what extent present day climatic parameters and floristic/vegetation zones correlate with pollen counts. Cluster analysis on raw data and on principal component scores yields six distinct pollen assemblages which are further examined by discriminant analysis. Pollen concentration maps for eastern Canada are also presented here and used as an aid in interpreting the percentage data.
Journal of Ecology, 2006
Species-level pollen identifications within the genera Acer , Fraxinus and Juglans have the potential to increase the detail available from regional-and landscape-scale studies of palaeo-forest dynamics. 2 Data from the North American Pollen Database (NAPD) and the North American Modern Pollen Database (NAMPD) for sites in eastern North America for which species-level identifications have been recorded enabled us to consider pollen taxonomy at high resolution. 3 Species within each of Acer , Fraxinus and Juglans have important differences in habitat, functional type and responses to climatic change. Analysis of the modern distribution of these taxa and their pollen rains confirms that species-level pollen identifications provide detailed ecological information, but the lack of distinction to the species level in many fossil and modern pollen studies renders palaeoenvironmental reconstructions incomplete. 4 Within each of three selected high-resolution sites, ordinations indicate that individual species of Acer , Fraxinus and Juglans follow different trajectories through the Holocene, showing that analysing only generic categories results in the loss of ecologically valuable information. For example, pollen of Acer rubrum increased in abundance in response to canopy openings in a southern Ontario forest around 500 years ago, while that of A. saccharum declined. Similarly, Juglans nigra pollen percentages increased while J. cinerea decreased at this time. 5 Regional-scale comparisons of pollen percentage curves indicate that, despite the uncertainties associated with the low temporal resolution and the chronologies, it is reasonable to conclude that individual species of Acer , Fraxinus and Juglans responded synchronously to palaeoclimatic changes within each region. 6 Taking analyses to the specific level shows that different species followed different tracks in their post-glacial history, a fact previously blurred by less resolved taxonomy. This information is meaningful in biogeographical terms, providing much more specific evidence of how the selected trees behaved in the past.
Review of Palaeobotany and Palynology, 1993
The abundance of exotic western hemlock pollen was studied at Waterdevil Lake, northern British Columbia, in order to determine whether or not its depositional history was independent of changes in pollen productivity in the likely source area, coastal forests of western hemlock-Sitka spruce, about 30 km to the southwest. A comparison with the abundance of western hemlock pollen at Lily Lake, Alaska, which lies within the coastal source area, supports this notion. The one major Vegetational change during the late Holocene at Waterdevil Lake, the transition from subalpine fir forest to lodgepole pine-subalpine fir forest, coincides with an increased abundance of exotic western hemlock pollen. These preliminary results suggest that a study of exotic pollen in this region may be useful for interpreting past changes in circulation patterns.
20. Data Report: Initial Results of Pollen Analyses from Sites 1018, 1020, 1021, and 1022 1
2000
The climatic effects of major geologic events of the last 6 m.y., such as the variations in arctic and Antarctic icecaps and the uplift of major mountain ranges, are reasonably well documented in the marine realm. On land, however, such evidence is limited, and chronostratigraphic control is minimal. Only ~12 widely separated floras are available to reconstruct discrete events in the evolution of vegetation and climate of California and Oregon forests during the late Neogene, an interval in which major climatic changes are reflected in the replacement of Miocene mesophytic forests by temperate coniferous forests (Axelrod, 1977). Cores taken on the California margin during Leg 167 provide an opportunity to continuously monitor vegetation of the northwest coast of North America (using marine pollen assemblages), to set the terrestrial vegetation and climate records in accurate age frameworks provided by other components in the cores, and to directly relate late Neogene changes in ocea...
Report on the Distribution of Dwarf Birches and Present Pollen Rain, Baffin Island, N.W.T., Canada
ARCTIC, 1980
A distribution map for the dwarf birches is presented for the region from Frobisher Bay northward to Cumberland Peninsula. These shrubs are restricted to favourable habitats which, at the northern limit of the species (67" 40' N), are found on south-facing slopes above the immediate local cooling influence of the sea. Pollen studies within the zone of scattered dwarf birch indicate that pollen dispersal from these low, prostrate shrubs is minimal. Samples of moss collected beneath the bushes have 5-36% Betula pollen: whereas sites no more than 50 m away from Betula shrubs. have percentages of <2%. These data will be useful in considering the Holocene and Pleistocene histories of these Low Arctic shrubs in the Eastern Canadian Arctic.
Pollen morphology of the Rosaceae of Western Canada
Grana, 1988
This paper begins a systematic SEhl and Lhl study of the pollen grains of the Rosaceae in Western Canada with genera Agrimonia, Alclietnilla, Amelanchier, Arrrnciis, Cliamaerhodos, and Crataegus. The above genera have tricolporate-tectate pollen grains in monads. Agrimonia gryposepala and A. striata have distinct striate sculpturing perpendicular to the colpus. Alchemilla occidentalis pollen is psilate except in the colpus area which is microechinate. The exine is thickened in the intercolpium. Antncos sjlwsrer pollen is very small and exhibits a coarsely striate sculpture. Cl~amaerliodos erecta pollen has a characteristic protruding pore area with a fusiform operculum over the aperture. The sculpturing consists of patches of short ridges. Crataegirs and Amelanchier pollen have pores with a characteristic equatorial bridge or flaps when open. Dimensions of the grains vary with degree of distension. Amelanchier alnifolia pollen exhibits geographic variability. Native North American Crataegiis species: C. doirglasii, C. rotitndifolia and C. sirccirlerzta have pollen which exhibits morphological variability and requires more study. In the suney so far, surface sculpturing is the most distinctive feature and, in combination with characteristics of the pore area, seems to distinguish the types. A table of characters permits the pollen of most taxa studied to be identified using Lhl and SEhl