| dc.description.abstract | To assess the patterns of phenotypic variation in cone and
needle characters of jack pine relative to spatial, climatic and
ecological data, collections were made from ten trees in each of 64
sites in northwestern Ontario. Nineteen cone and forty needle
characters were measured on five cones and five needles per tree.
Climatic data from 27 Canadian and 10 American weather stations
in and surrounding the study area were interpolated, using a
geographic information system, to produce weather data for each
collection site. Vegetation and soil data for each collection site
were determined using the system developed by the Ontario Ministry
of Natural Resources in the Northwestern and North Central regions
for the Forest Ecosystem Classification program.
Discriminant analysis indicated that the populations in the
study areas formed a single group but were spatially organized into
two groups, west and east, including the Armstrong area, of Lake
Nipigon. A trend surface of the discriminant scores revealed a
steep dine at a longitude of 88°15', Nipigon area. Simple
regression of discriminant scores against the spatial, climatic and
ecological data indicated that the patterns of variation expressed
by cone and needle characters may be a result of adaptation to local
environments.(see document for elevations)
Multiple regression coefficients from regressions of spatial and
climatic data against discriminant scores for both cone and needle
data were compared with the variance component among groups
from the nested analysis of variance to assess the amount of the
total variation attributable to the local environment. The
comparison revealed that most of the variation among sites could
be explained by spatial and climatic data. In addition, a steep dine
could be discerned at a longitude of 88°15’ on the the trend surface
of maximum June temperature.
The correlations of the patterns of variation with the spatial
and climatic data suggest that climate may be the causal agent for
the patterns of variation in cone and needle characters in
Northwestern Ontario. However, the patterns of cone and needle
characters are similar suggesting that the modern patterns of
variation may be a result of two migration routes or two refugia. | |
