Plant communities of New Brunswick in relation to environmental variation

The objective of this study was to quantitatively describe vegetation-envir onment relationships at a regional scale within the Province of New Brunswi ck, Canada, using vegetation and environment data from 3947 provincial fore stry sample plots. The major plant community types in the province were ide ntified using cluster analysis. Relationships of these communities to clima te, topography and soil variables were analyzed by Canonical Correspondence Analysis (CCA), using both a reduced data set consisting of cluster likeli hood scores x sample plots and an unreduced species x sample plots data mat rix. The vegetation types and major axes of environmental variation were ma pped to examine the geographic distributions of these factors within the pr ovince. Eight communities were identified and described in terms of enhance d/reduced species (significantly higher or lower frequencies of occurrence in a specific community type relative to all plots) and common species (spe cies in the community type with the highest frequencies of occurrence). The canonical axes explained 25% of the variation in the vegetation cluster da ta. Vegetation composition was related to three major environmental gradien ts representing climate and elevation, soil moisture, and soil fertility. T he geographic distributions of vegetation communities exhibited predictable but weak correspondence to the geographic distributions of individual envi ronmental factors. Our findings emphasize the overriding importance of clim ate and topography and the secondary importance of soil factors in controll ing vegetation pattern at the regional scale.