Floristic boundaries in the Gulf of St. Lawrence region: a numerical approach based on the moss flora

• Published in: Canadian Journal of Botany
• Main Author: Belland, René J.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1989
• Subjects: Plant Science; Arctic; Breton Island; Newfoundland
• Online Access: http://dx.doi.org/10.1139/b89-206; http://www.nrcresearchpress.com/doi/pdf/10.1139/b89-206

Possible phytogeographic boundaries within the Gulf of St. Lawrence region are examined using the moss floras of 29 smaller geographic units. Principal coordinates analysis (PCoA) shows floristic change in the Gulf to be gradual and to follow two major gradients, a north–south gradient and an east–west gradient. These are positively correlated to the distributions of temperate and arctic species, respectively. PCoA ordinations also show no evidence of distinct boundaries between adjacent units, but indicate that Cape Breton Island and Gaspé Peninsula have floras of intermediate composition to those of the Maritimes and Newfoundland. Randomly generating floras for adjacent units using Monte Carlo simulation supports the results obtained from PCoA. The real Jaccard similarities between adjacent units are found to be greater than those expected from simulation. The lack of distinct boundaries in the Gulf of St. Lawrence region is attributed to the high diversity of species distributions possible in a region with complex environmental gradients.