Stream macroalgae of the eastern boreal forest region of North America

Abstract

Fifty-one stream segments were sampled in northwestern Newfoundland, central Labrador, and west-central Quebec during June and July 1987. There was a great range in stream size, current velocity, pH, and ion content. The eastern boreal forest was found to be one of the most diverse regions in North America for stream macroalgae, having a flora of 67 species. The major divisions in terms of species numbers were the Chlorophyta (43%), Cyanophyta (21%), Chrysophyta (19%), and Rhodophyta (16%). Mats were the most widespread form (51% of the species), followed by filaments (27%), colonies (13%), tissues (5%), and palmelloid forms (3%). Species number was positively correlated with water temperature and total cover and negatively correlated with pH. The most widespread species was Batrachospermum moniliforme, which occurred in 31% of the stream segments examined. Distribution was patchy, with total cover varying from < 1 to ca. 60% of the stream bottom. Species numbers per segment ranged from 1 to 11. The most closely associated species were Microspora pachyderma, Mougeotia sp., and Batrachospermum keratophytum. The known distribution range of the rare rhodophyte Boldia erythrosiphon was extended north by ca. 1000 km.