Flora and vegetation of an old field community at Erindale, southern Ontario

Abstract

A stable old field 5.4 ha in extent and undisturbed for at least 50 years is described qualitatively and in quantitative terms. Despite relative physiognomic uniformity, seven homogeneous areas were studied using presence and frequency and estimated cover in randomly distributed 1-m2 quadrats. Of the rich total flora of 118 species, 99 were found in the communities and only 61 had measurable cover. Agropyron repens, Vicia cracca, and Poa pratensis were major dominants followed by Solidago altissima, Phleum pratense, and Hieracium pratense. Although native (52%) outnumber introduced species (48%) in the field as a whole, in terms of cover, exotic plants may exceed indigenous species by at least 2:1 and perhaps as high as 4:1, depending on the designation of species of controversial origin. Solidago species seem to be the only native plants clearly capable of coping with the competition provided by exotics. Species respond to small differences in site moisture and to different stages of succession toward forest which appear to vary mainly with position in the field.