Studies on the Bryophytes of Southern Manitoba. VII. Distribution of Terrestrial Bryophytes in a Black Spruce Bog in Bird's Hill Provincial Park

Abstract

The seventeen most common terricolous bryophytes in calcareous black spruce bog forest occur in three distinct groups occupying different microtopographic sites. The chief factors governing the distribution of these groups are moisture availability, shade, and competition. There have been few attempts to study in detail the ecology of terrestrial bryophytes in coniferous bog forests. Even the studies of Bevis (1960), Jeglum (1971), Reichle and Doyle (1965), and Sjors (1961) have little quantitative information relating bryophyte species to microsite factors, although in other respects they provide much useful data on the bryophytes of bog forests and bogs. Bevis (1960) used transects in his phytosociological study on bogs and bog forests, but his rather large sampling units (2 X 2 m quadrats) were not intended to sample the mosaic of microsites. According to Kil'dyushevskii (1964), a study of the distribution of species in the immediate soil cover with respect to the elements of the microrelief can reveal much concerning the biology and ecology of these species. With this observation in mind, we undertook this study in an attempt to elucidate the microtopographic distribution of bryophytes in hummocky black spruce bog forest, and to find how microenvironmental factors might account for these distribution patterns. The site chosen was in Bird's Hill Provincial Park, an area of coniferous and mixedwood forest some 36 hectares in extent approximately 25 km northeast of downtown Winnipeg. The park lies in the transition zone between the Aspen-Oak and Manitoba Lowlands sections of the Boreal Forest Region (Rowe, 1959). On Bird's Hill itself, white spruce (Picea glauca) with some jack pine (Pinus banksiana) are associates of the dominant oak (Quercus macrocarpa) and aspen (Populus tremuloides). However, most of the coniferous forest is in wet, poorly drained areas, where bog forests of black spruce (Picea mariana) and tamarack (Larix laricina) have developed, usually on deep layers of peat. We will report in separate publication other aspects of our work on the bryophytes of the park, which have not previously been studied.