Certain ecological aspects of selected bogs in Newfoundland

Pollett, F. C. (Frederick C.) (1967) Certain ecological aspects of selected bogs in Newfoundland. Masters thesis, Memorial University of Newfoundland.

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Abstract

Six areas of Newfoundland were selected for the purpose of investigating the various bog types on the island. These study regions extended from the Avalon Peninsula (Region I) west to St. George's (Region V) and north to Daniel's Harbour (Region VI). A total of 178 peat deposits were studied, which included bogs, fens, and to a lesser extent, marsh accumulations. -- The rate and type of accumulation of these deposits is controlled by physiographic factors, such as climate and geology. Pleistocene glaciation has played an important role by the formation of depressions and by damming water, thus creating an environment favourable for bogland development. Fire has resulted in paludification which encouraged the expansion of bogs over relatively dry ground. It was found that climate is the predominant factor controlling the growth and expansion of bogs in Newfoundland. Blanket bogs are most common in Newfoundland, especially in the coastal areas, and predominate in all but Terra Nova (Region IV). In Region IV raised bogs are more prevalent than blanket bogs; in Region I raised bogs are found but only in localized depressions surrounded by forested slopes. In some areas there are larger bogs formed by the combination of raised centers coalesced by blanket bog. Paludification in all regions result in blanket bog expansion. Wesleyville (Region III) has the largest blanket bogs, in any of the study regions, covering many square miles spreading over bare granite bedrock within the past forty years. -- From the study of peat cores, cross-sections were compiled showing the types of peat in some Newfoundland bogs. Bog development is preceded by a growth of fen species, gradually dominated by Cyperaceae and then by the Sphagnum species. Surfaces of both blanket and raised bogs have similar species with sedges Scirpus spp. and Carex spp. more abundant in blanket bogs; Scirpus cespitosus. Sphagnum spp. and ericaceous shrubs dominate the raised bog surface. Raised bogs generally have a good regeneration complex with Sphagnum cuspidatum in flashets, Sphagnum magellanicum the dominating mat component and Sphagnum rubellum, Sphagnum fuscum, Sphagnum flavicomans and Sphagnum imbricatum the hummock-forming species. Ericaceous shrubs, lichens and bryophytes (other than Sphagnum) are commonly found occupying drier surfaces. Other species such as Myrica gale, Menyanthes trifoliata and Carex spp. are principally found in minerotrophic sites such as soaks, drainage channels or bog borders. -- The surface features, types of peat, their origin and development; the affects of physiographic processes and fire on bog formation and expansion are discussed.

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