Geological History and Ecosystems Evolution at Big Meadow Bog, Brier Island, Nova Scotia

An understanding of the geological history and ecosystems evolution of Big Meadow Bog peatland at Brier Island, Nova Scotia is an important element of informing the conservation management of critical habitats for a complex of nationally listed, rare, disjunct wetland species. The ecology of the peatland is influenced by both chemistry and morphology of the bedrock and glacial sediments within the watershed. The Big Meadow Bog peatland is bordered to the north and south along its long axis by basaltic ridges of the North Mountain. Drainage from these watershed ridges flows to the peatland, which has both a northern and southern outflow to the sea. Paleogeographic reconstruction suggests that Brier Island was deglaciated sooner than the rest of southwestern Nova Scotia. Big Meadow Bog peatland contains a stratigraphic record of a late Holocene transition to a moister climate shortly after 3000 cal. BP. However, several periods of late Holocene drying took place from 1950 cal. BP until present, one of which is recorded stratigraphically by the presence of a conifer forest indicating significant lowering of the local water table. Under these conditions, both wetland productivity and water table varied considerably. When designing potential habitat preservation and restoration strategies, these site-specific records of moisture and habitat structure variability need to be considered. Specific sites in the Brier Island peatlands may respond very differently to particular restoration strategies aimed at establishing long-term residency of threatened and endangered species at wetland sites.