I have a post specifically on Peat Bogs, but there is one very special Island bog that merits its own post: Black Marsh at North Cape.
Today, Black Marsh (Photo 1) sits atop a cliff at the northern tip of the Island, exposed to brutal coastal winds and salt spray. But this wasn’t always the case. Immediately following the end of the last Ice Age some 12,500 years ago, Western PEI remained depressed by the immense weight of those ice sheets. (Think of the land a bit like memory foam: when you press and remove your hand, the foam takes some time to rebound). At that time, it’s estimated this part of the Island was under more than 20 metres (75 feet) of water.
As the land rebounded, relative sea level fell. The remains of freshwater algae found in marine sediments between PEI and the Magdalen Islands suggest that roughly 9,500 years ago sea level may have been as much as 70 metres (230 feet) lower than it is today. At this time, Black Marsh would have been far from the shore and likely began much as our other bogs did. As the glaciers continued to melt, sea level rose. The inland pond that was to become Black Marsh was likely a barrier beach pond for a time, eventually transitioning to today’s unusual exposed coastal bog.
This inland-to-coastal transition, coupled with the extreme exposure at this site, has lead to the creation of a provincially-unique habitat. Species more characteristic of subalpine and alpine areas thrive here, such as Twisted Whitlow Grass (Draba incana, a member of the Mustard Family rather than a grass) and Loose-flowered Alpine Sedge (Carex rariflora). Black Marsh is the only location on the Island where these plants are found. The Provincially-uncommon Bakeapple (aka Cloudberry, Rubus chamaemorus, Photo 2) is abundant here.
Coastal species not normally found in bogs also occur here, including Three-toothed Cinquefoil (Sibbaldia tridentata, Photo 3), Silvery Cinquefoil (Potentilla anserina, Photo 4) and even Marram Grass (Ammophila breviligulata). Adding to this site’s ecological importance is the presence of coastal krummholtz forest (you can read more about that in a separate post).
Fortunately, this important area is publicly owned and accessible. The Black Marsh Trail winds about 5 km through coastal forest, along cliffs and into the bog on a raised boardwalk with a viewing platform. Along the route are spectacular views and interpretive signage. If you haven’t visited this site, I recommend adding it to your PEI bucket list.
Black Marsh: rare, important and among the coolest of PEI habitats!
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