Protecting Significant Fen Habitat

Protecting Significant Fen Habitat

By April Mathes, Ontario Nature’s Stewardship Coordinator

Ontario Nature is fortunate to own one of the finest shoreline fens in all of Ontario – Petrel Point Nature Reserve on the Bruce Peninsula at the shores of Lake Huron. The nature reserve consists of a bed of wet sand overlying limestone bedrock. Slight changes in elevation in the fen separate distinct communities of plants, many of them rare. “A garden of wildflowers” is a turn of phrase that recurs often in descriptions of Petrel Point. The wonderful sprinklings of pink, mauve, red, blue and yellow that fill the fen through the seasons can only inspire a passion for nature.

Fens are a type of wetland (also known as meadow marshes) characterized by a high water table with slow internal drainage by seepage down low gradients. Fens are not as low in nutrients as bogs and as a result, are more productive. The Petrel Point fen is a hospitable home to many unusual wildflowers because what would typically be acidic groundwater that keeps it constantly wet is actually basic. This is due to the calcium in the limestone bedrock that the percolating groundwater passes through. Clear evidence of this is the accumulation of marl precipitate, a ghostly white muck lying at the bottom of the fen’s shallow pools of standing water.

Petrel Point is part of a Life Science Area of Natural and Scientific Interest (ANSI) and a Provincially Significant Wetland. A portion of the property is a scientific reserve and is off-limits to visitors. Due to the delicacy of the plant life in the open fen, visitors can explore the remainder of the reserve only from the walkways provided.

A constant concern at Petrel Point Nature Reserve has been the impact of drainage created for nearby cottage developments and roads. Areas of the fen may be drier than normal during the summer months because of increased drainage, and this in turn may be affecting the very character of these portions of the fen. Additional research is necessary to determine the effect that the development is having on this unique wetland.

Other stewardship concerns include people picking wildflowers, trampling vegetation for photography (particularly orchids) and leaving the boardwalk. With Ontario Nature’s help, several nature reserve neighbours have joined to form a local stewardship group in the hopes of establishing a presence on the property so as to encourage visitors to respect the permitted uses while educating them about the importance of the fen ecosystem. The volunteer stewards will also help undertake an ecological monitoring program on the property.

Ontario Nature has taken several proactive measures to address these concerns including developing interpretive signs to educate visitors about the significance and fragility of the fen. Also, additional sections of boardwalk have been constructed with the help of volunteers from our Volunteer for Nature working vacations program. This allows people to visit more of the nature reserve, while protecting its significant features.

Back in 1961, Ontario Nature started what is now one of Ontario’s largest member-owned nature reserve systems. With 21 properties totalling over 1,900 hectares (4,800 acres), the system preserves some of the province’s best remaining examples of imperilled and vulnerable habitats. You can check out Petrel Point and our other nature reserves on our

Volunteer for Nature is a provincial conservation program designed in partnership between Ontario Nature and the Nature Conservancy of Canada. Conservation volunteers work outdoors and learn new skills while working alongside experts in the field.Wetlands are restored, habitat is created, hiking trails are maintained, surveys are conducted and species-at-risk are monitored – all through the efforts of volunteers.

For more information, contact April Mathes, Ontario Nature’s Stewardship Coordinator, at 416.444.8419 x 264 or




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Images courtesy of Steven Huyser-Honig,
West Grand Boulevard Collaborative, & Yellow Dog Watershed Preserve.