Lakeside daisy (Photo by Charles Peirce)
This spring, Canada Post issued a special stamp featuring the lakeside daisy, a small perennial in the aster family and one of Canada's rarest plants.
This bright yellow flower that blooms in early spring is globally rare and found only along the Great Lakes. In Canada, it only occurs on the grasslands and pavement alvars of the Saugeen Bruce Peninsula and Manitoulin Island in Ontario (bottom right). These populations of lakeside daisy account for about 95 per cent of the populations existing in the world. It is also one of very few plant species with most of its global range in Ontario.
The lakeside daisy is found mostly in alvars: naturally open areas with either a thin layer of soil or no soil over a base of limestone or dolostone bedrock. These globally rare ecosystems are found off the coast of Sweden, the eastern European Baltic regions, the United Kingdom and the North American Great Lakes Basin. Alvars support many rare and threatened species, including the lakeside daisy, with more than 60 per cent of North American alvars located in Ontario.
Lakeside daisies grow on pavement alvars, among a mosaic of exposed rock covered in lichen and moss. Grykes, joint fractures in the rock shaped by water erosion, are home to many of the wildflowers, ferns and other plants found on pavement alvars. Soil accumulates over time in these cracks to allow for plants such as low calamint, maidenhair spleenwort and lakeside daisy to take root. This unique habitat is kept open and sunny through natural disturbances such as drought, fire or wind erosion, which remove taller trees and shrubs that would otherwise shade out sun-loving plants like the lakeside daisy.
Hyménoxys herbacé, île Manitoulin, Ontario (Photo de CNC)
Thriving on adversity
Like many of the plant and animal species found on alvars, the lakeside daisy is able to survive harsh conditions: spring floods, summer droughts and temperatures as high as 52°C. Due to the extreme variations in temperature, moisture and disturbance on alvars, only specific plants, animals and invertebrates can thrive in this habitat. A variety of birds, mammals (including deer and rabbits) and insects eat the lakeside daisy, or its seeds, making it an important part of alvar ecosystems.
A threatened species
The lakeside daisy is listed as threatened under the Endangered Species Act in Ontario, and threatened federally under the Species at Risk Act, due to loss of habitat and its small range. Unfortunately, due to the open nature of alvars and this habitat's abundance of limestone rock, they are prone to development. Lakeside daisies are also found along shorelines and inland areas that are popular for hiking and recreation, where they can be accidentally trampled. The Nature Conservancy of Canada (NCC) has protected significant alvar habitat, including habitat for the lakeside daisy, on Manitoulin Island. There are significant populations of this plant found on NCC’s Tasker Wilderness Shore property on Manitoulin. NCC is also working to control gold-moss, an invasive plant that threatens the lakeside daisy.