Summer 2017 NCC Magazine

T
his 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.
STAMP: CANADA POST. MAP: NCC.
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.
RARE HABITAT
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 such as the lakeside daisy.
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 the
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.1
FACT SHEET
SCIENTIFIC NAME
Tetraneuris herbacea
SIZE AND WEIGHT
This perennial plant can grow up
to 35 centimetres tall.
RANGE
The lakeside daisy is restricted to the
Great Lakes region of North America
and is present in Ohio, Illinois, Michigan
and southern Ontario.
POPULATION TREND
The total size of the Canadian
population has not experienced
significant changes; however,
populations that have been monitored
in the most heavily travelled areas
are declining noticeably.
STATUS IN CANADA
Threatened both federally
and provincially.
DID YOU KNOW?
Alvars provide habitat for many
at-risk and globally rare species.
The Saugeen Bruce Peninsula and
Manitoulin Island support some of
the best examples of alvar habitat
in the world, and are key areas for
conservation in North America.
Elliot Lake
Gore Bay
Lake Huron
Manitoulin
Island
Killarney
Tobermory
Ontario range
Species occurrence
• Species recorded on NCC property
Sudbury
Georgian
Bay
Owen Sound
Parry
Sound
natureconservancy.ca
SUMMER 2017 13