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Freshwater Coastal Dunes

The variety of habitats in Pinery help make the park a unique place. The protection of these habitats is just one example of how Ontario Parks helps to preserve Ontario's ecological diversity through its system of provincial parks. One of these unique habitats is the freshwater coastal dunes which can be found along the shores of Lake Huron in Pinery Park.

The sand dunes in Pinery are exposed to extreme temperatures and harsh conditions.  Summer temperatures can reach a staggering 70ºC in the day and drop to 15ºC overnight.  Most of Pinery's dune insects, moths and mammals become active when the temperatures drop at night.

Building of the beaches with wind and waves

The sand on Pinery's beach is carried here from as far away as 80 kilometers.  It comes from the shores and bluffs north of Grand Bend.  Prevailing Northwest winds create waves that erode the bluffs.  Sand from the bluffs moves South with the lake's long shore currents.  Kettle Point, a headland to the south of Pinery, blocks the sand from travelling further.  The equivalent of 8,000 dump-truck loads of sand arrives at Pinery's beaches in this way every year.

Dune Builders

After being washed onto the shore by waves, sand grains blow over the beach like snow over a field.  Driftwood and other objects on the beach create small pockets of still air, where the sand grains settle.  As the sand piles up, it forms an "embryo dune".  If vegetation begins growing in the sand at this stage, it provides a foot hold for a larger dune to build on.

Nature's Snowfence

Marram grass rhizomes help stabilize the dunes.Only dune grasses are hardy enough to survive the shifting sands of a newly formed beach.  These grasses are able to survive being buirred by up to one metre of sand.  Tough underground stems called rhizomes push their needle-like points through deepening sand to reach the surface where blowing sand actually stimulates growth.   Though food and moisture are scarce, dune grasses thrive and stabilize the dunes, allowing other plants to become established.


Pinery's Desert

Between the first and second dune ridge lies Pinery's desert.  On a hot summer day, ground level temperatures can reach 70ºC (166ºF)!  The parched sand offers little moisture or food for the plants that live here.

Plants Suited to this Harsh Environment

Thick, waxy leaves help Bearberry to retain water.  Since its leaves are evergreen, Bearberry does not need an abundance of nutrients to grow a new set of leaves every year.

An insulating layer of cool air is trapped in the hairs that grow around the puccoon's stem.Yellow Puccoon protects its stem from the searing heat by growing hairs that hold onto a layer of cool air.  Its tap root digs down as much as two metres below the surface for water.

Wormwood is covered in light coloured hairs that keep it cool by reflecting the Sun's intense rays.  It survives in poor soils by taking two full summers to store energy before it produces seeds.

Parabolic Dunes

A 'blow out' in the second dune ridge.Behind the first dune ridge lies the undulating edge of Pinery's parabolic dunes.  These dunes form when strong winds undercut the vegetation and "blow out" sections of the dune ridge.  The U-shaped dunes funnel the wind and intensify the movement of drifting sand.  Reaching heights of 20 to 30 metres, the parabolic dunes advance like an army on the march, covering everything in their path.


Halting the Sand

Without their protective blanket of vegetation, sand dunes would soon be leveled and blown away in the wind.  In the past, human activity has disrupted Pinery's natural defenses.  We now work to restore and preserve dunes many ways:

  • In the early 1970's, lower limits were set for the number of visitors allowed to use the park at one time.
Traffic over the dunes was destroying the vegetation.
  • Nature reserves limit access to sensitive areas and minimize human interference with natural processes.
  • Boardwalks allow visitors to cross the dunes without trampling vegetation underfoot.
Each footprint on the dune ruins underlying vegetation.
  • Playing and climbing on the dunes is no longer allowed.
  • Volunteer groups and park staff have planted over one million dune grasses since 1978.

Learning More

You can help plant dune grasses to stabilize slopes.During the summer months, Park Visitors may wish to join a Park Naturalist during an evening program or for conducted walk to learn more about the dunes. All of these programs are part of our well-known Summer Interpretive Program.

School and youth groups may wish to learn more about Pinery's dunes by booking a program such as Sand Dune Succession.  This, and other programs, can be booked through our Group Education Program.


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