A bog is an unusual place formed under
very particular conditions. Camosun Bog's history can be
traced back ten thousand years. What were the special
conditions that allowed it to form, and what were some of
the changes it went through during its evolution?
The glaciers that advanced
over south-eastern British Columbia 25,000 years
ago took over the landscape. They destroyed all
living things that could not escape and brought the
arctic winter to the south.
over 10,000 years a moving layer of ice over a
kilometre deep scraped over the earth. When the ice
receded about 12,000 years ago it left the land
scoured clean. Gradually life came back. It is here
that our story begins with a small depression in
the land formed by the weight of an enormous block
The depression left after the
ice receded filled with water and a lake was
created. Along the shallow edges of this lake,
sedges and cattails grew. Streams continued to feed
the lake bringing in more sediment.
the lake filled in, becoming shallow throughout,
and plants were able to grow over the whole area.
In place of a lake a swamp formed. This happened
about 5,000 years ago.
Between 5,000 and 2,000 years
ago the area remained a swamp with fast-growing
sedges and grasses. As these plants grew, the dead
leaves and stalks fell into the water and
eventually blocked the streams carrying in the
fresh water and nutrients the swamp depended on.
The oxygen in the water was used up in the process
of rotting of the dead plants.
standing water with low oxygen and no replenishment
of its nutrients created conditions allowing the
invasion of sphagnum moss. For the last 2000 years
this sphagnum has maintained the conditions of high
water level and low nutrient and oxygen levels
characteristic of a bog.
in the last 90 years have things begun to change
due to human interference.