|
It's springtime and if you don't live in the city, you've probably
been hearing the spring peepers. Even if you do, you're probably
still familiar with the "peep peep!" of these tiny
orange frogs that appear as early as March in Nova Scotia. You've
probably been hearing these frogs every spring for your whole
life, but what you may not realize is that you're hearing less
and less frogs. |
|
Every year, more and more of Canada's wetlands are being destroyed.
About 90% of wetlands within or near to city centres no longer
exist. These marshes, swamps, and ponds are the main habitats
for amphibians and many other animals. Pollution, building development,
road construction, logging and agriculture all contribute to
the destruction of frogs' habitat every day. As well as being
important to animal life, these wetlands are crucial to the overall
health of the environment.
These wetlands help control flooding and drought by absorbing
snow melt and rain in the spring, and gradually releasing water
in drier times. Plants that are indigenous to the wetlands help
reduce global warming by reducing the carbon dioxide in the atmosphere
and replacing it with oxygen. Even though no one likes mosquitoes
and black flies, they are essential to the food chain and their
life cycles mainly take place in our wetlands.
Since the 1800s, an estimated 8 million hectares (20 million
acres) - one-seventh of Canada's total wetlands - have been drained
or lost. A lot of those that haven't been destroyed have been
polluted beyond restoration. Amphibians, such as frogs, are very
sensitive to environmental changes and pollutants. One of the
most startling ways that this shows up is the mutation in frogs.
In many places in the United States, as well as here in Canada,
reports of frogs with extra hind legs or the wrong number of
eyes, feet or other appendages have turned up over the past few
years.
One possible explanation is retinoids in pesticides. Retinoids
are powerful molecules that can stimulate growth of any limb
anywhere on the body. When there are extra retinoids, or retinoids
in the wrong place, an extra limb or body part can grow. Retinoids
have been known to cause birth defects in humans, when pregnant
women took the acne treatment Accutane. Methoprene is a pesticide
that is widely used against mosquitoes and other flies. It works
to prevent the insects from growing into reproducing adults.
It is so strong that one teaspoon is enough for an acre of land.
However, this pesticide is not used in all locations where deformed
frogs have been found. Other possible causes include parasites
and ultra-violet radiation.
The Museum of Natural History in Halifax has a way you can
help monitor the frog population and the condition of our wetlands.
Frogwatch is an environmental and educational program that is
for anyone interested. To join or to find out more, visit the
museum or check out their
Frogwatch website. |
