Conservation
Concerns
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Reptiles first appeared on Earth around 260 million years ago and
the number
of species quickly expanded as species occupied a variety of
ecological niches.
Today, we are losing populations and entire species of reptiles
because of
increasing changes we are making to the world. Many reptiles are
long-lived
and do not produce many young so they are sensitive to rapid
changes to the
environment. To date, Canada has lost two species of reptiles: the
Pygmy Short-horned
Lizard in British Columbia and
the Timber
Rattlesnake from southern Ontario. There
are a number of threats to reptiles and we list some of the major
ones faced
in Canada:
Habitat Destruction
The destruction of forests and wetlands affect many species of
wildlife.
The Pygmy Short-horned Lizard may have been eliminated from British
Columbia
because of the increase in agriculture in that area. Likewise, the
Blue Racer, now
found only on Pelee Island in southern
Ontario, is facing extinction in Canada from development on the
island.
Traffic Mortality
Thousands of reptiles are killed every year on our roads and
highways. Many
snakes are drawn to roads in the evenings because the tarmac is
warmer than
the surrounding environment. When large hibernacula are separated
from the
summer range by a road, slaughter is often the result. In Manitoba,
up to
10 000 Common Garter
Snakes are killed annually,
primarily during the fall, along a 3 km stretch of road.
Turtles also often fall victim to cars, particularly in early
summer when
adult females are looking for good nesting areas to lay their eggs.
Because
most turtles are long-lived, with low rates of adults mortality,
even slight
increases in mortality can wipe out an entire population.
Predators
There is a fine balance between predators and their prey. When a
predator
specializes on another species the two populations tend to keep
each other
in check. However, many predators prey on many different species
and eliminating
one prey species does not affect their populations. Many snakes and
turtles
are particularly prone to nest predators such as Raccoons and
Skunks. Such
species have flourished around areas of human settlements and it is
estimated
that there may be twenty times as many Raccoons in North America
now, compared
with half a century ago. In many areas, Raccoons destroy virtually
all nests
made by turtles.
Contaminants
Pollution is an increasing problem as new chemicals continue to be
created
and sold. Many toxins such as polychlorinated biphenyls (PCBs),
dioxins and
furans are absorbed by animals in the food they eat. Animals higher
up the
food chain often have very high levels of contaminants because each
prey
species down the food chain has concentrated the toxins. Females
often secrete
these contaminants into their eggs. In the Great Lakes basin up to
40% of
Snapping Turtle eggs
in some areas either do not
hatch or result in deformed young. In addition, DDT and its
breakdown products
are still found in the tissues of Snapping Turtles
despite its ban in Canada approximately 30 years ago.
Other chemicals may not cause death or obvious deformities but have
just
as important effects. Certain chemicals are very similar to natural
hormones
and can affect individuals reaching maturity. For example, some
chemicals
will mimic the female hormone estrogen and can prevent juvenile
males from
properly maturing. It is unclear what effects these chemicals are
having
on humans.
Pet Trade
The reptile pet trade is big business. Most companies are
conscientious,
honest and reputable. They raise animals in captivity and ensure
that would-be
owners know what they are getting into when they purchase an animal
that
may live 20 or 30 years. Unfortunately, others simply see a way to
make
a quick buck or two. The collecting of wild animals to be sold as
pets is
a notorious practice which can have devastating effects on a
population.
One unscrupulous dealer even approached a Canadian university
professor,
who has dedicated his life to reptile conservation, with the offer
of buying
all the Wood Turtles
he could catch. He also had
advice on how to catch the entire population.
If you wish a reptile as pet make sure you are dealing with dealer
that can
be trusted. Find out where the animals come from. Talk with other
pet shops
or even local conservation officers to find out if any complaints
have been
lodged against the dealer. Don't let your interest in a species
help cause
it to go extinct.
Introduced Species
Unwanted pets are often released into the wild. Most perish in a
short time,
either because they are tame and therefore not wary of predators,
or they
cannot cope with the long, cold Canadian winter. Some individuals
do survive
and appear to even thrive in their new homeland. That is a problem,
because
exotic species can cause a number of problems. First of all, exotic
species
compete with native species and may actually be able to displace
some native
species. Exotics may also bring foreign diseases that native
species are
not able to cope with.
The most widespread exotic species in Canada is the Red-eared
Slider, a turtle
native to the southeastern USA. Although their importation to
Canada is now
banned, eggs are still imported. From 1992-1996, US government
records indicate
almost 500 000 eggs entered Canada. These turtles are sold as 3-4
cm juveniles,
but when they reach 10-15 cm in length many people release them.
Red- eared
Sliders are quite common now in the Great Lakes area. Over 100 are
known
to live at Riverdale Farm in Toronto, where they have virtually
displaced
all other species of turtles. Other introduced species in Canada
include
the Eastern Box Turtle in southern Ontario and the Western Pond
Turtle and
European Wall Lizard in British Columbia.
Eliminating exotic species is difficult and what should be done
with the
individuals? It is generally impossible to return them to their
native area
and often euthanasia is the only solution. It is unfortunate that
the animal
must pay for the mistakes of humans.
Persecution
Many people do not like reptiles, particularly snakes. The Timber
Rattlesnake
was wiped out from Canada because of deliberate persecution. While
a healthy
respect for rattlesnakes is necessary as a bite can be fatal
(though generally
it is not), these creatures are not unusually aggressive. A
rattlesnake's
rattle is to alert you to keep your distance. If it wanted to
attack, it
would not signal it's intent first. The rattlesnake's venom is for
immobilizing
its prey, which is generally small mammals. Rattlesnakes don't eat
people
and they only attack people when threatened. More people die from
bee stings
every year than from snake bites.
Despite this many people kill rattlesnakes on sight. Unfortunately
a number
of other snakes will imitate a rattlesnake by vibrating their tails
in dry
leaves. Such action may deter some would-be predators, but it
causes many
harmless snakes to be killed.
In a world where one group of people cannot get along with another
group
because of cultural, religious or political differences, it is
probably too
much to expect that one species that considers itself intelligent
can show
tolerance for other species. But we can always hope.
Additional Reading
If you would like to read more about reptile conservation or
particular species
you might like to check out the following articles:
Blue
Racer.............................................
English..........
French
Spiny Softshell
Turtle..............................English..........
French
Black Rat Snake & the
Massasauga........English..........
French
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