Conservation Concerns
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
Redsided
Gartersnakes 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 adult mortality, even slight increases in mortality
can wipe out an entire population.
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Click here to learn how you can help reduce turtle
road mortality |
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 Pacific
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:
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