Science column: World’s Amphibians under attack
Published: Monday, September 23, 2013
Updated: Monday, September 23, 2013 22:09
A violent, icky, deadly fungus called Chytridiomycosis is terrorizing Earth’s amphibians and threatening to cause a mass extinction. It baffles scientists, kills innocent frogs and is certainly something that could affect everyone.
A fungus is not quite a plant, not quite an animal and not quite a single-celled organism such as a bacterium or virus. Examples of fungi include mushrooms, yeast and mold (like you find on bread or cheese that you leave out). Fungi are fairly hard to define and definitely a little freaky. They don’t get their energy from the sun, like plants do, but from breaking down a food source like animals do, such as a plant, animal or other organic matter they’re growing in or on.
Amphibians include frogs, toads, salamanders, newts and eel-like aquatic salamanders called sirens. Amphibian means “both kinds of life” in its original Greek, referring to the fact that amphibians live in water and on land. They are similar to reptiles (both groups are cold-blooded, meaning they can’t generate their own heat or get their heat from their surroundings), but amphibians need water to lay their eggs in, whereas reptile eggs have hard shells and can be laid on land.
Their young mature via metamorphosis. Frogs, for example, lay eggs that hatch into small swimming tadpoles, which slowly grow legs and lungs, lose their tails and become land-dwelling frogs. Amphibians are commonly poisonous—one of the most poisonous animals on the planet, the golden poison frog, is an amphibian.
Amphibians are very delicate creatures. Many of them live in very specific habitats and some of them are even endemic, meaning they aren’t found anywhere else on the planet. This means they are very vulnerable to extinction due to things like climate change and habitat loss. Also, their skin is extremely porous. They need to live in moist climates close to water because they can become dehydrated very quickly.
This is why Chytridiomycosis is such a big deal. It’s a disease caused by a fungus that scientists first discovered in Australia in 1993. Since then it has been proven the killer of amphibians in North America, South America, Central America, Australia and some Caribbean islands. It has impacted more than one-third of the world’s amphibian species, and scientists are anxious to see if they can stop it from spreading to the other continents. The disease works by basically dehydrating the amphibians. Since their skin is so thin and porous, it doesn’t take very long for them to dry up and die.
While amphibians have responded well to anti-fungal treatments (such as coating and medication) in a lab setting, scientists aren’t sure how to administer things like anti-fungal cream to a whole host of wild amphibians. The disease is still being widely researched in the hopes that we can stop a worldwide amphibian extinction.
So why should we care? I mean, why does it matter if we lose a few tiny frogs and salamanders? In fact…wouldn’t we be better off if a whole host of poisonous animals were wiped off the planet? Not true! Amphibians, like all living things, are part of a worldwide ecosystem. This means if something like a tiny Australian frog goes extinct, we could have huge problems.
For example, some frogs are vital to an ecosystem’s insect control. If those frogs die, the insect populations skyrocket. This means that whatever they eat (other insects, trees, flowers and animal blood) will suddenly be under massive attack. If, for example, this causes the tree that the insect eats to go extinct, then another link in the ecosystem chain is gone. Pretty soon things like crop farming, livestock, ecotourism and the harvesting of natural resources, such as wood, chemical compounds, oil, gas, ore and food, will be impacted and perhaps even no longer possible.
That being said, things go extinct all the time. Right now, 99.9 percent of the species that have ever lived have already gone extinct. We can’t panic every time we’re about to lose a species, because chances are that species would’ve been gone right about now anyways—with or without human interaction. Nature goes on as it always will, and someday even humans will go the way of the mighty dinosaur, the giant shark and the over-sized insect.