Sunday 24 January 2016

Feels for the Frogs - the Chytrid Fungus problem.


In my 23-and-a-bit years of experience, I've met a lot of people who like frogs, and I've met a lot of people who don't like frogs. I've also met some people who are neither here nor there on the concept of a frog, but if I'd started by talking about those people, this blog post wouldn't have had such a thrilling opening...

But whether you love them, or hate them, or are wildly indifferent to them, frogs, and amphibians in general, are a crucial part of ecosystems the world over. They control insect populations and they're a good food source for birds, to name a few of their niches in life. So we need frogs to maintain any sort of resemblance to what we could call balance in the natural world.

Enter the Chytrid Fungus.

Formally known as Batrochochytrium dendrobaditis (it literally has 'bad' in the name), but known to most as the Chytrid Fungus. As a fungus, it is related to the mushrooms that you might chop and put in a nice salad, or fry for your hangover-curing breakfast. However, this fungus is more at home, not on your plate, but in frogs (see the link I'm going for here?).

The Chytrid Fungus spreads by releasing its spores (a mobile bit of the fungus used for asexual reproduction) into water. Now, our amphibians like a bit of the ol' H2O, because it's where they can catch food and lay their eggs and go about their slimy business. So, once an amphibian has entered a water source containing these spores, it becomes infected with the Chytrid Fungus, and it grows inside the amphibian, and does mean and nasty things to it, eventually leading to death for the amphibian. However, before the poor amphibian is killed, the fungus uses it to further itself, by sending out more spores into the water sources that it has hitched a ride to.

A scanning electron microscopy showing the spore of the 
Chytrid Fungus (Batrochochytrium dendrobaditis).
Ugly little thing, ain't it?
Photo credit: CSIRO


At this point, you may be thinking to yourself, "So what? Yes, animals get infected with diseases and they die. It happens to humans too. Stop wasting my time and let me go and watch videos of cats dressed as Jedi on YouTube" (https://www.youtube.com/results?search_query=cats+dressed+as+jedi&page=&utm_source=opensearch). And I agree, animals do get diseases and they die. But, the Chytrid Fungus is different. It has been spread across the world so much, most likely by human travel and exploration, that is very difficult to tell where it started. The best guess at the moment is that it started in Africa, and hitched rides all over the globe, and is now infecting species all over the shop. And when plants and animals are exposed to diseases that they haven't evolved with, they usually have little to no resistance, and the disease ravages and spreads, causing huge declines in the populations of the affected species.

And this is exactly what has happened with amphibians the world over. The Chytrid Fungus is spreading through populations at unbelievable speeds, and is causing really high mortality rates in countless amphibian species. It is estimated to have affected around 30% of all amphibian species. That's a lot of unhappy hoppers. And to be honest, it's most likely our fault. It's not the most stupid thing humanity has done to doom species (I'll save that for another blog post) but it just shows how much of an impact we're having on our planet. We can't even travel to other countries and continents without endangering countless species of squishy friends. We need to be more careful.

Dead Southern Mountain Yellow-Legged Frogs (Rana muscosa)
killed by Chytrid Fungus in Sixty Lake Basin, 
King's Canyon National Park, California USA.
Photo credit: Vance T. Vredenburg.

I'm afraid this isn't a happy conservation story where I tell you what you can do to help, and what's already being done to help and that we're sure to see recovery of every animal ever in the next few minutes, as you can probably tell from the picture above. So if you need something happy, I suggest you follow the link I posted previously and go and watch some cats embrace the force. Because, at the moment, we don't know how to stop this fungus from wiping out all of these species. We don't know how to cure all of these amphibians with this disease. We're trying, but it's not looking great. More species than we'd like to think about have gone extinct already because of this fungus, some we didn't even know about before they went extinct.

So if I'm not writing this to try and recruit you to donate money (although you can do that at http://www.savethefrogs.com/threats/chytrid/), or to kiss a frog, then why am I writing it?
So you know about it, I suppose. Awareness is the key in these kind of things. So, now you know that humanity has an enormous footprint and that we need to be more careful, if you didn't know already. We don't own the planet, so we can't doom everything else on it. We need to think.




For more information on this subject, read The Sixth Extinction by Elizabeth Kolbert, or follow these links:
http://www.savethefrogs.com/threats/chytrid/
https://en.wikipedia.org/wiki/Chytridiomycosis#cite_note-2
http://www.amphibianark.org/the-crisis/chytrid-fungus/
Thank you.
Feel free to leave any comments.