Do Frogs Have a Future?

Today, a study was published in Science that painted a bleak picture for the future of the world's amphibians: ‘Amphibian fungal panzootic causes catastrophic and ongoing loss of biodiversity." Here's a video summary produced by Katie Garrett and myself:  https://www.youtube.com/watch?v=xJme6rIBYys&feature=youtu.be

And you can read the full paper here: https://science.sciencemag.org/cgi/doi/10.1126/science.aav0379

In brief, this study describes the shocking results of a re-evaluation of the damage caused by amphibian chytrid fungus and shows that over TWICE as many species are at risk of decline and extinction than previously estimated by scientists, bringing that number up to 501 from approximately 200 species estimated in 2007. The uncontrolled spread of chytrid is now causing the most severe disease-driven loss of biodiversity in recorded history, and is largely contributing towards a global mass extinction event. And to make matters worse, this only takes into account the chytrid fungus Batrachochytrium dendrobatidis, while North America remains threatened by a potential future invasion by the salamander chytrid fungus Batrachochytrium salamandrivorans.

As a co-author on this paper, many people have been asking me questions about this body of work and whether there's any hope for amphibians. Here are some of my answers to the most frequent questions that I'd like to share with everyone:

How is chytrid spreading?

This was the central topic of my PhD thesis at James Cook University. We're not exactly sure how chytrid was able to spread between continents 100+ years ago, but today, the primary activity causing chytrid to spread and generate new disease outbreaks is the international wildlife trade. Millions of live frogs are shipped around the world every year. About half of them are eaten by people (e.g. bullfrogs sold for frog legs) and the other half are sold as exotic pets. Many of these animals carry chytrid fungus, as well as ranavirus, and potentially other pathogens as well.

If chytrid is primarily spreading through the wildlife trade, how does it arrive in remote areas, like mountains and rainforests, where there is no frog trade?

This is still a big mystery, especially since chytrid cannot survive drying out or exposure to elevated temperatures for extended periods of time. A few years ago, my research team detected the presence of chytrid in rainwater, so it's very possible that chytrid can spread in the wind to remote areas, and from mountain top to mountain top during severe weather events. For example, if a hurricane with 60 mph winds blow through a rainforest with frogs dripping chytrid spores into water droplets that become aerosolized, then perhaps chytrid could be carried and dropped 60 miles away before the storm subsides. More research is needed, but I believe it's unlikely that viable chytrid can spread in the wind for very long distances, and this is why biosecurity is still sorely needed to prevent transcontinental spread. Once you allow that to happen, and trade moves infected animals around the world in just a few days, then there becomes many more opportunities for chytrid to spread short distances and quickly become difficult to control. 

Why do frogs matter?

Many kinds of tadpoles are herbivorous and eat plant matter found in bodies of water. If the amphibians were to disappear, a large portion of this material would decompose, fouling the clean water that many people and wildlife depend on. Meanwhile, some are carnivorous, and control populations of mosquitoes and other insects, which can spread tropical diseases to humans like malaria, zika, and dengue. Amphibians are often very abundant where they live, and thus provide a source of food for many other species including birds and mammals. If amphibians disappear, other animals are likely to suffer and may have difficulty adapting to other food sources. Everything in nature is connected, and many parts are especially connected to amphibians due to their time spent both on land and in the water.

Are you still optimistic about the future of frogs? 

Absolutely! I hope this paper convinces people to finally recognize how truly severe this disease event has become and that now, more than ever, we need to take a stand for amphibians. While we can certainly save some species from extinction, others won't be so lucky. My optimism lies in knowing that this biological catastrophe presents an incredible learning opportunity to discover ways to prevent this from happening again, as caused by the international wildlife trade. Although I really do love frogs, I also see this issue from a much larger perspective -- to me, it's not just about frogs. It's about the consequences of rapid globalization without rapidly developing new policies and regulations to minimize the damages it can cause---like the spread of pathogens that were previously isolated in one corner of the world. Diseases caused by chytrid and ranavairus are now spreading like wildfire. There is so much we can learn from our past mistakes to protect wildlife in the future, and I would love to be the person to step into this complex political biological area and help fix things. I've already developed a policy proposal that could drastically reduce the spread of chytrid overnight and I'm looking for an outlet that would like to publish it so that our data can help others interested in promoting a cleaner wildlife trade. 

Will things get worse?

It depends on the choice we make right now. Unless we develop and implement policies to control the spread of chytrid as soon as possible, and reduce the likelihood that another hybrid event will create a deadlier strain of chytrid, then we could very well face another global wave of disease, which could be similar, different, or even worse than the one we’re facing now.

Can you help support my conservation? Visit https://www.patreon.com/MyFrogCroaked

Please comment below if you have additional comments or questions! I'd love to hear them all.

?

Thanks,

Jonathan Kolby, Ph.D.

National Geographic Explorer

Director, Honduras Amphibian Rescue & Conservation Center

www.FrogRescue.com