By Morgan Erickson-Davis
A fungus that has decimated frog populations around the world could get even deadlier, according to new research. The study found that hybridization of different types of the fungus creates strains that can cause greater mortality in frogs. And it warns that deforestation could make this impact worse.
The fungus is called Batrachochytrium dendrobatidis—Bd for short—and it causes a disease called chytridiomycosis that affects a frog's ability to absorb water and electrolytes through its skin. Scientists first started to take notice in the 1970s when frog populations in Central and South America started disappearing.
By the 1990s Bd had spread around the world, likely aided by the laboratory trade in African clawed frogs and invasions of American bullfrogs. By 2007 it had been implicated in the decline or extinction of some 200 species.
Today, biologists consider it one of the biggest threats to amphibians globally.
Some research has offered a bit of hope for frogs, with a study published earlier this year in Science finding populations may be able to develop resistance to Bd.
But a new study published last week in Scientific Reports adds another hurdle for frogs, finding that hybridization between a native strain of Bd in Brazil and the one that's caused the global pandemic can lead to greater infection rates and illness strength than either can alone.
The study was conducted by researchers from universities in Brazil and the U.S. who looked at infection in several frog species native to Brazil's Atlantic Forest. They chose that region because of its high amphibian biodiversity (despite being one of the most deforested ecosystems on the planet) and because it's the only known region in the world where multiple strains of Bd coexist and hybridize.
Deforestation for agriculture and other development has reduced Brazil's Atlantic Forest to less than 15 percent of its original extent.Mongabay
Scientists believe the Brazilian strain of Bd (Bd-Brazil) evolved along with amphibian populations there and, because of this, is not as harmful to them as the Global Pandemic Lineage (Bd-GPL). But when the team compared infection and illness rates of the two types of Bd and a third hybridized one, they found that the latter had a significantly worse impact on two of the three frog species they examined.
The researchers write that this effect may be due to a phenomenon called "hybrid vigor" (also referred to as "heterosis"), by which the sudden surge in genetic diversity caused by hybridization leads to a more dramatic expression of advantageous physical traits. Take, for example, mules, which tend to be stronger (and smarter, according to at least one study) than either their horse or donkey parents. The same might be happening for Bd. Combining the genes of different strains of Bd could make a hybrid strain even stronger than Bd-GPL.
Another reason why hybrid Bd may be affecting frogs so profoundly is reduced genetic diversity in the frogs themselves. The authors write the pumpkin toadlet (Brachycephalus ephippium), one of the frog species that experienced high death rates when infected with the strain, lives in isolated, patchy habitats that "may have limited its exposure to pathogens throughout its evolutionary history or lowered its immunogenetic diversity."
The study's results appear to be already playing out in the real world, with previous research from the team finding that frog populations are declining and disappearing more quickly in the zone where the two Bd strains are known to hybridize.
And they warn that deforestation "may tip the host-pathogen balance further in favor of the pathogen" as habitat loss stands to increasingly isolate frog populations, further reducing their genetic diversity, while "even the most fragmented landscapes in the Atlantic Forest" don't seem to be a barrier to Bd.
The researchers say their results indicate frogs may face a future even more dire than anticipated as different strains of Bd spread around the world and combine into more harmful forms. They call for increasing global monitoring efforts to detect these shifts before they lead to new outbreaks.
"With globalization facilitating pathogen spread across continents, hybridization of chytrids might lead to new epidemic waves reducing amphibian biodiversity in both tropical and temperate regions," said study coauthor Gui Becker, assistant professor of biological sciences at the University of Alabama.
Some Tropical Frogs May Be Developing Resistance to a Deadly Fungal Disease – But Now Salamanders Are at Risk… https://t.co/xdA3kEf1Fy— EcoWatch (@EcoWatch)1526548206.0
Reposted with permission from our media associate Mongabay.
Each product featured here has been independently selected by the writer. If you make a purchase using the links included, we may earn commission.
The bright patterns and recognizable designs of Waterlust's activewear aren't just for show. In fact, they're meant to promote the conversation around sustainability and give back to the ocean science and conservation community.
Each design is paired with a research lab, nonprofit, or education organization that has high intellectual merit and the potential to move the needle in its respective field. For each product sold, Waterlust donates 10% of profits to these conservation partners.
Eye-Catching Designs Made from Recycled Plastic Bottles
waterlust.com / @abamabam
The company sells a range of eco-friendly items like leggings, rash guards, and board shorts that are made using recycled post-consumer plastic bottles. There are currently 16 causes represented by distinct marine-life patterns, from whale shark research and invasive lionfish removal to sockeye salmon monitoring and abalone restoration.
One such organization is Get Inspired, a nonprofit that specializes in ocean restoration and environmental education. Get Inspired founder, marine biologist Nancy Caruso, says supporting on-the-ground efforts is one thing that sets Waterlust apart, like their apparel line that supports Get Inspired abalone restoration programs.
"All of us [conservation partners] are doing something," Caruso said. "We're not putting up exhibits and talking about it — although that is important — we're in the field."
Waterlust not only helps its conservation partners financially so they can continue their important work. It also helps them get the word out about what they're doing, whether that's through social media spotlights, photo and video projects, or the informative note card that comes with each piece of apparel.
"They're doing their part for sure, pushing the information out across all of their channels, and I think that's what makes them so interesting," Caruso said.
And then there are the clothes, which speak for themselves.
Advocate Apparel to Start Conversations About Conservation
waterlust.com / @oceanraysphotography
Waterlust's concept of "advocate apparel" encourages people to see getting dressed every day as an opportunity to not only express their individuality and style, but also to advance the conversation around marine science. By infusing science into clothing, people can visually represent species and ecosystems in need of advocacy — something that, more often than not, leads to a teaching moment.
"When people wear Waterlust gear, it's just a matter of time before somebody asks them about the bright, funky designs," said Waterlust's CEO, Patrick Rynne. "That moment is incredibly special, because it creates an intimate opportunity for the wearer to share what they've learned with another."
The idea for the company came to Rynne when he was a Ph.D. student in marine science.
"I was surrounded by incredible people that were discovering fascinating things but noticed that often their work wasn't reaching the general public in creative and engaging ways," he said. "That seemed like a missed opportunity with big implications."
Waterlust initially focused on conventional media, like film and photography, to promote ocean science, but the team quickly realized engagement on social media didn't translate to action or even knowledge sharing offscreen.
Rynne also saw the "in one ear, out the other" issue in the classroom — if students didn't repeatedly engage with the topics they learned, they'd quickly forget them.
"We decided that if we truly wanted to achieve our goal of bringing science into people's lives and have it stick, it would need to be through a process that is frequently repeated, fun, and functional," Rynne said. "That's when we thought about clothing."
Support Marine Research and Sustainability in Style
To date, Waterlust has sold tens of thousands of pieces of apparel in over 100 countries, and the interactions its products have sparked have had clear implications for furthering science communication.
For Caruso alone, it's led to opportunities to share her abalone restoration methods with communities far and wide.
"It moves my small little world of what I'm doing here in Orange County, California, across the entire globe," she said. "That's one of the beautiful things about our partnership."
Check out all of the different eco-conscious apparel options available from Waterlust to help promote ocean conservation.
Melissa Smith is an avid writer, scuba diver, backpacker, and all-around outdoor enthusiast. She graduated from the University of Florida with degrees in journalism and sustainable studies. Before joining EcoWatch, Melissa worked as the managing editor of Scuba Diving magazine and the communications manager of The Ocean Agency, a non-profit that's featured in the Emmy award-winning documentary Chasing Coral.