Amphibians such as frogs and salamanders are incredibly sensitive to changes in their environment. Whether it’s a temperature change or a change in water quality, amphibians are likely to notice. New research has revealed that 2% of amphibians are already overheating due to global warming, and it’s expected to get much worse. Most amphibians are born in the water with gills to breathe. As they grow into adults, they lose their gills, develop lungs, and breathe through their skin. Because their skin takes in the air and water around them, they are uniquely vulnerable to threats from environmental changes, like rising temperatures.
Climate change and habitat loss threaten the survival of the poison dart frog.
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How Do Amphibians Regulate Their Body Temperature?
Amphibians are ectothermic, meaning they use the environment they are in to regulate their internal temperature. Mammals, on the other hand, generate internal heat to stay at the right temperature. When ectothermic animals feel cold, they look for a warm, sunny spot to sit in. When they get overheated, they head to the shade or go in the water. This makes amphibians even more susceptible to temperature change than other animals. Scientists call amphibians an “indicator species.” Scientists can study indicator species to understand the overall health of an ecosystem.
Natural Habitats Are Unsurvivable for 2% of Amphibians Due to Rising Temperatures
In a recent study published in the journal Nature, scientists found that out of 5,203 amphibian species, 104 individual species are already overheating in today’s climate. The scientists compared the heat tolerances of amphibians across different habitats. They examined conditions under the current level of global warming, as well as two future scenarios: one with a 2-degree Celsius increase and another with a 4-degree Celsius increase.
“We wanted to better understand the risk climate change poses to amphibians, and so put together the most comprehensive compilation of heat tolerance limits to date,” says Patrice Pottier, lead author of the study and a postdoctoral researcher at the University of New South Wales, in a statement.
The Dangers of a Warming World
The researchers discovered that if the world warms to the 4-degree Celsius scenario, over 400 amphibian species, or about 8% of those studied, do not have the heat tolerance to survive the change in their ecosystems. That’s a rise from 2% to 7.5%. “Heat tolerance limits are the maximum temperature amphibians can tolerate before their physiological systems fail,” Dr. Pottier explains.
Global climate change is contributing to droughts, causing the Euphrates River to dry up, affecting amphibians and other wildlife that call the river home.
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According to a report from New Scientist, despite attempts to limit greenhouse gas emissions, the world is expected to heat up between 1.9 and 3.7 degrees Celsius by 2100. It gets even worse in the 22nd century. Dr. Pottier says, “There is an increase in impact between the current climate and a 2°C rise in warming; however, the impacts increase disproportionately under a 4°C rise. Going above 2°C of global warming could be a tipping point, leading to many local extinctions.”
Terrestrial Amphibians Are the Most at Risk
The scientists found that amphibians living in water or in trees were better able to tolerate excessive heat events, while terrestrial amphibians were the most at risk. Terrestrial amphibians were the most at risk. Regionally, the researchers found that tropical species in the southern hemisphere were the most in danger of overheating. In the northern hemisphere, amphibians living outside the tropics are at a higher risk.
Amphibians Are Already Under Threat
The International Union for Conservation of Nature Red List of Threatened Species (IUCN Red List) issued a report that warned that 41% of amphibians are currently threatened by global extinction. Salamanders are in the most danger, with three out of every five species at risk of extinction. According to the report, climate change is a leading threat.
The Chinese giant salamander is one of the amphibian species that are critically endangered.
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What Can We Do to Help?
Beyond curbing carbon emissions, Dr. Pottier says, “vegetation and water bodies are critical in buffering amphibians during heat waves.” He explains that providing amphibians “with enough water and enough shade” can help them “survive extreme heat events.”
Scientists have been working to find solutions to address the current crisis facing amphibians. Researchers from Macquarie University and the University of Melbourne created mini medical spas for frogs suffering from chytridiomycosis. This is a fungal disease that is both fast-spreading and fatal for amphibians. The researchers built small shelters for the animals where they could stay warm. If the shelters keep the frogs warm enough, the fungal disease is less likely to develop. Scientists are continuing to work to find creative and low-cost ways to protect amphibians from changing environmental threats.
In the end, the most effective way to help amphibians and other species on the planet is to take action to prevent or limit climate change. Dr. Pottier says, “All efforts to limit global warming are needed to protect the world’s amphibians.”
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