Habitat destruction and disease are well-documented causes of amphibian decline. But now a new study has revealed that climate change is emerging as one of the biggest threats to these species (frogs, toads, salamanders, newts…).
The second major global assessment on the status of amphibians, which has analyzed 8,011 species of this class of vertebrates (2,286 new species studied for the first time), confirms the deterioration of these populations.
40.7% of these species – two out of every five – are threatened (that is, they are critically endangered, endangered or vulnerable, according to technical terminology).
This represents a worsening compared to the previous evaluation, since in 1980 37.9% of amphibians were threatened with extinction and in 2004 39.4%.
This is a global phenomenon, particularly serious in the case of salamanders and intense in the tropical region of America (from southern Mexico to Brazil).
It was already noted that diseases and habitat loss led to a worsening of the conservation status of 91% of amphibians between 1980 and 2004. But climate change has now aggravated concerns about their conservation status.
In fact, between 2004 and 2022, various threats have pushed more than 300 amphibians to the point of near extinction. And in these 20 years, climate change has been the main factor leading to a degradation of conservation status (39%, 119 species), above the loss of habitats and ecological degradation (37%, 112 species). .
This fact is particularly clear in the case of the amphibians typical of the Venezuelan plateau, which are very vulnerable to changes, since they cannot make vertical migrations or dispersions.
In general, climate change is especially worrying for amphibians, because they are sensitive to changes in their environment, say the authors of the study published in Nature.
“As humans drive changes in climate and habitats, amphibians are becoming climate captives, unable to move very far to escape the increasing frequency and intensity of extreme heat, wildfires, droughts and climate change-induced hurricanes,” said Jennifer Luedtke Swandby, one of the authors of the study and coordinator of the IUCN amphibian group.
In eastern Australia and the western United States, climate change is increasing the frequency, duration and severity of droughts and fires, exacerbating previous threats (disease and habitat loss).
Reduced rainfall due to climate change in the humid tropics of Australia and the Atlantic forests of Brazil is also expected to reduce the reproductive success of frogs due to their high dependence on beds with a mixture of soil and leaves to prevent desiccation. of the eggs.
The study also concludes that three in five salamander species are threatened by extinction, primarily as a result of habitat destruction and climate change, making this the most endangered group of amphibians in the world.
For example, five species of salamanders in the United States have seen their conservation status degraded due to an increase in the effects of fires and a reduction in soil moisture.
However, given the paucity of studies on the effects of climate change on amphibians, it is estimated that the true extent of these impacts may have been underestimated. Therefore, it is expected that as these studies increase and this knowledge improves, the conservation status categories may be downgraded.
North America is home to the most biodiverse salamander community in the world, including a group of lungless salamanders abundant in the Appalachians in the eastern United States.
Given this situation, conservationists are concerned that a deadly salamander disease found in Asia and Europe, called Batrachochytrium salamandrivorans (Bsal), could enter the Americas.
“Bsal has not yet been detected in the United States, but because humans and other animals can introduce the fungus to new places, it may only be a matter of time before we see the second global amphibian disease pandemic,” said Dede Olson. , ecologist and member of the IUCN amphibian specialist group and co-author of the study.
“It is critical that we continue to implement proactive conservation actions to prevent the spread of Bsal to the United States, including effective biosecurity practices for both wild and captive amphibians, and rapid detection and response measures,” says this expert. Currently, a strategic control plan is being monitored with close monitoring in which the public, private and government sectors collaborate
Additionally, twenty-seven species have been additionally considered critically endangered and are now considered possibly extinct, bringing the total to more than 160 critically endangered amphibians that are considered possibly extinct.
Since 2004, four amphibian species have been documented to have disappeared: the frog (Atelopus chiriquiensis) from Costa Rica; the sharp-snouted torrent frog (Taudactylus acutirostris) of Australia; the Craugastor myllomyllon, and the Jalpa false salamander (Pseudoeurycea exspectata), both from Guatemala.
The evaluation also found that 120 species improved their status on the Red List since 1980. In this sense, the study highlights the effectiveness of habitat protection measures, which explains why there have been cases of species that have become best category.
Of the 63 species that have improved as a result of conservation actions, in the majority of cases this was due to the protection of their habitats and management.
However, the creation of protected spaces is not always synonymous with improvement. That is why the “urgency to stop the degradation and destruction of their habitats” is invoked.
“The very history of amphibian conservation demonstrates how vital this information is,” said Adam Sweidan, president and co-founder of Synchronicity Earth.
“If the IUCN Red List had been updated in the 1970s, on a similar scale to today, we could have tracked the wide-ranging amphibian diseases 20 years before they devastated their populations. “It is not too late. We have this large amount of information, we have the Action Plan for Amphibian Conservation, but the plans and information are not enough. We need to act. We need to act quickly,” adds this expert.
“Amphibians are disappearing faster than we can study them, but the list of reasons to protect them is long and includes their role in medicine, pest control, their ability to alert us to environmental conditions and make the planet more beautiful ”said Kelsey Neam, another of the authors of the Nature study.
“And although our work focuses on the effects of climate change on amphibians, it is also vitally important to highlight that the protection and recovery of amphibians is a solution to the climate crisis due to their key role in keeping animals healthy. ecosystems that store carbon. As a global community, it is time to invest in the future of amphibians, which is an investment in the future of our planet,” adds this specialist.
Conservationists will use the information from this study to help advise on global conservation action plans, prioritize conservation actions globally, seek additional resources, and influence policies that can help reverse the negative trend for amphibians.
