Over the next 100 years, our planet’s tropical amphibians may go extinct.
A new study found that in the last 30-40 years, 200 frog species have gone extinct around the world and that hundreds more may disappear in the next century. Habitat loss and destruction, climate change and deadly diseases are the factors that put these amphibians at risk.
John Alroy, associate professor in biological sciences at the Macquarie University in Australia authored the study. To estimate the number of extinct species, he looked at samples from museums of amphibians and reptiles in nine different regions and compared them to published observations.
Some of the worst rates of extinction were in Latin America, possibly due to the chytrid fungus. Alroy says:
“There’s pretty good agreement that the biggest threat for amphibians is the [chytrid] (Batrachochytrium dendrobatidis) fungus. However, I think habitat destruction might have a bigger role than people realize — and future climate change is going to have huge and unpredictable consequences.”
While tropical amphibians face high extinction rates, those in the Southeast United States do not. In addition, reptiles in all regions faced low extinction rates except in a few areas like Madagascar.
As the planet warms, cold-blooded animals will have trouble adjusting. According to a study by two biologists, cold-blooded animals, which cannot regulate their internal temperatures, will struggle with climate change.
The biologists, Alex R. Gunderson and Jonathon H. Stillman from the University of California, Berkeley and San Francisco State University, analyzed 230 cold-blooded species from 112 published studies on plasticity – or the ability of animals to modify their thermal tolerance when they experience new environmental temperatures. They found that cold-blooded animals have an particularly tough time adjusting and that on average most aren’t flexible to warming climate changes.
“Overall, we found that even though all of the animals have some plasticity, they all have relatively low levels of plasticity. As environmental temperatures rise due to global warming, the animals will get closer and closer to their thermal limits, and plasticity won’t do much to help them.”
Gunderson and Stillman discovered that the plasticity of animals differs based on their habitat. So cold-blooded species like lizards and insects have less plasticity than fish and crustaceans, and thus will have a more difficult time surviving in the changing climate. Gunderson explains:
“The difference between terrestrial and aquatic animals is that the aquatic ones have a higher capacity to adjust, but it is still relatively low. Ideally, if temperatures went up three degrees, the animals’ tolerance would go up three degrees as well. But that’s not what we see.”
The study’s analysis suggests that certain animals – such as lizards, insects and snakes – can’t depend on plasticity. Rather, they will have to rely on behavior modifications, like moving to greater altitudes or more shaded habitats. But unfortunately, not all animals live in regions where such behavioral adaptations are feasible and in those cases, the species will have to evolve higher tolerance for the heat in order to survive.
As we venture farther into 2016, it’s always good to reflect back on the previous year. Today, we are reflecting on animals that were either declared endangered or were upgraded from endangered to critically endangered in 2015.
1. Mexican Wolf
The U.S. Fish and Wildlife Service (USFWS) declared the Mexican Wolf as endangered earlier in 2015. Over-hunting almost wiped out the entire population 40 years ago. Now, the Mexican Wolf has new protections to conserve this rare mammal.
The USFWS placed multiple species of sawfish on the endangered species list in 2015. Several populations have fallen victim to overfishing and negative human factors.
3. Steppe Eagle
The Steppe Eagle was upgraded to “endangered” this year by the IUCN because of changes to the raptor’s environment. Habitat disturbances, such as agricultural development and a veterinary drug spreading toxic effects through its ecosystem, have caused the eagle’s population to drastically drop.
4. New Zealand Sea Lion
The IUCN classified the New Zealand Sea Lion as endangered due to “fishing-related mortality” and other threats from disease and food limitations. It is one of the rarest sea lions in the world with a population of around 10,000 and decreasing.
5. White Headed Vulture
In 2015, the IUCN upgraded the status of the White Headed Vulture from threatened to critically endangered. The vulture’s population has declined because of human threats, including poisonings and persecution.
6. Great Green Macaw & Military Macaw
The USFWS listed both the Great Green Macaw and the Military Macaw as endangered in October, 2015. The two species’ already small populations are declining due to poaching and habitat loss, fragmentation and degradation.
7. Ishikawa’s Frog
The IUCN declared the Ishikawa’s Frog, a Japanese amphibian, as an endangered species in 2015. The frog population is in serious decline because of habitat loss from dam and road construction.
8. Honduran Emerald Hummingbird
The USFWS classified the Honduran hummingbird as endangered in 2015, which gives federal officials in the U.S. the authority to prosecute anyone smuggling the bird across the border. The population has dropped to 5,000-10,000 breeding pairs after facing habitat loss and other human-related changes.
9. Narrow-striped Mongoose (also known as Boky Boky)
In 2015, the IUCN placed the Narrow-striped Mongoose, also know as the boky boky, on the endangered list. The small Madagascan mammal’s population has been negatively affected by hunting, logging and several environmental factors.
10. Splendid Toadfish
The IUCN upgraded the Splendid Toadfish from threatened to endangered in 2015 because of tourism and over-fishing. It is a mud-dwelling fish that lives in the waters of Cozumel and Belize, but has experienced habitat loss with decreasing coral reefs.