Frogs have colonised almost every corner of the planet, from the frozen Arctic tundra to the dry deserts of Namibia, but a third of all species are in danger of extinction
In total, there are around 6,500 known species of frogs and toads, and they come in a huge variety of shapes, sizes and colours. Frogs tend to be springier and damper, with long legs made for bouncing, while toads are stocky and often dry, with characteristic warts. Many frogs are patterned to disguise themselves amongst their surroundings, while others are painted in bright warning shades to alert predators to their toxic skin. Wood frogs can stop their hearts for days at a time to survive being frozen. Desert rain frogs dive beneath the sand to escape the effects of the Sun, and tomato frogs make a toxic white glue that irritates predators. Some cover themselves in wax so that they don’t dry out, and others puff themselves up to make life harder for predators. These quirky little animals are amphibians; they cannot make their own body heat, and they go through a process of transformation from juveniles into adults. Frogs have no necks, and cannot turn their heads. Their skin is permeable, meaning that they can use it to absorb water and even oxygen directly through their skin. These incredible creatures gobble up insects and other pests, help keep fresh water clean, and provide a convenient meal for countless animals. But as many as a third of all species are in peril.
Why frogs need our help
Amphibians have been around for 300 million years, but today they are struggling. Of all frogs assessed by the IUCN, nearly a third are threatened or extinct, and a lot of their problems are down to habitat destruction, disease and invasive species. Frogs are particularly vulnerable to changes in their environment. Their delicate skin and eggs need to be kept moist, and are sensitive to changes in the seasons, droughts and increased exposure to UV. They are also very sensitive to pollutants like heavy metals, which can leach into water as a result of mining and other industrial activity. Stresses like these might not kill the frogs immediately, but they affect their breeding cycles and their ability to resist disease. And disease is a real problem for amphibians at the moment. The transport of different species across the world for the pet trade, research, food and pest control has spread diseases through frog populations, and with devastating effects. One of the worst culprits is chytridiomycosis, a fungus that has already claimed an entire species – the sharp snouted day frog – and has triggered serious declines in other frog populations across the world. Urgent research is underway to find out how to stop more extinctions.
A world without frogs
Amphibians are sometimes described as the ‘canaries in the coal-mine’, referring back to birds taken down into mines to detect the presence of deadly gases. The canaries would die first, warning the miners that something was wrong. With their damp, absorbent skin, frogs are extremely vulnerable to climate change and pollution. They are in grave danger, and it is seen by conservationists as a warning sign that other species will soon be in peril too. If frogs were to disappear, whole ecosystems would suffer. Tadpoles help to control algae, and without them, the quality of the water changes. Adult frogs keep insect numbers down, including munching on the mosquitoes that carry malaria. And that’s not to mention the species that rely on frogs for food; eggs, tadpoles and adult frogs provide protein for a huge range of species, from tiny spiders, all the way up to snakes and birds. And if damage to the food web isn’t enough, there is huge untapped scientific potential. Frog skin is unusual, and many species produce strange chemicals. Poison dart frogs are perhaps the most famous, capable of killing dozens of people with their toxic secretions, but there are dozens more with skin that could aid wound healing, defeat infection, and even lower blood pressure. Frogs need to be protected.
World’s Most endangered frogs
Morelet’s tree frog
Island forest frog
Lehmann’s poison frog
Ginger tree frog
What makes frogs and toads worth saving?
All amphibians are worth saving as they are extremely important to how their ecosystems function. Many frogs have aquatic tadpoles which are important in the transfer of nutrients between aquatic to terrestrial ecosystems. Frogs are also important pest controllers, as well as being key prey for the survival of many other species.
You’re currently working on a project to save mountain chicken frogs, what does that involve?
The mountain chicken frog is the largest native amphibian in the Caribbean. Recently, the remaining populations have crashed due to the chytrid fungus, a major cause of amphibian mortality. When chytrid struck the island of Dominica in 2002, the Zoological Society of London initiated a Darwin-funded project to study the disease and build capacity on the island to monitor chytrid. Our current conservation strategy covers both islands [Montserrat and Dominica]and focuses around three points; stopping the species going extinct in the wild, understanding how we can restore the species on these islands and building capacity within the region to lead this restoration into the future.
And what does the future look like for those frogs?
With the strength of the collaborative conservation project and the dedication of all those involved, I think we can remain optimistic about the future of the frogs. Although on Montserrat we only know of two mountain chicken frogs left in the wild, a male and female, on Dominica there is still a small wild population, and some evidence that they are breeding.
What can our readers do to contribute to frog conservation?
We can all start by protecting frogs on our doorstep. Building a pond in your garden is a great way to encourage wildlife. It is however important to let amphibians colonise garden ponds by themselves, as moving amphibians or their eggs between ponds has the potential to spread disease.
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