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amphibiens

Amphibians: The biggest extinction’s wave of our time

We wouldn’t believe it, and still… according to the IUCN, 23 928 out of the 82 954 studied species are endangered. Out of these 23 928 species, 13% are birds, 26% mammals and 42% amphibians!

As you already guessed, those animals are the most endangered living group on our planet nowadays. Amphibians exist since approximately 300 million years, and yet, for the last decades, more than 120 species have disappeared.

Causes of mortality of amphibians

The decline’s factors of the amphibians’ population are numerous: destruction and modification of their living environment, hunting, pollution, invasive species, etc. Two causes stand out and seem to be the main factors of this disaster.

The changing of their living environments

Ecosystem’s disruptions, whether chemical or physical, always have a very harmful impact on amphibians.

Waterways’ pollution is especially catastrophic since it impacts the mating areas of these animals. According to a study from the “Service de l’observation et des statistiques” (observation and statistics service) published end January, 90% of the French waterways contain traces of herbicide and insecticide. This pollution is mostly due to intensive farming, but also to the maintenance of our gardens, and to a lesser extent to the maintenance of the highways.

Physical disruptions also modify ecosystems where the amphibians live. Building a road can have a huge impact on a species’ chances of surviving. During Spring, many amphibians leave their winter’s quarters to reach watering places where they mate. They then have to face many obstacles and roads can be extremely murderous. A toad can need 20 minutes to cross a road! Studies showed that 60 vehicles per hour can eliminate close to 90% of a population.

Infectious disease chytridiomycosis: a deadly fungus

In 1998, the PNAS (Proceedings of the National Academy of Science in the United States of America) discovered a fungus, Batrachochydium dendrobatidis, which seems to be responsible to the “death wave” of the frogs in South America. Transmitted through contact between batrachians or water, it sneaks through the skin of the animal before rotting it suffocating the victim.

Nowadays, batrachians became the icons of the lowering of our biodiversity and the infamous sixth mass extinction. Chytridiomycosis caused the lowering and the extinction of more than 200 species. Some biologists consider that, excepting human, this fungus is probably the biggest threat for biodiversity.

In some areas in Central America, it is responsible for the elimination of more than 40% of the amphibian species. If we find it all around the world, it is among others due to the moving of species made by humans, since this phenomenon happens in regions which shouldn’t have been infected by this fungus such as Africa. We also count many losses in Europe, Australia and North America.

According to an inquiry, global warming might greatly influence the capability of the amphibians to protect themselves from this disease, modifying their biological capabilities.

The important part of the amphibians in the environment’s balance

Why is it so important to protect the amphibians? Apart from the pleasure that the contemplation of these little pieces of jewellery gives, they play an essential part in our environment’s balance.

  • Amphibians are one of the main links of the food chain in many ecosystems: predators as much as preys, they regulate the population of the animals they eat. Moreover, being food for many species, amphibian’s disappearance might compromise the survival of many reptiles and mammals which eat them.

  • These strange creatures also have a “chemical” part on their environment: during their metamorphosis (going from a larval to an adult form), amphibians handle the transfer of essential nutrients from the water to the ground. That’s why moving frogs from their natural habitat can have a considerable impact on algae, invertebrates, predator’s dynamics, plant litter’s decomposition or even the nutrient cycling. Therefore, the preservation of the diversity of those species is essential if we want to live in a healthy environment.

To sum it up, the lowering of the amphibians’ population – and their possible extinction – is already and would be a catastrophe. Our environment would be totally unbalanced in terms of fauna as well as flora.

What is an amphibian?

Amphibians, formerly called batrachians, are tetrapod (4 legged) vertebrates of the class Amphibia. This latest splits into three orders:

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Les anoures (carpeaux, grenouilles)

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Les urodèles (salamandres, tritons)

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Les apodes, aux pattes atrophiées

Their specificity consists of living in two different milieus during their life. In fact, “amphibian” means “which lives in two different environments.”

Indeed, most of these animals are born in the water and live there as larvas. During this period, they breathe thanks to gills. After their metamorphosis, the amphibians (now having lungs) live on the solid ground and come back to the water to breed and lay their eggs.

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However, if amphibians have lungs, many of them also partially – or sometimes even exclusively – breathe through their skin which is permeable. Moreover, just like reptiles, these animals are ectothermic, meaning that their body temperature varies with the external temperature.

Because of this specificity, amphibians are extremely sensitive to the modification of their environment and are the first affected by the ecosystem’s modification.

Be thought of as ecological indicators, the death of hundreds of them means that a large-scale environmental disaster is about to happen.

Take action for the amphibians!

Here are the addresses of some associations which actively combat for the sake of amphibians, go and check it out!

  • The SNPN: National Society for the Protection of Nature [in France].
  • ASPAS: Association for the Wildlife Protection
  • Bufo: Studies and Protection for the Amphibians and Reptiles in Alsace
  • Karch : Center of Coordination for the protection of amphibians and reptiles in Swiss.
  • Hyla 63

You can also take action at home to locally protect amphibians:

Eat organic food when you can. By supporting an environmentally aware agriculture, you directly help to reduce the use of phytosanitary products which badly affecting amphibians.

 ♣ Do not forget to put aside the insecticides and the chemical weedkillers when you take care of your garden. More than harming frogs and other amphibians’ health, you also deprive them of their food.

 ♣ don’t eat frog’s legs. In the 90’s, Europeans were consuming 120 millions of them by themselves.

 ♣ To conclude, if you have a garden and you love nature, don’t hesitate to give a part of it to these tiny beasts: drop some dead wood off, big rocks, etc, so they can settle in. You can also let the aquatic vegetation growing in the water, which gives them shelter and a laying place for their eggs.