WHY DO
DISAPPEAR
Chytrid fungus
Batrachochytrium dendrobatidis
Batrachochytrium dendrobatidis
FROGS
Nearly a third of the world's amphibians are in danger of extinction
The chytrid fungus is a killer of frogs
FROGS
300-350
200
32%
is the common name for a group of animals in the order of the tailless amphibians
Approximately that many frog species have disappeared since 1970
million years ago
At the end of the Devonian period of the Paleozoic Era, the first amphibians appeared on Earth; frogs survived three mass extinctions, including the one that wiped out the dinosaurs
Of the approximately 6,000 amphibian species, 12 percent of bird species and 23 percent of mammal species are endangered compared with 12 percent of bird species and 23 percent of mammal species
Solving the amphibian extinction crisis represents the greatest problem of species conservation in human history
why does
this tragedy
happen?
In some places, the decline in frog populations is due to habitat destruction, pollutants, climate change, and the introduction of alien predators, parasites, and competitors
Chytridiomycosis
1998
Now chytridiomycosis is the worst animal epidemic known to mankind!
Every year there are many publications devoted to this problem, for which there is still no solution
Researchers have identified a chytrid fungus called Batrachochytrium dendrobatidis (Bd). The fungus has infected more than 500 amphibian species, mostly in North and South America and Australia, and destroyed as many as 90 species
Since 1893, there had been mass extinctions of frogs and toads in Australia unlike anything scientists had seen before. It went so far that streams were literally swamped with the corpses of animals!
And to infect the next individual, contact with water where the zoospores float, contact with an infected frog, or even contact with soil where the frog has walked or jumped
The fungus infects the amphibian's skin and starts growing inside it, the skin begins to keratinize, which results in stopping the amphibian from working. The amphibian slowly suffocates or dies from kidney failure, or simply from cardiac arrest
"You are working in your clearing with, let's say, 30 species of frogs jumping around at the same time. Suddenly, your colleague finds a dead frog a kilometer away from the clearing, clearly dead from chytridiomycosis.
And you realize that in a couple of days in your whole clearing where you've been doing years of scientific work, instead of 30 species there will be two. And everything will be covered with the decomposing corpses of the other 28 species of frogs..."
17-50
km/year
Distribution of the fungus Batrachochytrium dendrobatidis worldwide
FUNGUS
appearance
It most likely came to the U.S. with spore frogs (Xenopus) from Africa. Until the 1960s, they were used as a test for pregnancy: adding a pregnant woman's urine, containing certain hormones, to the aquarium causes the frogs to drop their eggs
After the advent of modern pregnancy tests, these frogs became unnecessary, and they were simply thrown into water bodies. Except that they turned out to be infected. Spurred frogs themselves do not dying from violent pathogen: most likely, in the process of evolution they have learned to coexist
frogs need
land AND
water
Natural droughts cause serious damage to a population or even an entire species. There is evidence of the effects of climate change on frog survival rates and abundance
They are very sensitive to habitat changes because they spend their time migrating between land and water throughout the year. Water sources such as wetlands, ponds, and streams are necessary for laying eggs and raising young, but many adults spend most of their time on land.
human impact
The other half -"enigmatic decline," or "the reasons for the decline are enigmatic
overfishing in nature for sale, food, use in folk medicine
habitat destruction (deforestation, drainage of swamps, road construction, etc.)
use of pesticides
habitat destruction (deforestation, drainage of swamps, road construction, etc.)
use of pesticides
Keeping in captivity
As pets, amphibian enthusiasts often keep frogs in terrariums, aquaterrariums and aquariums, and also breed and use them as live food for some "home zoo" and/or "living corner" representatives
About half of amphibians disappear for fairly classic reasons
frog venom
Frog venom has long been used to make poisoned arrows and darts. The South American Indians used the skin secretions of the dreaded leafhopper to make poisoned arrows. These poisons are being investigated for their application in medicine
22 000
mice
batrachotoxin
homobatrachotoxin
The combination of the two toxins present in these secretions is so strong that the venom of a single frog is presumably enough to kill
Cooking
Wild frogs are eaten by humans every year, according to the UN
1 billion
tons
Frog’s feet are consumed in different countries. The main importers of paws France, Belgium, Luxembourg and USA, and the main exporters Indonesia and China. The annual sales turnover of American bullfrog, which is commercially bred in China, reaches 2.4 thousand tons
research area
The first successful experiment on cloning vertebrates by nuclear transplantation. Robert Briggs and Joseph King cloned a frog by somatic cell nuclear transplantation (later Dolly the sheep was cloned)
Frogs are used in embryology research
The alkaloid epibatidine, a painkiller 200 times more potent than morphine, has been found in species of the genus Leafhoppers
A peptide suspected of blocking the reproduction of the HIV virus has been isolated from the skin of frogs
Frogs are used in practical dissection classes in schools and universities
the first cloned animal in human history
1952
Joseph King
Robert Briggs
The alkaloid epibatidine
Dissection — dissection, autopsy, anatomical examination of animal corpses
conservation measures
Survival Secret
Like Covid-19 in humans, fungal Bd infection can affect humans very differently, even within the same species. By figuring out the secret to human survival, the researchers hope they can replicate these conditions for other frogs and tilt the odds in their favor
It is also known that the Bd fungus prefers cool, moist areas, and it cannot grow much higher than about 28 degrees C
Smithsonian researcher Blake Klock uses radio transmitter to track harlequin frogs
Manipulation of frogs
Exposing several species of frogs to Bd induces an immune response that protects them from future infection. Ideally, you can vaccinate a frog without exposing it to any infection
Habitat change
Some researchers are looking for ways to manipulate the environment itself. By covering clay bricks with a mini greenhouse, he can easily create hot spots with temperatures of 30 degrees Celsius and higher. Green and gold bell frogs will climb inside the tents, killing Bd on their skin
Bathing frogs in solutions with probiotics
Bathing with beneficial bacteria can also help frogs resist chytrid
Scientists smear skin of Panamanian golden frog looking for traces of genetically modified antifungal bacteria
Dr. Matthew Becker weighs a Panamanian golden frog participating in a probiotic study
Development of genetically modified bacteria
Frog skin under a microscope
Help from organizations
The International Union for Conservation of Nature (IUCN) Species Survival Task Force (DAPTF) has been formed within the framework of the International Union for Conservation of Nature (IUCN) Commission on Species Survival. The World Association of Zoos and Aquariums (WAZA) has teamed up with two chapters of the IUCN Species Survival Commission to form the Amphibian Ark (AArk). Since 2006, the Amphibian Ark has helped zoos and aquariums save species
what is the
extinction?
threat of frog
Frogs are considered natural bioindicators, something that measures the health of the environment
Less research and testing
The food chain collapses
Increased greenhouse gas emissions
There will be many more insects
Disease outbreak
Tadpoles help keep water clean
?
?
?
?
?
?
11% of all Nobel Prize winners in medicine and physiology have used frogs in their research. Scientists use amphibian embryos to test the effects of toxins, mutagens and teratogens, also for genetic and genomic studies. This has allowed scientists to study Alzheimer's disease and Amyotrophic Lateral Sclerosis
Amphibian tadpoles eat algae. Without frogs, many water bodies will develop algae blooms that will make the water too toxic to drink or harvest for food
The number of animals that eat frogs will go extinct, then the animals that eat them will starve, and their population will decline. This will continue up the food chain
With frogs as a natural population control, insect infestations will become rampant. Insects can damage crops, which can lead to the use of more chemicals and pesticides. And this is probably one reason why frogs are dying out in the first place
When trees and plants die, they release carbon dioxide as they decompose, and insects eat them, and they provide nutrients for other vegetation. However, if there are too many insects, they eat too many decomposing plants, and the vegetation doesn't get the nutrients it needs to survive. If there are too few insects, the forest will suffocate in its own waste, releasing more carbon dioxide. There will be fewer trees and plants to absorb it. All this will lead to higher levels of greenhouse gases. Forests of all kinds around the world will rot and die
Without frogs, the mosquito population would explode. Mosquitoes carry diseases including malaria, Zika virus, West Nile virus, dengue fever, Lyme disease, encephalitis and leishmaniasis. Health systems around the world will be overwhelmed, and this will increase mortality rates
Avoid using pesticides on the lawn and in the garden
How you can help the frogs
Frogs are especially sensitive to the chemicals used in pesticides. Avoid the use of pesticides, and you can also help reduce pesticide use in agriculture by choosing organic products
STOP PESTICIDE
Donate to the Frog Conservation Initiative
There are many conservation activities around the world to prevent the extinction of frog species. You can donate to Amphibian Rescue & Conservation in Panama or to Amphibian Ark, an organization supported by the International Union for Conservation of Nature and the World Association of Zoos and Aquariums
