Climate change is a fact and for the time being this phenomenon is hitting the animal kingdom harder than humans. This is also the case with the frog, which has been going extinct in Spain and Portugal since the end of the 1980s. Moreover, scientists revealed the cause this week.
In recent decades, various animal species have already had to leave their natural habitats in an attempt to survive elsewhere. However, some species fail to adapt and die. An example of this is the frog in Spain and Portugal. Since the late 1980s, this species is becoming extinct on the Iberian Peninsula and the number of frogs has declined by as much as a third in the past 5 years.
Climate change causes massive frog deaths
Researchers attribute this entirely to global warming. The number of frogs in Spain is disappearing at an increasing rate, mainly due to the disappearance of the Spanish wetlands, pollution of rivers, weed killers that prevent the males from being fertile and a thinner ozone layer that exposes the young frogs to too much UV radiation.
Ranavirus kills frogs and thrives in warmer temperatures
Between 1980 and 1990, it was already noted that there were fewer frogs, even in areas where human influence was minimal, such as in reserves. Now a study, published Tuesday in the scientific journal of iScience, shows that frogs in the Iberian Peninsula are dying en masse due to an increasing number of viruses that are deadly to frogs.
Scientists call these viruses epizootic, contagious diseases that only circulate among animals that affect an abnormal number of animals in the same place and spread quickly. For amphibians, that is the ranavirus. Ranaviruses are large viruses that can infect fish, reptiles and amphibians. The viruses associated with amphibians fall into three main groups: frog virus 3, midwife toad virus and Ambystoma tigrinum virus.
Link between emergence of ranavirus and global warming
Now it seems as if the ranavirus is the main culprit. Yet the same scientists show that the ranavirus can develop and spread better due to global warming. Moreover, the Iberian Peninsula in particular would be a hotspot for viruses like this one.
Frogs’ biggest enemy are viruses
SOSanfibios, an organisation that fights dangerous viruses and diseases for amphibians, also endorses these conclusions. The biggest enemy of amphibians is emerging viruses. These are currently the main causes of death from the mass frog deaths in Spain and Portugal. They are caused by introduced pathogens (fungi and viruses) that humans have been spreading around the world for decades. Furthermore, these viruses indeed thrive at higher temperatures.
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