“Climate change over the last century has made the habitat in the southern Chinese Yunnan province suitable for more bat species,” a researcher in the University of Cambridge’s Department of Zoology Dr Robert Beyer said.
The researchers created a map of the world’s vegetation as it was a hundred yeas ago, using the data about temperature, precipitation, and cloud cover. Then they used the information about the vegetation requirements of the world’s bat species to define the global spread of each species in the early 1900s. Comparing this to current distributions allowed them to see how bat ‘species richness’, the number of different species, has changed across the globe over the last century due to climate change.
The research showed large-scale changes in the type of vegetation in south Chinese Yunnan province and adjacent regions in Myanmar and Laos during the past century. The climate changes, including the increases in temperature, sunlight, and atmospheric carbon dioxide - which affect the growth of plants and trees - have changed natural habitats from tropical shrubland to tropical savannah and deciduous woodland. This created a suitable environment for many bat species that predominantly live in forests.
The study found that an additional 40 bat species have moved into the southern Chinese Yunnan province in the past century, harboring around 100 more types of bat-borne coronavirus.
This region could become a ‘hot spot’ for the spread of SARS-CoV-2.
“As climate change altered habitats, species left some areas and moved into others - taking their viruses with them. This not only altered the regions where viruses are present but most likely allowed for new interactions between animals and viruses, causing more harmful viruses to be transmitted or evolve,” Beyer said.
The world’s bat population carries around 3,000 different types of coronavirus, with each bat species harboring an average of 2.7 coronaviruses - most without showing symptoms.
An increase in the number of bat species in a particular region, driven by climate change, may increase the likelihood that a coronavirus harmful to humans is present, transmitted, or evolves there.
Most coronaviruses carried by bats cannot jump into humans. But several coronaviruses known to infect humans are very likely to have originated in bats, including three that can cause human fatalities: Middle East Respiratory Syndrome (MERS) CoV, and Severe Acute Respiratory Syndrome (SARS) CoV-1 and CoV-2.
“Understanding how the global distribution of bat species has shifted as a result of climate change may be an important step in reconstructing the origin of the COVID-19 outbreak,” Beyer noted.
The region identified by the study as a hotspot for a climate-driven increase in bat species richness is also home to pangolins, which are suggested to have acted as intermediate hosts to SARS-CoV-2. The virus is likely to have jumped from bats to these animals, which were then sold at a wildlife market in Wuhan - where the initial human outbreak occurred.
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