Deforestation efforts have long been linked to a wide array of severe environmental challenges and a generally less healthy planet. Now, new research says this ongoing loss of forest land on Earth may also be behind another threat to human survival that has come under fresh scrutiny in a Covid-19 world: the rise of infectious diseases.
While many often associate deforestation with the well-documented forest loss in the rainforests of South America and Africa, experts have long warned that reckless changes to Earth’s forests could have global consequences. Deforestation has resulted in a sweeping loss of habitats for endangered creatures, greatly contributed to atmospheric climate change and has gravely threatened the livelihoods of indigenous populations that rely on the resources of the forest to survive.
There is one consequence of Earth’s ever-depleting forests that has generally received less exploration among scientific circles, however; how exactly deforestation contributes to the spreading of potentially dangerous diseases. While some studies have linked deforestation with spikes in malaria outbreaks in Brazil, little has been done to document how deforestation influences the spread of diseases on a global level --- until today.
In a new study published Tuesday in Frontiers in Veterinary Science, researchers reveal they have completed a comprehensive look into how changes to Earth’s forests have contributed to infectious disease outbreaks around the entire world.
Their findings suggest that deforestation, commercial palm plantations and other reforestation activities have a direct correlation with a rise in two major disease types: vector-borne diseases such as Lyme disease and malaria that are transmitted through mosquitoes and ticks, and zoonotic diseases like the novel coronavirus that come into being by making a jump from an animal host to a human one.
Serge Morand, lead author of the study and researcher at the Centre National de la Recherche Scientifique (CNRS) in France and Kasetsart University in Thailand, says that while researchers are still trying to figure out exactly how this relationship functions, it is clear that human-led changes to the environment are making it easier for diseases to thrive and spread.
"We don't yet know the precise ecological mechanisms at play, but we hypothesize that plantations, such as oil palm, develop at the expense of natural wooded areas, and reforestation is mainly monospecific forest made at the expense of grasslands," Morand said with the release of the study. "Both land use changes are characterized by loss of biodiversity and these simplified habitats favor animal reservoirs and vectors of diseases."
Researchers took a hard look at forest changes that took place between 1990 and 2016, and compared those changes with population densities and disease outbreak data.
After poring over this wide spectrum of information, researchers found that previous hypothesis suggesting a correlating relationship between forest changes and disease outbreaks largely held up. Experts say they found a striking connection between deforestation and epidemics, such as Ebola and malaria outbreaks, in a host of a tropical nations like Brazil and Peru. They also found that grassland conversion efforts in more temperate countries like the United States and China had a direct link with rises in vector-borne diseases such as Lyme disease.
Experts further determined that palm oil plantations, even in nations with relatively little deforestation, still shared a connection with disease outbreaks. In Asian nations like China and Thailand they found expansions in palm oil plantations directly resulted in increased outbreaks that came from mosquitos, like zika and yellow fever.
Their findings point to a clear and striking message: healthier forests help to make a healthier planet. As the world continues to reel from the devastating consequences born from Covid-19, experts stress as that as we look toward combating these viral outbreaks in the future, we need to take into account how we prioritize the health and wellbeing of Earth’s countless forest domains.
“We hope that these results will help policymakers recognize that forests contribute to a healthy planet and people, and that governing bodies need to avoid afforestation and agricultural conversion of grasslands," Morand said. "We'd also like to encourage research into how healthy forests regulate diseases, which may help better manage forested and planted areas by considering their multidimensional values for local communities, conservation and mitigation of climate change."