Despite knowledge of the consequences, humans continually engage in unsustainable activities that put the future of our planet, and thus our own species, at risk. A classic example is the Amazon rainforest which, among others, we are tearing down at an alarming rate, and it’s not good. The situation is now so dire that more than half of its tree species are likely globally threatened. If confirmed, that would drive up the number of threatened plant species on Earth by a staggering 22 percent. These findings have been published in Science Advances.
“When people hear about deforestation and threats to species, one inclination is to believe things have gotten worse,” study author Nigel Pitman told IFLScience. “I want to emphasize that is not what we are reporting. Before this study we just didn't have a good idea about the proportion of trees that were threatened; this is one of the first good estimates we have.”
Deforestation across the Amazon is not a new thing: Throughout much of human history, farmers have been clearing patches in order to grow crops and raise livestock. But that was on a much, much smaller scale than today. Over the past few decades, more than 750,000 square kilometers (289,000 square miles) have been slashed, primarily to make way for cattle and soybean production.
While we know the consequences at the ecosystem level, such as climate alteration and habitat loss, less is known about how deforestation has affected populations of animals and plants throughout history, and what might happen in the future. This means that the conservation status of the 15,000 species of trees that reside in this area, one of the most diverse plant hotspots in the world, remains unknown.
To fill in this gap, a large collaboration of scientists collected data from forest surveys and layered those onto maps and models of current and predicted deforestation rates. This allowed the researchers to estimate where each of the 15,000 species has been affected. Alongside providing information on species loss, the geographical data allowed them to see the proportion of populations that are located in protected or indigenous areas, which would afford them some shielding.
Using data from the International Union for Conservation of Nature’s (IUCN) Red List of Threatened Species, the authors concluded that between 36 and 57 percent of the Amazon’s tree species would likely fall under the category of threatened with extinction. These two figures reflect two different scenarios that the researchers looked at for 2050: “pessimistic” (business as usual where nothing changed), or “optimistic” (governments act and successfully curb deforestation).
They also found that their trends are not limited to the Amazon and can be applied to other forests across the globe, suggesting that the majority of the world’s 40,000 species of trees probably share the same status. With the IUCN threshold for qualifying as threatened sitting at a loss of 30 percent, Pitman explained to IFLScience this would mean that both Asia, which has lost about 35 percent over the past 150 years, and Africa, which has lost 55 percent, would also fall under the same category.
But there are some positives to be drawn from the data. It turns out that protected areas and indigenous territories now account for roughly half of the Amazon basin, both of which have been shown to confer significant benefits to biodiversity. Furthermore, these areas were found to contain large populations of a lot of the species that are threatened. But of course, these areas are still not immune to deforestation.
“The vast majority of protected areas in the Amazon have no management plan or budget and few resident qualified personnel,” Rafael Salomão from Brazil’s Emilio Goeldi Museum in Belem said in a statement.
“Either we stand up and protect these critical parks and indigenous reserves, or deforestation will erode them until we see large-scale extinctions,” added William Laurance from Australia’s James Cook University.