A new study is putting environmentalists on edge: researchers from the University College London warn that the extinction of species around the world may have already dropped below a “safe” level for the health of the planet. Published in the journal Science, the paper examines the rate of decline in animal, plant and other living species around the globe, and attempts to estimate the potential impact of new extinctions on the world’s ecosystems.
While many of us have heard about the accelerating rate of extinction in areas like the Amazon, the British researchers behind the new paper found that the issue is actually incredibly widespread. By their estimates, a disturbing 58 percent of the planet’s surface has already endured losses beyond what the paper considers sustainable.
To measure the global loss of biodiversity, the researchers analyzed more than 2.3 million records cataloguing 40,000 species from 18,600 sites around the world. They compared past and present records and found that, globally, only 84.6 percent of the species that existed before humans altered their habitat are still in existence. When newly-discovered species are accounted for, it increases to 88 percent. (To put that in perspective, other research shows that we’ve wiped out at least 322 types of animals in the past 500 years.)
While the disappearance of 12-16 percent of species across the planet may not sound devastating, it’s important to remember that some key species play absolutely vital roles in their local ecosystems. Bees are a good example because, if they continue to die off in large numbers and disappear, there are huge numbers of plant species that will struggle to pollinate and reproduce. If that happens, both animals and humans will have a hard time finding enough to eat. Removing one or two species from an area could completely disrupt the entire food chain.
The calculations are based on a theory that assumes a given habitat should retain 90 percent of its original species, before humans altered the landscape, in order to be considered “intact.” Once more than 10 percent of biodiversity is lost, no one is sure what will happen to that ecosystem — depending on the species lost, it could recover or it could fall into chaos.
Surprisingly, not all researchers agree that this dip is enough to threaten other species. Some believe that only 70 percent of the original species in an area need to survive to maintain equilibrium. Even if it turns out that the margin is wider than estimated, we need to see statistics like this as a wake-up call.
For one thing, the areas hardest hit by this loss are the world’s grasslands — the areas where most of our agriculture is based. This means that the areas humans depend on for our very survival are the most at risk. Preserving the natural habitats we have left and finding ways to farm that are more in tune with the environment should be a top priority. Other countries could stand to take some hints from China’s plan to preserve the biodiversity of its most ecologically valuable areas.
At the very least, we need to identify the species that serve the most important ecological functions, and funnel resources into protecting them. Pollinators are one obvious target for this kind of intervention. While we may not be able to strictly preserve as much overall diversity as once existed, protecting those key species may be enough to stave off the worst of the disaster ahead.
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