The Earth is losing species at a rate about a hundred times faster than historical (also called "background") levels. For specific groups, that number is higher still, with research indicating amphibians are going extinct about 211 times faster than they normally should be. This phenomenon is so widespread and profound that scientists think it may be the beginning of the planet's sixth mass extinction. And, it seems, we humans are driving it.
But a new study is aiming to provide a bit of hope. Published last week in BioScience along with an accompanying interactive map, the study was conducted by a multidisciplinary team of scientists that analyzed regional ecosystem types (or "ecoregions"), land cover changes, and protected area extent around the world. Their aim was to figure out just how much land needs to be protected -- and where protection efforts would best be focused -- if half the world's habitat is to be safeguarded.
Why half? Previous research indicates that around 50 percent of the planet's land areas need to be conserved to ensure proper functioning of an ecosystem and, consequentially, the survival of the plants, animals and human communities that depend on that ecosystem. Termed "Nature Needs Half," this concept has been embraced by many in the conservation science community.
To see how the planet's faring in respect to that 50 percent conservation goal, the researchers assessed the protection statuses and health of its major ecoregions and assigned them to four categories: "Half Protected" if they had more than 50 percent protection; "Nature Could Reach Half" if they didn't have 50 percent protection but could achieve that mark through additional conservation efforts. Ecoregions that had between 20 and 50 percent protection and would need restoration to reach 50 percent were assigned "Nature Could Recover." The group for the poorest-scoring ecoregions was "Nature Imperiled" -- these areas had protected areas and natural habitat that together covered less than 20 percent of their land areas.
In all, the researchers looked at 846 ecoregions over the planet's 14 biomes. Overall, they found 12 percent of ecoregions qualified as Half Protected, 37 percent as Nature Could Reach Half, 27 percent as Nature Could Recover, and 24 percent as Nature Imperiled.
Their results turned up a few surprises, both good and bad, according to the researchers.
First, the good news: Almost 100 of the planet's ecoregions stand at Half Protected, with another 40 close behind at the upper end of Nature Could Reach Half.
"I think the greatest surprise is that at the outset, we already have 98 ecoregions with at least 50% protected -- that is 98 success stories," study coauthor Eric Dinerstein told Mongabay. "Another 40 are very close to that target and a small effort will boost them past that threshold."
But while Dinerstein, who is Director of Biodiversity and Wildlife Solutions at the environmental NGO RESOLVE, said that there were more well-protected ecoregions than he and his colleagues expected, they also found the same thing when it came to the lowest-scoring group.
"I did not expect that we would have 207 ecoregions as Nature Imperiled; I thought that number would be more like 150," said Dinerstein, adding that these poorly protected, degraded areas double as Biodiversity Hotspots -- regions home to diverse arrays of plants and animals, but which are highly threatened by destruction. "More alarming is that…the average amount of remaining habitat outside that protected is only 4% of the ecoregion. So it will take a concerted effort to push these to even 20% protected -- a minimum threshold."
Yet even for these areas, Dinerstein expressed a bit of rallying optimism.
"But we must do it where we can," he said. "It's Easter, a good time to think about ecological resurrection!"
And where this ecological resurrection should be aimed, the researchers say, depends on more than just how degraded and unprotected an ecosystem is. They urge that biodiversity be a considered a big part of the equation.
The study singles out the tropical dry forest biome as the most endangered, in that it contains the most Nature Imperiled ecoregions. Closely behind it are two others: the tropical grasslands, savannas, and shrublands biome, and the Mediterranean forests, woodlands, and scrub biome. All are highly biodiverse, providing habitat for many species.
Tropical dry forests are found in places like southern India, where they provide important habitat for endangered wildlife like tigers, dholes, and elephants. The dry forests of northern Madagascar have been extensively logged and cleared for agriculture, and many of their endemic lemurs are threatened with extinction. The tropical grasslands, savannas, and shrublands biome includes the Cerrado in South America, considered the biologically richest savanna in the world; however, most of the Cerrado has been converted for agriculture and only around 1 percent is officially protected. The Mediterranean forests, woodlands, and scrub biome includes South Africa's fynbos's fynbos ecosystem, one of the most biodiverse places on the planet -- and of which less than 10 percent remained as of 1999.
"In these places, we need to be focused on saving the last remnants in the short term and then massive restoration over the next 30 years," Dinerstein said in a press release.
The researchers write that conservation efforts should focus on these tropical Nature Imperiled ecoregions rather than on those in temperate regions because they, along with the most tropical forests biome, are the planet's most biodiverse areas. In other words, more species stand to become extinct if these areas continue to be converted.
"In contrast, most of the species in temperate grasslands are widespread across those ecoregions and within the [biogeographic] realm within that same biome," Dinerstein said, adding that "losing 5% more of fynbos habitat in [South] Africa or 5% more of Madagascar moist forests, or 5% more of Cerrado, or 5% more of [Madagascar] or New Caledonia dry forests, would be far more consequential for biodiversity than losing another 5% of the southern shortgrass prairie in the US or Durian steppe."
Currently, around 15 percent of the Earth's land area is protected, and the United Nation's Convention on Biological Diversity is aiming to up that to 17 percent by 2020. But Dinerstein and his colleagues say this is not enough. They are calling on world leaders to protect half the terrestrial realm by 2050, proposing a plan called "A Global Deal for Nature" that has four major pillars: expanding habitat protection, respecting indigenous conservation, emphasizing large mammal conservation, and developing technology that would allow for more ecologically conscientious infrastructure expansion.
"There is one Earth," Dinerstein wrote in an accompanying blog post. "We must honor a new-found commitment to save the space necessary to conserve most all of nature's species, and the processes that sustain life on it -- we must create a global safety net for the web of life.
"It took 3.8 billion years to create the world we live in; we are now called upon to change course in order to keep it healthy. With enough public support we can generate the political will for governments and local communities to ensure that the 21st century becomes the most hopeful for nature and humanity."
The researchers write that at current rates, the amount of land under official protection increases 4 percent per decade. To achieve 50 percent protection by 2050, they say this rate needs to be doubled to 8 percent. They estimate that increasing protections and restoring degraded land would cost somewhere between $8 billion and $80 billion per year, and could employ people in underemployed rural communities.
While this may sound like a lofty goal, the study's authors and other conservationists maintain it's a necessary one if important ecological processes are to be maintained and mass extinction avoided.
"For the survival of the chimpanzees of Gombe and the rest of life around the world we need to dramatically scale up conservation," Jane Goodall, renowned primate researcher, founder of the Jane Goodall Institute and UN Messenger of Peace, said in a press release. "This paper provides hope for it not only recognizes that Nature Needs Half it also shows how it is possible."
Dinerstein echoes the sentiment of possibility, saying that "with some restoration -- needed for biospheric function as much as biodiversity conservation -- the goal by 2050 is still possible.
"We can save life on Earth."
Dinerstein, E., Olson, D., Joshi, A., Vynne, C., Burgess, N. D., Wikramanayake, E., … & Hansen, M. An Ecoregion-Based Approach to Protecting Half the Terrestrial Realm. BioScience.