This week the UN released a horrifying report—by hundreds of authors around the world—warning that a million species of plants and animals face extinction in the next few decades. That’s one in four species on this planet that could soon disappear. Virtually every human activity—agriculture, energy production, fishing, urbanization—is conspiring to destroy life on Earth as we know it.
The scale of the problem is difficult to comprehend, let alone solve without eliminating all humans. But on the same day that the UN dropped its alarming report, another group of scientists published research that could help conservationists fight the most important battle in Earth’s recent history.
The study involved two cryptic species of bat—meaning they look nearly identical, yet have distinct genetics—living in Europe, which is expected to transform dramatically under the weight of climate change. The researchers found separate populations within these two species by looking at their DNA. What they discovered was that those populations’ genetic differences made them better suited to their particular environments.
“We can identify, first of all, parts of the genome that are associated with climatic conditions,” says Orly Razgour, a molecular ecologist at the University of Southampton and lead author on the new paper in the journal PNAS. “The second step, we look at these specific regions only, and within them we can divide our individuals into those that are more adapted to warm and dry conditions, and those that are more adapted to cold and wet conditions.”
Matt Simon covers cannabis, robots, and climate science for WIRED.
What’s new in this study isn’t the existence of populations with subtly different genetics within a species. The new bit here is the potential to exploit specific regions of the genome that might code for climate resilience to inform conservation efforts. Theoretically, this genetic diversity would make the bats more resilient to climate change, because a population that’s more adapted to arid conditions can interbreed with a population that’s less so, in essence “gifting” the cold-adapted population the genes necessary to survive a warmer world.
Using this data, the researchers could model projected range losses in the bats, and found that the losses were less severe when considering a species as distinctly adapted populations, as opposed to one genetically homogenous population across an entire range. “What this really means is that we may be overestimating for some species projected range losses,” says Razgour. “When we think about which species we need to prioritize under climate change, we may not actually be prioritizing the right ones, because we're not taking into account the adaptive potential of some species.”
This is where things get much more complicated on a number of levels. For one, generation times are a big consideration when it comes to the adaptability of species. One of the reasons bacteria are so deft at developing resistance to antibiotics is that they reproduce extremely rapidly—E. coli, for example, divides every 20 minutes. New bacteria with the lucky mutations that keep them alive pass those mutations along to their descendants, while their less-lucky compatriots perish.
The same principle is behind climate-related genes spreading through a bat population, only on a much slower scale. “If the generation time of these bats is one to two years,” says Razgour, “and you have one young per year, it takes a very, very long time for anything to spread through the population.”
Problem number two is mobility. You’d assume that bats would be among the most mobile creatures, what with the wings and all, but that’s not necessarily the case. If climate change affects the growth of forests in these forest bats’ European range, that could further isolate the hot-loving and cold-loving populations, keeping them from breeding. And consider an inherently immobile species like an earthworm, and how much difficulty it’d have shifting its population to more habitable areas as the climate rapidly transforms.
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Even if the bats are able to mix and adapt to a warmer climate, that’s just one consideration for their survival in the coming decades. The warm-weather bats might bring with them the genes required to survive a warming planet, but mixing with cold-weather bats might make the population less suited for survival in other ways. “Maybe these individuals are better adapted to the changing climate, but they're not necessarily better adapted to other environmental conditions in these areas,” says Razgour. “So we don't really know what will be the consequences of that.”
This brings us back to the horror of the UN biodiversity report: Species the world over aren’t just facing climate change, but a galaxy of other threats. Bats alone are up against deforestation, pollution, and urbanization too. The UN report “shows the importance of considering adaptive genetic variation because many organisms will not be able to shift their ranges in response to climate change,” says Razgour, “due to the extensive land use changes and fragmentation that has already occurred and is continuing to occur across the globe, especially in the most biodiverse regions.”
Even if a species is able to move into a new habitat and adapt, individuals might find themselves struggling to secure resources. This bat work, for instance, shows that the two cryptic species could be forced to overlap in their distribution, and would therefore compete for food. “That means that interspecific competition is likely to be something quite major that will affect species distribution, and perhaps their ability to survive,” says Razgour.
The problem is ultimately that no species lives in a vacuum. “The stage is the environment and the species are the players,” says Sophie Parker, an ecologist and senior scientist at the Nature Conservancy. “You need to have the stage in order for the players to have somewhere to be, to interact with one another and tell their stories.”
So how do we give the species of the world a stage on a planet we have so thoroughly spoiled? When it comes to climate change, we have to reduce emissions drastically, and immediately. When it comes to managing ecosystems, one strategy known as “room to roam” is a relatively low lift with a big impact. “Protecting places we know are important for movement of species is an important part of allowing species to adapt to climate change,” says Parker. “That includes riparian corridors and places along the coast but also broad swaths of natural land along mountains that allow for that type of movement.”
Matters grow all the more precarious on islands, home to 40 percent of endangered animals on this planet. Here, a single invasive species like a rat can wreak ecological havoc, tearing through bird and reptile eggs in particular. When those populations dwindle, genetic diversity falls as well, making those species more vulnerable to other threats like disease.
Methodically remove that invasive species, though, as the group Island Conservation has done with poison-dropping drones , and those endangered species will bounce back. “As populations continue to grow, there's often more genetic variability that can develop and persist in those populations, which helps them adjust to any future scenarios, including different climate scenarios,” says Erin Hagen, the group’s director of conservation.
So yes, we humans have seriously imperiled life on Earth—the new UN report makes that clear in the most terrifying detail yet. But with better understanding of the genetics of threatened populations, we might still save some species from doom.
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