Human cities and towns are standing in the way of animal highways

Half of the Earth’s land surface not covered with ice remains relatively wild, research shows.

However, many of these “low human-impact” areas are broken into small, isolated pieces, which threatens their future.

The study in Scientific Reports concludes that despite widespread environmental damage inflicted by human development, such as cities and farms, there’s still an opportunity to protect vast, relatively wild regions of the Earth for the benefit of people and other living species.

“It’s not too late to aim high,” says lead author Andrew Jacobson, a geographic information systems professor at Catawba College in North Carolina. Jacobson led a team of researchers using satellite-based mapping techniques to measure human impacts across the globe and to identify areas of lowest human pressure and highest potential for saving intact habitat.

Where are these wild spaces?

Most of the low impact areas identified by the survey were in the remote boreal forests of northern Canada and Russia, in the highlands of Central Asia, especially Tibet and Mongolia, in the deserts of North Africa and Australia, and in the tropical rain forests of the Amazon Basin of South America.

“This is good news for the planet,” says Jacobson, a scientific and geo-spatial advisor to the National Geographic Society. “The findings here suggest that roughly half of the ice-free land is still relatively less altered by humans, which leaves open the possibility of expanding the global network of protected areas and building bigger and more connected habitats for species.”

Isolated pieces

The study focused not only on the location of low human-impact areas but also on their sizes and shapes. Here, the findings were more sobering, showing that many low-impact zones are fragmented into small, isolated pieces, separated either by natural features (water, rocks, ice) or increasingly by human development.

Jason Riggio, a conservation scientist at the University of California, Davis and a coauthor of the report, notes the fragility of these fragments. “Half of all segments located in temperate forests, dry tropical forests, or tropical conifer forests were within one mile of human disturbance,” he says.

Fragmentation can devastate wildlife populations. Animals are cut off from potential mates, food supplies, and migration patterns, and they are increasingly exposed to pesticides and other causes of mortality, such as roads. Extinction is the eventual result.

“The findings demonstrate that our most diverse systems are among the most threatened and even the low-impact areas, which are often less biologically diverse, are fragmented. If we wish to meet global climate targets and sustainable development goals while averting an extinction crisis, we must encourage greater protection of our remaining natural ecosystems,” says coauthor and chief advisor Jonathan Baillie, the National Geographic Society’s executive vice president and chief scientist.

“This paper shows that it’s late in the game, but not too late,” Jacobson says. “We can still greatly increase the extent of the world’s protected areas, but we must act quickly. Pressures are mounting, and habitat loss and fragmentation are rapidly eroding natural systems and the diversity of species they contain.”