What climate change pushes, human activity aggravates. In another 50 years, high emissions could push most of the habitats of 35% of mammals and 29% of birds outside the spaces they live in now and into different countries. But if they tried to move to these new spaces, political boundaries might not let them.
A new and recent study by researchers from Durham University, BirdLife International and Newcastle University, published in the ‘Proceedings of the National Academy of Sciences of the USA’, has mapped the impact of the 32,000km of fortified international borders on wildlife and found that 696 species of non-flying mammals would be affected. And three political barriers pose the biggest conservation challenges — along US-Mexico, India-Myanmar and China-Russia.
“For the India-Myanmar border we estimate that 128 species of non-flying mammals could be unable to cross if barriers were completed along much of its length,” joint study lead Mark Titley told TOI. That includes the endangered Indian pangolin, banteng, large-spotted civet, and vulnerable sloth bear. It is difficult to estimate just how many have already been affected. “But we calculated that 783 species of birds and mammals live around this border, including 44 that are threatened with extinction according to the IUCN Red List.”
Of the 12,700 species of terrestrial mammals and birds they studied, 60% of mammals and 71% of birds occur across national boundaries. And poorer countries, with lower CO2 emissions, could face greater losses. “The stark inequities between those who contributed most to climate change and those who will be most impacted raise really important questions of international justice,” Titley said.
Areas where mammals are most likely to have to move and find new homes are in the US-Mexico border, western Amazonia, the Andes, central and eastern Africa, the Himalayan region, and the China–Russia border. For birds, western Amazonia was found to be most vulnerable.
Border fencing is problematic from a conservation point of view to begin with. Adding political barriers would mean a species would be facing different kinds of threats on either side of a border, “especially in areas of conflict,” the study said. “The Himalayan region … is a globally important biodiversity hotspot that also spans a range of altitudes and different climate zones. That means a lot of species can move to higher elevations to stay cool as the climate gets hotter, and may need to cross political borders as they do so,” Titley explained.
A Himalayan goral, for instance, can be found at an elevation between 900m and 4,000m. But if the shrublands and temperate forests it lives in were no longer where they used to be, because of climate change, it would have to move.
If it did, in China and Nepal, it would face the threat of hunting. In Bhutan, the challenge would be overgrazing. And in India, its habitat is being altered in the lower reaches of the Himalayas and northeast India, the IUCN says.
Joint study lead Professor Stephen Willis said, “If we’re serious about protecting nature, expanding transboundary conservation initiatives and reducing the impacts of border barriers on species will be really important – although there’s no substitute for tackling the greenhouse gas emissions at the root of the issue.”