From the Great Wall of China to the terraces of Machu Picchu, world heritage sites preserve the beauty and historic import of humanity’s greatest accomplishments. Others, like the breathtaking Río Plátano Biosphere Reserve in Honduras, highlight the natural beauty and biodiversity of some of Earth’s most beautiful spots. But could humans inadvertently destroy the very sites they hold so dear? A new study suggests just that, warning that over 100 precious natural heritage sites are already being damaged by human activity.
In a new study published in the journal Biological Conservation, researchers assessed how human activities impact natural world heritage sites. They relied on an international standard called the Human Footprint, an index that shows the relative influence of humans in different parts of the world by measuring their buildings, infrastructure, agriculture, population density, night lights and other factors. They also assessed forest loss with the help of Global Forest Watch, a real-time monitoring map, and Google Earth satellite observations. Both measurements also capture changes over the years.
When the team layered that data over the physical locations of Unesco Natural World Heritage Sites, they found that human pressure has increased nearby. Since 1993, human pressure has increased in 63 percent of the sites on non-European continents, with Asian countries at particular risk. Forest loss rose even more; 91 percent of the sites that contain woodlands lost forests since 2000. On average, the team found, human pressures and forest loss actually increased more the closer to Natural World Heritage Site they were measured.
Several sites are at particular risk. Manas Wildlife Sanctuary, which protects grasslands and tiger habitat in the Himalayas, had the greatest increase in human footprint between 1993 and 2009. The Río Plátano Biosphere lost 8.5 percent of its forest since 2000. And though the impacts were heaviest in Asia, even heritage sites in the United States were at risk. The Waterton Glacier International Peace Park, which is located at the border of the U.S. and Canada and combines Canada’s Waterton Lakes National Park and the United States’ Glacier National Park, lost 23 percent of its forested area since 2000. Even Yellowstone and the Grand Canyon lost forest area (6.3 percent and 9.9 percent respectively).
The news isn’t all bad: Some sites, like Sinharaja Forest Reserve in Sri Lanka, actually experienced a reduced human footprint. Sites in Europe didn’t experience the same dramatic impacts. And the research provides an important baseline for future efforts to preserve the sites in question. But the report does highlight a need to act now to make sure that human activities don’t further damage precious natural resources that may not easily bounce back from things like farming, urbanization and forest loss.
“Any place that is listed as a World Heritage site is a globally important asset to all of humanity,” notes the paper’s senior author, James Watson, in a release. “The world would never accept the Acropolis being knocked down, or a couple of pyramids being flattened for housing estates or roads, yet right now, across our planet, we are simply letting many of our natural World Heritage sites be severely altered.” Perhaps this new report will draw attention to the dangers humans pose to the very sites they wish to protect, providing an extra push for others to figure out how to curb those dangers before it's too late.