China’s Enormous Sinkholes Attract Tourists, Posing Risks to Ancient Internal Ecosystems

A couple observes from the precipice of a steep limestone cliff. Below them, over 100 metres (328ft) down, lies a secluded realm of ancient forests, flora, and fauna. Their view is limited to the canopy of trees, and they perceive only the reverberating sounds of cicadas and birds against the cliff faces. For millennia, this “heavenly pit,” known as “tiankeng” in Mandarin, remained undiscovered. Local beliefs held that demons and ghosts resided within the mists that ascended from its depths. However, the deployment of drones and the efforts of a few intrepid individuals who descended into these locations, undisturbed since the era of dinosaurs, have uncovered new wonders. This has transformed China’s sinkholes into a popular tourist destination. China hosts two-thirds of the world’s more than 300 sinkholes, primarily located across its western regions. Guangxi province in the south contains more of these features than any other area, with 30 identified tiankeng. The most significant and recent discovery there, made two years prior, was an ancient forest featuring trees up to 40m (130ft) tall. These geological formations act as time capsules, safeguarding distinct and fragile ecosystems for hundreds of years. Nevertheless, their unearthing has started to attract both tourists and developers, prompting concerns that these remarkable and scarce discoveries might be permanently jeopardized. “I’ve never done this kind of thing before,” stated 25-year-old Rui, gazing into the abyss. “It’s very cool. It will be the first time but not the last time.” She inhaled deeply before she and her boyfriend moved backward, departing from the edge and into the open air. Fei Ge, who had just thoroughly inspected Rui and Michael’s harnesses before their descent over the cliff, possesses a profound understanding of the sensation of rappelling from the edge. He was among the initial explorers of these sites. Currently in his 50s, he serves as a tour guide, assisting individuals in uncovering the mysteries of Guangxi’s sinkholes. During his upbringing in a neighboring village, Fei was instructed to avoid the sinkholes. “We thought that if humans went into the sinkholes, demons would bring strong winds and heavy rain. We thought ghosts brought the mist and fog.” Fei Ge, also referred to as Brother Fei, learned that these sinkholes possess distinct microclimates. The wind’s movement through the tunnels and the evaporation of water from subterranean rivers within the caves generate the mist. Ultimately, Brother Fei’s inquisitiveness prevailed, leading him to discover an entry point into a sinkhole during his childhood. “Every tiny stone caused loud noises and echoes,” he recounted. He remembered experiencing wind, rain, and even “mini tornadoes.” “At first, we were afraid.” Despite his initial fear, he continued his explorations. His understanding of the sinkholes’ unique nature solidified only after he introduced scientists to the location. “The experts were astonished. They found new plants and told us they’ve been doing research for decades and never seen these species. They were very excited. We couldn’t believe that something we had taken for granted nearby was such a treasure.” Following the publication of scientific findings in academic journals and the dissemination of news regarding their discovery, other researchers arrived to investigate the sinkholes. Fei noted that explorers from the UK, France, and Germany have visited over the past decade. Sinkholes are uncommon geological formations. China, especially Guangxi, possesses a high concentration of them due to its plentiful limestone. The process begins when a subterranean river gradually erodes the surrounding limestone, forming a cave that expands vertically towards the surface. Eventually, the ground above collapses, resulting in a vast opening. To be classified as a sinkhole, its depth and width must each be at least 100m. Certain sinkholes, such as the one discovered in Guangxi in 2022, are considerably larger, extending 300m deep and 150m wide. For scientists, these expansive pits represent a temporal journey, offering an environment to examine animals and plants previously believed to be extinct. Researchers have also identified previously unknown species, such as specific wild orchid varieties, translucent cave fish, and various spiders and snails. Shielded by steep cliffs, rugged mountains, and limestone caverns, these organisms have flourished deep within the Earth. A joyful shriek is heard as Rui hangs suspended in the air, prior to commencing her rappel. This marks merely the beginning of the expedition for her and Michael, who anticipate further rope maneuvers within the cave’s interior. Following a brief trek through a labyrinth of stalactites, Michael is lowered into the darkness. The guides use torches to illuminate the overhead arch, revealing a system of caves, and then direct their lights into the confined passages beneath, where a river once sculpted the rock. This is their intended destination. The guides exert considerable effort to position the ropes. “I am not a person that does much exercise,” Michael remarked, his voice reverberating through the cave. This experience represents the pinnacle of the Shanghai couple’s two-week vacation in Guangxi, a type of getaway they had longed for during China’s extended Covid lockdowns. “This kind of tourism is more and more familiar on the Chinese internet,” he noted. “We saw it and thought it looked pretty cool. That’s why we wanted to try it.” Videos showcasing the Guangxi sinkholes have achieved widespread popularity on social media platforms. While offering an enjoyable and adventurous activity for younger generations, these sites also provide a vital source of income for a province that recently emerged from poverty. Guangxi’s distinctive yet beautiful landscape offers limited agricultural land, and its mountainous frontiers complicate trade with both the rest of China and neighboring Vietnam. Nevertheless, visitors are drawn by the scenery. Over a million Chinese tourists annually visit the pristine rivers and towering karst peaks of Guilin and Yangshuo in the northern part of the province. Images of Guangxi’s misty landscapes have even been featured on the 20-yuan banknote. Despite this, Ping’e village, the closest community to the sinkholes, remains largely unknown. This situation, however, is evolving. Brother Fei indicates that a consistent influx of tourists is improving the economic prospects for some residents of Ping’e. “It used to be very poor. We started developing tourism and it brought lots of benefits. Like when the highways were built. We were really happy knowing we have something so valuable here.” However, apprehensions exist that the pursuit of tourism revenue might overshadow the requirements of scientific investigation. Approximately 50km from Ping’e, developers have constructed what they claim is the world’s highest viewing platform, offering a vantage point over Dashiwei, the planet’s second-deepest sinkhole. From this location, tourists can observe 500m down into this specific “heavenly pit.” “We should better protect such habitats,” stated Dr Lina Shen, a prominent sinkhole researcher in China. “Sinkholes are paradises for many rare and endangered plant species. We are continuing to make new discoveries.” Through the study of sinkholes, scientists also aim to ascertain how the Earth has transformed over tens of thousands of years and to gain a clearer understanding of climate change’s effects. At least one sinkhole in Guangxi has already been made inaccessible to tourists to safeguard its distinctive orchid species. “Overdevelopment could cause tremendous damage. We should maintain their original ecological state,” Dr Shen asserted, further suggesting that the resolution involves achieving equilibrium. She proposed, “Hot air balloons, drones for aerial photography, and appropriate pathways for observation from a distance could allow tourists to closely yet remotely view sinkholes, while disturbing as few organisms as possible.” Brother Fei concurs with this perspective, emphasizing the existence of “clear rules” designed to protect the sinkholes and their contents. For him, these sites represent a valuable discovery that has transformed his life. He is currently recognized as one of Guangxi’s most skilled climbers and a distinguished guide for both tourists and scientists, a role that has brought him “very happy”. While traversing extensive areas of verdant forest within the sinkhole, he indicated a cliff face above. He advised a return visit during the rainy season to witness the waterfalls cascading down its side, assuring that the spectacle is worthwhile. Rui and Michael are being secured with ropes, mutually encouraging each other to rappel deeper into the cave. Below them, only a narrow, torch-lit chasm is discernible, representing the remnants of a riverbed that was instrumental in the formation of this sinkhole. “We need to balance this joy with protecting this place,” Michael stated, surveying his surroundings. He smiled as he was gradually lowered and vanished into the cave. Copyright 2024 BBC. All rights reserved. The BBC bears no responsibility for the content found on external websites. Information regarding their external linking policy is available.