The planet we live on is rapidly losing its most beautiful, precious, and pristine white – the glaciers around the world are swiftly receding. It is estimated that by 2100, between 49% to 83% of glaciers will have disappeared. The green expanses of the Arctic and Antarctic are continuously growing, while glaciers on continental mountains are melting rapidly, revealing vast tracts of rock terrain devoid of any trace of life.

The Cordillera Blanca in Peru is part of the largest mountain range in the world—the Andes. Stretching 8,900 kilometers across seven South American countries, including Peru. Studies have shown that over the past 20 years, the permanent ice cap of the Cordillera Blanca has retreated an average of 19 meters per year, with a total reduction in area by about one-third. Previously, its meltwater provided year-round water for the northern region of Peru. But as the glaciers gradually disappear, the metallic rocks beneath them, along with acidic rocks rich in elements like sulfur and iron, are being washed downstream by water, posing threats to the safety of drinking water for local residents and livestock.

Peru itself holds 70% of the world's tropical glaciers, but at least 50% of these glaciers have been lost in the last 50 years. Researcher Anaïs Zimmer has a keen interest in the early stages of forest ecosystem development. They want to explore, as these beautiful glaciers vanish, how the rocky terrain left by the retreating glaciers will come back to life. In field surveys, Zimmer and her team observed that in the place where the Uruashraju glacier of the Cordillera Blanca once existed, it could take hundreds of years for the ground to revive and vegetation to reemerge.

However, locals have a different perspective; they believe in a magical animal—the large llama (Llama glama), which might hasten the ecological recovery through their feces, fallen hair, and saliva. This animal looks similar to the commonly known alpaca (Lama pacos) but is larger in size, with less lanolin in its wool, making it soft and fluffy to the touch. They are very intelligent and can quickly learn simple tasks and repetitive operations. Archaeological evidence indicates that the large llama originated in the Great Plains of North America about 40 million years ago and migrated to South America during the Great American Interchange about 3 million years ago. Upon their arrival in South America, the large llamas became closely integrated with the culture of the native population in the Andes, becoming an important cultural symbol there. There's a belief in the local culture that llamas in the sky drink seawater, and that rainfall is the process of them urinating on the earth.

However, with the development of local animal husbandry and large-scale agriculture, the large llamas of the Cordillera Blanca disappeared in the 19th century. Now, the large llamas may play a vital role in ecosystem recovery, their presence possibly key to accelerating revitalization.

Since ancient times, the rearing of large llamas has become a local traditional custom, says local schoolteacher Jorge Mattel. Mr. Mattel leads Llama 2000 Asociación, an organization of Andean herders focused on reviving cultural identity and promoting mountain tourism. They are working hard to reintroduce large llamas to the area.

With the support of these diligent pastoralists, Zimmer and his colleagues delved into the key role that large llamas play in altering the rock and soil of the glacier foreland regions. In September of last year, they published their findings in the journal Scientific Reports. Zimmer pointed out that large llamas, through simple activities such as defecation, salivation, hair shedding, and trampling, revitalize these barren and cold lands, acting like natural gardeners bestowed by the heavens upon the area.

Due to the difference in environmental and soil composition after glacier degradation, the content of phosphorus and nitrogen in glacier soil is usually very limited. Initially, the colonization of microorganisms is crucial to soil development, but harsh climates and limited nutrients pose barriers to their growth. In alpine environments, mammals such as pikas, voles, foxes, and mustelids become key mediators in promoting the exchange between microbes and plants. Once the soil develops properly, the rich vegetation that researchers most anticipate will have the opportunity to take root here.

For the Sierra Blanca, plants are particularly important as they can serve as a buffer, preventing hazardous upstream deposits from flowing into downstream ecosystems, and provide shelter for species adapted to cold environments.

In June 2019, Zimmer and his team began collaborating with pastoralists from the Llama 2000 Association to test the impact of large llamas on improving the soil of the glacier foreland regions. They selected 8 plots for experimentation, all situated at an altitude of about 4700 meters, in areas where glaciers had melted from 1979 to 1995. Half of these plots were used for grazing large llamas, while the other half served as controls in their natural state.

Over the next three years (2019 to 2022), with the assistance of pastoralists, the research team monitored the quantity of feces, soil quality, and plant species distribution across the experimental plots. The experiment also specifically adjusted details such as the number of large llamas introduced into each plot, their grazing time, and the time of withdrawal. Three years later, the study found that plots with large llama activity had a 57% increase in plant cover compared to those without.

The movement of large llamas at high altitudes and in downstream areas brought new plant seeds to the experimental sites. Moreover, seeds of 12 plant species were found in the feces of large llamas, 4 of which were only found in plots with large llamas.

The rich nutrients provided by the feces of large llamas play a significant role in amending the soil of rocky plots. The study shows that the organic carbon content in these plots is 15.4%, nine times that in the control plots, and the total nitrogen content is 5.07%, thirty-six times that of the control plots. Besides promoting the enrichment of soil nutrients and increasing plant cover, large llamas, after eating, spread active seeds to the soil through their stomachs, hair, and hooves, helping to spread plant populations. Additionally, large llamas help secure the nutrients and microorganisms in the soil through their trampling action.

The activities of large llamas in this region are very stable, and their environmental impact is long-term and continuous. The historical influence of large llamas cannot be overlooked. Archaeologists have discovered that the prosperity of the Inca Empire and Andean civilization is likely linked to large llamas. A study published in Antiquity in 2011 indicated that the Incas primarily used large llama feces as fertilizer for corn—their principal crop—which enabled them to transition from hunting and gathering to agriculture. In a 2019 Scientific News report, an ancient lake sediment containing a large amount of large llama feces recorded the rise and fall of the entire Inca Empire. During the time of the Inca Empire, large caravans of llamas passed by this lake, and the feces they left behind when drinking water and excreting provided food for mites. With the death and sedimentation of mites, layers of sediment piled up, reflecting the prosperity of the Inca Empire at that time.

In the modern era, residents of the Blanca mountain range may also need llamas to maintain their safety and livelihood. Reports indicate that local water sources, contaminated by metallic and acidic rocks, have led to serious issues such as heavy metal poisoning and the disappearance of fish populations, and acidic water flows are destroying crops. According to Mattel, he has several friends who have suffered from stomach cancer, which he believes is directly linked to the pollution. Due to a lack of water treatment systems, local residents cannot drink river water or use it to irrigate crops, and must instead rely on often inadequate rainfall. Zimmer believes that better vegetation coverage could help filter heavy metals from the water since some plants are capable of absorbing these metals through their roots or leaves. She and her colleagues will in the future conduct research to assess whether llamas can reduce the concentration of heavy metals in the soil.

Global climate change has caused glaciers to gradually recede, posing a threat to residents living in glacial regions in terms of drinking water, electricity generation, and farming. A BBC news report on the tracking results of Europe's Cryosat spacecraft showed that about 200,000 glaciers worldwide have lost approximately 272 billion tons of ice in the past decade, with 89% of the loss caused by melting due to climate warming. Venezuela may become the first country in modern history to lose all its glaciers. As the terrain under each glacier is different, the problems experienced by the affected residents also vary. In some places, such as Iceland and certain island regions, the degradation of glaciers might lead to quicker emergence of primary ecosystems.

Delving into the glaciers and natural environments of different regions is key to understanding how life adapts and alters its surroundings and forms an important basis for humans to optimize survival strategies. Only through such sustained exploration can we gain a deeper understanding of these phenomena.