Animal poop can literally transform barren landscapes into lush ecosystems

Glaciers worldwide are shrinking due to rising temperatures, reshaping landscapes and posing serious challenges for the organisms that inhabit them. Yet in the lofty reaches of the Andes Mountains, a wild relative of the llama is helping new life take root in areas newly exposed by ice retreat. 

By depositing substantial piles of dung, vicuñas are speeding up plant colonization on freshly deglaciated terrain, a process that would otherwise take more than a century.

This fascinating discovery, published in Nature Scientific Reports, underscores an unexpected strategy through which species are adjusting to climate change. 

While this unique animal behavior offers hope for reviving scarred alpine landscapes, the study’s authors caution that the overall pace of climate change outstrips many species’ ability to find suitable new habitats.

Crucial ecological role of vicuñas 

Vicuñas are one of two wild South American camelids, with llamas and alpacas as their domesticated counterparts.

These hardy animals live at high altitudes in the Andes and have a notable habit: much like how people consistently use designated bathrooms, vicuñas gather in communal latrines.

Cliff Bueno de Mesquita is the study’s co-first author and a research scientist at the Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder. 

“It’s interesting to see how a social behavior of these animals can transfer nutrients to a new ecosystem that is very nutrient poor,” said Bueno de Mesquita. 

However, the current rate of climate change still outpaces the ability of many species to find new habitats.

Plant growth in vicuñas’ latrines

The key finding is that vicuñas’ dung accelerates plant establishment on deglaciated ground by more than a hundred years.

Glacial melt in high-altitude areas typically reveals a desolate landscape of rock and gravel, lacking essential nutrients for plant growth. 

Over the last ten years, Steven Schmidt, the paper’s senior author and a professor in the Department of Ecology and Evolutionary Biology, and his team noticed small patches of vegetation emerging wherever vicuña dung piles accumulated.

The researchers ventured to sites in the Peruvian Andes, nearly 18,000 feet above sea level, that had previously been covered by glaciers. They analyzed the composition of soil in and around these communal dung piles and discovered notable differences.

Enhanced soil quality

Vicuña latrine soils contained considerably higher levels of organic carbon, nitrogen, and phosphorus than adjacent barren soils – enough to promote rapid plant germination.

Better water retention

Despite the arid conditions at high altitudes, the latrine soils held more moisture, further supporting plant life in an otherwise harsh environment.

Microbial diversity

Soil samples from latrines revealed a wide variety of microorganisms, suggesting the latrines serve as fertile ground for microbes and, consequently, plants.

This rich blend of nutrients, water, and microbes helps seeds from lower elevations – carried to high altitudes via vicuñas’ dung – take root more easily in newly revealed terrain.

Glacial retreat and barren landscapes

Normally, the newly exposed soil left by retreating glaciers can remain plant-free for a century or more due to nutrient deficits and low moisture levels.

Through their dung piles, vicuñas deposit an essential mix of nutrients, seeds, and microorganisms that jumpstart the formation of a new ecosystem. 

Over time, this vegetation encourages other animals, including herbivores and predators like pumas, to move in.

Camera footage confirms that the presence of nascent vegetation has drawn a surprising variety of wildlife, including species rarely seen at such extreme altitudes.

In turn, vicuñas themselves also graze on the plants that spring up around their latrines, creating a cyclical benefit.

According to Kelsey Rider, an animal ecologist at James Madison University, it could take centuries for the deglaciated area to transform into grassland.

This might help mitigate the negative impacts that many animal species preferring colder climates face as their habitats shrink. The process, while beneficial, lags behind the rapid pace of glacial melting worldwide.

Anthropogenic climate change 

Scientists note that vicuñas, despite effectively fertilizing and rejuvenating new habitats, cannot fully counteract the accelerating glacier loss. 

Over the past two decades, global glacier melt has surged, with non-polar glaciers losing around 267 billion tons of ice each year between 2000 and 2019.

If warming trends persist, up to 68% of Earth’s glaciers could disappear, imperiling water supplies for almost a quarter of the world’s population.

“The vicuñas are probably helping some alpine organisms, but we can’t assume they’ll all be okay, because in Earth’s history, we’ve never seen climate change happen at this speed,”

Bueno de Mesquita said. “Current anthropogenic climate change is probably the most severe crisis our planet and all living things have faced in the past 65 million years.”

Wildlife in a drastically changing climate 

The role of vicuñas in the Andes serves as a compelling illustration of how species can adapt to a changing planet.

By pooling nutrients in communal dung piles, these animals foster micro-environments that favor plant life, effectively creating oases in barren landscapes.

Although this adaptation stands as a beacon of resilience, the overarching message remains stark: climate change is unfolding too quickly for many species to keep pace. 

Without significant reductions in greenhouse gas emissions and robust conservation efforts, ecosystems around the globe – including the high Andes – risk suffering irreversible damage.

Ultimately, the study emphasizes that while behaviors like the vicuñas’ communal latrines can offer localized reprieves from the stresses of global warming, far more comprehensive measures are needed to ensure that both wildlife and human communities can endure in a drastically shifting environment.

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