A little poop goes a long way: vicuñas boost ecosystem recovery
Vicuña poop is helping ecosystems adapt to melting glaciers.
An international collaboration of researchers led by senior author Steven Schmidt (University of Colorado, Boulder, CO, USA) has found that the poop of vicuñas provides nutrients to deglaciated land, speeding up the process of plant colonization by up to a century.
Climate change is melting glaciers around the world, including the Andes Mountains, which form a continuous highland along the western edge of South America. The melted glaciers expose a sea of rocks and gravel, with soil so depleted of nutrients and water that the land can remain plant-free for over a century. However, one surprising factor is helping to bring flora to the area: vicuña poop.
Vicuñas are a South American camelid that live in the high alpine areas of the Andes. Similar to humans, vicuñas like to poop in a designated area shared by multiple members of a social group – referred to by scientists as a latrine. During expeditions over the past decade, Schmidt and his colleagues observed small patches of plants that appeared to have grown from these vicuña latrines.
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To investigate this, the team trekked to sites in the Peruvian Andes previously covered by glaciers and took samples of both vicuña latrine soils and barren soils just a few feet away. Analyses found that latrine soils contained significantly more moisture and key nutrients, like organic carbon, nitrogen and phosphorus, than barren soils. In one example, in an area that had been exposed for 85 years, latrine soil contained 62% organic matter, whereas the barren soil contained only 1.5% organic matter.
At high elevations, temperatures can vary greatly throughout the day, often dropping below freezing at night, even in summer. “It’s really hard for things to live, but that organic matter made it so that temperatures and moisture levels didn’t fluctuate nearly as much. The latrines created a different microclimate than the surrounding area,” Schmidt explained.
The researchers extracted DNA from the soil, used a fluorometer to measure DNA concentrations, and then amplified and sequenced the extracted DNA. They found high concentrations of DNA and a range of microorganisms in the latrine soils, suggesting that the latrines create an ecosystem for microbes and plants to thrive.
The team believes that vicuña droppings likely sped up the process of plant colonization in a deglaciated habitat by 100 years. These droppings deposit nutrients and plant seeds from lower elevations onto the exposed land, allowing the seeds to germinate. This, in turn, attracts various organisms, including animals that feed on the plants. Camera footage showed the patches of plants have attracted various animals, including pumas and rare species not normally seen at such high elevations.
“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,” commented co-author Cliff Bueno de Mesquita. “Current anthropogenic climate change is probably the most severe crisis our planet and all living things have faced in the past 65 million years.”
