Using eDNA to solve Everest’s Wildlife Mysteries

Using eDNA to solve Everest’s Wildlife Mysteries

Environmental DNA (eDNA) was used by a team of scientists led by the Wildlife Conservation Society (WCS) and Appalachian State University to document the breadth of high-alpine biodiversity present on the world’s highest mountain, 29,032-foot Mt. Everest (8,849 m).

The team collected eDNA from water samples over a four-week period in ten ponds and streams between 14,763 feet (4,500 meters) and 18,044 feet (4,500 meters), as described in the journal iScience (5,500 meters). The sites included areas of the alpine zone, which exists above the tree line and contains a variety of flowering plants and shrub species, as well as the aeolian zone, which extends beyond the range of flowering plants and shrubs in the biosphere’s uppermost reaches. From just 20 liters of water, they identified organisms belonging to 187 taxonomic orders, which corresponds to 16.3 percent, or one sixth, of the total known orders across the tree of life — a family tree of Earth’s biodiversity.

eDNA looks for trace amounts of genetic material left behind by organisms and wildlife and provides a more accessible, rapid, and comprehensive method of increasing survey capacity for assessing biodiversity in aquatic environments. Samples are collected in a sealed cartridge with a filter that captures genetic material, which is then analyzed in a lab using DNA metabarcoding and other sequencing methodologies. WCS has been using eDNA to detect rare and threatened species ranging from humpback whales to Swinhoe’s softshell turtles, one of the world’s rarest species.

We went in search for life on the roof of the world. This is what we found. However, the story does not end here. There is more to be discovered and we hope our findings help to inform future exploration.

Dr. Marisa Lim

Although the Everest study focused on order-level identification, the team was able to identify many organisms to the genus or species level.

For example, the team discovered rotifers and tardigrades, two tiny animal organisms that live in the harshest and most extreme environments and are thought to be among the most resilient animals on Earth. Furthermore, they identified Tibetan snow cocks, which are found in Sagarmatha National Park, and were surprised to find species such as domestic dog and chicken, demonstrating how human activities are influencing the landscape.

They also identified pine trees, which are only found far downhill from where they sampled, demonstrating how wind-blown pollen can make its way high up into these watersheds. Mayflies, which are known indicator species for environmental change, were also identified from multiple sites.

Solving Everest’s wildlife mysteries with eDNA

The eDNA inventory will aid future high-Himalayan biomonitoring and retrospective molecular studies to assess changes over time as climate-driven warming, glacial melt, and human-caused influences reshape this rapidly transforming world-renowned ecosystem.

Said Dr. Tracie Seimon of WCS’s Zoological Health Program, co-lead of the Everest biology field team and lead of the study: “High-alpine and aeolian environments, which have often been thought of as barren and mostly devoid of life, in fact have abundant biodiversity. High mountain environments including Mount Everest should be recognized as a target for sustained long-term biodiversity monitoring of high-alpine taxa to complement bioclimatic monitoring and climate change impact assessments.”

Said Dr. Marisa Lim of the Wildlife Conservation Society: “We went in search for life on the roof of the world. This is what we found. However, the story does not end here. There is more to be discovered and we hope our findings help to inform future exploration.”

This work is part of the 2019 National Geographic and Rolex Perpetual Planet Everest Expedition.

Dr. Anton Seimon, co-leader of the field study and Research Assistant Professor at Appalachian State University, stated: “When asked why he went to Mt Everest a century ago, British mountaineer George Mallory famously replied, ‘Because it’s there.’ Our 2019 team took a different approach: we went to Mt Everest because it is educational and can teach us about the world we live in.”

By making this open-source dataset available to the research community, the authors hope to contribute to ongoing efforts to build molecular resources for studying and tracking changes in biodiversity on Earth’s highest mountain.