Investigating Life at the Extremes on Ice: Over 73 'Glacier-Endemic Species' and Diverse Ecosystems Face Extinction by Century's End

An international research group involving Professor Nozomu Takeuchi from the Center for Environmental Remote Sensing at Chiba University has published the first comprehensive study revealing the global diversity of unique animal species inhabiting glaciers and their impacts from climate change. By meticulously reviewing 482 records from past literature, this study demonstrates that glaciers are not merely blocks of ice, but rich ecosystems with complex food webs. Simultaneously, it shows that these animals face a severe extinction crisis due to glacial melting occurring at an unprecedented rate.

The research findings were published online by PNAS on June 15, 2026 (Eastern Time, USA). (Paper available here: 10.1073/pnas.2514455123)

Figure: The disappearing Himalayan glaciers (a) and glacier-endemic species: larva of the glacier midge and glacier water flea (b), glacier stonefly (c), tardigrade (d), ice worm (e)

Research Background

Glaciers and ice sheets, covering about 10% of Earth's land surface, have long been regarded as 'barren lands of life.' However, in reality, cryobiota—organisms adapted to extreme cold environments (Note 1)—have established unique ecosystems (Figure). Yet, the global diversity of these animal species and their relationship with climate change remained unclear. Currently, glaciers worldwide are melting at an unprecedented pace due to global warming. There is a growing concern that entire ecosystems could vanish before the unknown biological traits of cryobiota are fully understood, making it urgent to clarify their actual status and scientifically predict future extinction risks.

Key Research Findings

1. Construction of the World's First 'Glacier Animal Database': By integrating literature from around the world, the team constructed the first comprehensive global dataset. The study found that glaciers host 152 animal species across 7 phyla and 14 classes, including nematodes, tardigrades, insects, and earthworms that spend their entire lives on glaciers. Among them, 73 species were identified as glacier-endemic animals (Note 2).

2. Dispersal Ability Determined by 'Wind': Microscopic animals transported by wind (e.g., tardigrades) show wide distributions, whereas independently walking insects exhibit more localized distributions, suggesting limited dispersal across glaciers. Additionally, the study revealed a historical pattern: regions with relatively stable past climate changes tend to harbor more surviving species today.

3. Future Prediction of Complete Habitat Loss by 2100: Combining the latest glacier melt simulations with the collected animal distribution data, the study predicts that even under moderate warming scenarios, most glacier-endemic species will lose their habitats by 2100. In regions such as the Alps, Scandinavia, and the Caucasus Mountains, multiple endemic species are expected to lose their glacial habitats entirely, potentially vanishing from Earth before their ecology and evolutionary history can be fully understood.

Future Outlook

This study proves that glacier-endemic animal species, which inhabit only glaciers worldwide, are among the most severely threatened biological groups due to habitat loss from glacial melt within this century. With 2025 designated as the 'International Year of Glacier Preservation,' it is essential to consider not only the physical disappearance of glaciers but also the conservation of the biodiversity they support. Moving forward, conservation strategies beyond traditional frameworks—such as laboratory breeding (ex-situ conservation)—must be explored.

Glossary

Note 1) Cryobiota: Organisms adapted to extreme cold environments such as glaciers, ice sheets, and snowfields, spending all or part of their lives there. Includes photosynthetic microorganisms like algae, as well as heterotrophic animal species dependent on their production.

Note 2) Glacier-endemic animal species: Highly specialized animal species capable of surviving and reproducing only under the extreme low-temperature conditions of glaciers.

Publication Information

Title: The global diversity and decline of glacier animals

Authors: Andrea Simoncini, Isabel Cantera, Simone Giachello, Barbara Valle, Mauro Gobbi, Diego Fontaneto, Krzysztof Zawierucha, Ronald Laniecki, Stephen Coulson, Valeria Lencioni, Sophie Cauvy-Fraunié, Alejandra Moràn-Ordóñez, Gianalberto Losapio, Nozomu Takeuchi, Qiao Liu, Daniel Shain, Heather Fair, Karel Janko, Miloslav Devetter, Marco Antonio Jiménes-Santos, Marie Šabacká, Mattia Falaschi, Silvio Marta, Gentile Francesco Ficetola

Journal: Proceedings of the National Academy of Sciences of the United States of America (PNAS)

DOI: 10.1073/pnas.2514455123

Research Project Funding

This study was supported by Grants-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (JSPS) (Grant Numbers 26247078, 19H01143, 24H00260).