Headwaters fed by subterranean ice: Potential climate refugia for alpine stream communities?

Western North American Naturalist
By: , and 



Near-term extirpations of macroinvertebrates are predicted for mountain streams worldwide as a warming climate drives the recession of high-elevation ice and snow. However, hydrological sources likely vary in their resistance to climate change, and thus streams fed by more resistant sources could persist as climate refugia for imperiled biota. In 2015–2016, we measured habitat characteristics and quantified macroinvertebrate community structure along 6 alpine streams in the Teton Range, Wyoming, USA. Strong differences in habitat characteristics (e.g., temperature, bed stability, conductivity) confirmed 3 major stream sources: surface glaciers, perennial snowfields, and subterranean ice. Subterranean ice-fed streams—termed “icy seeps”—appear common in the Teton Range and elsewhere, yet are globally understudied. Midges in the family Chironomidae dominated our study sites, representing 78.6% of all specimens sampled, with nematodes, caddisflies (Neothremma), and mayflies (Epeorus) also common. At the community scale, glacier- and snowmelt-fed streams differed significantly in multivariate space, with icy-seep communities intermediate between them, incorporating components of both assemblages. Because the thermal environment of subterranean ice, including rock glaciers, is decoupled from large-scale climatic conditions, we predict that icy seeps will remain intact longer than streams fed by surface ice and snow. Furthermore, our results suggest that icy seeps are suitable habitat for many macroinvertebrates occupying streams fed by vulnerable hydrological sources. Thus, icy seeps may act as key climate refugia for mountain stream biodiversity, an idea in need of further investigation.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Headwaters fed by subterranean ice: Potential climate refugia for alpine stream communities?
Series title Western North American Naturalist
DOI 10.3398/064.080.0311
Volume 3
Issue 80
Year Published 2020
Language English
Publisher Monte L. Bean Life Science Museum, Brigham Young University
Contributing office(s) Northern Rocky Mountain Science Center
Description 13 p.
First page 395
Last page 407
Country United States
State Wyoming
Other Geospatial Grand Teton National Park, Jedediah Smith Wilderness
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