Global evidence that cold rocky landforms support icy springs in warming mountains

Climate change is reducing the extent of cold aquatic habitats and their unique biodiversity in mountain areas. However, a variety of cold rocky landforms (CRLs) are thermally buffered and feed cold springs (< 2°C) that may represent climate refugia for cold-adapted organisms. These landforms, hitherto overlooked by freshwater research, include rock glaciers, debris-covered glaciers, talus slopes, protalus ramparts, and young moraines. Here, we investigated the warm-season water temperature of 228 springs from clean (ice) glaciers, CRLs, and reference slopes (not sourced by any of these features) in 13 mountain ranges of Europe, South America, and North America. Only springs from glaciers (90%) and CRLs (45%) had average stream temperatures below the thermal optimum for coldwater organisms of 2°C. Springs fed by CRLs were 3-5°C (up to 9°C) colder than those from nearby reference slopes. In general, cold springs were rarer in mediterranean/semi-arid climates than in temperate and sub-polar climates. Landforms comprising barren and coarse rocky surfaces or ice/rock mix, having a simple or absent soil/vegetation structure, and higher likelihood of permafrost more often supported cold springs. When water temperatures were compared to air temperature, most CRL springs were thermally buffered against warm periods, cumulative heat, and daily temperature fluctuations. With cold conditions maintained in a variety of climates and mountain landscapes, CRL springs in mountains likely have high conservation value. We call for integrated ecological and hydrological research for these ecosystems, aimed at understanding their potential as climate refugia.

Fil: Brighenti, Stefano. Eco Research; Italia. Free University of Bolzano; Italia

Fil: Millar, Constance. United States Department of Agriculture; Estados Unidos

Fil: Hotaling, Scott. State University of Utah; Estados Unidos

Fil: Reato, Agustina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagónica. Universidad Nacional de la Patagonia "San Juan Bosco". Centro de Investigación Esquel de Montaña y Estepa Patagónica; Argentina

Fil: Wiegand, Tim. University of Wuerzburg; Alemania

Fil: Hayashi, Masaki. University of Calgary; Canadá

Fil: Carturan, Luca. Università di Padova; Italia

Fil: Morriss, Matthew. Utah Geological Survey; Estados Unidos

Fil: Bearzot, Francesca. University of Calgary; Canadá

Fil: Lencioni, Valeria. Muse-museo Delle Scienze; Italia

Fil: Scotti, Alberto. Apem Ltd.; Reino Unido

Fil: Janicke, Andrina. Institute For Interdisciplinary Mountain Research ; Austrian Academy Of Sciences;

Fil: Fischer, Melina Andrea. Institute For Interdisciplinary Mountain Research ; Austrian Academy Of Sciences; . Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Fil: Larsen, Stefano. Research And Innovation Centre, Fondazione Edmund Mach,; Italia

Fil: Benech, Andrea. University Of Turin; Italia

Fil: Gschwentner, Andreas. Institute For Interdisciplinary Mountain Research ; Austrian Academy Of Sciences;

Fil: Tolotti, Monica. Research And Innovation Centre, Fondazione Edmund Mach; Italia

Fil: Bruno, Maria Cristina. Research And Innovation Centre, Fondazione Edmund Mach; Italia

Fil: Finn, Debra S.. Missouri State University; Estados Unidos

Fil: Freppaz, Michele. University Of Turin; Italia

Fil: Herbst, David. Sierra Nevada Aquatic Research Laboratory; Estados Unidos

Fil: Tronstad, Lusha. University Of Wyoming (uw);

Fil: Comiti, Francesco. Università di Padova; Italia

Fil: Colombo, Nicola. University Of Turin; Italia