Fig. 4. Boulder Stream (BSC) on the Kuna Crest
Increases in western North America temperatures have been twice the global average over the past 50 years; mountain regions experienced accelerated warming above lowland averages. The Sierra Nevada (SN), CA, lies in a Mediterranean climate where warming climates are anticipated to impose significant...
| Main Authors: | , , , , |
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.205.8324 http://www.fs.fed.us/psw/publications/millar/posters/millar_etal_poster_agu2007.pdf |
| Summary: | Increases in western North America temperatures have been twice the global average over the past 50 years; mountain regions experienced accelerated warming above lowland averages. The Sierra Nevada (SN), CA, lies in a Mediterranean climate where warming climates are anticipated to impose significant ecological stress on already marginal alpine habitats. For example, the American pika, Ochotona princeps, endemic to alpine talus slopes, is the first animal species to be petitioned for listing as endangered by climate change (CBD 2007). SIERRA NEVADA ROCK GLACIERS AND ROCK-ICE ICE FEATURES (RIFs ( RIFs) GC41A-0098 Although considerable research has documented rapid melting of glaciers, diminishing snowpacks, and earlier stream runoff, rock glaciers have been mostly overlooked. Modern and Pleistocene RIFs and their till are abundant in the high SN from the Tahoe Basin southward. Due to rock mantling and unique cold-air circulation patterns, RIFs in other parts of the world have been shown to be in disequilibrium with climate change, to lag in response to warming, and to retain permafrost more than 1000m below the regional levels. We propose that SN RIFs respond similarly to climate change and thus provide important and overlooked sources of water in alpine regions and refugial habitat for cold- and wetland-dependent alpine species. Previously, we mapped and classified RIFs of the Sierra Nevada (Fig. 1A) into 6 categories, 3 of which are relevant here: Cirque Rock Glaciers (Fig. 2), Valley Wall Rock Glaciers (Fig. 3), and Boulder Streams (Fig. 4) (Millar and Westfall in press). Fig. 1. A) Distribution of Rock-Ice Features (RIFs) mapped in the Sierra Nevada (Millar & Westfall in press); B) Distribution of American pika sites collected in the Sierra Nevada and W |
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