Geomorphic determinants of species composition of alpine tundra, Glacier National Park, U.S.A.

Arctic, Antarctic, and Alpine Research
By: , and 

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Abstract

Because the distribution of alpine tundra is associated with spatially limited cold climates, global warming may threaten its local extent or existence. This notion has been challenged, however, based on observations of the diversity of alpine tundra in small areas primarily due to topographic variation. The importance of diversity in temperature or moisture conditions caused by topographic variation is an open question, and we extend this to geomorphology more generally. The extent to which geomorphic variation per se, based on relatively easily assessed indicators, can account for the variation in alpine tundra community composition is analyzed versus the inclusion of broad indicators of regional climate variation. Visual assessments of topography are quantified and reduced using principal components analysis (PCA). Observations of species cover are reduced using detrended correspondence analysis (DCA). A “best subsets” regression approach using the Akaike Information Criterion for selection of variables is compared to a simple stepwise regression with DCA scores as the dependent variable and scores on significant PCA axes plus more direct measures of topography as independent variables. Models with geographic coordinates (representing regional climate gradients) excluded explain almost as much variation in community composition as models with them included, although they are important contributors to the latter. The geomorphic variables in the model are those associated with local moisture differences such as snowbeds. The potential local variability of alpine tundra can be a buffer against climate change, but change in precipitation may be as important as change in temperature.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Geomorphic determinants of species composition of alpine tundra, Glacier National Park, U.S.A.
Series title Arctic, Antarctic, and Alpine Research
DOI 10.1657/1938-4246-44.2.197
Volume 44
Issue 2
Year Published 2012
Language English
Publisher Institute of Arctic, Antarctic, and Alpine Research
Publisher location Boulder, CO
Contributing office(s) Northern Rocky Mountain Science Center
Description 9 p.
First page 197
Last page 209
Country United States
State Montana
Other Geospatial Glacier National Park