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Adaptations and Origins of Alpine Plants
W. D. Billings
Arctic and Alpine Research
Vol. 6, No. 2 (Spring, 1974), pp. 129-142
Published by: INSTAAR, University of Colorado
Stable URL: http://www.jstor.org/stable/1550081
Page Count: 14
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Alpine environments are characterized by short, cold, unpredictable growing seasons. Outside of the Arctic this growing season is characterized by cold nights as well. Alpine plant adaptations are much like those of the Arctic in morphological and physiological characteristics. However, they appear to acclimate metabolically to changes in temperature more easily than do arctic ecotypes. In fact, almost all representatives of arctic-alpine species are ecotypically different from their congeners in the Arctic. This is particularly true in reproduction and metabolism, the real heart of adaptation to cold alpine environments. While there are relatively ancient alpine plant taxa, the accelerated rise of new mountain ranges in late Pliocene and Pleistocene times has led to new floristic aggregations in alpine vegetations by migration and adaptive radiation. Fluctuations in Pleistocene glaciations have alternately allowed migrations and blocked them. Interglacial refugia may be more important than glacial refugia in consolidating evolutionary changes in alpine taxa which evolve in response to decreasing temperatures, increasing light intensities, and in some cases to increasing drought stress.