Trees and Shrubs at Their Poleward Limits in a Warming World
Capers, R.S. and Stone, A.D. 2011. After 33 years, trees more frequent and shrubs more abundant in northeast U.S. alpine community. Arctic, Antarctic, and Alpine Research 43: 495-502.
In an attempt to learn more about this phenomenon, Capers and Stone "studied a community in western Maine, comparing the frequency and abundance of alpine plants in 2009 with frequency and abundance recorded in 1976," while noting that "the 2009 survey was designed to provide a fair comparison with that of 1976," which was conducted and described by Stone (1980).
According to the two researchers, the 2009 survey "provided evidence of the increasing importance of woody plants - both trees and shrubs - in the alpine community," commenting that "the most widespread tree species increased dramatically." In addition, they say they "recorded an increase in total species richness of the community with the addition of four lower montane species that had not been recorded previously." And in another important positive finding, they say they "found no evidence that species with high-arctic distributions had declined more than other species."
Given such findings, Capers and Stone say the changes they recorded "are consistent with those reported in tundra communities around the world." And although there is some concern that the observed increase in species richness could ultimately turn out to be temporary if alpine species were to disappear because of competition from the new species appearing on the scene, they state that "species losses resulting from competition have not typically been found with rising richness in high alpine areas, possibly because newly arriving species occupy different microhabitats," citing the work of Walther et al. (2005).
Thus, it looks like the planet itself has decided to Go Green! ... as ice makes way for life.
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