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Experimental Warming of Icelandic Plant Communities
Reference
Jonsdottir, I.S., Magnusson, B., Gudmundsson, J., Elmarsdottir, A. and Hjartarson, H.  2005.  Variable sensitivity of plant communities in Iceland to experimental warming.  Global Change Biology 11: 553-563.

What was done
Climate models predict that the world's Arctic regions will experience the greatest temperature increases in response to CO2-induced global warming, and that the warming of high latitude tundra ecosystems will result in significant losses of species and reduced biodiversity.  In a test of this hypothesis, Jonsdottir et al. conducted a field experiment to learn how vegetation might respond to moderate warming at the low end of most climate model temperature projections.  Specifically, they studied the effects of 3-5 years of modest surface warming (1-2°C) on two widespread but contrasting tundra plant communities, one of which was a nutrient-deficient and species-poor moss heath and the other of which was a species-rich dwarf shrub heath.

What was learned
No changes in community structure were detected in the moss heath.  In the dwarf shrub heath, on the other hand, the number of deciduous and evergreen dwarf shrubs increased more than 50%, bryophytes decreased by 18% and canopy height increased by 100%.  In addition, the authors state that "contrary to some other studies of tundra communities, we detected no changes in species richness or other diversity measures in either community and the abundance of lichens did not change."

What it means
Although Jonsdottir et al.'s study was a relatively short-term experiment as far as ecosystem studies go, its results are encouraging, as they indicate that a rise in temperature need not have a negative effect on the species diversity of high latitude tundra ecosystems and that it may actually have a positive influence on plant growth, which consequences are a far, far cry from the ecological disasters that climate alarmists typically claim will occur in response to rising temperatures.

Reviewed 22 June 2005