Global Warming, Graminoid Grasses, and the Grazing Geese of Greenland - CO2 Science Magazine

Global Warming, Graminoid Grasses, and the Grazing Geese of Greenland

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Reference
Madsen, J., Jaspers, C., Tamstorf, M., Mortensen, C.E. and Riget, F. 2011. Long-term effects of grazing and global warming on the composition and carrying capacity of graminoid marshes for moulting geese in East Greenland. Ambio 40: 638-649.

Background
In the abstract of their paper, the authors write that in 1982-1984 they "studied the ecology of non-breeding moulting geese in Jameson Land, low Arctic East Greenland," finding that the geese there at that time "consumed most of the graminoid production in available moss fens," which led them to conclude that "the geese had filled up the available habitat." Nevertheless, they came back in 2008, to see what had happened over the intervening period of significant global - and local - warming.

What was done
In their newest study, Madsen et al. replicated what they had done in their earlier study in terms of both methodology and analysis. In addition, they determined the aboveground biomass of the graminoid marsh vegetation, in order to compare it with what it had been determined to be in 1983 and 1984 by Madsen and Mortensen (1987).

What was learned
According to the five researchers, the data they obtained in late July 2008 yielded a standing crop biomass of 98.2 g/m², which was 2.34 times greater than what had been measured in the same location in late July 1984. And after listing three different lines of evidence for concluding from their original field studies in 1982-1984 that the "habitat capacity of Jameson Land for moulting geese was close to being reached," they now report that between that earlier time and 2008, "the number of moulting geese in Jameson Land tripled."

In further support of the validity of their observations, they note that "on Bylot Island, northeast Canada, graminoid above-ground production in wetlands has increased by 84% between 1990 and 2007, most likely as a consequence of climate warming," citing Cadieux et al. (2008), while adding that "on Svalbard, it is known that early snow melt has a dramatic positive effect on the density of nesting geese and their fecundity," citing Madsen et al. (2007) and noting that "the climate in East Greenland has been warming during the last 30 years."

What it means
In light of Madsen et al.'s amazing findings, it would appear that many of earth's higher-latitude terrestrial ecosystems might well be able to sustain considerably greater primary productivity, as well as much larger numbers of higher-trophic-level consumers, in a CO2-enriched and warmer world than what has long been believed possible.

References
Cadieux, M.C., Gauthier, G., Gagnon, C.A., Bety, J. and Berteaux, D. 2008. Monitoring the Environmental and Ecological Impacts of Climate Change on Bylot Island, Sirmilik National Park. Universite Laval, Quebec, Canada.

Madsen, J. and Mortensen, C.E. 1987. Habitat exploitation and interspecific competition of moulting geese in East-Greenland. Ibis 129: 25-44.

Madsen, J., Tamstorf, M., Klaassen, M., Eide, N., Glahder, C., Riget, F., Nyegaard, H. and Cottaar, F. 2007. Effects of snow cover on the timing and success of reproduction in high-Arctic pink-footed geese Anser brachyrhynchus. Polar Biology 30: 1363-1372.

Reviewed 2 May 2012