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Grassland Responses to Climate Change Induced Drought
Craine, J.M., Ocheltree, T.W., Nippert, J.B., Towne, E.G., Skibbe, A.M., Kembel, S.W. and Fargione, J.E. 2012. Global diversity of drought tolerance and grassland climate-change resilience. Nature Climate Change 3: 63-67.

The authors write that "drought reduces plant productivity, induces widespread plant mortality and limits the geographic distribution of plant species," and, therefore, they say that "as climates warm and precipitation patterns shift in the future, understanding the distribution of the diversity of plant drought tolerance is central to predicting future ecosystem function and resilience to climate change."

What was done
To better understand the nature of drought tolerance in grasslands, Craine et al. experimentally assessed this important physiological property for 426 grass species out of the more than 11,000 that are found throughout the world. This they did with seeds collected from all six continents, ranging from 8% of the total from Australia to 33% from Asia.

What was learned
According to the seven scientists who conducted the study, they found that (1) physiological drought tolerance - which varied tenfold among the 426 species they studied - is well distributed both climatically and phylogenetically, and that (2) "physiologically drought-tolerant species had higher rates of water and carbon dioxide exchange than intolerant species," suggesting that "most native grasslands are likely to contain a high diversity of drought tolerance."

What it means
In the words of Craine et al., "our findings suggest that diverse grasslands throughout the globe have the potential to be resilient to drought in the face of climate change through the local expansion of drought-tolerant species," citing as an example of this phenomenon the fact that "plant productivity in Kansas and Nebraska grasslands was maintained during drought in the 1930s not by the immigration of drought-tolerant species, but by local expansion of those species after less-tolerant species perished," citing Weaver et al. (1935) and Weaver (1968).

Weaver, J.E., Stoddart, L.A. and Noll, W. 1935. Response of the prairie to the Great Drought of 1934. Ecology 16: 612-629.

Weaver, J.E. 1968. Prairie Plants and their Environment: A Fifty Year Study in the Midwest. University of Nebraska Press, Lincoln, Nebraska, USA.

Reviewed 26 June 2013