The relative abudndance of three plant functional types in temperate grasslands and shrublands of North and South America: effects of projected climate change

EPSTEIN, H.E.; GILL, R.A.; PARUELO J. M.; LAUENROTH, W.K.; JIA, G.; BURKE, I.C.

JOURNAL OF BIOGEOGRAPHY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2002 vol. 29 p. 875 - 888

0305-0270

Aim Use a regression model that relates climatic variables to the relative abundances ofshrubs, C4 and C3 grasses to project the plant functional type composition of temperategrasslands and shrublands within North and South America in response to climate change.Location The temperate zone grassland and shrubland regions of North and South America.Methods We used a regression model to project changes in the relative abundances ofshrubs, C4 and C3 grasses under three general circulation model (GFDL, GISS, UKMO)climate change scenarios. The three climate change scenarios were applied to a global data setof mean monthly temperatures and precipitation. The regression model, which incorporatesmean annual temperature, mean annual precipitation and seasonality of precipitation as inputvariables, was used to project plant functional type changes. Spatial patterns of change wereanalysed using a geographical information system.Results Relative abundance of C4 grasses were projected to increase >10% throughout mostof the study region at the expense of C3 grasses. There were essentially no areas where C4grasses decreased in abundance, and the areas with no change were largely the southern GreatPlains and the Intermountain Basin and Range of North America. C3 grasses declinedthroughout with the exception of the north-western Great Plains of the US and Canada, andnorth central Argentina. Changes in shrub abundance were mixed with some increases inPatagonia and the desert regions of the south-western US; there were also some projecteddecreases, however, the locations varied across models.Main conclusions The projections made by our regression model were consistent withthose of other more complex vegetation dynamics models. Changes in plant communitycomposition in response to climate change may be substantial in certain areas and willprobably lead to changes in water and nutrient cycling.