Potential impacts of climate change on grazing capacity of native grasslands in the Canadian prairies

Thorpe, J., Wolfe, S. A. and Houston, B. 2008. Potential impacts of climate change on grazing capacity of native grasslands in the Canadian prairies. Can. J. Soil Sci. 88: 595-609. Relationships between climate and native grassland production in the Canadian prairies were modelled and used to estimate the potential impacts of climate change on grazing capacity. Field measurements of production were related to climate variables and water balance estimates using regression analysis. Historical time series showed that year-to-year production is most closely correlated with annual actual evapotranspiration, whereas geographic patterns revealed that average production is most closely related to the annual water deficit. Climate and production estimates from the US Great Plains represent potential analogues for the Canadian prairies in the 2050s. Analysis of geographic patterns using Canadian and US data showed that production can be related to actual evapotranspiration (Model 1) or the ratio of actual to potential evapotranspiration (Model 2). The proportion of warm-season (C-4) grasses has a significant effect oil production in these models. A third independent model (Model 3) using US production data was used for comparison. Five general circulation model (GCM) scenarios covering a range of predictions simulated warmer climates of the 2050s. The production models Were used to estimate changes in grassland production. Oil loamy soils, Model I predicts increases in production whereas Models 2 and 3 predict decreases. However, all predicted changes are modest, indicating that Canadian grasslands will probably remain productive over the next 50 yr. In addition. warm-season grasses could increase, particularly on sandy soils, thus benefiting productivity.