Land Use, Land Cover, and Climate Change in Southern Ontario: Implications for Nutrient Delivery to the Lower Great Lakes

Southern Ontario is home to over a third of the Canadian population and is also one of the most productive agricultural areas in the country. This mosaic of a large and growing urban population and prime agricultural land creates particular challenges for soil and water resource management. While urban areas continue to expand in southern Ontario, changes in agricultural cover and practices within the headwaters are also important to consider. There have been dramatic increases in tile-drained cash crop production (principally grain, corn, and soybean) in southern Ontario over the past few decades, largely at the expense of pasture and forage land. Urban populations will continue to expand into the future, but there is considerable scope for further agricultural change in the headwaters as well. Expansions in urban land cover and intensification of agriculture affect the hydrologic response to extreme events as well as water quality and nitrate leaching in particular. It is important to consider the effects of shifts in both types of land cover on stream flow and water quality in the variable landscape and climatic conditions of the lower Great Lakes.