Not all forms of energy extraction have negative impacts on waterfowl populations on a continental level. Coal mining and nuclear power generation, for example, may be unsightly and have local environmental impacts, but they often don’t significantly affect waterfowl habitats at large scales. This is fortunate, as these energy sources provide 25 percent and 6 percent of the world’s energy, respectively. Nevertheless, their impacts bear watching as small-scale habitat alterations can affect large numbers of birds in migration, wintering, and molting areas. In addition, changes in water quality and other “downstream” effects can have surprisingly broad impacts on wetlands and waterfowl habitat in large watersheds.
Other forms of energy extraction can have both positive and negative impacts on waterfowl habitat. Hydroelectric dams can inundate floodplain wetlands and alter natural river flows, reducing the number of oxbows and backwater wetlands available to ducks. At the same time, reservoirs created by hydroelectric dams can provide feeding and roosting habitat for waterfowl as well as irrigation water for growing grain crops eaten by field-feeding ducks and geese. In addition, tailwater ponds, warm-water sloughs, and other wetlands supplied by irrigation can partially mitigate the loss of natural wetlands.
Production of ethanol and other biofuels is also a double-edged sword for ducks. Ethanol produced from corn has contributed to increases in commodity prices that can drive conversion of grassland to cropland. In the Prairie Pothole Region (PPR), grassland provides vital nesting cover for waterfowl, and the loss of this habitat results in reduced duck populations. In addition, runoff from cornfields can degrade adjacent wetlands by overloading them with nitrogen and phosphorous. Lastly, corn ethanol production requires three to four gallons of water for every gallon of ethanol that is produced, and this doesn’t include water used for crop irrigation.