The Impact of Agriculture on Waterfowl Abundance: Evidence from Panel Data

Agricultural expansion and intensification in Canada’s Prairie Pothole Region (PPR) have contributed to declining waterfowl populations since the 1970s. Although this region represents a mere 10% of North America’s waterfowl breeding habitat, it produces over 50% of the continent’s duck population and roughly 60% of Canada’s agricultural output. Thus, intense competition exists between private economic interests and public benefits in the PPR. To better understand the conflict between agricultural and wildlife uses of land, panel methods are used to examine the spatiotemporal variation of waterfowl populations and agricultural land use intensity in the PPR from 1961-2006. For the main static model, we find that a one percent increase in cropland or pasture decreases duck density by 6%, while a similar increase in summerfallow area decreases duck density by 7%. Estimates based on a dynamic specification are more conservative. For the lagged dependent variable model, a 1% increase in cropland and pasture decreases duck density by 4.6%, while a decline of 4.7% is predicted for increases in summerfallow area. The spatial autoregressive model allows the derivation of measures for assessing direct and indirect impacts. The estimated direct impacts fall between those obtained from the standard and dynamic models, but, when spillover effects are included, the impacts exceed those predicted by the standard model. It would appear that conserving wetlands in one location has the added benefit of increasing productivity of wetlands at other locations.