Hotspots of Accelerated North American Bird Decline Linked to Agricultural Activity

Though previous research has shown that bird populations are declining across North America, a new study is the first to show that the pace of loss has picked up speed since the mid-1980s in three regions: the Midwest, California and Mid-Atlantic states. The work appears in Science.

Intensive agriculture emerges as culprit

After these hotspots of accelerated bird decline were revealed, researchers looked for factors that could explain the difference in the rates of decline, examining climate measures and human activity-related data. A top predictor of where the accelerated abundance loss occurred became clear, overlapping with locations of agricultural intensity as indicated by the extent of cropland and the use of fertilizer and pesticides.

“Agriculture intensity is the main driver associated with accelerated loss of abundance, but we cannot disentangle which of these three metrics is most important because this is a correlative analysis,” said lead author François Leroy, a postdoctoral scholar in evolution, ecology and organismal biology at The Ohio State University.