Population trends of grassland birds in North America are linked to the prevalence of an agricultural epizootic in Europe

Abstract

Globalization of trade has dramatic socioeconomic effects, and, intuitively, significant ecological effects should follow. However, few quantitative examples exist of the interrelationship of globalization, socioeconomics, and ecological patterns. We present a striking illustration of a cascade in which bovine spongiform encephalopathy (BSE; “mad cow disease”) outbreaks in Europe exerted pressure on global beef markets, subsequently affecting North American hayfields and grassland bird populations. We examined competing models, which linked the prevalence of BSE in five focal countries, volume of beef exports to those countries from North America, and the amount of hayfield harvested and the abundance of grassland birds in North America. We found that ( i ) imports from North America increased 1 y after BSE outbreaks; ( ii ) probably because fewer cattle remained, the hay harvest in North America was reduced 2 y after the outbreak; ( iii ) the reduced hay harvest yielded a positive response in grassland bird populations 3 y after the outbreak.

The grasshopper sparrow as an indicator species in tallgrass prairies

“…Grasshopper sparrows have been identified as a species of conservation concern at state and regional levels within the Midwestern United States because of population declines (Bakker , Ringelman et al , Minnesota Prairie Plan Working Group , Minnesota Department of Natural Resources ). Declines in grasshopper sparrow populations are consistent with other grassland bird species (Herkert , Nocera and Koslowsky , Sauer et al ). This species is moderately abundant in the Prairie Pothole Region of Minnesota and Iowa during the breeding season (20–25 birds/100 ha; Quamen ), which suggests its density may be well suited for statistical analysis.…”

Bobolink reproductive response to three hayfield management regimens in southern Ontario

“…Shifts in the agriculture industry, such as shifts in beef demand (Nocera & Koslowsky 2011), increased mechanization and productivity for growing forage crops, and greater economic benefits of growing row crops (Sargeant et al 1998;Agriculture and Agri-Food Canada 2005;Eilers et al 2010), have decreased the area of land used for hayfields and pastures in favour of monoculture crops and other human development, and an increasing amount of land has been left fallow (Askins 1993;Herkert 1997). In the last half-century, hay harvests have become more frequent and happen earlier, commonly overlapping with the nesting period of many grassland birds and inducing complete nest failure (Bollinger et al 1990;Perlut et al 2006).…”

Grassland birds and dairy farms in the northeastern United States

“…Some recent studies have in fact taken an interdisciplinary global approach in evaluating population declines. For example, Nocera and Koslowsky () linked a European outbreak of bovine spongiform encephalopathy with global beef markets, North American hayfield crops, and how pressure on these crops impacts breeding birds. While insightful, this work is difficult to apply and therefore use in conservation planning.…”