Monthly Archives: January 2012

A new paper in the journal Nature Climate Change finds evidence that declining snowfall in the southwestern US indirectly influences plants and associated birds by allowing greater over-winter herbivory by elk. Abundances of deciduous trees and associated songbirds have declined with decreasing snowfall over 22 years of study in montane Arizona. The researchers experimentally tested the hypothesis that declining snowfall indirectly influences plants and associated birds by allowing greater over-winter herbivory by elk, by excluding elk from one of two paired snowmelt drainages and replicating this paired experiment across three distant canyons. Over six years, the exclosures reversed multi-decade declines in plant and bird populations by experimentally inhibiting heavy winter herbivory associated with declining snowfall. Predation rates on songbird nests decreased in exclosures, despite higher abundances of nest predators, demonstrating the over-riding importance of habitat quality to avian recruitment.
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