Reduced winter snowfall damages the structure and function of wintergreen ferns.

• Premise of the study: The full impact of climate change on ecosystems and the humans that depend on them is uncertain. Anthropogenic climate change is resulting in winters with less snow than is historically typical. This deficit may have an impact on wintergreen ferns whose fronds lie prostrate under the snowpack and are thereby protected from frost.• Methods: Frost damage and ecophysiological traits were quantified for three species of wintergreen fern (Dryopteris intermedia, Dryopteris marginalis, and Polystichum acrostichoides) near Delhi, NY following the winters of 2012 (which had very little snowfall) and 2013 (which had typical snowfall).• Key results: Dryopteris intermedia was the most common species and had the highest percentage of frost-damaged fronds and the highest percentage of its cover damaged in 2012. Frost damage was significantly less in 2013 for all species. Polystichum acrostichoides had the highest vernal photosynthetic rate in undamaged fronds, and all three species had a negative net photosynthetic rate in frost-damaged fronds. The wintergreen fern community lost 36.69 ± 2.80% of its productive surface area to frost damage in 2012. Dryopteris intermedia had the thinnest leaves and this trait may have made it the most susceptible to frost damage.• Conclusions: These results demonstrate that repeated winters of little snow may have a significant impact on the structure and functioning of the wintergreen fern community, and species will respond to a reduced snowpack on an individual basis.