J. Ecol. doi:10.1111/j.1365-2745.2009.01554.x (2009)

Many studies of Arctic warming have focused on summer temperatures, but a new study suggests that vegetation can be damaged by unseasonably warm winter weather.

Stef Bokhorst of the University of Sheffield, UK, and his colleagues looked at how the mountain crowberry (Empetrum hermaphroditum), the dominant shrub in northwestern Scandinavia, fared after a sudden, rapid warming in the region in December 2007. The following summer, many of the shrubs had dead shoots, and overall vegetation growth across an area of 1,424 square kilometres was 26% lower than in the previous year.

An ecosystem-manipulation experiment that heated the ground produced a similar drop-off in shoot growth.