n. The layer above the soil and below the snowpack that serves as a winter refuge for many species.
2016
The small area between the snowpack and the ground, called the subnivium (from the Latin nivis for snow, and sub for below), might be the most important ecosystem that you have never heard of.
2015
With the heavy snow starting in mid-January, I predicted the critters of the subnivium would have an easy time of munching on the garden shrubbery, and that certainly came true, at least in our area.
2014
Two key features help the subnivium support its tenants: temperature stability and air pockets that give animals a little breathing room.
2013 (earliest)
Previous authors have described the “subnivean space" or "subnivean environment" as the interface between the soil and snow (Halfpenny and Ozanne 1989) and the environment under snowpack (Marchand 1996); here, we coin the term "subnivium" to describe the "below snow" seasonal refugium because it provides environmental stability and serves as a habitat to which species can retreat to during changing environmental conditions.
The subnivium: "nature's igloo". Source: National Science Foundation