Land animals in the Arctic have experienced increasingly frequent population
crashes in the last few decades. Many of these crashes can be attributed to
layers of surface ice that form over mosses and grasses, forming a barrier
between primary consumers, such as lemmings, musk ox, and reindeer, and the
plants they wish to eat (6).

Milder weather and wetter snow pose threats for burrowing animals, such as
lemmings and voles. Wetter snow leads to reduced stability within the burrow
spaces and the regular melting and refreezing of the snow surface actually
reduces the insulating properties of the snow pack (9).

The loss of these foragers and herbivores puts a stress on the predators that
feed on them, such as snowy owls, weasels, and ermine. Often this will result
in similar population crashes among these higher order consumers, though
sometimes it is possible for some species to broaden their diet to include
other prey. The Arctic fox, for example, adapted to preying on birds,
particularly waders. This alleviated much of the immediate problem for the fox,
but has added to the pressures currently on these bird populations (2). With the increasing warming and inconsistent shifting of habitable zones through the region, it seems likely that this problem will get worse before it gets better.