Answer :

The tundra is considered a desert because of its dry, cold weather. The amount of flora in a tundra is comparable to that of a desert, little to none. A vertical feeding pattern is when an animal or person eats while standing up.
AL2006
A desert is an area that receives very little precipitation (rain or snow), and
has very sparse vegetation.  Tundra fits this description.

"Vertical feeding pattern" in an area means that different species are able to
coexist there because some of them feed from the ground or down near it ...
like eating grass, bugs, or small rodents ... while other species feed from
higher up ... eating like leaves, tree fruits, or birds.