Water and Sand Dune Ecology

“The surface of the sand was moist and pockmarked from raindrops, but showed no other sign of the rainstorm just past. This was, indeed, a vivid object lesson in the absorbing capacities of sand dunes. Sand dunes are less arid than they appear; in fact, they are among the moistest of desert habitats. Like a sponge, dunes soak up every drop of rain that falls on them. No water runs off dunes, and since the top several inches of dry sand insulate moist sand beneath, little water evaporates. Even during hot, rainless summers, when the air temperature is 100F and the sand surface is 140F, the sand is cool and moist just six to twelve inches below the surface.” —Dune Country