Skyships of the Wastes
As the the stream waters flowing out from Oases sink below the thirsty sands, the land is still livable, but harsh. This area that exists between plentiful and empty is called the fringe. Any oasis of reasonable size has a fringe around it. The larger the oasis, the larger the fringe. Life exists there, but must scrabble to survive. Fringe lands can be arid grassy steppes, scrub-lands, or desert with drinking holes scattered through out.
Fringelanders scorn the soft lives of oasis dwellers.