Desert was teeming at first with antelope (9)
I believe the answer is:
wasteland
'desert' is the definition.
(I've seen this before)
'was teeming at first with antelope' is the wordplay.
'at first' says to take the initial letters.
'with' means one lot of letters go next to another.
'antelope' becomes 'eland' (eland is a kind of antelope).
The first letter of 'teeming' is 't'.
'was'+'t'+'eland'='WASTELAND'
(Other definitions for wasteland that I've seen before include "Useless tract" , "Barren tract" , "desolation" , "(T. S. Eliot's) desert" , "Lewd Santa included in 'The . . . . . . . . .', poem by T S Eliot" .)