A dearth? Gather so, surprisingly (8)
I believe the answer is:
shortage
'a dearth?' is the definition.
('shortage' can be a synonym of 'dearth')
'gather so surprisingly' is the wordplay.
'surprisingly' indicates anagramming the letters.
'gather'+'so'='gatherso'
'gatherso' with letters rearranged gives 'SHORTAGE'.
(Other definitions for shortage that I've seen before include "Deficit" , "Scarcity" , "Horse tag (anag.)" , "Need" , "Dearth, lack" .)