Proliferate in Australian spring (6)
I believe the answer is:
abound
'proliferate' is the definition.
(thesaurus)
'australian spring' is the wordplay.
'australian' becomes 'A'.
'spring' becomes 'bound' (synonyms).
'a'+'bound'='ABOUND'
'in' is the link.
(Other definitions for abound that I've seen before include "flow" , "Be in ample supply" , "Be plentiful, swarm" , "Be plentiful, exist in great quantities" , "Be widely available" .)