Discussion topics, say, implementing switch in limits to visitors for wildlife protection zones (12,5)
I believe the answer is:
conversation piece
'discussion topics say implementing switch in limits to visitors for wildlife protection zones' is the definition.
I can't judge whether this defines the answer.
'discussion topics say' is the wordplay.
'discussion' becomes 'conversation' (I've seen this before).
'topics say' becomes 'piece' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'conversation'+'piece'='CONVERSATION PIECE'
Can you help me to learn more?
(Other definitions for conversation piece that I've seen before include "It's sure to cause comment" , "Something to talk about?" , "it provokes discussion" , "Object inspiring comment" .)