Place for wild animals always keeping a lot of the other ones upset (7)
I believe the answer is:
reserve
'place' is the definition.
(I know that reserve is a type of place)
'always keeping a lot of the other ones upset' is the wordplay.
'always' becomes 'ever' (synonyms).
'keeping' means one lot of letters goes inside another (some letters kept inside).
'a lot of the other ones' becomes 'res' (I can't explain this - if you can you should give a lot more credence to this answer).
'upset' is a reversal indicator.
'ever' enclosing 'res' is 'evreser'.
'evreser' written backwards gives 'RESERVE'.
'for wild animals' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for reserve that I've seen before include "keep for oneself" , "Reticence" , "Conservation area" , "8 [RESTRAINT]" , "Wine kept" .)