Advice from conservationist, perhaps to no avail (7)
I believe the answer is:
useless
'to no avail' is the definition.
(I've seen this in another clue)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for useless that I've seen before include "Incompetent" , "Is Sue less impractical?" , "Without purpose" , "Futile and unavailing" , "Good for nothing" .)