Environments somewhat surrounded by boaters for example (8)
I believe the answer is:
habitats
'environments' is the definition.
(I know this)
'somewhat surrounded by boaters for example' is the wordplay.
'somewhat' becomes 'a bit' (a bit).
'surrounded by' means one lot of letters goes inside another.
'boaters for example' becomes 'hats' (boater is a kind of hat).
'abit' placed inside 'hats' is 'HABITATS'.
(Other definitions for habitats that I've seen before include "Natural environments of animals or people" , "Natural environments of organisms" .)