Small piece on British flora and fauna (5)
I believe the answer is:
biota
'flora and fauna' is the definition.
(both can mean animal and plant life)
'small piece on british' is the wordplay.
'small piece' becomes 'iota' (I have seen 'Tiny piece' mean 'iota' so perhaps 'piece' could also mean 'iota'. I am not sure about the 'small' bit.).
'on' is a charade indicator (letters next to each other).
'british' becomes 'b' (abbreviation e.g. in BBC).
'iota' after 'b' is 'BIOTA'.
Can you help me to learn more?
(Other definitions for biota that I've seen before include "The animal and plant life of a region or period" , "Region's creatures, plants" , "Animal and plant life in an area" .)