Modern-day spiritualist initially notes ecological venture (3,4)
I believe the answer is:
new ager
'modern-day spiritualist' is the definition.
'initially notes ecological venture' is the wordplay.
'initially' says to take the initial letters.
'venture' becomes 'wager' (wager is a kind of venture).
The first letters of 'notes ecological' is 'ne'.
'ne'+'wager'='NEW AGER'
(Other definitions for new ager that I've seen before include "Hippy" , "Latter-day hippie" .)