Assigning the forty-sixth angel to nature and the environment is a good case study in how the offices of the seventy-two are actually determined, because here the mechanism is recent enough to be visible.
The elements available to whoever made the assignment were: a three-letter Hebrew root with no obvious lexical meaning; a position at fifteen to twenty degrees of Scorpio; a decan and its planetary ruler; a tarot card; a choir and a sephirah; and a name that in English looks like Ariel. Of these, the one carrying an obvious association for a modern compiler is the last, and the association it carries, Ariel as an angel of nature, postdates the list by centuries and comes from an entirely different body of writing.
The result is a loop. A popular angelology assigns nature to a figure called Ariel. A compiler of the seventy-two, finding an Ariel at position forty-six, imports the association. The attribute is then printed in tables of the seventy-two and reads as traditional.
This is not a hypothesis about a hidden process; it is the ordinary way lists of correspondences grow, and it can be watched happening in comparable cases across the literature. Nor is it unique to the modern period. The same thing must have happened repeatedly in the centuries when this material was being assembled, and it is one reason the offices have no derivable rule behind them.
The value of this particular case is that the dates are known. A reader who understands what happened at position forty-six has a working model for what probably happened at the other seventy-one, where the evidence is thinner and the confidence of the sources is no lower.