He expected that there would be a higher diversity of bumble bees where there is a higher diversity of food plants, provided that there is a broad range of flower depths available.
(a higher diversity of food plants; provided; that there is a broad range of flower depths available) (He; expected; that there would be a higher diversity of bumble bees)
a higher diversity of food plants He
provided expected
that there is a broad range of flower depths available
that there would be a higher diversity of bumble bees