As nouns the difference between conservation and conservancy
is that conservation
is the act of preserving, guarding, or protecting; the keeping (of a thing) in a safe or entire state; preservation while conservancy
is the conservation of a resource.
As nouns the difference between conservancy and conservatory
is that conservancy
is the conservation of a resource while conservatory
is (obsolete) that which preserves from injury or conservatory
can be a greenhouse or hothouse for the display of plants.
As a adjective conservatory is
(rare) pertaining to conservation.