A trapper from Northern Quebec may consider Mont Tremblant to be civilization, whereas a vacationer from the Montreal area considers it to be wilderness. Wilderness is also sometimes defined by size. Wilderness, then, seems to be a place where nature and natural forces have more influence on the land than humans do. Essentially, wilderness does equal nature. This is where the lack of definition for all three terms becomes obvious.
Biodiversity is considered the same as nature and wilderness is considered to be the same as nature.
Both terms were defined for management purposes. Parks Canada National Park System Plan and the Endangered Spaces Campaign take both of these factors into consideration.