Different value systems (or combination of) correspond to different conservation perspectives, which were introduced at different points in time (the timeline is approximate for illustrative purpose; see also Mace 2014). A nature for itself perspective can be either ecocentric, biocentric, or both. Under new conservation, an anthropocentric perspective is considered necessary to achieve a desirable outcome under a biocentric perspective (⟹). Under the people and nature approach, anthropocentric, biocentric and ecocentric perspectives are considered simultaneously (+). Underlying concepts and movements pre-dating conservation approaches are indicated in grey italic at the approximate period they originated.