The NatureServe conservation status system, maintained and presented by NatureServe in cooperation with the Natural Heritage Network, was developed in the United States in the 1980s by The Nature Conservancy (TNC) as a means for ranking or categorizing the relative imperilment of species of plants, animals, or other organisms, as well as natural ecological communities, on the global, national and/or subnational levels. These designations are also referred to as NatureServe ranks, NatureServe statuses, or Natural Heritage ranks. While The Nature Conservancy is no longer substantially involved in the maintenance of these ranks, the name TNC ranks is still sometimes encountered for them.