The International Union for the Conservation of Nature (IUCN) Red List
As of September, 2014, the Red List identifies: (1) 828 extinct species; (2) 69 species extinct in the wild; (3) 4574 critically endangered species; (4) 6,830 endangered species; (5) 10,772 vulnerable species; (6) 4,980 near threaten species; and (7) 33,607 species of least concern.
The definition of IUCN Red List terms is as follows:
1. Extinction: No known species in existence.
2. Extinct in the wild: Known only to exist in captivity.
3. Critically endangered: extremely high risk for extinction in the wild.
4. Endangered species: High risk of extinction in the wild.
5. Vulnerable: High risk of endangerment in the wild.
6. Near threatened: Species likely to become threatened in the near future.
7. Least Concern: Species at the lowest risk of extinction in the wild.
Numerous studies employ the IUCN data to examine issues related to species extinction. These data have been employed in green criminological studies, including those by: Petrossian and Clake (2013); Clarke and Rolf (2013); and Pires and Clarke (2012, 2011).
Clarke, Ronald V., and A. Rolf. (2013). “Poaching, habitat loss and the decline of neotropical parrots: a comparative spatial analysis.” Journal of Experimental Criminology 9, 3: 333-353.
Petrossian, Gohar A., and Ronald V. Clarke. (2013). “Explaining and Controlling Illegal Commercial Fishing An Application of the CRAVED Theft Model.” British Journal of Criminology doi: azt061.
Pires, Stephen, and Ronald V. Clarke.(2012). “Are parrots CRAVED? An analysis of parrot poaching in Mexico.” Journal of research in crime and delinquency 49, 1: 122-146.
Pires, Stephen F., and Ronald V. Clarke. (2011). “Sequential foraging, itinerant fences and parrot poaching in Bolivia.” British Journal of Criminology doi: 10.1093/bjc/azq074.