Conservation status
 

The “IUCN Red List of Threatened Species” is essentially a scientifically-based call to action for preventing the extinction of wild species around the world. Compiled by the IUCN’s Species Survival Commission (SSC), with support from the IUCN Species Program, the Red List guidelines and criteria have been modified at different times since its inception in 1963. But it still relies largely on a massive voluntary effort by global scientists to sustain the flow of Red List information. In this regard, SSC specialist groups such as the CSG have been responsible for undertaking Red List assessments. Indeed, specialist groups were involved in evaluating and testing the new generation of Red List criteria upon which these assessments are made.

Notwithstanding deficiencies in the Red List criteria (eg Webb 2008; Godfrey and Godley 2008; Seminoff and Shanker 2008), it still provides important guidance on the allocation of species to the Appendices of CITES. In the case of crocodilians the status of different species has more or less been in line with their listing on the CITES Appendices, and thus their ability to be traded internationally.

Of the 23 species of crocodilians, 5 are currently listed as Critically Endangered, 2 as Endangered, 3 as Vulnerable, 12 as Least Risk and 1 as Data Deficient. These categories are defined by the Red List as:
Critically Endangered (CR)
  Considered to be facing an extremely high risk of extinction in the wild.
Endangered (EN)
  Considered to be facing a very high risk of extinction in the wild.
Vulnerable (VU)
  Considered to be facing a high risk of extinction in the wild.
Least Risk (LR)
  Widespread and abundant taxa, which can be further subdivided into one of three sub-categories; Conservation Dependent (cd), Near Threatened (nt) and Least Concern (lc).
Data Deficient (DD)
  Inadequate information to make a direct, or indirect, assessment of its risk of extinction based on distribution and/or population status. Data Deficient is not a category of threat.
 
Current IUCN Red List categories for crocodilians
Common Name Species Category
Chinese Alligator Alligator sinensis CR
Philippine Crocodile  Crocodylus mindorensis CR
Orinoco Crocodile  Crocodylus intermedius CR
Siamese Crocodile  Crocodylus siamensis CR
Indian Gharial  Gavialis gangeticus CR
Cuban Crocodile  Crocodylus rhombifer EN
False Gharial Tomistoma schlegelii EN
American Crocodile Crocodylus acutus VU
Mugger Crocodile Crocodylus palustris VU
Dwarf Crocodile Osteolaemus tetraspis VU
Morelet’s Crocodile Crocodylus moreletii LR (cd)
Black Caiman Melanosuchus niger LR (cd)
American Alligator Alligator mississippiensis LR (lc)
Australian Freshwater Crocodile Crocodylus johnstoni LR (lc)
Nile Crocodile Crocodylus niloticus LR (lc)
New Guinea Freshwater Crocodile Crocodylus novaeguineae LR (lc)
Saltwater Crocodile Crocodylus porosus LR (lc)
Spectacled Caiman  Caiman crocodilus LR (lc)
Broad-snouted Caiman  Caiman latirostris LR (lc)
Yacare Caiman Caiman yacare LR (lc)
Cuvier’s Smooth-fronted Caiman Paleosuchus palpebrosus LR (lc)
Schneider’s Smooth-fronted Caiman Paleosuchus trigonatus LR (lc)
African Slender-snouted Crocodile Crocodylus cataphractus DD

The Red List categories apply to species at a global level. Thus, some species such as C. porosus may be secure in some countries (eg Australia, Papua New Guinea and Indonesia) but greatly reduced and/or threatened in others (eg Philippines, Malaysia, Singapore, etc.) - but at a global level C. porosus is not considered to be at high risk of extinction.

The Red List is used as a guide by the CSG to prioritise its work, but it also relies on a suite of other information when evaluating issues requiring specific action. For example, information from CSG members, NGOs and wildlife authorities is vital to directing the CSG’s efforts. Efforts to re-establish international trade on a legal and sustainable basis have clearly assisted the recovery of many crocodilian species, but some will require ongoing efforts.

Major conservation initiatives are currently underway with the five Critically Endangered species of crocodilian (C. mindorensis, C. intermedius, C. siamensis, G. gangeticus, A. sinenis), each of which has a reintroduction element associated with it. High human populations (eg Thailand, China, India, Philippines) have been implicated as a threat to most of these species.

Trade was implicated in reduction of wild populations of Orinoco crocodiles, but since protection and an active reintroduction program the status of this species has improved greatly. Trade remains a potential threat to the wild Siamese crocodile population in Cambodia, there has been successful breeding of reintroduced crocodiles in Vietnam, but little is known about the status of the species in Indonesia (Kalimantan). Hybridisation between Siamese crocodiles and Saltwater and Cuban crocodiles in captivity is also an ongoing concern in relation to the wild Siamese crocodile populations.

The CSG-Tomistoma Task Force is working with the Endangered Tomistoma schlegelii, and habitats on the Isle of Youth in Cuba have been restocked with Cuban crocodiles derived from captive breeding. Natural hybridisation between sympatric American crocodiles and Cuban crocodiles is a concern for the former species.

The population status of three species of crocodilian in West Africa (C. niloticus, C. cataphractus, O. tetraspis) is now a major focus of the CSG. A recent sub-regional meeting was a first step towards increased participation in this important sub-region.
 
Suggested reading
  • Godfrey, M.H. and Godley, B.J. (2008). As we see it: seeing past the red - flawed IUCN global listings for sea turtles. Endanger. Species Res. (in press).
     
  • IUCN (2007). 2007 IUCN Red List of Threatened Species. <www.iucnredlist.org>. Downloaded on 16 March 2008.
     
  • Seminoff, J.A. and Shanker, K. (2008). Marine turtles and IUCN Red Listing: A review of the process, the pitfalls, and novel assessment approaches. J. Exp. Mar. Biol. Ecol. (in press).
     
  • Webb, G.J.W. (2008). The dilemma of accuracy in IUCN Red List categories of extinction risk. Endanger. Species Res. (in press).