Slender-snouted crocodile populations are projected to decline 60-90%, making the species extinct within one generation.
Based on the current estimated subpopulation declines and local extinctions throughout the Sahel, Lake Mweru, and Lake Tanganyika it is anticipated that slender-snouted crocodile subpopulations will become extinct within one generation into the future.
Additionally, while the Sene-Gambia subpopulation is currently well protected, any loss of will to continually protect the chimpanzee (Pan troglodytes) colonies will result in near instantaneous extinction of this subpopulation. Slender-snouted crocodiles are significantly reduced in at least the Sahel zone and Lake Tanganyika and Mweru locations with anticipated complete extirpation in the near future.
There is also continuing decline in the extent and quality of the habitat based on deforestation and forest degradation throughout this species range, especially in West Africa, which has resulted in sedimentation effecting prey species populations, as well as human settlement/encroachment and reduction in breeding habitat.
There is no reason to expect the decline to slow, hence future reduction over the next 75 years, or three generations, is projected to be between 60–90% based on ongoing loss of range and habitat, exploitation and competition with other introduced crocodilian species. The future reduction is hard to quantify mostly due to extremely different threats and levels of active protection between West and Central Africa. On a global basis, however, this species is expected to lose 100% of mature individuals outside of protected areas and 60–90% inside of protected areas where fishing, hunting, and forest clearing remain issues.
In West Africa, subpopulations have already been reduced to the point where even small perturbations will result in localized extinctions and the state of protected area management (where most individuals are confined today) suggests that these reductions will continue into the future. For example, this species continues to exist in The Gambia solely due to the level of protection afforded the artificial chimpanzee colonies on the islands on which it breeds in the interior of the River Gambia National Park – it does not occur up or downstream of these core islands. Additionally, with increasing habitat conversion the West African crocodile (Crocodylus suchus) will be able to occupy previously exclusive slender-snouted crocodile habitat and out-compete them. Without intervention, in Central Africa the only remaining subpopulations at the end of three generations will be restricted to well-managed protected areas and remote areas of Gabon. In West Africa, this species is anticipated to go completely extinct without significant revisions in protected area policy and management, as well as assisted efforts such as reintroductions.
Looking at a combination of the information on past and future reductions it is estimated that population reduction would be between 50–80%, once again resulting in a Critically Endangered listing. From 2013 to 2035 it is estimated that continued habitat loss, habitat conversion for agriculture, such as for palm oil and rubber developments throughout Gabon, the Democratic Republic of the Congo, Cote d’Ivoire, Liberia and Sierra Leone, and increasing human pressures on natural resources, notably freshwater fisheries, will greatly increase this species extinction risk.
• Image | ©️ Markus Schroeder, Some Rights Reserved (CC BY-NC-ND 2.0)
• Sources | (Kofron, 1992; Lavinder & Megevand, 2013; Pauwels, et al., 2003; Shirley, 2013, 2014; Waitkuwait, 1989)
Learn More About the Slender-Snouted Crocodile
