Abstract
All great ape taxa are considered endangered due to a combination of habitat loss, hunting, disease outbreaks and human population increase. The bush-meat trade is thought to be the biggest threat to the survival of chimpanzees, bonobos and gorillas. However, assessments of the reduction of wild populations are notoriously unreliable since they are mostly based on indirect evidence such as brief surveys of markets and interviews with hunters. We use a direct approach and measure annual loss from the wild through intake rates of sanctuaries in Africa which currently hold close to 1000 apes. From these, we calculate loss to the wild populations by relating arrivals into sanctuaries to the proportions of infants in wild groups, hunting strategies, and the likelihood that captured babies make it to a sanctuary. We focus on the most endangered chimpanzee subspecies, Pan troglodytes vellerosus, found in eastern Nigeria / western Cameroon. Our calculations, based on intake rates since 1986 into four sanctuaries in Cameroon and Nigeria, suggest that current rates of hunting are 2 – 13 times higher than sustainable rates. Moreover, VORTEX – a population viability analysis tool – predicts that this chimpanzee subspecies will go extinct in as little as 20 years. The dramatic results emphasise the need for immediate conservation measures. Ape sanctuaries are, at times, considered to be a waste of resources, which could be better diverted to habitat protection. However, it is extremely unlikely that hunting pressure can be significantly reduced, and many local ape populations are already effectively extinct. Sanctuaries will therefore play an increasingly important role as ape conservation tools, if only for the fact that they may, in a couple of decades, harbour more apes than survive in the wild. We propose to apply our method of measuring extinction risk to other taxa of apes across Africa and Asia.
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Adanu, J. (1997). Determination of Life-span of Chimpanzee Nests (Nest-aging) in Gashaka-Gumti National Park. Report to NCF & WWF-UK.
Akçakaya, H. R. (1998). RAMAS metapop: Viability analysis for stage-structured metapopulations, Version 3.0. Software Program.
Ammann, K. (2001). Bushmeat hunting and the great apes. In Beck, B. B., Stoinski, T. S., Hutchins, M., Maple, T. L., Norton, B., Rowan, A., Stevens, E. F. & Arluke, A. (eds.), Great Apes and Humans: the Ethics of Co-existence. Washington: Smithsonian Institution Press, pp. 71–85.
Ammann, K. & Pearce, J. (1995). Slaughter of the Apes: How the Tropical Timber Industry is Devouring Africa’s Great Apes. London: WSPA.
Baillie, J. E. M., Hilton-Taylor, C. & Stuart, S. (2004). IUCN Red List of Threatened Species: A Global Species Assessment. Gland, Switzerland & Cambridge / UK: IUCN.
Beck, J. & Chapman, H. (2008). A population estimate of the endangered chimpanzee Pan troglodytes vellerosus in a Nigerian montane forest: implications for conservation. Oryx 42: 448–451.
Boesch, C. & Boesch-Achermann, H. (2000). The Chimpanzees of the Taï Forest. Behavioural Ecology and Evolution. Oxford: Oxford University Press.
Bowen-Jones, E. (1998). A Review of the Commercial Bushmeat Trade with Emphasis on Central / West Africa and the Great Apes. Cambridge / UK: Flora and Fauna International.
Bowen-Jones, E. & Pendry, S. (1999). The threat to primates and other mammals from the bushmeat trade in Africa, and how this threat could be diminished. Oryx 33: 233–246.
Butynski, T. M. (2001). Africa’s great apes. In Beck, B. B., Stoinski, T. S., Hutchins, M., Maple, T. L., Norton, B., Rowan, A., Stevens, E. F. & Arluke, A. (eds.), Great Apes and Humans: the Ethics of Co-Existence. Washington: Smithsonian Institution Press, pp. 3–56.
Butynski, T. M. & Kalina, J. (1998). Gorilla tourism: a critical look. In Milner-Gullard, E. J. & Mace, R. (eds.), Conservation of Biological Resources. Oxford: Blackwell, pp. 280–300.
Caldecott, J. & Miles, L. (ed.) (2005). World Atlas of Great Apes and Their Conservation. Los Angeles: University of California Press.
Campbell, G., Kuehl, H., N’Goran Kuamé, P. & Boesch, C. (2008). Alarming decline of West African chimpanzees. Current Biology 18: R903–R904.
Cavalieri, P. & Singer, P. (ed.) (1993). The Great Ape Project. Equality Beyond Humanity. New York: St. Martin’s Press.
Chapman, C. A. & Peres, C. A. (2001). Primate conservation in the new millennium: the role of scientists. Evolutionary Anthropology 10: 16–33.
Chapman, C. A., Wrangham, R. & Chapman, L. J. (1994). Indices of habitat-wide fruit abundance in tropical forests. Biotropica 26: 160–171.
Cowlishaw, G. & Dunbar, R. (2000). Primate Conservation Biology. Chicago: The University of Chicago Press.
Cole, L. C. (1954). The population consequences of life history phenomena. The Quarterly Review of Biology 29: 103–137.
De Merode, E., Homewood, K. & Cowlishaw, G. (2004). The value of bushmeat and other wild foods to rural households living in extreme poverty in Democratic Republic of Congo. Biological Conservation 118: 573–581.
Dunn, A. (1993). The Large Mammals of Gashaka-Gumti National Park, Nigeria: Line Transect Surveys from Forest and Savannah. Report to WWF-UK, NCF & Federal Ministry of Agriculture, Water Resources and Rural Development / Nigeria.
Dunn, A. (1999). Gashaka Gumti National Park: a Guidebook. Lagos: Gashaka Gumti National Park, NCF / WWF-UK.
Edroma, E. L., Rosen, N. & Miller, P. S. (1997). Conserving the Chimpanzees of Uganda: Population and Habitat Viability Assessment for Pan troglodytes schweinfurthii. Apple Valley, Minnesota: IUCN / SSC Conservation Breeding Specialist Group.
Fa, J. E. & Purvis, A. (1997). Body size, diet and population density in Afrotropical forest mammals: a comparison with neotropical species. Journal of Animal Ecology 66: 98–112.
Fa, J. E., Currie, D. & Meeuwig, J. (2003). Bushmeat and food security in the Congo Basin: linkages between wildlife and people’s future. Environmental Conservation 30: 71–78.
Fa, J. E., Garcia Yuste, J. E. & Castelo, R. (2000). Bushmeat markets on Bioko island as a measure of hunting pressure. Conservation Biology 14: 1602–1613.
Fa, J. E., Peres, C. A. & Meeeuwig, J. (2002). Bushmeat exploitation in tropical forests: an intercontinental comparison. Conservation Biology 16: 232–237.
Foster, K. L. (1998). Censusing Chimpanzees in Gashaka-Gumti National Park, Taraba and Adamawa States, Nigeria. Report to WWF-UK, NCF & Federal Ministry of Agriculture, Water Resources and Rural Development / Nigeria.
Fowler, A. (2006). Socio-ecology of Nigerian Chimpanzees at Gashaka. PhD thesis, University of London.
Fowler, A & Sommer, V. (2007). Subsistence technology in Nigerian chimpanzees. International Journal of Primatology 28: 997–1023.
Gonder, M. K., Oates, J. F., Disotell, T. R., Forstner, M. R. J., Morales, J. C. & Melnick, D. J. (1997). A new West African chimpanzee subspecies? Nature 338: 337.
Goodall, J. (1986). The Chimpanzees of Gombe: Patterns of Behaviour. Cambridge, MA: Harvard University Press.
Hill, K., Boesch, C., Goodall, J., Pusey, A., Williams, J. & Wrangham, R. W. (2001). Mortality rates among wild chimpanzees. Journal of Human Evolution 40: 437–450.
Hogarth, S. A. (1997). The Distribution and Abundance of the Chimpanzees (Pan troglodytes troglodytes) of the Lowland Gallery Forest of Gashaka-Gumti National Park Nigeria: A Preliminary Report to the Gashaka Sector. Report to WWF-UK, NCF & Federal Ministry of Agriculture, Water Resources and Rural Development / Nigeria.
Hughes, N. (2003). Great Ape Sanctuaries in Nigeria and Cameroon: a Window into the Bushmeat-Trade. MSc in Human Evolution and Behaviour thesis, University College London.
Inskipp, T. (2005). Chimpanzee (Pan troglodytes). In Caldecott, J. & Miles, L. (eds.), World Atlas of Great Apes and Their Conservation. Los Angeles: University of California Press, pp. 53–81.
IUCN (2007). IUCN Red List of Threatened Species. Gland / Switzerland & Cambridge / UK: IUCN / SSC.
Kemf, E. & Wilson, A. (1997). Great Apes in the Wild. Gland: WWF.
Kormos, R., Boesch, C., Bakarr, M. I. & Butynski, T. M. (eds.) (2003). West African Chimpanzees. Status Survey and Conservation Action Plan. Gland & Cambridge UK: IUCN / SSC Primate Specialist Group.
Lacy, R., M. Borbat & Pollack, J. (2003). VORTEX: A Stochastic Simulation of the Extinction Process. Version 9 User’s Manual. Apple Valley / Minnesota: Conservation Breeding Specialist Group (SSC / IUCN).
Lameed, G. A. (2002). Chimpanzee (Pan troglodytes) population density and structure in Gashaka Gumti National Park. ROAN: The Journal of Conservation 1: 88–93.
Leendertz, F., Ellerbock, H. Boesch, C., Couacy-Hymann, E., Mätz-Rensing, K., Hakenback, R., Bergmann, C., Abaza, P. Junglen, S., Moebius, Y., Vigilant, L., Formenty, P. Pauli, G. (2004). Anthrax kills wild chimpanzees in a tropical rainforest. Nature 430: 451–452.
MacKinnon, J. 1977. The future of orang-utans. New Scientist 74: 697–699.
Matthews, A. & Matthews, A. (2004). Survey of Gorillas (Gorilla gorilla gorilla) and chimpanzees (Pan troglodytes troglodytes) in Southwestern Cameroon. Primates 45: 15–24.
McManus, E. (2005). Federal Republic of Nigeria. In Caldecott, J. & Miles, L. (eds.), World Atlas of Great Apes and Their Conservation. Los Angeles: University of California Press, pp. 378–383.
Miller, P. S. & Lacey, R. C. (1997). VORTEX: A Stochastic Simulation of the Extinction Process. Version 8 User’s Manual. Apple Valley / Minnesota: Conservation Breeding Specialist Group (SSC / IUCN).
Milner-Gullard, E. J. & Akçakaya, H. R. 2001. Sustainability indices for exploited populations. Trends in Ecology and Evolution 18: 686–692.
Mittermeier, R. & Cheney, D. (1987). Conservation of primates and their habitats. In Smuts, B. B., Cheney, D. L., Seyfarth, R. M., Wrangham, R. W. & Struhsaker, T. T. (eds.), Primate Societies. Chicago: The University of Chicago Press, 477–490.
Morgan, B. J & Abwe, E. E. (2006). Chimpanzees use stone hammers in Cameroon. Current Biology 16: R632–R633.
Morin, P. A. (1993). Reproductive strategies in chimpanzees. Yearbook of Physical Anthropology 36: 179–212.
Ngalla, P. T., Miles, L. & Caldecott, J. (2005). Republic of Cameroon. In Caldecott, J. & Miles, L. (eds.), World Atlas of Great Apes and Their Conservation. Los Angeles: University of California Press, pp. 305–314.
Oates, J. F. (2006) Is the chimpanzee, Pan troglodytes, an endangered species? It depends on what endangered means. Primates 47: 102–112.
Oates, J. F., Groves, C. & Jenkins, P. D. (2008). The type locality of Pan troglodytes vellerosus (Gray, 1862), and implications for the nomenclature of West African chimpanzees. Primates 50: 78–80.
Peres, C. A. (1991). Humboldt’s woolly monkeys decimated by hunting in Amazonia. Oryx 25: 89–95.
Peterson, D. & Ammann, K. (2003). Eating Apes. California: University of California Press.
Peterson, D. & Goodall, J. (1993). Visions of Caliban: on chimpanzees and people. Boston: Houghton Mifflin Company.
Robinson, J. G. & Redford, K. H. (1991). Neotropical wildlife use and conservation. Chicago: The University of Chicago Press.
Rose, A. L. (1998). Finding paradise in a hunting camp: turning poachers to protectors. Journal of the Southwestern Anthropological Association 38: 4–11.
Rose, A. L., Mittermeier, R. A., Langrand, O., Ampadu-Agyei, O., Butynski, T. M. & Ammann, K. (2003). Consuming Nature. A photo essay on African rain forest exploitation. Palos Verdes, CA: Altisima.
Rosen, N., Cox, D., Montgomery, C. & Cress, D. (2002). Pan African Sanctuaries Alliance (PASA) Workshop Report. Apple Valley / Minnesota: Conservation Breeding Specialist Group (SSC / IUCN).
Rosen, N., Seal, U. S., Cox, D., Montgomery, C. Boardman, W. (2001). Pan African Sanctuary Alliance (PASA) Workshop Report. Apple Valley / Minnesota: Conservation Breeding Specialist Group (SSC / IUCN).
Ross, C. (1992). Environmental correlates of the intrinsic rate of natural increase in primates. Oecologica 90: 383–390.
Slade, N. A., Gomulkiewicz, R. & Alexander, H. M. (1998). Alternatives to Robinson and Redford’s method for assessing over harvest from incomplete demographic data. Conservation Biology 12: 148–155.
Soave, O. (1982). The rehabilitation of chimpanzees and other apes. Laboratory Primate Newsletter 21: 3–8.
Sommer, V. (2008). Schimpansenland. Wildes Leben in Afrika. Munich: C. H. Beck.
Sommer, V. & Ammann, K. (1998). Die Großen Menschenaffen: Orang-utan, Gorilla, Schimpanse, Bonobo. Munich: BLV.
Sommer, V., Adanu, J., Faucher, I. & Fowler, A. (2004). The Nigerian Chimpanzee (Pan troglodytes vellerosus) at Gashaka: Two years of habituation efforts. Folia Primatologica 75: 295–316.
Teleki, G. (1980). Hunting and Trapping Wildlife in Sierra Leone: Aspects of Exploitation and Exportation. Washington: WWF.
Teleki, G. (1989). Population status of wild chimpanzees (Pan troglodytes) and threats to survival. In Heltne, P. G. & Marquardt, L. A. (eds.), Understanding Chimpanzees. Cambridge: Harvard University Press, pp. 312–353.
Teleki, G. (2001). Sanctuaries for great ape refugees. In Beck, B. B., Stoinski, T. S., Hutchins, M., Maple, T. L., Norton, B., Rowan, A., Stevens, E. F. & Arluke, A. (eds.), Great Apes and Humans: The Ethics of Co-Existence. Washington: Smithsonian Institution Press, pp. 133–149.
The Sunday Times (1999). Chimps on the menu in Brussels restaurants. 16th May.
Tutin, C. E. G., Ancrenaz, M., Paredes, J., Vacher-Vallas, M., Vidal, C., Goossens, B., Bruford, M. W. & Jamart, A. (2001). Conservation biology framework for the release of wild-born orphaned chimpanzees into the Conkouati Reserve, Congo. Conservation Biology 15: 1247–1257.
Walsh, P. D., Abernathy, K. A., Bermejo, M., Beyers, R., De Wachter, P., Akou, E. M., Huijbregts, B., Mambounga, DI, Toham, A. K., Kilbourn, A. M., Lahm, S. A., Latour, S., Maisels, F., Mbina, C., Mihindou, Y., Obiang, S. N., Effa E. N., Starkey, M. P., Telfer, P., Thibault, M., Tutin, C. E. G., White, L. J. T. & Wilkie, D. S. (2003). Catastrophic ape decline in western equatorial Africa. Nature 422: 611–614.
Werikhe, S., Macfie, L., Rosen, N. & Miller, P. (1998). Can the Mountain Gorilla Survive? Population and Habitat Viability Assessment Workshop for Gorilla gorilla beringei. Conservation Breeding Specialist Group. Minnesota: Apple Valley.
Whiten A., Goodall, J., McGrew, W. C., Nishida, T., Reynolds, V., Sugiyama, Y., Tutin, C. E. G, Wrangham, R. W. & Boesch, C. (1999). Cultures in chimpanzees. Nature 399: 682–685.
Wilkie, D. S. & Carpenter, J. F. (1999). Bushmeat hunting in the Congo Basin: an assessment of impacts and options for mitigation. Biodiversity and Conservation 8: 927–955.
Wilkie, D. S. (2001). Bushmeat trade in the Congo Basin. In Beck, B. B., Stoinski, T. S., Hutchins, M., Maple, T. L., Norton, B., Rowan, A., Stevens, E. F. & Arluke, A. (eds.), Great Apes and Humans: the Ethics of Co-Existence. Washington: Smithsonian Institution Press, pp. 86–109.
Wilkie, D. S. & Godoy, R. A. (2001). Income and price elasticities of bushmeat demand in lowland Amerindian societies. Conservation Biology 15: 761–769.
Williams, J. M., Liu, H. Y. & Pusey, A. E. (2002). Costs and benefits of grouping for female chimpanzees at Gombe. In Boesch, C., Hohmann, G. & Marchant, L. F. (eds.), Behavioural Diversity in Chimpanzees and Bonobos. Cambridge: Cambridge University Press, pp. 192–203.
World Bank (2002). World Development Indicators 2002.
Wrangham, R. W. (2002). The cost of sexual attraction: is there a trade-off in female Pan between sex appeal and received coercion? In Boesch, C., Hohmann, G. & Marchant, L. F. (eds.), Behavioural Diversity in Chimpanzees and Bonobos. Cambridge: Cambridge University Press, pp. 204–215.
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Hughes, N., Rosen, N., Gretsky, N., Sommer, V. (2011). Will the Nigeria-Cameroon Chimpanzee Go Extinct? Models Derived from Intake Rates of Ape Sanctuaries. In: Sommer, V., Ross, C. (eds) Primates of Gashaka. Developments in Primatology: Progress and Prospects, vol 35. Springer, New York, NY. https://doi.org/10.1007/978-1-4419-7403-7_14
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