Current Status of Wild Gorilla Populations and Strategies for Their Conservation

  • Patrick T. Mehlman
Part of the Developments in Primatology: Progress and Prospects book series (DIPR)


Western Lowland Gorilla Western Gorilla Gorilla Population Gorilla Group Bushmeat Hunting 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



The author would like to thank the efforts of Peter Walsh and John Oates, who through comprehensive and thorough reviews, substantially improved this chapter. Stuart Nixon, who with his wife, Francine Nixon, led the Maiko South Survey, also reviewed and improved this work. The author would also like to thank Tara Stoinski and Alexia Lewnes for review and commentary. Bradley Mulley kindly provided several of the maps in this work: Figures 1.1, 1.3, 1.4, and 1.8. A portion of the author's salary and all support for DFGFI fieldworkers and partners is provided by Conservation International, through USAID CARPE funding and through Conservation International's Global Conservation Fund. Further, the surveys described in this chapter, both in Maiko and in Tayna, were supported by funds from the USAID Gorilla Directive, Conservation International's Global Conservation Fund, and USAID CARPE funding from Conservation International, the Louisville Zoo, and the Thorne Foundation. This study would not have been possible without the support of the author's organization, the Dian Fossey Gorilla Fund International. The author also gratefully acknowledges the contributions of the field staff who contributed heavily to data presented in this chapter and are members of UGADEC, the Tayna Gorilla Reserve, and Maiko National Park, ICCN. The 21st century is theirs indeed.


  1. Albrecht, G.H., Gelvin, B.R., and Miller, J.M.A. (2003). The hierarchy of intraspe-cific craniometric variation in gorillas: A population-thinking approach with implications for fossil species recognition studies. In: Taylor, A.B., and Goldsmith, M.L. (eds.), Gorilla Biology: A Multidisciplinary Perspective. Cambridge University Press, New York, pp. 62–103.Google Scholar
  2. 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., and Arluke, A. (eds.), Great Apes and Humans: The Ethics of Coexistence, Smithsonian Institute Press, Washington D.C., pp. 71–85.Google Scholar
  3. Barnes, R.F.W. (1990). Deforestation trends in tropical Africa. Journal of Ecology 28:161–173.Google Scholar
  4. Barnes, R.F.W. & Jensen, K.L. (1987). How to count elephants in the forest. African Elephant & Rhino Specialist Group Technical Bulletin 1:1–6.Google Scholar
  5. Bishikwabo, K. (2001). Gorillas without elephants? A query for research. Gorilla Journal 22:17.Google Scholar
  6. Boesch, C, and Boesch-Achermann, H. (1995). Taï chimpanzees confronted with a fatal Ebola virus. Pan Africa News 2:2–3.Google Scholar
  7. Butynski, T.M. (2001). Africa's great apes. In: Beck, B.B., Stoinski, TS., Hutchins, M., Maple, TL., Norton, B., Rowan, A., Stevens, E.F., and Arluke, A. (eds.), Great Apes and Humans: The Ethics of coexistence, Smithsonian Institute Press, Washington D.C., pp. 3–56.Google Scholar
  8. Butynski, T.M., and Kalina, J. (1998). Gorilla tourism: A critical look. In: Milner-Gulland, E.J., and Mace, R. (eds.) Conservation of Biological Resources, Blackwell Science, Oxford, pp. 294–313.CrossRefGoogle Scholar
  9. Caroll, R. (1988) Relative density, range extension, and conservation potential of the lowland gorilla (Gorilla gorilla gorilla) in the Dzanga-Sangha region of southwestern Central African Republic. Mammalia 52:309–323.Google Scholar
  10. Casimir, M.J. (1975). Feeding ecology and nutrition of an eastern gorilla group in the Mt. Kahuzi region (Republique du Zaire). Folia Primatologica 24:81–136.CrossRefGoogle Scholar
  11. Clifford, S.L., Abernethy, K.A., White, L.J.T, Tutin, C.E.G, Bruford, M.W, and Wickings, E.J. (2003). Genetic studies of western gorillas. In: Taylor, A.B., and Goldsmith, M.L. (eds.), Gorilla Biology: A Multidisciplinary Perspective. Cambridge University Press, New York, pp. 269–292.Google Scholar
  12. Clifford, S.L., Anthony, N.M., Bawe-Johnson, M., Abernethy, K.A., Tutin, C.E., White, L.J.T., Bermejo, M., Goldsmith, M.L., McFarland, K., Jeffery, K.J., Bruford, M.W., and Wickings, E.J. (2004). Mitochondrial DNA phylogeography of western lowland gorillas (Gorilla gorilla gorilla). Molecular Ecology 13(6):1551–1565.CrossRefPubMedGoogle Scholar
  13. Clover, G. (2004). The End of the Line: How Over-fishing Is Changing the World and What We Eat. Ebury Press, London.Google Scholar
  14. Doumenge, C. (1998). Forest diversity, distribution, and dynamics in the Itombwe mountains, South Kivu, Congo Democratic Republic. Mountain Research and Development 18(3):249–264.CrossRefGoogle Scholar
  15. Draulans, D., and Van Krunkoisven (2001) The impact of war on forest areas in the Democratic Republic of Congo. Oryx 36(1):35–40.Google Scholar
  16. Eberhardt, L.L. (1978). Transect methods for population studies. Journal of Wildlife Management 42:1–31.CrossRefGoogle Scholar
  17. Emlen, J.T., and Schaller, G.B. (1960). Distribution and status of the mountain gorilla (Gorilla gorilla beringei), 1959. Zoologica 45:41–52.Google Scholar
  18. Fay, JM. (1989). Partial completion of a census of the western lowland gorilla (Gorilla g gorilla (Savage and Wymand) ) in southwestern Central African Republic. Mammalia 53(2):203–215.CrossRefGoogle Scholar
  19. Fay, J.M., and Agnagna, M. (1992). Census of gorillas in northern Republic of Congo. American Journal of Primatology 27(4):275–284.CrossRefGoogle Scholar
  20. Garner, K.J., and Ryder, O.A. (1996). Mitochondrial DNA diversity in gorillas. Molecular Phylogenetics and Evolution 6(1):39–48.CrossRefPubMedGoogle Scholar
  21. Ghiglieri, M.P 1984. The chimpanzees of Kibale Forest: a field study of ecology and social structure. Columbia University Press, New York.Google Scholar
  22. Gonzalez-Kirchner, J.P. (1997). Census of western lowland gorilla population in Rio Muni region, Equatorial Guinea. Folia Zoologica 46(1):15–22.Google Scholar
  23. Gray, J.P. (2001) Why our drug laws have failed and what we can do about it: A judicial indictment on the war on the drugs. Temple University Press, Philadelphia.Google Scholar
  24. Groom, A.FG (1973). Squeezing out the mountain gorilla. Oryx 12:207–215.CrossRefGoogle Scholar
  25. Groves, C.P (1967). Ecology and taxonomy of the gorilla. Nature 213:890–893.CrossRefPubMedGoogle Scholar
  26. Groves, C.P. (1970). Population systematics of the gorilla. Journal of Zoology 161:287–300.CrossRefGoogle Scholar
  27. Groves, C.P. (2001). Primate Taxonomy Smithsonian Institution Press, Washington, D.C.Google Scholar
  28. Groves, C.P. (2003). A history of gorilla taxonomy. In: Taylor, A.B., and Goldsmith, M.L. (eds.), Gorilla Biology: A Multidisciplinary Perspective. Cambridge University Press, New York, pp. 15–34.Google Scholar
  29. Groves, C.P, and Napier, J.R. (1966). Skulls and skeletons of gorilla in British collections. Journal of Zoology 148:153–161.CrossRefGoogle Scholar
  30. Groves, C.P, and Stott, K.W (1979). Systematic relationships of gorillas from Kahuzi, Tshiaberimu and Kayonza. Folia Primatologica 32:161–179.CrossRefGoogle Scholar
  31. Grubb, P., Butynski, T.M., Oates, J.F, Bearder, S.K., Disotell, T.R., Groves, C.P, and Struhsaker, T.T. (2003). Assessment of the diversity of African primates. International Journal of Primatology 24(6):1301–1357.CrossRefGoogle Scholar
  32. Hall, J.S., Saltonstall, K., Inogwabini, B.I., and Omari, I. (1998a). Distribution, abundance and conservation status of Grauer's gorilla. Oryx 32(2):122–130.CrossRefGoogle Scholar
  33. Hall, J.S., White, L.J.T., Inogwabini, B.I., Omari, I., Morland, H.S., Williamson, E.A., Saltonstall, K., Walsh, P., Sikubwabo, C, Bonny, D., Kiswele, K.P., Vedder, A., and Freeman, K. (1998). Survey of Grauer's gorillas (Gorilla gorilla graueri) and eastern chimpanzees (Pan troglodytes schweinfurthi) in the Kahuzi-Biega National park lowland sector and adjacent forest in eastern Democratic Republic of Congo. International Journal of Primatology 19(2):207–235.CrossRefGoogle Scholar
  34. Harcourt, A.H. (1996). Is the gorilla a threatened species? How should we judge? Biological Conservation 75(2):165–176.CrossRefGoogle Scholar
  35. Harcourt, A.H., and Curry-Lindahl, K. (1979). Conservation of the mountain gorilla and its habitat in Rwanda. Environmental Conservation 6:143–147.CrossRefGoogle Scholar
  36. Harcourt, A.H., and Fossey, D. (1981). The Virunga gorillas: Decline of an “island” population. African Journal of Ecology 19:83–97.CrossRefGoogle Scholar
  37. Harcourt, A.H., and Groom, A.F.G. (1972). Gorilla census. Oryx 11:355–363.CrossRefGoogle Scholar
  38. Hart, J.A., and Hall, J.S. (1996). Status of eastern Zaire's forest parks and reserves. Conservation Biology 10(2):316–324.CrossRefGoogle Scholar
  39. Hart, J., and Liengola, I. (2005). Post conflict inventory of Kahuzi Biega National Park. Gorilla Journal 30:3.Google Scholar
  40. Hart, J.A., and Sikubwabo, C. (1994). Exploration of the Maiko National park of Zaire 1989–1992. Working Paper No. 2. Wildlife Conservation Society, New York.Google Scholar
  41. Horta, K. (1992). Logging in the Congo: Massive fraud threatens the forests. World Rainforest Report No. 24.Google Scholar
  42. IUCN/SSC Primate Specialist Group (PSG). (2000). Threatened African Primates.Google Scholar
  43. IUCN/SSC PSG Workshop on Primate Taxonomy. Conservation International, Washington, D.C., Unpublished report.Google Scholar
  44. Jensen-Seaman, M.I., Altheide, T.K., Deinard, A.S., Hammer, M.F., and Kidd, K.K. (2001). Nucleotide diversity at autosomal, Y-chromosomal, and mitochondrial loci of African apes and humans. American Journal of Physical Anthropology 32:86.Google Scholar
  45. Kakule, P., and Mehlman, P.T. (2004). Community-based conservation and the creation of protected areas in eastern Democratic Republic of Congo. Folia Primatologica 75(S1):286.Google Scholar
  46. Kano, T., and Asato, R. (1994). Hunting pressure on chimpanzees and gorillas in the Motaba River area, northeastern Congo. African Study Monographs 15(3):143–162.Google Scholar
  47. Kormos, R., and Boesch, C. (2002). Regional Action Plan for the Conservation of Chimpanzees in West Africa (Pan troglodytes versus and Pan troglodytes vellerosus). Conservation International. Washington, D.C.Google Scholar
  48. Laake, J.L., Buckland, S.T., Anderson, D.R., and Burnham, K.P. (1994). DISTANCE User's Guide V2.1. Colorado Cooperative Fish and Wildlife Research Unit, Colorado State University, Fort Collins, CO.Google Scholar
  49. Leigh, S.R., Relethford, J.H., Park, PB., and Konigsberg, L.W. (2003). Morphological differentiation of gorilla subspecies. In: Taylor, A.B., and Goldsmith, M.L. (eds.), Gorilla Biology: A Multidisciplinary Perspective. Cambridge University Press, New York, pp. 104–131.Google Scholar
  50. Leroy, E.M., Rouquet, P., Formenty, P., Souquière, S., Kilbourne, A., Froment, J.M., Bermejo, M., Smit, S., Karesh, W, Swanepoel, R., Zaki, S.R., and Rollin, P.E. (2004). Multiple Ebola virus transmission events and rapid decline of central African wildlife. Science 303 (5656):387–390.CrossRefPubMedGoogle Scholar
  51. Lilly, A.A., Mehlamn, P.T., and Doran, D. (2002). Intestinal parasites in gorillas, chimpanzees, and humans at Mondika Research site, Dzanga-Ndoki National Park, Central African Republic. International Journal of Primatology 23(3):555–573.CrossRefGoogle Scholar
  52. McNeilage, A., Plumptry, A., Doyle, A.B., and Vedder, A. (1998). Bwindi Impenetrable National Park, Uganda Gorilla and Large Mammal Census, 1997. Wildlife Conservation Society, New York, pp. 52.Google Scholar
  53. Mehlman, P. (1986). Male intergroup mobility in a wild population of the Barbary macaque (Macaca sylvanus), Ghomaran Rif Mountains, Morocco. American Journal of Primatology 10(1):67–81.CrossRefGoogle Scholar
  54. Mehlman, P.T. (1989). Comparative density, demography, and ranging behavior of Barbary macaques (Macaca sylvanus) in marginal and prime conifer habitats. International Journal of Primatology 10(4):269–292.CrossRefGoogle Scholar
  55. Mehlman, P.T., and Doran, D.M. (2002). Nest building in western lowland gorillas (Gorilla gorilla), Mondika, Central African Republic. International Journal of Primatology 23(6):1257–1285.CrossRefGoogle Scholar
  56. Morgan, B.J., Wild, C, and Ekobo, A. (2003). Newly discovered gorilla population in the Ebo Forest, Littoral Province, Cameroon. International Journal of Primatology 24(5):1129–1137.CrossRefGoogle Scholar
  57. Nixon, S.C., Ngwe' E.E., Mufabule, K., Nixon F., Bolamba, D., and Mehlmam, P.T. (2005). The status of Grauer's gorilla in the Maiko South Region: A Preliminary Report. Gorilla Journal November.Google Scholar
  58. Oates, J.F., McFarland, K.L., Groves, J.L., Bergl, R.A., Linder, J.M., and Disotell, T.R. (2003). The Cross River gorilla: Natural history and status of a neglected and critically endangered subspecies. In: Taylor, A.B., and Goldsmith, M.L. (eds.) Gorilla Biology: A Multidisciplinary Perspective. Cambridge University Press, New York, pp. 472–497.Google Scholar
  59. Omari, I., Hart, J.A., Butynski, TM., Birhashirwa, NR., Upoki, A., M'Keyo, Y, Bengana, F, Bashonga, M., and Bagurubumwe, N. (1999). The Itombwe Massif, Democratic Republic of Congo: Biological surveys and conservation, with an emphasis on Grauer's gorilla and birds endemic to the Albertine Rift. Oryx 33(4):301–322.CrossRefGoogle Scholar
  60. Plumptre, A.J. (2000) Monitoring mammal populations with line transect techniques in African forests. Journal of Applied Ecology 37:356–368.CrossRefGoogle Scholar
  61. Plumptre, A.J., and Reynolds, V. (1997). Nesting behavior of chimpanzees: Implications for censuses. International Journal of Primatology 18(4):475–485.CrossRefGoogle Scholar
  62. Redmond, I. (2001). Coltan boom, gorilla bust. Gorilla Journal 22:13–16.Google Scholar
  63. Reitbergen, S. (1992). Forest management. In: Sayer, J.A., Harcourt, C.S., and Collins, N.M. (eds.) Africa: The Conservation Atlas of Tropical Forest. Macmillan, London, pp. 62–68.Google Scholar
  64. Rose, A.L. (1997). Growing commerce in bushmeat destroys great apes and threatens humanity. African Primates 3(1–2):6–12.Google Scholar
  65. Ruvulo, M., Pan, D., Zehr, S., Goldberg, T., Disotell, T.R., and von Durnom, M. (1994). Gene trees and hominid phylogeny Proceedings of the National Academy of Sciences USA 91:8900–8904.CrossRefGoogle Scholar
  66. Ryder, O.A. (2003). An introductory perspective: Gorilla systematics, taxonomy, and conservation in the era of genomics. In: Taylor, A.B., and Goldsmith, M.L. (eds.) Gorilla Biology: A Multidisciplinary Perspective. Cambridge University Press, New York, pp. 239–246.Google Scholar
  67. Ryder, O.A., Garner, K.J., and Burrows, W. (1999). Non-invasive molecular genetic studies of gorillas: Evolutionary and systematic implications. American Journal of Physical Anthropology 28:238.Google Scholar
  68. Sarmiento, E.E. (2003). Distribution, taxonomy, genetics, ecology, and causal links of gorilla survival: The need to develop practical knowledge for gorilla conservation. In: Taylor, A.B., and Goldsmith, M.L. (eds.), Gorilla Biology: A Multidisciplinary Perspective. Cambridge University Press, New York, pp. 432–471Google Scholar
  69. Sarmineto, E.E., and Butynski, T.M. (1996). Present problems in gorilla taxonomy. Gorilla Journal 12:5–7.Google Scholar
  70. Sarmiento, E.E., and Oates, J.F. (2000). The Cross River gorillas: A distinct subspecies, Gorilla gorilla diehli Matschie 1904. American Museum Novitates 3304:1–55.CrossRefGoogle Scholar
  71. Sarmiento, E.E., Butynski, T.M., and Kalina, J. (1996). Gorillas of Bwindi-Impenetrable Forest and the Virunga Volcannoes: Taxonomic implications of morphological and ecological differences. American Journal of Primatology 40(1):1–21.CrossRefGoogle Scholar
  72. Schaller, G.B. (1963). The Mountain Gorilla: Ecology and Behavior. University of Chicago Press, Chicago, pp. xvii, 431.Google Scholar
  73. Seaman, M.I., Saltonstall, K., and Kidd, K.K. (1998). Mitochondrial DNA diversity and biogeography of Eastern gorillas. American Journal of Physical Anthropology 26:199.Google Scholar
  74. Sholley, C.R. (1991). Conserving gorillas in the midst of guerrillas. AAZPA Annual Conference Proceedings, pp. 30–37.Google Scholar
  75. Sivalingana-Matsitsi, D., Kamal-Piliplili, M., Eliba-Omba, B., N'Sasi-Soki, M., Mutakilo-Ngoy, E., Mutsorwa, B., Kambale-Kioma, G., Mufabule, K., Paluku-Mukakirwa, A., Kakule, P., and Mehlman, P.T. (2004). Redefining the geographical distribution of Grauer's gorilla in eastern Democratic Republic of Congo. Folia Primatologica 75(S1):334.Google Scholar
  76. Sunderland-Groves, J.L., Oates, J.F, and Bergl, R. (2005) Box 7.1 The Cross River gorilla (Gorilla gorilla diehli). In: Caldecott, J., and Miles, L. (2005) World Atlas of Great Apes and Their Conservation. Prepared at UNEP-WCMC. University of California Press, Berkeley.Google Scholar
  77. Struhsaker, TT (1996). A biologist's perspective on the role of sustainable harvest in conservation. African Primates 2:72–75.Google Scholar
  78. Tegera, A. (2002) The coltan phenomenon: How a rare mineral has changed the life of the population of war-torn North Kivu province in the East of the Democratic Republic of Congo. Pole Institute, Goma.Google Scholar
  79. Teleki, G (1997). Human relations with chimpanzees: A proposed code of conduct. African Primates 3:35–38.Google Scholar
  80. Thalmann, O., Hebler, J., Poinar, H.N., Paabo, S., and Vigilant, L. (2004). Unreliable mtDNA data due to nuclear insertions: a cautionary tale from analysis of humans and other great apes. Molecular Ecology 13(2):321–335.CrossRefPubMedGoogle Scholar
  81. Tutin, C.E.G., and Fernandez, M. (1984). Nationwide census of gorilla (Gorilla g. gorilla) and chimpanzee (Pan t. troglodytes) populations in Gabon. American Journal of Primatology 6(4):313–336.CrossRefGoogle Scholar
  82. Tutin, C, Stokes, E., Boesch, C, Morgan, D., Sanz, C, Reed, T, Blom, A., Walsh, P., Blake, S., and Kormos, R. (2005). Regional Action Plan for the Conservation of Chimpanzees and Gorillas in Western Equatorial Africa. Conservation International, Washington D.C.Google Scholar
  83. Vedder, A., Aveling, C, and Condiotti, M. (1986). Census update on Virunga gorilla population (Gorilla gorilla beringei): 1986. Primate Report 14:199.Google Scholar
  84. Walsh, P.D., Lahm, S.A., White, L.J.T., and Blake, S. (unpublished manuscript). Methods for monitoring African apes: some cold, hard facts about bias.Google Scholar
  85. Walsh, P.D., Abernethy, K.A., Bermefo, M., Beyers, R., De Wachter, P., Akou, M.E., Huijbregts, B., Mambounga, D.I., 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.O., Telfer, P., Thibault, M., Tutin, CE.G, White, L.J.T., and Wilkie, D.S. (2003). Catastrophic ape decline in western equatorial Africa. Nature 422(6932):611–614.CrossRefPubMedGoogle Scholar
  86. Watts, D.P. (1991). Mountain gorilla reproduction and sexual behavior. American Journal of Primatology 24(3/4):211–225.CrossRefGoogle Scholar
  87. Weber, A.W. (1987). Socioecologic factors in the conservation of afromontane forest reserves. In: Marsh, C.W, and Mittermeier, R.A. (eds.) Primate Conservation in the Tropical Rain Forest. Alan R. Liss, New York, pp. 205–229.Google Scholar
  88. Weber, A.W, and Vedder, A. (1983). Population dynamics of the Virunga gorillas: 1959–1978. Biological Conservation 26(4):341–366.CrossRefGoogle Scholar
  89. White, L., and Edwards, A. (2000). Conservation Research in the African Rain Forests: A Technical Handbook. Wildlife Conservation Society, New York, pp. xvi, 454.Google Scholar
  90. 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., and Arluke, A. (eds.), Great Apes and Humans: The Ethics of Coexistence. Smithsonian Institute Press, Washington D.C., pp. 86–109.Google Scholar
  91. Williams, J. (2000). The lost continent: Africa's shrinking forests. In: Ammann, K. (ed.) Bushmeat: Africa's Conservation Crisis. World Society for the Protection of Animals, London, pp. 8–15.Google Scholar
  92. Woodford, M.H., Butynski, T.M., and Karesh, WB. (2002). Habituating the great apes: The disease risks. Oryx 36(2):153–160.CrossRefGoogle Scholar
  93. Yamagiwa, J. (2003). Bushmeat poaching and the conservation crisis in Kahuzi-Biega National Park, Democratic Republic of the Congo. Journal of Sustainable Forestry, 16:115–135.CrossRefGoogle Scholar
  94. Yamawiga, J.N., Mwanza, N. Spangenberg, A., Maruhashi. T, Yumoto, T, Fisher, A., and Steinhauer-Burkart, B. (1993). A census of the eastern lowland gorillas (Gorilla gorilla graueri) in Kahuzi-Biega National Park with reference to mountain gorillas in the Virunga Region, Zaire. Biological Conservation 64:83–89.CrossRefGoogle Scholar
  95. Yapp, WB. (1956) The theory of line transects. Bird Study 3:93–104.CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC 2008

Authors and Affiliations

  • Patrick T. Mehlman
    • 1
  1. 1.Conservation InternationalArlington22202

Personalised recommendations