Effects of Habitat Fragmentation on the Cross River Gorilla (Gorilla gorilla diehli): Recommendations for Conservation

  • Edem A. Eniang


Cross River State, Nigeria, is in the tropical moist forest zone (or Guinean forest region) and home to a diverse assemblage of primates (Figure 1). Detailed description of this tropical moist rain forest is given in Onochie (1979), Richards (1981), and Sayer et al. (1992). Increasing human population and the attendant desperate economic situation of the people following years of military rule and failing economy has led to unsustainable forest resource exploitation and destruction (Olajide and Eniang, 2000). Chapman and Lambert (2000) have shown that the tropical forest and the animals they support are being threatened by accelerating rates of forest conversion and degradation. Mittermeier (1988) ranked Nigeria as 8th among the countries of the world with the highest primate diversity and 7th in terms of degree of primate species endemism. Therefore, it becomes extremely necessary to pursue a multifaceted conservation strategy to save the myriads of primates and biodiversity inherent in the tropical moist forest ecosystem. The declining status of the tropical moist forest and wildlife, in general, and decimation of primates, in particular, requires urgent realistic and effective steps, including all people and factors involved. Eniang (1998) listed several factors as being responsible for the decline of non-human primate populations in southeastern Nigeria. The deplorable conservation status of the Cross River gorilla and other primates can be found in Oates (1996).


Habitat Fragmentation Forest Reserve Wildlife Sanctuary Tropical Moist Forest Bush Fire 
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  1. Bassey, A. E., and J. F. Oates, eds., 2001, Proceedings of the International Workshop and Conference on the Conservation of Cross River Gorillas, 6th-9th April, 2001, Calabar, CRS, Nigeria.Google Scholar
  2. Brandon, K. E., and Wells, M., 1992, Planning for people and parks: Design dilemmas, World Development 20: 557–570.CrossRefGoogle Scholar
  3. Burkey, T. V., 1989, Extinction in nature reserves: The effect of fragmentation and the importance of migration between fragments, Oikos 55: 75–81.CrossRefGoogle Scholar
  4. Butynski, T. M., and Kalina, J., 1998, Gorilla tourism: A critical look, in: Conservation of Biological Resources, E. J. Millner, ed., Outland and R. Mace, Oxford, Blackwells pp. 294–313.CrossRefGoogle Scholar
  5. Chapman, C. A., and Lambert, J. E., 2000, Habitat alteration and the conservation of African primates: A case study of Kibale National Park, Uganda, Am. J. Primatol. 50: 169–186.CrossRefGoogle Scholar
  6. Critchley, W. R., 1968, Final report on Takamanda gorilla survey, Unpublished report to Winston Churchill Memorial Trust, London.Google Scholar
  7. Coolidge, H. J., Jr., 1929, A revision of the genus Gorilla, Memoirs of the Museum of Comparative Zoology at Harvard College 50: 291–381.Google Scholar
  8. Cowlishaw, G., and Dunbar, R., 2000, Primate Conservation Biology, The University of Chicago Press, Chicago and London.Google Scholar
  9. Cox, C., 1987, Social behaviour and reproductive status of drills (Mandrillus leucophaeus), Regional proceedings of the American Association of Zoological Parks and Aquaria, AAZPA, Wheeling WV, pp. 321–328.Google Scholar
  10. Diamond, J. M., 1975, The island dilemma: Lessons of modern biogeographic studies for the design of natural preserves, Biol. Cons. 7: 129–146.CrossRefGoogle Scholar
  11. Diamond, J. M., 1984, “Normal” extinction of isolated populations, in: Extinctions, M. H. Nitecki, ed., University of Chicago Press, Chicago, pp. 191–246.Google Scholar
  12. Dietz, J. M., Dietz, L. A., and Nagagata, E. Y., 1994, The effective use of flagship species for conservation: The example of the lion tamarin, in: Creative Conservation, P. J. S. Olney, G. M. Mace, and A. T. C. Feistner, eds., Chapman and Hall, London, pp. 32–49.CrossRefGoogle Scholar
  13. Dorst, J., and Dandelot, P., 1986, Larger Mammals of Africa: A Field Guide, Collins, London. pp. 51–83.Google Scholar
  14. Eniang, E. A., 1998, In situ and ex situ conservation of drill (Mandrillus leucophaeus R) in the tropical rain forest of South Eastern Nigeria.Google Scholar
  15. Eniang, E. A., 2001, The role of the Cross River National Park in gorilla conservation, Gorilla J. No. 22, Berggorilla and Regenwald Direkthilfe, Germany.Google Scholar
  16. Eniang, E. A., and Nwufoh, E. I., 2001, Sites of special scientific interest for the conservation of primates in Nigeria, Trans. Nig. Soc. Biol. Consery 7: 45–54.Google Scholar
  17. FAO, 1995, Food for all, Fifty years of FAO and 15th World Food Day, Rome.Google Scholar
  18. Groves, C., 2001, Primate Taxonomy, Smithsonian Institute Press, Washington and London.Google Scholar
  19. Groves, C. P., 1970, Population systematics of the gorilla, J. Zool. 161: 287–300.CrossRefGoogle Scholar
  20. Groves, C. P., 1967, Ecology and taxonomy of the gorilla, Nature 213: 890–893.CrossRefGoogle Scholar
  21. Groves, J., and Maisels, F., 1999, Report on the large mammal fauna of the Takamanda Forest Reserve, South West Province, Cameroon, with special emphasis on the gorilla population, Unpublished report to World Wildlife Federation-Cameroon, Yaounde.Google Scholar
  22. Hanski, I., 1998, Metapopulation dynamics, Nature 396: 41–49.CrossRefGoogle Scholar
  23. Hanski, I., 1999, Metapopulation Ecology, Oxford University Press, Oxford.Google Scholar
  24. Happold, D. C. D., 1991, Large Mammals of West Africa, West African Nature Handbooks,Longman, pp. 73–78.Google Scholar
  25. Harcourt, A. H., 1995, Population viability estimates: Theory and practice for a wild gorilla population, Cons. Bio. 9: 134–142.CrossRefGoogle Scholar
  26. Harcourt, A. H., and Fossey, D., 1981, The Virunga gorillas: Decline of an “Island” population, Afr. J. Ecol. 19: 83–97.CrossRefGoogle Scholar
  27. Harcourt, A. H., Stewart, K. J., and Inahoro, I. M., 1988, Nigeria’s gorillas: A survey and recommendations, unpublished report.Google Scholar
  28. Harcourt, A. H., Stewart, K. J., and Inahoro, I. M., 1989, Gorilla quest in Nigeria, Orxy 23: 7–13.CrossRefGoogle Scholar
  29. Koontz, F., Horwich, R., Glander, K., Westrom, W., Koontz, C., Saqui, E. Saqui, H., 1994, Reintroduction of black howler monkeys (Acouattor pigra) into the Cockscomb Basin Wildlife Sanctuary, Belize, in: AZA Annual Conference Proceedings, Bethesda, Maryland, pp. 104–111.Google Scholar
  30. Konstant, W. R., and Mittermeier, R. A., 1982, Introduction, reintroduction, and translocation of Neotropical primates: Past experiences and future possibilities. Int. Zoo. Yrbk 22: 69–77.CrossRefGoogle Scholar
  31. Lacy, R. C., 1993, VORTEX: A computer simulation model for population viability analysis, Wildlife Res. 20: 45–65.CrossRefGoogle Scholar
  32. Lawlor, T. E., 1986, Comparative biogeography of mammals on islands, Biol. J. Linn. Soc. 28: 99–125.CrossRefGoogle Scholar
  33. Lande, R., Engen. S., and Saether, B. E., 1994, Optimal harvesting, economic discounting, and extinction risk in fluctuating populations, Nature 372: 88–90.Google Scholar
  34. Lindenmeyer, D. B., and Nix, H. A., 1993, Ecological principles for the design of wildlife corridors, Cons. Bio. 7: 627–630.CrossRefGoogle Scholar
  35. Mace, G. M., 1988, The genetic and demographic status of western lowland gorilla (Gorilla g. gorilla) in Google Scholar
  36. captivity, J. Zool. 216:629–654.Google Scholar
  37. Mace, G. M., and Lande, R., 1991, Assessing extinction threats: Toward a reevaluation of IUCN threatened categories, Cons. Biol. 5: 148–157.CrossRefGoogle Scholar
  38. March, E. W., 1957, Gorillas of Eastern Nigeria, Oryx 4: 30–34.CrossRefGoogle Scholar
  39. Marsh, C. W., Johns, A. D., and Ayres, J. M., 1987, Effect of habitat disturbance on rainforest primates, in: Primate Conservation in the Tropical Rain Forest, C. W. Marsh and R. A. Mittermeier, eds., Alan R. Liss, New York, pp. 83–107.Google Scholar
  40. McFarland, K., 1994, Update on gorillas in Cross River State, Nigeria, Gorilla J. 17: 14–15.Google Scholar
  41. Mittermeier, R. A., 1988, Primate diversity and the tropical forest: Case studies from Brazil and Madagascar and the importance of the Megadiversity countries, in: Biodiversity, E. O. Wilson, ed., National Academy Press pp. 145–154.Google Scholar
  42. Mittermeier, R. A., 1987, Effect of hunting on rainforests primates, in: Primates Conservation in the Tropical Rainforest, C. W. Marsh and R. A. Mittermeier, eds., Alan R. Liss, publisher, New York, pp. 305–220.Google Scholar
  43. Murcia, C., 1995, Edge effects in fragmented forests: Implications for conservation, TREE 10: 58–62.Google Scholar
  44. Nwufoh, E. 1., 1999, Survey of gorilla in Boshi Extension portion of the Cross River National Park, Obudu, Nigeria, unpublished report submitted to the World Wildlife Federation-CRNP Project, Nigeria, and to WPTI, Pennsylvania.Google Scholar
  45. Oates, J. F., 1998, The gorilla population in the Nigerian-Cameroon border, Gorilla Conservation News 12: 6.Google Scholar
  46. Oates, J. F., White, D., Gadsby, E. L. and Bisong, P. O., 1990, Conservation of gorillas and other species, Appendix 1 to Caldecott, J. O., Oates, J. F., and Ruistenbee, H. J., Cross River National Park (Okwangwo Division): Plan for Developing the Park and Its Support Zone, Godalming, Surrey World Wildlife Federation, UK.Google Scholar
  47. Oates, J. F., 1996, Habitat alteration, hunting, and the conservation of folivorous primates in African forests, Aust. J. Ecol. 21: 1–9.CrossRefGoogle Scholar
  48. Obot, E., Barker, J., Edet, C., Ogar, G., and Nwufoh, E., 1997, Status of gorilla (G. gorilla gorilla) populations in Cross River National Park and Mbe Mountain, Cross River National Park (Okwangwo Division) Technical Report No. 3, pp. 14.Google Scholar
  49. Olajide, O., and Eniang, E. A., 1999, Conservation of diverse bioresources of Nigeria: Forest regeneration methods in perspective, in: Proceedings of the 8th Annual Scientific Conference of Nigeria Society for Biological Conservation (NSBC), 13th-17th September, 1999, University of Uyo, Nigeria.Google Scholar
  50. Olajide, O., and Eniang, E. A., 2000, Unguided forest resources exploitation and destruction in Nigeria: Socio-ecological impacts, Int. J. Env. Devel. 4 (1): 39–43.Google Scholar
  51. Onochie, C. F. A., 1979, The Nigerian rainforest ecosystem: An overview, in: The Nigerian Rainforest Ecosystem, D. U. U. Okali, ed., Proceedings of Mab. UI Conference Centre, 24–26 January, 1979.Google Scholar
  52. Pope, T. R., 1996, Socioecology, population fragmentation, and patterns of genetic loss in endangered primates, in: Conservation Genetics: Case Histories from Nature, J. C. Arise and J. L. Harwick, eds., Chapman and Hall, London, pp. 119–159.Google Scholar
  53. Richards, P. W., 1981, The Tropical Rain Forest: An Ecological Study, Cambridge University Press, London. Ross, C., 1988, The intrinsic rate of nature increase and reproductive effort in primates, J. Zool., Lond. 214: 199–219.Google Scholar
  54. Ross, C., 1992, Environmental correlates of the intrinsic rate of natural increase in primates, Oecologia 90: 383–390.CrossRefGoogle Scholar
  55. Rothschild, W., 1904, Notes on anthropoid apes, in: Proceedings of the Zoological Society of London 1904 (2): 413–440.Google Scholar
  56. Rothschild, W., 1908, Note on Gorilla gorilla diehli Matschie, Zoologicae 15: 391–392.Google Scholar
  57. Sayer, J. A., Harcourt, C. S., and Collins, N. M., 1992, The Conservation Atlas of Tropical Forests: Africa, Macmillan, London.Google Scholar
  58. Simberloff, D., and Cox, J., 1987, Consequences and cost of conservation corridors, Cons. Biol. 1: 63–71.CrossRefGoogle Scholar
  59. Smith, F. D. M., Mary, R. M., Pellew, R., Johnson, T. H., and Walter, K. S., 1993, How much do we know about the current extinction rate? TREE 18: 375–378.Google Scholar
  60. Starin, E. D., 1989, Threats to the monkeys of Gambia, Oryx 23: 208–214.Google Scholar
  61. Strum, S. C., and Southwick, C. H., 1986, Translocation of primates, in: Primates: The Road to self-sustaining populations, K. Benirschke, ed., Springer, New York, pp. 949–958.Google Scholar
  62. Swart, J., Lawes, M. J., and Perrin, M. R., 1993, A mathematical model to investigate the demographic viability of low-density Samango monkey (Cercopithecus mitis) populations in Natal, S. Africa, Ecol. Modelling 70: 289–303.CrossRefGoogle Scholar
  63. Swart J., and Lawes, M. J., 1996, The effect of habitat patch connectivity on Samango monkey (Cercopithecus mitis) metapopulation persistence, Ecol. Modelling 93: 57–74.CrossRefGoogle Scholar
  64. Taylor, B., 1995 The reliability of using population viability analysis for risk classification of species, Cons. Bio. 9: 551–558.CrossRefGoogle Scholar
  65. Tilman, D., May, R. M, Lehman C. L., and Nowak, M. A., 1994, Habitat destruction and the extinction debt, Nature 371: 65–66.CrossRefGoogle Scholar
  66. Tudge, C., 1992, Last Animals at the zoo: How mass extinction can be stopped, Oxford University Press, pp. 42–48.Google Scholar
  67. Tutin, C. E. G., 1999, Fragmented living: Behavioural ecology of primates in a forest fragment in the Lope Reserve, Gabon, Primates 40: 249–265.CrossRefGoogle Scholar
  68. Tutin, C. E. G., and Oslisly, R., 1995, Homo, Pan, and Gorilla: coexistence over 60,000 years at Lope in Central Gabon, J. Hum Evol. 28: 597–602.Google Scholar
  69. White, F., 1983, The Vegetation of Africa: a Descriptive Memoir to accompany the UNESCO/AETFAT/UNSO Vegetation Map of Africa, Unesco, Paris, pp. 356.Google Scholar
  70. Woltheim, J. H., 1983, Primates of the World: Distribution, Abundance, and Conservation, University of Washington Press, Seattle.Google Scholar
  71. World Bank, 2002, World Debt Tables, Washington, DC.Google Scholar

Copyright information

© Springer Science+Business Media New York 2003

Authors and Affiliations

  • Edem A. Eniang
    • 1
    • 2
  1. 1.Department of Forestry and WildlifeUniversity of UyoUyoNigeria
  2. 2.Biodiversity Preservation GroupCalabarNigeria

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