Skip to main content
    • Aa
    • Aa

Remote sensing analysis reveals habitat, dispersal corridors and expanded distribution for the Critically Endangered Cross River gorilla Gorilla gorilla diehli

  • Richard A. Bergl (a1), Ymke Warren (a2), Aaron Nicholas (a2), Andrew Dunn (a3), Inaoyom Imong (a3), Jacqueline L. Sunderland-Groves (a2) and John F. Oates (a4)...

Habitat loss and fragmentation are among the major threats to wildlife populations in tropical forests. Loss of habitat reduces the carrying capacity of the landscape and fragmentation disrupts biological processes and exposes wildlife populations to the effects of small population size, such as reduction of genetic diversity and increased impact of demographic stochasticity. The Critically Endangered Cross River gorilla Gorilla gorilla diehli is threatened in particular by habitat disturbance because its population is small and it lives in an area where high human population density results in intense exploitation of natural resources. We used remotely-sensed data to assess the extent and distribution of gorilla habitat in the Cross River region and delineated potential dispersal corridors. Our analysis revealed > 8,000 km2 of tropical forest in the study region, 2,500 km2 of which is in or adjacent to areas occupied by gorillas. We surveyed 12 areas of forest identified as potential gorilla habitat, 10 of which yielded new records of gorillas. The new records expand the known range of the Cross River gorilla by > 50%, and support genetic analyses that suggest greater connectivity of the population than previously assumed. These findings demonstrate that considerable connected forest habitat remains and that the area could potentially support a much larger gorilla population if anthropogenic pressures such as hunting could be reduced.

Corresponding author
*North Carolina Zoological Park, Asheboro, North Carolina, USA. E-mail
Linked references
Hide All

This list contains references from the content that can be linked to their source. For a full set of references and notes please see the PDF or HTML where available.

M. Ancrenaz , L. Ambu , I. Sunjoto , E. Ahmad , K. Manokaran , E. Meijaard & I. Lackman (2010) Recent surveys in the forests of Ulu Segama Malua, Sabah, Malaysia, show that orang-utans (P. p. morio) can be maintained in slightly logged forests. PLoS One, 5(7), e11510.

R.P. Anderson , D. Lew & A.T. Peterson (2003) Evaluating models of species’ distributions: criteria for selecting optimal models. Ecological Modelling, 162, 211232.

C.A.M. Attwell & F.P.D. Cotterill (2000) Postmodernism and African conservation science. Biodiversity and Conservation, 9, 559577.

R.F.W. Barnes (1990) Deforestation in tropical Africa. African Journal of Ecology, 28, 161173.

R.A. Bergl , B.J. Bradley , A.M. Nsubuga & L. Vigilant (2008) Genetic effects of habitat fragmentation, population size and demographic history on primate populations: the Cross River gorilla in a comparative context. American Journal of Primatology, 70, 848859.

R.A. Bergl , J.F. Oates & R. Fotso (2007) Distribution and protected area coverage of endemic taxa in West Africa’s Biafran forests and highlands. Biological Conservation, 134, 195208.

R.A. Bergl & L. Vigilant (2007) Genetic analysis reveals population structure and recent migration within the highly fragmented range of the Cross River gorilla (Gorilla gorilla diehli). Molecular Ecology, 16, 501516.

D.T. Bolger , T.A. Scott & J.T. Rotenberry (2001) Use of corridor-like landscape structures by bird and small mammal species. Biological Conservation, 102, 213224.

D.S. Boyd & W.J. Duane (2001) Exploring spatial and temporal variation in the middle infrared reflectance measured from the tropical forests of West Africa. International Journal of Remote Sensing, 22, 18611878.

T. Brooks , A. Balmford , N. Burgess , J. Fjeldså , L.A. Hansen , J. Moore . (2001) Towards a blueprint for conservation in Africa. BioScience, 51, 613624.

G.M. Buchanan , S.H.M. Butchart , G. Dutson , J.D. Pilgrim , M.K. Steininger , K.D. Bishop & P. Mayaux (2008) Using remote sensing to inform conservation status assessment: estimates of recent deforestation rates on New Britain and the impacts upon endemic birds. Biological Conservation, 141, 5666.

C.A. Chapman , M. Lawes & H.A.C. Eeley (2006) What hope for African primate diversity? African Journal of Ecology, 44, 116133.

B. Czech (2002) A transdisciplinary approach to conservation land acquisition. Conservation Biology, 16, 14881497.

J. Ebeling & M. Yasué (2008) Generating carbon finance through avoided deforestation and its potential to create climatic, conservation and human development benefits. Philosophical Transactions of the Royal Society, B, 363, 19171924.

P.J. Ferraro & R.D. Simpson (2002) The cost-effectiveness of conservation payments. Land Economics, 78, 339353.

E.J. Gustafson & R.H. Gardner (1996) The effect of landscape heterogeneity on the probability of patch colonization. Ecology, 77, 94107.

A.H. Harcourt (1996) Is the gorilla a threatened species? How should we judge? Biological Conservation, 75, 165176.

A.H. Harcourt & D.A. Doherty (2005) Species-area relationships of primates in tropical forest fragments: a global analysis. Journal of Applied Ecology, 42, 630637.

U. Ite & W. Adams (2000) Expectations, impacts and attitudes: conservation and development in Cross River National Park, Nigeria. Journal of International Development, 12, 325342.

A. Johns & J. Skorupa (1987) Responses of rainforest primates to habitat disturbance: a review. International Journal of Primatology, 8, 157191.

A. Kiss (2004a) Is community-based ecotourism a good use of biodiversity conservation funds? Trends in Ecology & Evolution, 19, 232237.

A. Kiss (2004b) Making biodiversity conservation a land-use priority. In Getting Biodiversity Projects to Work: Towards More Effective Conservation and Development (eds T.O. McShane & M.P. Wells ), pp. 98–123. Columbia University Press, New York, USA.

A. Kobler & M. Adamic (2000) Identifying brown bear habitat by a combined GIS and machine learning method. Ecological Modelling, 135, 291300.

S. Köndgen , H. Kühl , P.K. N’Goran , P.D. Walsh , S. Schenk , N. Ernst . (2008) Pandemic human viruses cause decline of endangered great apes. Current Biology, 18, 260264.

H.F. Kühl , F. Maisels , M. Ancrenaz & E.A. Williamson (2008) Best Practice Guidelines for Surveys and Monitoring of Great Ape Populations. IUCN/Species Survival Commission Primate Specialist Group, Gland, Switzerland.

H.F. Kühl , C. Nzeingui , S. Le Duc Yeno , B. Huijbregts , C. Boesch & P.D. Walsh (2009) Discriminating between village and commercial hunting of apes. Biological Conservation, 142, 15001506.

N. Laporte , S. Goetz , C. Justice & M. Heinicke (1998) A new land cover map for central Africa derived from multi-resolution, multi-temporal AVHRR data. International Journal of Remote Sensing, 19, 35373550.

J.L. Larkin , D.S. Maehr , T.S. Hoctor , M.A. Orlando & K. Whitney (2004) Landscape linkages and conservation planning for the black bear in west-central Florida. Animal Conservation, 7, 112.

M.B. Main , F.M. Roka & R.F. Noss (1999) Evaluating costs of conservation. Conservation Biology, 13, 12621272.

B. Martinez-Cruz , A. Godoy & J.J. Negro (2004) Population genetics after fragmentation: the case of the endangered Spanish imperial eagle (Aquila adalberti). Molecular Ecology, 13, 22432255.

P. Mayeaux , T. Richards & E. Janodet (1999) A vegetation map of central Africa derived from satellite imagery. Journal of Biogeography, 26, 353366.

G.J. McDermid , R.J. Hall , G.A. Sanchez-Azofeifa , S.E. Franklin , G.B. Stenhouse , T. Kobliuk & E.F. LeDrew (2009) Remote sensing and forest inventory for wildlife habitat assessment. Forest Ecology and Management, 257, 22622269.

W.S. McGraw (2005) Update on the search for Miss Waldron’s red colobus monkey (Procolobus badius waldroni). International Journal of Primatology, 26, 605619.

A. McNeilage , A.J. Plumptre , A. Brock-Doyle & A. Vedder (2001) Bwindi Impenetrable National Park, Uganda: gorilla census 1997. Oryx, 35, 3947.

L. Miller , A. Savage & H. Giraldo (2004) Quantifying remaining forested habitat within the historic distribution of the cotton-top tamarin (Saguinus oedipus) in Colombia: implications for long-term conservation. American Journal of Primatology, 64, 451457.

A.J. Noss (1997) Challenges to nature conservation with community development in central African forests. Oryx, 31, 180188.

J.F. Oates , M. Abedi-Lartey , W.S. McGraw , T.T. Struhsaker & G.H. Whitesides (2000) Extinction of a West African red colobus monkey. Conservation Biology, 14, 15261532.

A. Pattanavibool & P. Dearden (2002) Fragmentation and wildlife in montane evergreen forests, northern Thailand. Biological Conservation, 107, 155164.

G.Q.K. Pence , M.A. Botha & J.K. Turpie (2003) Evaluating combinations of on- and off-reserve conservation strategies for the Agulhas Plain, South Africa: a financial perspective. Biological Conservation, 112, 253273.

A.J. Plumptre & V. Reynolds (1994) The effect of selective logging on the primate populations in the Budongo Forest Reserve. Journal of Applied Ecology, 31, 631641.

J. Pollini (2009) Carbon sequestration for linking conservation and rural development in Madagascar: the case of the Vohidrazana-Mantadia Corridor Restoration and Conservation Carbon Project. Journal of Sustainable Forestry, 28, 322342.

E. Rood & A.A. Ganie (2010) Using presence-only modelling to predict Asian elephant habitat use in a tropical forest landscape: implications for conservation. Diversity and Distributions, 16, 975984.

M. Rouget , R.M. Cowling , A.T. Lombard , A.T. Knight & G.I.H. Kerley (2006) Designing large-scale conservation corridors for pattern and process. Conservation Biology, 20, 549561.

A. Russon , A. Erman & R. Dennis (2001) The population density of orang-utans (Pongo pygmaeus pygmaeus) in and around the Denau Sentarum Wildlife Reserve, West Kalimantan, Indonesia. Biological Conservation, 97, 2128.

S. Schadt , F. Knauer , P. Kaczensky , E. Revilla , T. Wiegand & L. Trepl (2002) Rule-based assessment of suitable habitat and patch connectivity for the Eurasian lynx. Ecological Applications, 12, 14691483.

J.L. Sunderland-Groves , A. Ekinde & H. Mboh (2009) Cross River gorilla (Gorilla gorilla diehli) nesting behaviour at Kagwene Mountain, Cameroon: implications for assessing group size, age-structure and density at other Cross River gorilla localities. International Journal of Primatology, 30, 253266.

O. Thalmann , D. Wegmann , M. Spitzner , M. Arandjelovic , K. Guschanski , C. Leuenberger . (2011) Historical sampling reveals dramatic demographic changes in western gorilla populations. BMC Evolutionary Biology, 11, 85.

C. van Schaik , K. Monk & J. Yarrow Robertson (2001) Dramatic decline in orang-utan numbers in the Leuser ecosystem, Northern Sumatra. Oryx, 35, 1425.

E. Wikramanayake , M. McKnight , E. Dinerstein , A. Joshi , B. Gurung & D. Smith (2004) Designing a conservation landscape for tigers in human-dominated environments. Conservation Biology, 18, 839844.

S. Wunder , S. Engel & S. Pagiola (2008) Taking stock: a comparative analysis of payments for environmental services programs in developed and developing countries. Ecological Economics, 65, 843852.

Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

  • ISSN: 0030-6053
  • EISSN: 1365-3008
  • URL: /core/journals/oryx
Please enter your name
Please enter a valid email address
Who would you like to send this to? *



Altmetric attention score

Full text views

Total number of HTML views: 6
Total number of PDF views: 35 *
Loading metrics...

Abstract views

Total abstract views: 251 *
Loading metrics...

* Views captured on Cambridge Core between September 2016 - 25th March 2017. This data will be updated every 24 hours.