Skip to main content
    • Aa
    • Aa

Assessing reintroduction success in long-lived primates through population viability analysis: western lowland gorillas Gorilla gorilla gorilla in Central Africa

  • Tony King (a1), Christelle Chamberlan (a1) and Amos Courage (a2)

The use of population modelling has become an increasingly common tool in reintroduction planning and assessment. Although initial reintroduction success is often measured by quantifying post-release survival and reproduction, longer-term success is best assessed through measurements of population viability. Here we develop a population model capable of providing useful results for influencing management of a reintroduction programme for a long-lived and slow-reproducing primate, the western lowland gorilla Gorilla gorilla gorilla. We used post-release monitoring data from two reintroduced populations in the Batéké Plateau region of Congo and Gabon, complemented with published data on wild and captive populations, to develop a population model using Vortex. Sensitivity testing illustrated that the model was highly sensitive to changes in the input parameters for annual birth rates, the number of lethal equivalents, and for female annual mortality rates, especially for adults. The results of the population viability analysis suggested that the reintroduced gorilla populations have a reasonable chance of persistence (> 90% over 200 years) but illustrated that reinforcement of the populations could significantly improve probabilities of population persistence and retention of genetic diversity. Equally, catastrophic events could have significant negative impacts. Continued monitoring of the populations should allow refinement of the model, improving confidence in its predictions and its relevance to decision-making.

Corresponding author
(Corresponding author) 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.

D.P. Armstrong , I. Castro & R. Griffiths (2007) Using adaptive management to determine requirements of reintroduced populations: the case of the New Zealand hihi. Journal of Applied Ecology, 44, 953962.

D.P. Armstrong & J.G. Ewen (2002) Dynamics and viability of a New Zealand robin population reintroduced to regenerating fragmented habitat. Conservation Biology, 16, 10741085.

D.P. Armstrong & M.H. Reynolds (2012) Modelling reintroduced populations: the state of the art and future directions. In Reintroduction Biology: Integrating Science and Management (eds J.G. Ewen , D.P. Armstrong , K.A. Parker & P.J. Seddon ), pp. 165222. Wiley-Blackwell, Chichester, UK.

D.P. Armstrong & P.J. Seddon (2008) Directions in reintroduction biology. Trends in Ecology & Evolution, 23, 2025.

E.J. Asbjørnsen , B.-E. Sæther , J.D.C. Linnell , S. Engen , R. Andersen & A.T. Bretten (2005) Predicting the growth of a small introduced muskox population using population prediction intervals. Journal of Animal Ecology, 74, 612618.

S. Atsalis & S.W. Margulis (2006) Sexual and hormonal cycles in geriatric western lowland gorillas (Gorilla gorilla). International Journal of Primatology, 27, 16631687.

B. Beck , K. Walkup , M. Rodrigues , S. Unwin , D. Travis & T. Stoinski (2007) Best Practice Guidelines for the Re-introduction of Great Apes. IUCN/Species Survival Commission Primate Specialist Group, Gland, Switzerland.

B.J. Bradley , M.M. Robbins , E.A. Williamson , H.D. Steklis , N.G. Steklis , N. Eckhardt (2005) Mountain gorilla tug-of-war: silverbacks have limited control over reproduction in multimale groups. Proceedings of the National Academy of Sciences of the United States of America, 102, 94189423.

A. Britt , C. Welch , A. Katz , B. Iambana , I. Porton , R. Junge (2004) The restocking of captive-bred ruffed lemurs (Varecia variegata variegata) into the Betampona Reserve, Madagascar: methodology and recommendations. Biodiversity and Conservation, 13, 635657.

J. Bustmante (1996) Population viability analysis of captive and released bearded vulture populations. Conservation Biology, 10, 822831.

P.C. Cramer & K.M. Portier (2001) Modeling Florida panther movements in response to human attributes of the landscape and ecological settings. Ecological Modelling, 140, 5180.

W.J. Dimond & D.P. Armstrong (2007) Adaptive harvesting of source populations for translocation: a case study with New Zealand robins. Conservation Biology, 21, 114124.

J.M. Earnhardt , S.D. Thompson & K. Schad (2004) Strategic planning for captive populations: projecting changes in genetic diversity. Animal Conservation, 7, 916.

R. Frankham (2005) Genetics and extinction. Biological Conservation, 126, 131140.

R. Frankham , J.D. Ballou & D.A. Briscoe (2002) Introduction to Conservation Genetics. Cambridge University Press, Cambridge, UK.

J.M. Gaillard , M. Festa-Bianchet & N.G. Yoccoz (1998) Population dynamics of large herbivores: variable recruitment with constant adult survival. Trends in Ecology & Evolution, 13, 5863.

B. Goossens , S.M. Funk , C. Vidal , S. Latour , A. Jamart , M. Ancrenaz (2002) Measuring genetic diversity in translocation programmes: principles and application to a chimpanzee release project. Animal Conservation, 5, 225236.

B. Goossens , J.M. Setchell , E. Tchidongo , E. Dilambaka , C. Vidal , A. Ancrenaz & A. Jamart (2005) Survival, interactions with conspecifics and reproduction in 37 chimpanzees released into the wild. Biological Conservation, 123, 461475.

J.J. Groombridge , C. Raisin , R. Bristol & D.S. Richardson (2012). Genetic consequences of reintroductions and insights from population history. In Reintroduction Biology: Integrating Science and Management (eds J.G. Ewen , D.P. Armstrong , K.A. Parker & P.J. Seddon ), pp. 395440. Wiley-Blackwell, Chichester, UK.

M. Gusset , O. Jakoby , M.S. Müller , M.J. Somers , R. Slotow & V. Grimm (2009) Dogs on the catwalk: modeling reintroduction and translocation of endangered wild dogs in South Africa. Biological Conservation, 142, 27742781.

A.H. Harcourt (1995) Population viability estimates: theory and practice for a wild gorilla population. Conservation Biology, 9, 134142.

A.H. Harcourt & K.J. Stewart (2007) Gorilla Society: Conflict, Compromise, and Cooperation between the Sexes. University of Chicago Press, Chicago, USA.

I.G. Jamieson & R.C. Lacy (2012) Managing genetic issues in reintroduction biology. In Reintroduction Biology: Integrating Science and Management (eds J.G. Ewen , D.P. Armstrong , K.A. Parker & P.J. Seddon ), pp. 441476. Wiley-Blackwell, Chichester, UK.

I.G. Jamieson , L.N. Tracy , D. Fletcher & D.P. Armstrong (2007) Moderate inbreeding depression in a reintroduced population of North Island robins. Animal Conservation, 10, 95102.

L.F. Keller , I. Biebach , S.R. Ewing & E.A. Hoeck (2012) The genetics of reintroductions: inbreeding and genetic drift. In Reintroduction Biology: Integrating Science and Management (eds J.G. Ewen , D.P. Armstrong , K.A. Parker & P.J. Seddon ), pp. 360394. Wiley-Blackwell, Chichester, UK.

T. King (2008) Detectability and conservation of De Brazza's monkey (Cercopithecus neglectus) in the Lesio-Louna and south-west Lefini Reserves, Batéké Plateau, Republic of Congo. Primate Conservation, 23, 3944.

T. King , C. Chamberlan & A. Courage (2012) Assessing initial reintroduction success in long-lived primates by quantifying survival, reproduction and dispersal parameters: western lowland gorillas (Gorilla gorilla gorilla) in Congo and Gabon. International Journal of Primatology, 33, 134149.

S.G. Kohlmann , G.A. Schmidt & D.K. Garcelon (2005) A population viability analysis for the Island Fox on Santa Catalina Island, California. Ecological Modelling, 183, 7794.

R.C. Lacy (1997) Importance of genetic variation to the viability of mammalian populations. Journal of Mammalogy, 78, 320335.

T. Maran , M. Põdra , M. Põlma & D.W. Macdonald (2009) The survival of captive-born animals in restoration programmes—Case study of the endangered European mink Mustela lutreola. Biological Conservation, 142, 16851692.

A. Martínez-Abraín , H.M. Regan , C. Viedma , E. Villuendas , M.A. Bartolomé , J.A. Gómez & D. Oro (2011) Cost-effectiveness of translocation options for a threatened waterbird. Conservation Biology, 25, 726735.

M.A. McCarthy , D.A. Armstrong & M.C. Runge (2012). Adaptive management of reintroduction. In Reintroduction Biology: Integrating Science and Management (eds J.G. Ewen , D.P. Armstrong , K.A. Parker & P.J. Seddon ), pp. 256289. Wiley-Blackwell, Chichester, UK.

J.D. Nichols & D.P. Armstrong (2012) Monitoring for reintroductions. In Reintroduction Biology: Integrating Science and Management (eds J.G. Ewen , D.P. Armstrong , K.A. Parker & P.J. Seddon ), pp. 223255. Wiley-Blackwell, Chichester, UK.

J.J. O'Grady , B.W. Brook , D.H. Reed , J.D. Ballou , D.W. Tonkyn & R. Frankham (2006) Realistic levels of inbreeding depression strongly affect extinction risk in wild populations. Biological Conservation, 133, 4251.

E.H. Parlato & D.P. Armstrong (2012) An integrated approach for predicting fates of reintroductions with demographic data from multiple populations. Conservation Biology, 26, 97106.

P. Peignot , M.J.E. Charpentier , N. Bout , O. Bourry , U. Massima , O. Dosimont (2008) Learning from the first release project of captive-bred mandrills Mandrillus sphinx in Gabon. Oryx, 42, 122131.

M.M. Robbins , M. Bermejo , C. Cipolletta , F. Magliocca , R.J. Parnell & E. Stokes (2004) Social structure and life-history patterns in Western Gorillas (Gorilla gorilla gorilla). American Journal of Primatology, 64, 145159.

M.M. Robbins , M. Gray , E. Kagoda & A.M. Robbins (2009) Population dynamics of the Bwindi mountain gorillas. Biological Conservation, 142, 28862895.

M.M. Robbins & A.M. Robbins (2004) Simulation of the population dynamics and social structure of the Virunga mountain gorillas. American Journal of Primatology, 63, 201223.

A.M. Robbins , M.M. Robbins , N. Gerald-Steklis & H.D. Steklis (2006) Age-related patterns of reproductive success among female mountain gorillas. American Journal of Physical Anthropology, 131, 511521.

A. Robert (2009) Captive breeding genetics and reintroduction success. Biological Conservation, 142, 29152922.

S. Schadt , E. Revilla , T. Wiegand , F. Knauer , P. Kaczensky , U. Breitenmoser (2002) Assessing the suitability of central European landscapes for the reintroduction of Eurasian lynx. Journal of Applied Ecology, 39, 189203.

M. Schaub , R. Zink , H. Beissman , F. Sarrazin & R. Arlettaz (2009) When to end releases in reintroduction programmes: demographic rates and population viability analysis of bearded vultures in the Alps. Journal of Applied Ecology, 46, 92100.

P.J. Seddon , D.P. Armstrong & R.F. Maloney (2007) Developing the science of reintroduction biology. Conservation Biology, 21, 303312.

P. J. Seddon , W. M. Strauss & J. Innes (2012) Animal translocations: what are they and why do we do them? In Reintroduction Biology: Integrating Science and Management (eds J.G. Ewen , D.P. Armstrong , K.A. Parker & P.J. Seddon ), pp. 132. Wiley-Blackwell, Chichester, UK.

L. Slotta-Bachmayr , R. Boegel , P. Kaczensky , C. Stauffer & C. Walzer (2004) Use of population viability analysis to identify management priorities and success in reintroducing Przewalski's horses to southwestern Mongolia. Journal of Wildlife Management, 68, 790798.

A. South , S. Rushton & D. Macdonald (2000) Simulating the proposed reintroduction of the European beaver (Castor fiber) to Scotland. Biological Conservation, 93, 103116.

S.C. Strum (2005) Measuring success in primate translocation: a baboon case study. American Journal of Primatology, 65, 117140.

J. Swart & M.J. Lawes (1996) The effect of habitat patch connectivity on samango monkey (Cercopithecus mitis) metapopulation persistence. Ecological Modelling, 93, 5774.

G. Tavecchia , C. Viedma , A. Martínez-Abraín , M.-A. Bartolomé , J.A. Gómez & D. Oro (2009) Maximizing re-introduction success: assessing the immediate cost of release in a threatened waterfowl. Biological Conservation, 142, 30053012.

S.S. Taylor , I.G. Jamieson & D.P. Armstrong (2005) Successful island reintroductions of New Zealand robins and saddlebacks with small numbers of founders. Animal Conservation, 8, 415420.

C.R. Todd , S. Jenkins & A.R. Bearlin (2002) Lessons about extinction and translocation: models for eastern barred bandicoots (Perameles gunnii) at Woodlands Historic Park, Victoria, Australia. Biological Conservation, 106, 211223.

L.W. Traill , B.W. Brook , R.R. Frankham & C.J.A. Bradshaw (2010) Pragmatic population viability targets in a rapidly changing world. Biological Conservation, 143, 2834.

C.E.G. Tutin , M. Ancrenaz , J. Paredes , M. Vacher-Vallas , C. Vidal , B. Goossens (2001) The conservation biology framework of the release of wild-born orphaned chimpanzees into the Conkouati Reserve, Congo. Conservation Biology, 15, 12471257.

S.M. Wakamiya & C.L. Roy (2009) Use of monitoring data and population viability analysis to inform reintroduction decisions: peregrine falcons in the Midwestern United States. Biological Conservation, 142, 17671776.

D.P. Watts (1991) Mountain gorilla reproduction and sexual behavior. American Journal of Primatology, 24, 211225.

C.P. Yaeger (1997) Orang-utan rehabilitation in Tanjung Putting National Park, Indonesia. Conservation Biology, 11, 802805.

J. Yamagiwa & J. Kahekwa (2001) Dispersal patterns, group structure, and reproductive parameters of eastern lowland gorillas at Kahuzi in the absence of infanticide. In Mountain Gorillas: Three Decades of Research at Karisoke (eds M.M. Robbins , P. Sicotte & K. Stewart ), pp. 89122. Cambridge University Press, Cambridge, UK.

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: 25
Total number of PDF views: 100 *
Loading metrics...

Abstract views

Total abstract views: 394 *
Loading metrics...

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