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Using camera trap data to assess the impact of bushmeat hunting on forest mammals in Tanzania

  • Carla Hegerl (a1), Neil D. Burgess (a2), Martin R. Nielsen (a3), Emanuel Martin (a4), Marco Ciolli (a5) and Francesco Rovero (a6)...


Bushmeat hunting is a pantropical threat to rainforest mammals. Understanding its effects on species richness, community composition and population abundance is of critical conservation relevance. As data on the pre-hunting state of mammal populations in Africa are not generally available, we evaluated the impacts of illegal bushmeat hunting on the mammal community of two ecologically similar forests in the Udzungwa Mountains of Tanzania. The forests differ only in their protection status: one is a National Park and the other a Forest Reserve. We deployed systematic camera trap surveys in these forests, amounting to 850 and 917 camera days in the Forest Reserve and the National Park, respectively, and investigated differences between the two areas in estimated species-specific occupancies, detectabilities and species richness. We show that the mammal community in the Forest Reserve is degraded in all aspects relative to the National Park. Species richness was almost 40% lower in the Forest Reserve (median 18 vs 29 species, highest posterior density intervals 15–30 and 23–47, respectively). Occupancy of most species was also reduced significantly and the functional community appeared significantly altered, with an increase in rodents, and loss of large carnivores and omnivores. Overall, our results show how ineffective reserve management, with almost absent law enforcement, leads to uncontrolled illegal hunting, which in turn has a significant impact on the mammal fauna of globally important sites for conservation.

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Ahumada, J.A., Silva, C.E.F., Gajapersad, K., Hallam, C., Hurtado, J., Martin, E. et al. (2011) Community structure and diversity of tropical forest mammals: data from a global camera trap network. Philosophical Transactions of the Royal Society B, 366, 27032711.
Arroyo-Rodríguez, V. & Dias, P.A.D. (2010) Effects of habitat fragmentation and disturbance on howler monkeys: a review. American Journal of Primatology, 72, 116.
Bennett, E.L., Blencowe, E., Brandon, K., Brown, D., Burn, R.W., Cowlishaw, G. et al. (2007) Hunting for consensus: reconciling bushmeat harvest, conservation, and development policy in West and Central Africa. Conservation Biology, 21, 884887.
Bowkett, A.E., Rovero, F. & Marshall, A.R. (2008) The use of camera-trap data to model habitat use by antelope species in the Udzungwa Mountain forests, Tanzania. African Journal of Ecology, 46, 479487.
Bowkett, A.E., Jones, T., Laizzer, R.L., Plowman, A.B. & Stevens, J.R. (2013) Can molecular data validate morphometric identification of faecal pellets in Tanzanian forest antelope species? Conservation Genetics Resources, 5, 10951100.
Brashares, J.S., Arcese, P. & Sam, M.K. (2001) Human demography and reserve size predict wildlife extinction in West Africa. Proceedings of the Royal Society B, 268, 24732478.
Bshary, R. (2001) Diana monkeys, Cercopithecus diana, adjust their anti-predator response behaviour to human hunting strategies. Behavioral Ecology and Sociobiology, 50, 251256.
Burgess, N.D., Butynski, T.M., Cordeiro, N.J., Doggart, N.H., Fjeldså, J., Howell, K.M. et al. (2007) The biological importance of the Eastern Arc Mountains of Tanzania and Kenya. Biological Conservation, 134, 209231.
Burnham, K.P. & Anderson, D.R. (2002) Model Selection and Multimodel Inference: A Practical Information–Theoretic Approach, 2nd edition. Springer, New York, USA.
Chen, M.-H., Shao, Q.-M. & Ibrahim, J.G. (2000) Monte Carlo Methods in Bayesian Computation. Springer, New York, USA.
Coad, L., Schleicher, J., Milner-Gulland, E.J., Marthews, T.R., Starkey, M., Manica, A. et al. (2013) Social and ecological change over a decade in a village hunting system, Central Gabon. Conservation Biology, 27, 270280.
Croes, B.M., Laurance, W.F., Lahm, S.A., Tchignoumba, L., Alonso, A., Lee, M.E. et al. (2007) The influence of hunting on antipredator behavior in Central African monkeys and duikers. Biotropica, 39, 257263.
Cullen, L. Jr, Bodmer, R.E. & Pádua, C.V. (2000) Effects of hunting in habitat fragments of the Atlantic forests, Brazil. Biological Conservation, 95, 4956.
DeFries, R., Rovero, F., Wright, P., Ahumada, J., Andelman, S., Brandon, K. et al. (2010) From plot to landscape scale: linking tropical biodiversity measurements across spatial scales. Frontiers in Ecology and the Environment, 8, 153160.
Dorazio, R.M., Royle, J.A., Söderström, B. & Glimskär, A. (2006) Estimating species richness and accumulation by modeling species occurrence and detectability. Ecology, 87, 842854.
Eastern Arc Mountains Conservation Endowment Fund (2013) Baseline Survey Report in 8 Nature Reserves and 1 National Park in the Eastern Arc Mountains of Tanzania. Sokoine University of Agriculture, Morogoro, Tanzania.
Effiom, E.O., Birkhofer, K., Smith, H.G. & Olsson, O. (2014) Changes of community composition at multiple trophic levels due to hunting in Nigerian tropical forests. Ecography, 37, 367377.
Effiom, E.O., Nuñez-Iturri, G., Smith, H.G., Ottosson, U. & Olsson, O. (2013) Bushmeat hunting changes regeneration of African rainforests. Proceedings of the Royal Society B, 280, 20130246.
Fa, J.E. & Brown, D. (2009) Impacts of hunting on mammals in African tropical moist forests: a review and synthesis. Mammal Review, 39, 231264.
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, 7178.
Fa, J.E., Olivero, J., Real, R., Farfán, M.A., Márquez, A.L., Vargas, J.M. et al. (2015) Disentangling the relative effects of bushmeat availability on human nutrition in central Africa. Scientific Reports, 5, 8168.
Fa, J.E., Peres, C.A. & Meeuwig, J. (2002) Bushmeat exploitation in tropical forests: an intercontinental comparison. Conservation Biology, 16, 232237.
Fiske, I.J. & Chandler, R.B. (2011) unmarked: an R package for fitting hierarchical models of wildlife occurrence and abundance. Journal of Statistical Software, 43, 123.
Fjeldså, J. & Lovett, J.C. (1997) Biodiversity and environmental stability. Biodiversity and Conservation, 6, 315323.
Galetti, M. & Dirzo, R. (2013) Ecological and evolutionary consequences of living in a defaunated world. Biological Conservation, 163, 16.
Golden, C.D., Fernald, L.C.H., Brashares, J.S., Rasolofoniaina, B.J.R. & Kremen, C. (2011) Benefits of wildlife consumption to child nutrition in a biodiversity hotspot. PNAS, 108, 1965319656.
Government of Tanzania (2011) Nomination of Properties for Inclusion on the World Heritage List Serial Nomination: Eastern Arc Mountains Forests of Tanzania. Ministry of Natural Resources and Tourism, Dar es Salaam, Tanzania.
Hammer, Ø., Harper, D.A.T. & Ryan, P.D. (2001) PAST: Paleontological statistics software package for education and data analysis. Paleontologia Electronica, 4, 19.
Harmsen, B.J., Foster, R.J., Silver, S., Ostro, L. & Doncaster, C.P. (2010) Differential use of trails by forest mammals and the implications for camera-trap studies: a case study from Belize. Biotropica, 42, 126133.
Isaac, N.J.B. & Cowlishaw, G. (2004) How species respond to multiple extinction threats. Proceedings of the Royal Society B, 271, 11351141.
Jerozolimski, A. & Peres, C.A. (2003) Bringing home the biggest bacon: a cross-site analysis of the structure of hunter-kill profiles in Neotropical forests. Biological Conservation, 111, 415425.
Laurance, W.F., Croes, B.M., Tchignoumba, L., Lahm, S.A., Alonso, A., Lee, M.E. et al. (2006) Impacts of roads and hunting on central African rainforest mammals. Conservation Biology, 20, 12511261.
Linder, J.M. & Oates, J.F. (2011) Differential impact of bushmeat hunting on monkey species and implications for primate conservation in Korup National Park, Cameroon. Biological Conservation, 144, 738745.
Lovett, J.C. (1993) Climatic history and forest distribution in eastern Africa. In Biogeography and Ecology of the Rain Forests of Eastern Africa (eds Lovett, J.C. & Wasser, S.K.), pp. 2330. Cambridge University Press, Cambridge, UK.
MacKenzie, D.I., Nichols, J.D., Lachman, G.B., Droege, S., Royle, J.A. & Langtimm, C.A. (2002) Estimating site occupancy rates when detection probabilities are less than one. Ecology, 83, 22482255.
MacKenzie, D.I., Nichols, J.D., Royle, J.A., Pollock, K.H., Bailey, L.L. & Hines, J.E. (2006) Occupancy Estimation and Modeling. Academic Press, Burlington, USA.
MacKenzie, D.I., Nichols, J.D., Sutton, N., Kawanishi, K. & Bailey, L.L. (2005) Improving inferences in population studies of rare species that are detected imperfectly. Ecology, 86, 11011113.
Mazerolle, M.J. (2012) AICcmodavg: model selection and multi-model inference based on (Q)AIC(c). R package version 1.26. Http:// [accessed 12 March 2015].
McCauley, D.J., DeSalles, P.A., Young, H.S., Dunbar, R.B., Dirzo, R., Mills, M.M. & Micheli, F. (2012) From wing to wing: the persistence of long ecological interaction chains in less-disturbed ecosystems. Scientific Reports, 2, 15.
Milner-Gulland, E.J. & Bennett, E.L. (2003) Wild meat: the bigger picture. Trends in Ecology & Evolution, 18, 351357.
Mockrin, M.H. (2010) Duiker demography and dispersal under hunting in Northern Congo. African Journal of Ecology, 48, 239247.
Muller-Landau, H.C. (2007) Predicting the long-term effects of hunting on plant species composition and diversity in tropical forests. Biotropica, 39, 372384.
Museo Tridentino di Scienze Naturali (2007) Conservation Status, Connectivity, and Options for Improved Management of Southern Forest Reserves in the Udzungwa Mountains, Tanzania: Urgent Need for Intervention. Report to the Critical Ecosystem Partnership Fund. Trento Museum of Natural Sciences, Trento, Italy.
National Bureau of Statistics (2013) Population and Housing Census. Ministry of Finance, Dar es Salaam, Tanzania.
Newing, H. (2001) Bushmeat hunting and management: implications of duiker ecology and interspecific competition. Biodiversity and Conservation, 10, 99118.
Nielsen, M.R. (2006) Importance, cause and effect of bushmeat hunting in the Udzungwa Mountains, Tanzania: implications for community based wildlife management. Biological Conservation, 128, 509516.
Nielsen, M.R. (2011) Improving the conservation status of the Udzungwa Mountains, Tanzania? The effect of joint forest management on bushmeat hunting in the Kilombero nature reserve. Conservation & Society, 9, 106118.
Nielsen, M.R., Jacobsen, J.B. & Thorsen, B.J. (2014) Factors determining the choice of hunting and trading bushmeat in the Kilombero Valley, Tanzania. Conservation Biology, 28, 382391.
Nielsen, M.R. & Treue, T. (2012) Hunting for the benefits of joint forest management in the Eastern Afromontane Biodiversity Hotspot: effects on bushmeat hunters and wildlife in the Udzungwa Mountains. World Development, 40, 12241239.
Nummelin, M. (1990) Relative habitat use of duikers, bush pigs, and elephants in virgin and selectively logged areas of the Kibale Forest, Uganda. Tropical Zoology, 3, 111120.
Nyundo, B.A., Mtui, A. & Kissaka, H. (2006) An Assessment of Ecological and Social-Economic Impacts Caused by Collection of Deadwood, Medicinal Plants and Cutting of Grass for Thatching in Udzungwa Mountains National Park. Unpublished report for WWF–Tanzania Programme, Dar es Salaam, Tanzania.
O’Brien, T.G. (2011) Abundance, density and relative abundance: a conceptual framework. In Camera Traps in Animal Ecology: Methods and Analyses (eds O'Connell, A.F., Nichols, J.D. & Karanth, K.U.), pp. 7196. Springer, New York, USA.
Peres, C.A. (2000) Effects of subsistence hunting on vertebrate community structure in Amazonian forests. Conservation Biology, 14, 240253.
Peres, C.A. & Dolman, P.M. (2000) Density compensation in neotropical primate communities: evidence from 56 hunted and nonhunted Amazonian forests of varying productivity. Oecologia, 122, 175189.
Peterson, G., Allen, C.R. & Holling, C.S. (1998) Ecological resilience, biodiversity, and scale. Ecosystems, 1, 618.
Poulsen, J.R., Clark, C.J. & Bolker, B.M. (2011) Decoupling the effects of logging and hunting on an Afrotropical animal community. Ecological Applications, 21, 18191836.
Poulsen, J.R., Clark, C.J. & Palmer, T.M. (2013) Ecological erosion of an Afrotropical forest and potential consequences for tree recruitment and forest biomass. Biological Conservation, 163, 122130.
R Development Core Team (2013) R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing, Vienna, Austria.
Redford, K.H. (1992) The empty forest. BioScience, 42, 412422.
Rist, J., Milner-Gulland, E.J., Cowlishaw, G. & Rowcliffe, J.M. (2009) The importance of hunting and habitat in determining the abundance of tropical forest species in Equatorial Guinea. Biotropica, 41, 700710.
Robinson, J.G. & Bennett, E.L. (2004) Having your wildlife and eating it too: an analysis of hunting sustainability across tropical ecosystems. Animal Conservation, 7, 397408.
Rovero, F. & De Luca, D.W. (2007) Checklist of mammals of the Udzungwa Mountains of Tanzania. Mammalia, 71, 4755.
Rovero, F. & Marshall, A.R. (2009) Camera trapping photographic rate as an index of density in forest ungulates. Journal of Applied Ecology, 46, 10111017.
Rovero, F., Marshall, A.R., Jones, T. & Perkin, A. (2009) The primates of the Udzungwa Mountains: diversity, ecology and conservation. Journal of Anthropological Sciences, 87, 93126.
Rovero, F., Martin, E., Rosa, M., Ahumada, J.A. & Spitale, D. (2014a) Estimating species richness and modelling habitat preferences of tropical forest mammals from camera trap data. PLoS ONE, 9(7), e103300.
Rovero, F., Menegon, M., Fjeldså, J., Collett, L., Doggart, N., Leonard, C. et al. (2014b) Targeted vertebrate surveys enhance the faunal importance and improve explanatory models within the Eastern Arc Mountains of Kenya and Tanzania. Diversity and Distributions, 20, 14381449.
Rovero, F., Mtui, A., Kitegile, A., Nielsen, M. & Jones, T. (2010) Uzungwa Scarp Forest Reserve in Crisis: An Urgent Call to Protect one of Tanzania's Most Important Forests. Report by Tanzania Forest Conservation Group, Wildlife Conservation Society–Tanzania Programme, Dar es Salaam, Tanzania.
Rovero, F., Mtui, A.S., Kitegile, A.S. & Nielsen, M.R. (2012) Hunting or habitat degradation? Decline of primate populations in Udzungwa Mountains, Tanzania: an analysis of threats. Biological Conservation, 146, 8996.
Rovero, F., Rathbun, G.B., Perkin, A., Jones, T., Ribble, D.O., Leonard, C. et al. (2008) A new species of giant sengi or elephant-shrew (genus Rhynchocyon) highlights the exceptional biodiversity of the Udzungwa Mountains of Tanzania. Journal of Zoology, 274, 126133.
Rovero, F., Zimmermann, F., Berzi, D. & Meek, P. (2013) “Which camera trap type and how many do I need?” A review of camera features and study designs for a range of wildlife research applications. Hystrix, The Italian Journal of Mammalogy, 24, 148156.
Schaafsma, M., Morse-Jones, S., Posen, P., Swetnam, R.D., Balmford, A., Bateman, I.J. et al. (2014) The importance of local forest benefits: economic valuation of non-timber forest products in the Eastern Arc Mountains in Tanzania. Global Environmental Change, 24, 295305.
Shangali, C.F., Mabula, C.K. & Mmari, C. (1998) Biodiversity and human activities in the Udzungwa Mountain Forests, Tanzania. 1. Ethnobotanical survey in the Uzungwa Scarp Forest Reserve. Journal of East African Natural History, 87, 291318.
Silveira, L., Jácomo, A.T.A. & Diniz-Filho, J.A.F. (2003) Camera trap, line transect census and track surveys: a comparative evaluation. Biological Conservation, 114, 351355.
Solé, R.V. & Montoya, J.M. (2001) Complexity and fragility in ecological networks. Proceedings of the Royal Society B, 268, 20392045.
Taylor, G., Scharlemann, J.P.W., Rowcliffe, M., Kümpel, N., Harfoot, M.B.J., Fa, J.E. et al. (2015) Synthesising bushmeat research effort in West and Central Africa: a new regional database. Biological Conservation, 181, 199205.
TEAM Network (2011) Terrestrial Vertebrate Monitoring Protocol v. 3.1. Conservation International, Arlington, USA.
Terborgh, J., Nuñez-Iturri, G., Pitman, N.C.A., Valverde, F.H.C., Alavrez, P., Swamy, V. et al. (2008) Tree recruitment in an Empty Forest. Ecology, 89, 17571768.
Tobler, M.W., Carrillo-Percastegui, S.E., Leite Pitman, R., Mares, R. & Powell, G. (2008) An evaluation of camera traps for inventorying large- and medium-sized terrestrial rainforest mammals. Animal Conservation, 11, 169178.
Topp-Jørgensen, E., Nielsen, M.R., Marshall, A.R. & Pedersen, U. (2009) Mammalian density in response to different levels of bushmeat hunting in the Udzungwa Mountains, Tanzania. Tropical Conservation Science, 2, 7087.
Weckel, M., Giuliano, W. & Silver, S. (2006) Jaguar (Panthera onca) feeding ecology: distribution of predator and prey through time and space. Journal of Zoology, 270, 2530.
Wilkie, D.S., Bennett, E.L., Peres, C.A. & Cunningham, A.A. (2011) The empty forest revisited. Annals of the New York Academy of Sciences, 1223, 120128.
Wilkie, D.S. & Finn, J.T. (1990) Slash–burn cultivation and mammal abundance in the Ituri Forest, Zaire. Biotropica, 22, 9099.
Williams, B.K., Nichols, J.D. & Conroy, M.J. (2002) Analysis and Management of Animal Populations. Academic Press, San Diego, USA.
Wright, S.J. (2003) The myriad consequences of hunting for vertebrates and plants in tropical forests. Perspectives in Plant Ecology, Evolution and Systematics, 6, 7386.
Wright, S.J., Hernandéz, A. & Condit, R. (2007a) The bushmeat harvest alters seedling banks by favoring lianas, large seeds, and seeds dispersed by bats, birds, and wind. Biotropica, 39, 363371.
Wright, S.J., Stoner, K.E., Beckman, N., Corlett, R.T., Dirzo, R., Muller-Landau, H.C. et al. (2007b) The plight of large animals in tropical forests and the consequences for plant regeneration. Biotropica, 39, 289291.
Yoccoz, N.G., Nichols, J.D. & Boulinier, T. (2001) Monitoring of biological diversity in space and time. Trends in Ecology & Evolution, 16, 446453.


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