Central Chimpanzee

Pan t. troglodytes is one of the four recognized subspecies of the robust chimpanzee. Its geographic range includes most of Gabon, Equatorial Guinea and Republic of the Congo, parts of Angola (Cabinda), Cameroon (south of the Sanaga River), Central African Republic (the southwest), and a small area north of the Congo River in the Democratic Republic of Congo (Maisels et al. 2016). A comprehensive estimate of their populations puts the subspecies at 128,760 individuals (95% CI: 114,208–317,039). This is based on nest data collected over 89 surveys at 59 sites between 2003 and 2013 (Strindberg et al. 2018). The central chimpanzee is classified as Endangered on the IUCN Red List of Threatened Species (Maisels et al. 2016), indicating that it has a high risk of extinction in the wild.

Threats
The most important threats to central chimpanzees in the short term are poaching for bushmeat, and disease (especially Ebola virus disease) and in the longer term, habitat loss and degradation (Maisels et al. 2016, Strindberg et al. 2018). Despite the low rate of deforestation in Central Africa compared to other continents (Hansen et al. 2013), agroindustry will become a major driver of forest conversion in the region in coming decades. Industrial-scale selective logging, which does not completely remove the habitat, but does alter forest structure to some degree, is currently the most widespread land use throughout the geographic range of this taxon. However, if poaching in these forests and the closure of roads after use are not very strictly controlled, poaching is hugely facilitated by the easy access, along new logging roads, into once-remote, very sparsely populated forests. In addition, logging attracts large numbers of people. The combination of the improved access and the increased human population drives both bushmeat demand and opportunities for hunting and trafficking bushmeat to towns and cities.

This happens despite the fact that chimpanzees are on the totally protected species lists of all range states (and listed by CITES on Appendix I). The number of central chimpanzees traded across borders (and so against CITES regulations) is overwhelmingly due to the bushmeat trade, but some live infants, a byproduct of hunting for bushmeat, are also trafficked. If a mother chimpanzee is killed, the orphan may be kept alive for the illegal pet trade.

Great apes are vulnerable to many pathogens and diseases that affect humans. Despite low human population densities in chimpanzee inhabited regions, rural communities often have limited or no access to health services and typically are not vaccinated against diseases that can be transmitted to great apes with high mortality rates (Gilardi et al. 2015). Considering these risks, conservation and research activities, such as habituation and tourism, should adhere to strict protocols aimed at protecting great apes (Macfie & Williamson 2010).

Ebola has had a massive impact on some chimpanzee populations (e.g., Walsh et al. 2003). Female chimpanzees give birth for the first time at about age 14 and every 4–5 years thereafter. Even with perfect protection from hunting, it would take approximately 120 years for these chimpanzee populations to recover to pre-Ebola levels (Walsh et al. 2003).

Conservation
Many national, regional and international organisations are working to protect the central chimpanzee through conservation initiatives and research programmes. The subspecies is protected by national laws, international agreements, and many countries have long-established networks of protected areas. However, only 34% of the central chimpanzee population lives in protected areas protected by guards, or within logging concessions with guards, so over 65% of central chimpanzees live in unguarded forests (Strindberg et al. 2018).

Although the most recent population assessment could not detect a population decline between 2003-2013 (Strindberg et al. 2018), we know that huge areas of former habitat now have very few chimpanzees remaining- the Ebola outbreaks in Gabon (which occurred before 2002) wiped out a high proportion of the great apes in the area where it occurred, and hunting has removed most large-bodied mammals from areas of high human density within central chimpanzee range.

In 2013, IUCN convened a group of experts to develop a unified strategy and action plan for the conservation of this subspecies. The action plan also included similar measures to safeguard sympatric western lowland gorillas Gorilla gorilla gorilla. Combining expert opinion and the best available data, the following priority conservation areas were identified: Lac Télé-Likouala and Odzala-Lossi-Pikounda-Ngombe-Ntokou complexes (Republic of Congo); Sangha Trinational complex (Republic of Congo, Cameroon and CAR); Loango-Moukalaba-Doudou-Gamba complex (Gabon); Boumba-Bek-Nki and Dja Conservation complexes (Cameroon); and Lopé-Waka complex (Gabon) (IUCN 2014). Priority actions recommended included: improvement of judicial and law enforcement structures; development and promotion of national and transboundary structures; disease surveillance programmes and rapid response structure; capacity building for research skills generally and standardised protocols for bio-monitoring training and implementation; and public education and awareness programmes.

Overarching gaps in knowledge and capacity needed to effectively conserve chimpanzees included: an evaluation of innovative techniques to improve estimates of great ape abundance; capacity building opportunities in great ape research, monitoring methods and technical support for national researchers; and improved understanding of Ebola transmission dynamics and potential control measures, plus the evaluation of vaccine delivery methods to great ape populations. For example, to minimise the risk of disease transmitted from humans to great apes means that all activities where great ape occur should adhere to strict protocols aimed at protecting great apes, including guard patrols, research, and tourism (Macfie & Williamson 2010). Morgan et al. (2018) have shown that if poaching is strictly controlled, and coupled with reduced impact logging, chimpanzee (and gorilla) populations can be maintained in industrial logging concessions.

Implementation of the plan started in 2015, and is aimed at guaranteeing the survival of the majority of great apes remaining in the region. Many other species would benefit beside the chimpanzees. The action plan emphasizes that successful protection of great apes will require a collaborative effort – including integrated land-use planning – to establish, implement and monitor region-wide priorities. The plan also provides a series of immediate response needs and longer-term mitigation strategies for the three main threats consistent across the region (poaching, disease and logging). Anti-poaching, it is argued, should be the foundation upon which all other great ape conservation activities rest, as it is currently the most effective means of protecting great apes in western equatorial Africa (IUCN 2014).

References

Gilardi, K.V., Gillespie, T.R., Leendertz, F.H., Macfie, E.J., Travis, D.A., Whittier, C.A. & Williamson, E.A. (2015). Best Practice Guidelines for Health Monitoring and Disease Control in Great Ape Populations. IUCN SSC Primate Specialist Group, Gland, Switzerland. https://doi.org/10.2305/IUCN.CH.2015.SSC-OP.56.en

Hansen, M.C., Potapov, P.V., Moore, R., Hancher, M., Turubanova, S.A., Tyukavina, A., Thau, D., Stehman, S.V., Goetz, S.J., Loveland, T.R., Kommareddy, A., Egorov, A., Chini, L., Justice, C.O. & Townshend, J.R.G. (2013). High-resolution global maps of 21st-century forest cover change. Science 342: 850–853.

IUCN (2014). Regional Action Plan for the Conservation of Western Lowland Gorillas and Central Chimpanzees 2015–2025. IUCN SSC Primate Specialist Group, Gland, Switzerland. http://dx.doi.org/10.2305/IUCN.CH.2005.SSC-RAP.1.en

Macfie, E.J. & Williamson, E.A. (2010). Best Practice Guidelines for Great Ape Tourism. IUCN SSC Primate Specialist Group, Gland, Switzerland. https://portals.iucn.org/library/node/9636

Maisels, F., Strindberg, S., Greer, D., Jeffery, K., Morgan, D.L. & Sanz, C. (2016). Pan troglodytes ssp. troglodytes. The IUCN Red List of Threatened Species 2016: e.T15936A17990042.

Morgan, D., Mundry, R., Sanz, C., Ayina, C.E., Strindberg, S., Lonsdorf, E. & Kühl, H.S. (2017). African apes coexisting with logging: comparing chimpanzee (Pan troglodytes troglodytes) and gorilla (Gorilla gorilla gorilla) resource needs and responses to forestry activities. Biological Conservation 218: 277–286.

Strindberg, S., Maisels, F., Williamson, E.A., Blake, S., Stokes, E.J., Aba’a, R., Abitsi, G., Agbor, A., Ambahe, R.D., Bakabana, P.C., Bechem, M., Berlemont, A., Bokoto de Semboli, B., Boundja, P.R., Bout, N., Breuer, T., Campbell, G., De Wachter, P., Ella Akou, M., Esono Mba, F., Feistner, A.T.C., Fosso, B., Fotso, R., Greer, D., Inkamba-Nkulu, C., Iyenguet, C.F., Jeffery, K.J., Kokangoye, M., Kühl, H.S., Latour, S., Madzoke, B., Makoumbou, C., Malanda, G.-A.F., Malonga, R., Mbolo, V., Morgan, D.B., Motsaba, P., Moukala, G., Mowawa, B.S., Murai, M., Ndzai, C., Nishihara, T., Nzooh, Z., Pintea, L., Pokempner, A., Rainey, H.J., Rayden, T., Ruffler, H., Sanz, C.M., Todd, A., Vanleeuwe, H., Vosper, A., Warren, Y., Wilkie, D.S., 2018. Guns, germs, and trees determine density and distribution of gorillas and chimpanzees in Western Equatorial Africa. Science Advances 4: eaar2964.

Walsh, P.D., Abernethy, K.A., Bermejo, M., Beyersk, R., De Wachter, P., Akou, M.E., Huijbregts, B., Mambounga, D.I., Toham, A.K., Kilbourn, A.M., Lahmq, S.A., Latour, S., Maisels, F., Mbina, C., Mihindou, Y., Obiang, S.N., Effa, E.N., Starkey, M.P., Telfer, P., Thibault, M., Tutin, C.E.G., White, L.J.T. & Wilkie, D.S. (2003). Catastrophic ape decline in western equatorial Africa. Nature 422: 611–614.