Pan troglodytes ssp. troglodytes
|Scientific Name:||Pan troglodytes ssp. troglodytes (Blumenbach, 1799)|
See Pan troglodytes
|Taxonomic Source(s):||Mittermeier, R.A., Rylands, A.B. and Wilson D.E. 2013. Handbook of the Mammals of the World: Volume 3 Primates. Lynx Edicions, Barcelona.|
The four commonly recognised subspecies of Chimpanzee are: the Western Chimpanzee Pan troglodytes verus; the Nigeria-Cameroon Chimpanzee P. t. ellioti; the Central Chimpanzee P. t. troglodytes; and the Eastern Chimpanzee P. t. schweinfurthii. Recent mitochondrial DNA work (Gonder et al. 2011) suggests that there are three major clades of Chimpanzees: Pan troglodytes verus in West Africa, P. t. ellioti between the Dahomey Gap and the Sanaga River in Cameroon, and P. t. troglodytes in Central and East Africa, the last of which is usually subdivided into P. t. schweinfurthii and P. t. troglodytes (e.g., Fünfstück et al. 2015). The relative importance of different threats faced by each taxon varies across Africa, making a regional approach valuable for conservation purposes. We, therefore, use a four-subspecies classification, acknowledging that future work may lead to recognition of more or fewer subspecies.
|Red List Category & Criteria:||Endangered A4bcde ver 3.1|
|Assessor(s):||Maisels, F., Strindberg, S., Greer, D., Jeffery, K., Morgan, D.L. & Sanz, C.|
|Reviewer(s):||Williamson, E.A. & Mittermeier, R.A.|
|Contributor(s):||Baillie, J., Butynski, T.M., Dupain, J., Gatti, S., Tutin, C. & Walsh, P.D.|
Pan troglodytes troglodytes has a very large geographic range (over 700,000 km2) and a relatively large population size, currently estimated at about 140,000 individuals (Strindberg et al. in prep). However, this subspecies has experienced a significant population reduction since the 1970s. Between 1983 and 2000, the country of Gabon lost half its great ape population to poaching and disease, at an annual rate of decline 4% (calculated from Walsh et al. 2003). A more recent study examined nest survey data collected between 2003 and 2013 across the entire range of the taxon and created a predictive model to map Central Chimpanzee density and distribution (Strindberg et al. in prep). Although the results show no statistically significant decline during those 10 years, Central Chimpanzee populations remain highly vulnerable to poaching and disease. Due to their slow life history and a generation time estimated to be 25 years, Chimpanzee populations cannot sustain high mortality levels, whether disease-induced or caused by humans. Given the scale of the poaching problem across Central Africa, this taxon is likely to be experiencing declines significant in terms of the population status, which we do not have the statistical power to detect.
It is suspected that this reduction will continue for the next 30 to 40 years due to illegal hunting and expansion of the commercial bushmeat trade, and to habitat loss and degradation occurring at an increasing rate as a result of expanding human activities. The causes of the reduction, although largely understood, have certainly not ceased and are not easily reversible. The predicted continuation of the population decline is a precautionary approach based on the rapidly-increasing human population density in the region, and the expansion of land clearing for industrial-scale agricultural plantations, which requires the clearcutting of forest and is likely to accelerate in the next two to three decades. The effects of climate change will also become increasingly evident. At the same time, the threat of emerging infectious diseases is ongoing; there is, for example, evidence that Ebolavirus will continue to spread (Walsh et al. 2005), which would have devastating consequences for Central African great ape populations. At a conservative rate of loss of 1% each year, the population reduction over three generations (75 years) from 1975–2050 is likely to exceed 50%, hence qualifying Central Chimpanzees as Endangered under criterion A.
|Previously published Red List assessments:|
Pan troglodytes troglodytes (Blumenbach 1799) has a very large geographic range (just over 700,000 km²). The eastern limit of their distribution is the Ubangi River; the northwestern limit is the Sanaga River in Cameroon; the northern limit is the forest-savanna boundary to a maximum of roughly 6°N. The Congo River south of its confluence with the Ubangi, to the coast, then becomes the southern and southeastern limit. Distribution is closely related to the proportion of forest cover in each country in their range: most Central Chimpanzees are found in the Republic of Congo (42%), followed by Gabon (~34%) and southwestern Cameroon (17%) (Strindberg et al. in prep).
Native:Angola (Cabinda); Cameroon; Central African Republic; Congo; Congo, The Democratic Republic of the; Equatorial Guinea (Equatorial Guinea (mainland)); Gabon
|Range Map:||Click here to open the map viewer and explore range.|
Central Chimpanzees occur throughout almost all the protected areas and logging concessions in their geographic range, in both terra firma and swamp forests; the majority (81%) live outside the protected area network (Strindberg et al. in prep). Great ape population estimates are made using a standard index of abundance: night nest abundance and distribution, sometimes combined with predictive modelling. A recent meta-analysis examined 83 nest survey datasets collected using standardised methods across the entire range of Central Chimpanzees and western lowland gorillas between 2003 and 2013. Half the surveys were carried out in protected areas, the other half in logging concessions or unattributed forests, and a predictive model was produced to map great ape density and distribution. Excluding DRC where only a small number of Central Chimpanzees remain, the population is now estimated to be ~140,000 (Strindberg et al. in prep.), updating the previous estimate of 70,000–117,000 individuals (Oates et al. 2008). The results of the analysis show that no statistically-significant overall decline occurred in the decade between 2003 and 2013 (Strindberg et al. in prep.). However, there may be a time lag associated with these impacts on younger cohorts of individuals or on the overall reproductive fitness of these apes that is not detected with current survey methods. Thus, Central Chimpanzees are likely to be experiencing significant population declines that we do not have the statistical power to detect.
|Current Population Trend:||Decreasing|
|Habitat and Ecology:|
Central Chimpanzees are found predominantly in moist lowland tropical forests and swamp forests. Although they prefer mixed species forest, they will use other forest types for nesting and foraging, including monodominant forest stands comprised largely of medium- to large-sized Gilbertiodendron trees. Chimpanzees are omnivorous, and their diets vary greatly between populations and seasons. Ripe fruit is the major constituent of their diet; young leaves, bark, stems and flowers are also important (Morgan and Sanz 2006, Head et al. 2011). Faunivory has been documented in all groups studied and mammals comprise a small but significant component of their diet. Consumption of other primates has been documented, but appears to be less frequent in Central Chimpanzees than in conspecifics inhabiting the forests of East and West Africa. Chimpanzee community sizes of 64–71 individuals have been recorded (Morgan 2007). The size of Chimpanzee community home ranges in Goualougo, Republic of Congo, is 13.7–25.6 km² (Morgan 2007). In Loango, Gabon, minimum home range size can reach 45 km² (Arandjelovic et al. 2011).
Generation length is estimated to be 25 years (24.6 in Langergraber et al. 2012). Central Chimpanzees have an interbirth interval of 6.04±0.73 years between surviving offspring, which decreases to 3.39±0.77 years when an offspring does not survive (Morgan and Sanz, unpublished data).
|Generation Length (years):||24.6|
|Movement patterns:||Not a Migrant|
|Use and Trade:||
Chimpanzees are completely protected by national and international laws in all countries of their range, and it is, therefore, illegal to kill, capture or trade in live Chimpanzees or their body parts.
The major threats to P. t. troglodytes are:
While each of the major threats to the Central Chimpanzee's survival is described as an independent factor, these threats are often interconnected and may interact in ways that exacerbate their impacts on wildlife. For example, as access to forests is opened up, poaching intensifies in regions where Zaire ebolavirus and other pathogens are already significant threats. The extensive selective-logging regime applied over most of the Central Chimpanzee’s geographic range is leading to widespread habitat modification, while global warming is likely to cause additional changes in the extent and quality of habitats suitable for great apes. Global warming may also lead to increased exposure to novel pathogens, as Chimpanzees expand their diets to acquire adequate resources.
Pan troglodytes is listed on Appendix I of CITES and in Class A of the African Convention. National and international laws controlling hunting or capture of great apes exist in all habitat countries, but enforcement of protective legislation is inconsistent or lacking throughout much of the species’ range. Only around 33% of Central Chimpanzees and about 22% of their range are protected by forest guards, who work in most protected areas and in the well-managed logging concessions; the remainder of their range is unprotected and highly vulnerable to poachers.
Two targeted conservation action plans for the great apes of Western Equatorial Africa have been produced (Tutin et al. 2005, IUCN 2014). The areas where most of the world's Central Chimpanzees occur in geographically distinct blocks have been identified and a series of actions outlined for each, which can be broadly encapsulated as:
Maintaining large, intact and well-protected areas of forest will be key to maintaining great ape populations in the long term, and this can only be done by a combination of the actions detailed in the 2015–2025 IUCN Action Plan. Threats and conservation actions needed are outlined in greater detail in the action plans than is possible here. These documents can be downloaded at: http://www.primate-sg.org/action_plans
|Errata reason:||This is an errata version of the 2016 assessment to correct some grammatical errors in the Threats section, and to remove the estimate of "140000" mature individuals: this figure includes juveniles and subadults along with mature animals; the percentage that are mature individuals is not known.|
|Citation:||Maisels, F., Strindberg, S., Greer, D., Jeffery, K., Morgan, D.L. & Sanz, C. 2016. Pan troglodytes ssp. troglodytes (errata version published in 2016). The IUCN Red List of Threatened Species 2016: e.T15936A102332276.Downloaded on 17 March 2018.|