Dja Biosphere (or Faunal) Reserve

Central Africa > Cameroon > Dja Biosphere Reserve (or Faunal) Reserve

Summary

• Central chimpanzees (Pan troglodytes troglodytes) and western lowland gorillas (Gorilla gorilla gorilla) are present in Dja Biosphere Reserve.
• It has been estimated that XXXXX (CI: XXXX-XXXX) individuals occur in the site.
• The great ape population trend is decreasing.
• The site has a total size of XXXX km².
• Key threats to SPECIES NAME are XXXXX.
• Conservation activities have focused on XXXXXX.
• OPTIONAL: SPECIAL CHARACTERISTICS

Site characteristics

The Dja Biosphere Reserve includes the formal Dja Faunal Reserve and its buffer zone which comprise logging concessions (also known in Cameroon as Forestry Management Units - FMUs), settlements, and community forests. Rubber plantations and a hydroelectric dam with a reservoir on the Dja River in the western buffer zone, are also present (Bruce et al. 2018). Approximately 80% of the reserve is surrounded by the Dja River, providing a natural barrier and some limited protection to the reserve (Nguiffo 2001). The reserve is a relatively flat plateau of round-topped hills (UNESCO 2015) and ranges in altitude from 600-800 masl. The topography is mainly shallow valleys on either side of a ridgeline that cuts through the reserve east to west (MINFOF & IUCN 2015). In the floors of the valleys, swamp habitat becomes more common and tributaries throughout the reserve flow into the Dja River (UNESCO 2010, MINFOF & IUCN 2015). The three major types of forest in the reserve are mixed-species forest terra firma, monodominant forest where Gilbertiodendron dewevrei is the most abundant species, and periodically flooded forest (Djuikouo et al. 2010). The area comprises mainly dense evergreen Congo rainforest and is known to have a wide range of primate species. As the exploitation of timber resources increases, the Dja forest remains an important refuge for many plants and animal species, such as the moabi tree, Baillonella toxisperma (UNESCO 2015). The Dja Biosphere Reserve is home Western lowland gorilla, Central chimpanzee, Bongo (Tragelaphus eurycerus), giant pangolin (Manis gigantea), elephant (Loxodonta Africana cyclotis), mantled guereza (Colobus guereza), leopard (Panthera pardus), and many other species of wildlife (UNESCO 2015, Bruce et al. 2018). The reserve hosts a rich diversity of fauna including 109 mammal species, 360 bird species, and 61 fish species. It is also home to the world’s most important colony of grey-necked rockfowl (Picathartes oreas) with 50 active nests on the same rocky cliff (UNESCO 2015). More than 4,000 and 40,000 inhabitants live in the core and the surrounding areas of the Biosphere, respectively. Main ethnic groups in the area include the Badjoué, Boulou, Fang, Nzimé, Kakas, and the Baka pygmies. The two latter groups are semi-nomad. The Baka group are free to hunt within the reserve using traditional methods (UNESCO 2015). Table 1. Basic site information for Dja Biosphere Reserve

Area	5,260 km²
Coordinates	3.145201 N, 13.038452 E
Designation	Biosphere reserve
Habitat types	Subtropical/tropical dry forest, subtropical/tropical moist lowland forest, subtropical/tropical swamp forest

IUCN habitat categories Site designations

Ape status

Between 1995 and 2018, there is a declining trend in estimates of density for forest elephants and great apes. Western lowland gorillas showed a roughly five-fold decrease in estimated densities between the two surveys. However, methodological differences in survey practice and analysis may be magnifying these apparent sharp declines between the 2015 and 2018 inventories. This is supported by the fact that great ape and forest elephant population estimates from surveys completed prior to the 2015 inventory are more in line with a more gradual decline in numbers for great apes and forest elephants (for example, N’Goran et al. 2017). Using the DFR western lowland gorilla densities estimated by Williamson and Usongo (1995), we can estimate 8,971 gorillas in 1995. The 2018 population estimate for western lowland gorillas in the DFR is 1,371, suggesting a decline of approximately 83% in numbers since 1995. However, both Williamson and Usongo (1995) and Latour (2010) population estimates were based only on the north-east sector of the reserve. For central chimpanzees, the 1995 estimate would be 4,155 individuals with a decline of roughly 30% in 2018.

Table 2. Ape population estimates in Dja Biosphere Reserve

Species	Year	Abundance estimate (95% CI)	Density estimate [ind./ km²] (95% CI)	Encounter rate (nests/km)	Area	Method	Source	Comments	A.P.E.S. database ID
Pan troglodytes troglodytes	1995	4,155	0.79		620 sq.km	Line transects (Distance)	Willamson & Usongo (1995)	17 transects totaling 94.7km were walked twice at intervals of 5-7 months. Abundance estimate is an extrapolation to the whole surface of the park. Latour (2010) only estimated population densities for the north-east sector of the reserve.
Gorilla gorilla gorilla	1995	8,995	1.71		620 sq.km	Line transects (Distance)	Willamson & Usongo (1995)	17 transects totaling 94.7km were walked twice at intervals of 5-7 months. Abundance estimate is an extrapolation to the whole surface of the park. Latour (2010) only estimated population densities for the north-east sector of the reserve.
Pan troglodytes troglodytes	2010	3,524	0.67	0.48	620 sq.km	Line transects (Distance)	Latour (2010)	Abundance estimate is an extrapolation to the whole surface of the site. Williamson & Usongo (1995) only estimated population densities for the north-east sector of the reserve. 34 transects were walked in an area of 620 sq.km, totaling 43.4 km.
Gorilla gorilla gorilla	2010	9,362.8	1.78	1.18	620 sq.km	Line transects (Distance)	Latour (2010)	Abundance estimate is an extrapolation to the whole surface of the site. Williamson & Usongo (1995) only estimated population densities for the north-east sector of the reserve. 34 transects were walked in an area of 620 sq.km, totaling 43.4 km.
Pan troglodytes troglodytes	2018	2,313 (1,568–3,411)	0.43	0.472	Entire site (5260 sq.km)	Line transects (Distance)	Bruce et al. 2018	283 transects covered 298.2 km. Distance covered in recces: 1681.38 km.
Gorilla gorilla gorilla	2018	1,258 (779–2,031)	0.24	0.413	Entire site (5260 sq.km)	Line transects (Distance)	Bruce et al. 2018	283 transects covered 298.2 km. Distance covered in recces: 1681.38 km.

Threats

Dja’s unique ecosystem and wildlife are in crisis due to high levels of poaching, the expansion of extractive industries and a lack of capacity and support for the Cameroonian Government’s Conservation Service which manages the Reserve (ZSL). Commercial logging, mining, agriculture, and infrastructure development contribute to habitat loss and fragmentation in Dja (AWF.org). Recent human population growth has increased deforestation and also exacerbated the impacts of poaching and the illegal bushmeat trade. The populations of forest elephant, western lowland gorilla, and central chimpanzee within the Dja Faunal Reserve are relatively low compared to what the landscape and habitat could theoretically support. These populations are declining compared to prior surveys. Hunting for the illegal wildlife trade and bushmeat are likely the primary driver of the declines (Bruce et al. 2018). Indicators of human activity within the reserve are highest in the north-west and lowest in the southern sector towards the centre. The most frequently encountered sign of human activity were trails, machete cuts, and signs of human passage. Areas within the reserve that have few signs of human activity are uncommon (Bruce et al. 2018). Most human signs were recorded in the north-west of the reserve. The low encounter rates of wildlife in this area other than around Bouamir Research Station suggest that human activity continues to impact wildlife within the reserve. The wildlife hotspots were (1) the area around Bouamir Research Station (a hotspot for the elephant population), (2) the north-east corner of the reserve where great apes were most frequently encountered, and (3) the habitat around the Bali Bai and the east of the Southern Sector that has lower levels of human sign and where disturbance-sensitive species, such as leopard, golden cat and white-bellied duiker, most commonly occur (Bruce et al. 2018).

Table 3. Threats to apes in Dja Biosphere Reserve

Category	Specific threats	Threat level	Quantified severity	Description	Year of threat
1. Residential & commercial development	1.2 Commercial & industrial areas	Present, but threat severity is unknown			Ongoing (2018)
2. Agriculture & aquaculture	2.1 Annual & perennial non-timber crops	Unknown		Expansion of land for agriculture.	Ongoing
3. Energy production & mining		Unknown
4. Transportation & service corridors		Unknown
5. Biological resource use	5.1 Hunting & collecting terrestrial animals	High	Very high in the Northwest of the DBR, ca. 25% of the area	Intensity of signs of human activity in the northwest area of the reserve and low encounter rates of great ape nests and forest elephant dung in this area (apart from around Bouamir Research Station), suggests that human perturbation continues to influence the distribution of wildlife within the DFR (Bruce et al. 2018).	Ongoing (2018)
	5.3 Logging & wood harvesting	Present, but threat severity is unknown	Affecting buffer zones.	Around the Dja Faunal Reserve other significant threats include mining, logging, agricultural clearance, rubber plantations and the associated demands for bushmeat, and the ecological impacts of existing and planned hydroelectric dams (MINFOF & IUCN 2015).	Ongoing (2018)
6. Human intrusion & disturbance		Unknown
7. Natural system modifications	7.2 Dams & water management/use	Present, but threat severity is unknown			Ongoing (2018)
8. Invasive & other problematic species, genes, diseases		Unknown
9. Pollution		Unknown
10. Geological Events		Absent
11. Climate change & severe weather		Unknown
12. Other options		Absent

IUCN Threats list

Conservation activities

Conservation activities including the monitoring of biodiversity through wildlife surveys, improving law enforcement to combat wildlife crimes, anti-poaching patrols, and empowerment of local communities in and around the Dja Biosphere Reserve are conducted in the DBR by the Cameroon Ministry of Forest and Wildlife, the Zoological Society of London (ZSL) and the African Wildlife Foundation (AWF). During 2018, ZSL supported MINFOF eco-guards to carry out patrols throughout all four sectors of the Dja Biosphere Reserve using the Spatial Monitoring and Reporting Tool (SMART) approach. A total of 68 patrols were completed in all sectors of the Dja covering a distance of 7,769km and 93% of the Reserve. During these patrols, 14 arms were seized, along with 131 pieces of ammunition, and a total of 9 people were arrested on charges of poaching (ZSL 2018). Between January and December 2017, the AWF anti-poaching units conducted 559 patrols and destroyed 52 active hunting camps, seizing 82 kg of pangolin scale, as well as traditional guns, ammunition, and motorbikes. They also removed 264 traps and snares (AWF 2017).

Table 4. Conservation activities in Dja Biosphere Reserve

Category	Specific activity	Description	Year of activity
1. Residential & commercial development	Specific activity OR Not reported	Description	Year of activity
2. Agriculture & aquaculture	Not reported
3. Energy production & mining	Not reported
4. Transportation & service corridors	Not reported
5. Biological resource use	5.6. Conduct regular anti-poaching patrols		Ongoing (2018)
5. Biological resource use	5.9. Regularly de-activate/remove ground snares		Ongoing (2018)
5. Biological resource use	5.15. Implement monitoring surveillance strategies (e.g. SMART) or use monitoring data to improve effectiveness of wildlife law enforcement patrols		Ongoing (2018)
5. Biological resource use	5.17. Provide sustainable alternative livelihoods; establish fish- or domestic meat farms		Ongoing (2018)
6. Human intrusion & disturbance	Not reported
7. Natural system modifications	Not reported
8. Invasive & other problematic species, genes, diseases	Not reported
9. Pollution	Not reported
10. Education & Awareness	10.1. Educate local communities about primates and sustainable use
10. Education & Awareness	10.2. Involve local community in primate research and conservation management
11. Habitat Protection	11.2. Legally protect primate habitat	The site was declared a Biosphere Reserve in 1981.	Ongoing
12. Species Management	Not reported
13. Livelihood; Economic & Other Incentives	Not reported

Conservation activities list (Junker et al. 2017)

Challenges

Table 5. Challenges reported for Dja Biosphere Reserve

Challenge	Source
Not reported

Research activities

Documented behaviours

Table 6. Ape behaviors reported for Dja Biosphere Reserve

Behavior	Source
Not reported

External links

UNESCO Dja Biosphere Reserve

Relevant datasets

A.P.E.S Portal

References

Djuikouo, M.N.K., Doucet, J.‐L., Nguembou, C.K., Lewis, S.L. and Sonké, B. (2010), Diversity and aboveground biomass in three tropical forest types in the Dja Biosphere Reserve, Cameroon. African Journal of Ecology, 48: 1053-1063. https://doi.org/10.1111/j.1365-2028.2010.01212.x
MINFOF/UICN. (2015). Caractérisation de la population de grands et moyens mammifères dans la Reserve de Faune du Dja : Potentiel et menaces. Ministry of Forests and Wildlife, IUCN, Yaoundé, Cameroon. 31 pp.
Bruce T., Ndjassi, C., Fowler, A., Ndimbe, M., Fankem,O., Tabue Mbobda, R.B, Kobla,A.S., Wabo Puemo, F.A., Amin, R., Wacher, T., Grange-Chamfray,S.,& Olson, D. (2018). Faunal Inventory of the Dja Faunal Reserve, Cameroon – 2018. Ministry of Forests and Wildlife (MINFOF), Zoological Society of London – Cameroon Country Programme, African Wildlife Foundation, Yaoundé, Cameroon.
Latour, S. (2010). Reserve de Faune du Dja: Evaluation du Statut de grands singes. Rapport de BRL Ingenierie, GFA consulting, et DFS.
UNESCO (2015). http://www.unesco.org/new/fileadmin/MULTIMEDIA/HQ/SC/pdf/sc_mab_BR_Dja_EN.pdf (Accessed on 18.01.2021)
Williamson, E. & Usongo, L. (1995). Réserve de faune du Dja: recensement des populations de primates et inventaire des grands mammifères. ECOFAC, Bruxelles.
ZSL (2018).ZSL Cameroon Annual Report 2018 (https://admin.zsl.org/sites/default/files/Cameroon%20Annual%20Report%202018.pdf?_ga=2.24277757.615129097.1610992413-860504531.1610992413)

Page completed by: Tene Sop Date: 24/09/2021