Summary

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Central chimpanzees (Pan troglodytes troglodytes) & western lowland gorillas (Gorilla gorilla gorilla) are present in Nkwende Hills Forest Reserve.
The population size is unknown.
The population trend is unknown.
The site has a total size of 409.82 km².
Key threats to great apes
Conservation activities are not reported.

Site characteristics

The site is located in southwestern Cameroon and it is contiguous with Korup National Park. The name Nkwende means "a water source for animals" in Ejagham (Bobo, Aghomo & Ntumwel 2015). The highest peak at the site is about 737 m above sea level. Part of the reserve extends to the Okoroba village, where rock formations, commonly known as "chimpanzee stone" to the locals, are alleged to be a refuge to chimpanzees. The forest around the villages is secondary forest due to logging and agricultural activities, but primary forests still exist in higher altitudes (Bobo, Aghomo & Ntumwel 2015).

Table 1. Basic site information for Nkwende Hills Forest Reserve

Species	Pan troglodytes troglodytes, Gorilla gorilla gorilla
Area	409.82 km²
Coordinates	Lat: 5.410812 , Lon: 9.270493
Type of site	Protected area (Forest Reserve)
Habitat types	Subtropical/tropical moist lowland forest, Wetlands (lakes, rivers, streams, bogs, marshes), Agricultural land, Subtropical/tropical heavily degraded former forest
Type of governance

Types of sites Governance types Habitat types

Ape status

A 2002-2004 survey recorded the presence of chimpanzees; gorillas were not encountered (Forboseh, Eno-Nku & Sunderland 2007). According to a later study, chimpanzees are locally extinct (Bobo, Ntumwel & Aghomo 2013).

Table 2. Ape population estimates reported for Nkwende Hills Forest Reserve

Species	Year	Occurrence	Encounter or vistation rate (nests/km; ind/day)	Density estimate [ind./ km²] (95% CI)	Abundance estimate (95% CI)	Survey area	Sampling method	Analytical framework	Source	Comments	A.P.E.S. database ID
Pan troglodytes troglodytes	2002		0.72			Nkwende Hills Forest Reserve	Reconnaissance walk		Forboseh, Eno-Nku & Sunderland 2007
Gorilla gorilla gorilla	2002		0			Nkwende Hills Forest Reserve	Reconnaissance walk		Forboseh, Eno-Nku & Sunderland 2007

Sampling methods Analytical frameworks

Threats

Table 3. Threats to apes reported for Nkwende Hills Forest Reserve

Category	Specific threats	Threat level	Description	Year of threat
5 Biological resource use	5.1 Hunting & collecting terrestrial animals	High (more than 70% of population affected)	Cartridges, snares and hunting trails found during a survey in 2002-2004 (Forboseh, Eno-Nku & Sunderland 2007).	Ongoing (2007)

Threats

Conservation activities

Challenges

Table 5. Challenges reported for Nkwende Hills Forest Reserve

Challenges	Specific challenges	Source	Year(s)
	Not reported

Challenges

Enablers

Table 6. Enablers reported for Nkwende Hills Forest Reserve

Enablers	Specific enablers	Source	Year(s)
1 Site management
2 Resources and capacity
3 Engaged community
4 Institutional support
5 Ecological context
6 Safety and stability

Enablers

Research activities

Documented behaviours

Table 7. Behaviours documented for Nkwende Hills Forest Reserve

Category	Behavior	Observation type	Prevalence	Observation dates	Source	Habituation	Species	Comment
	Not reported

Behaviours

Exposure to climate change impacts

As part of a study on the exposure of African great ape sites to climate change impacts, Kiribou et al. subm. extracted climate data and data on projected extreme climate impact events for the site. Climatological characteristics were derived from observation-based climate data provided by the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP, www.isimip.org). Parameters were calculated as the average across each 30-year period. For 1981-2010, the EWEMBI dataset from ISIMIP2a was used. For the two future periods (2021-2050 and 2071-2099) ISIMIP2b climate data based on four CMIP5 global climate models were used. For future projections, two Representative Concentration Pathways (RCP) were used. RCP 2.6 is a scenario with strong mitigation measures in which global temperatures would likely rise below 2C. RCP 6.0 is a scenario with medium emissions in which global temperatures would likely rise up to 3C by 2100. For the number of days with heavy precipitation events, the 98th percentile of all precipitation days (>1mm/d) was calculated for the 1979-2013 reference period as a threshold for a heavy precipitation event. Then, for each year, the number of days above that threshold was derived. The figures on temperature and precipitation anomaly show the deviation from the mean temperature and mean precipitation for the 1979-2013 reference period.

The estimated exposure to future extreme climate impact events (crop failure, drought, river flood, wildfire, tropical cyclone, and heatwave) is based on a published dataset by Lange et al. 2020 derived from ISIMIP2b data. The same global climate models and RCPs as described above were used. Within each 30-year period, the number of years with an extreme event and the average proportion of the site affected were calculated (see Kiribou et al. subm. for details).

Table 8. Estimated past and projected climatological characteristics in Nkwende Hills Forest Reserve

Value	1981-2010	2021-2050, RCP 2.6	2021-2050, RCP 6.0	2071-2099, RCP 2.6	2071-2099, RCP 6.0
Mean temperature [C]	25.3	26.3	26.3	26.5	27.5
Annual precipitation [mm]	2769	2828	2868	2900	2853
Max no. consecutive dry days (per year)	33	29	30	26.4	31.3
No. days with heavy precipitation (per year)	5.9	6.2	6.4	7	6.6

Table 9. Projected exposure of apes to extreme climate impact events in Nkwende Hills Forest Reserve

Type	No. of years with event (2021-2050, RCP 2.6)	% of site exposed (2021-2050, RCP 2.6)	No. of years with event (2021-2050, RCP 6.0)	% of site exposed (2021-2050, RCP 6.0)	No. of years with event (2070-2099, RCP 2.6)	% of site exposed (2070-2099, RCP 2.6)	No. of years with event (2070-2099, RCP 6.0)	% of site exposed (2070-2099, RCP 6.0)
Crop failure	4	0.01	5.5	0.01	3.5	0.01	9	0.01
Drought	0	0	0	0	0	0	0	0
Heatwave	8	100	10.5	100	9.5	100	9	100
River flood	1.25	0.37	0.5	0.15	1.5	0.95	4.5	0.82
Tropical cyclone	0	0	0	0	0	0	0	0
Wildfire	30	0.7	30	0.73	29	0.71	29	0.76

External links

References

BOBO, K. S., NTUMWEL, C. B., & AGHOMO, M. F. (2013). 1. LOCAL PERCEPTION ON WILDLIFE USES AND RELATED LOSS OF CULTURAL VALUES AROUND THE NKWENDE HILLS FOREST RESERVE_ SOUTH-WEST CAMEROON By K. SERGE BOBO_ C. BONITO NTUMWEL AND MF FLORENCE AGHOMO. Life sciences Leaflets, 39, 1-to.

Bobo, K. S., Aghomo, F. F. M., & Ntumwel, B. C. (2015). Wildlife use and the role of taboos in the conservation of wildlife around the Nkwende Hills Forest Reserve; South-west Cameroon. Journal of ethnobiology and ethnomedicine, 11(1), 1-24.

Forboseh, P. F., Sunderland, T. C. H., & Eno-Nku, M. (2007). Priority setting for conservation in south-west Cameroon based on large mammal surveys. Oryx, 41(2), 255-262.

Page created by: APES Atlas Team Date: 2021-11-05