Kagwene Gorilla Sanctuary

Central Africa > Cameroon > Kagwene Gorilla Sanctuary

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Summary

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• Cross river gorillas (Gorilla gorilla diehli) are present in Kagwene Gorilla Sanctuary.
• Two groups occur in the site; the total population size is unknown.
• The gorilla population trend is unknown.
• The site has a total size of 19.44 km².
• Key threats to gorillas are livestock farming, conversion of land for agriculture, and hunting.
• Conservation activities have focused on anti-poaching patrols and research activities.

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  © Sunderland-Groves

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  © Sunderland-Groves

Site characteristics

Kagwene Gorilla Sanctuary was created in April 2008, in the Kagwene mountain range in northwestern Cameroon (Sunderland-Groves & Mboh 2009). The vegetation is a submontane forest-grassland mosaic, and the terrain is rocky, reaching an elevation of up to 2,037 m above sea level (Sunderland-Groves & Mboh 2009).

Table 1. Basic site information for Kagwene Gorilla Sanctuary

Species	Gorilla gorilla diehli
Area	19.44 km²
Coordinates	Lat: 6.1333 , Lon: 9.7000
Type of site	Protected area (Wildlife Sanctuary)
Habitat types	Subtropical/tropical moist montane forest, Grassland, Subtropical/tropical heavily degraded former forest
Type of governance

Types of sites Governance types Habitat types

Ape status

During a survey between 2003 and 2005, a total of 569 fresh night-nest sites containing 7,032 individual nests, including 7 solitary nests, were recorded (Sunderland-Groves & Mboh 2009). The mean night nest group size was 12.4. The survey results, coupled with a genetic study that identified 15 individuals (Bergl & Vigilant 2007), indicate the presence of an additional group at the site, outside of the core group of 13 (Sunderland-Groves & Mboh 2009).

A 2012-2013 survey recorded 249 fresh night nest sites, comprising 1,877 individual nests in Kagwene (Ikfuingei 2013). The mean count of nests of weaned individuals was 7.54 per nest site with a range from 2-12. The majority of nest sites were recorded in the northwest and centre of the sanctuary (Ikfuingei 2013).

Table 2. Ape population estimates reported for Kagwene Gorilla Sanctuary

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
Gorilla gorilla diehli	2012-2013	Present				Kagwene Gorilla Sanctuary	Reconnaissance walk		Ikfuingei 2013	survey effort: 1005.19 km in 268 days
Gorilla gorilla diehli	2003-2005	Present				Kagwene Gorilla Sanctuary	Reconnaissance walk		Sunderland-Groves & Mboh 2009		CMR0015

Sampling methods Analytical frameworks

Threats

Livestock farming and herding, agricultural activities and hunting are the main human pressures within the sanctuary (Ikfuingei 2013). Domestic animals (cattle, goats, sheep and horses) are common on the grassland patches within the sanctuary (Ikfuingei 2013). Wire snares have been recorded mainly around the Kenchi-Alumfa section of the sanctuary, coinciding with the core area for gorillas (Ikfuingei 2013).

Table 3. Threats to apes reported for Kagwene Gorilla Sanctuary

Category	Specific threats	Threat level	Description	Year of threat
1 Residential & commercial development	1.1 Residential areas	Present (unknown severity)	Eight farming communities and ca. 2,600 people live around the base of the mountain (Sunderland-Groves & Mboh 2009).	Ongoing (2009)
2 Agriculture & aquaculture	2.1 Annual & perennial non-timber crops	High (more than 70% of population affected)	Active farms with annual crops have been recorded on the Kenchi section of the sanctuary (Ikfuingei 2013).	Ongoing (2013)
2 Agriculture & aquaculture	2.3 Livestock farming & ranching	High (more than 70% of population affected)	Cattle herding on grassland patches within the sanctuary (Sunderland-Groves & Mboh 2009, Ikfuingei 2013).	Ongoing (2013)
5 Biological resource use	5.1 Hunting & collecting terrestrial animals	High (more than 70% of population affected)	Wire snares targeting other wildlife species in the sanctuary (Ikfuingei 2013). A local belief that gorillas are in fact humans has significantly protected them (Sunderland-Groves & Mboh 2009).	Ongoing (2013)
5 Biological resource use	5.2 Gathering terrestrial plants	Present (unknown severity)	Traditionally, local communities enter the forest to gather non timber forest products (Sunderland-Groves & Mboh 2009).	Ongoing (2009)

Threats

Conservation activities

Table 4. Conservation activities reported for Kagwene Gorilla Sanctuary

Category	Specific activity	Description	Implementing organization(s)	Year of activity
2 Counter-wildlife crime	2.3 Conduct regular anti-poaching patrols	In 2009, two MINFOF Ecoguards were appointed. The entire sanctuary is patrolled by MINFOF Eco-guards (Ikfuingei 2013).		Ongoing (2013)
2 Counter-wildlife crime	2.6 Regularly de-activate/remove ground snares	Since early 2006 a greater effort has been made in patrolling and removing snares at the site (Ikfuingei 2013).		2006-Ongoing (2013)
8 Permanent presence	8.1 Run research project and ensure permanent human presence at site	The Kagwene Gorilla Sanctuary is the site of a permanent WCS Research Camp (Ikfuingei 2013).		Ongoing (2013)

Conservation activities

Challenges

Table 5. Challenges reported for Kagwene Gorilla Sanctuary

Challenges	Specific challenges	Source	Year(s)
	Not reported

Challenges

Enablers

Table 6. Enablers reported for Kagwene Gorilla Sanctuary

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

A study on gorilla nesting behaviour discovered that Kagwene gorillas are reusing nests sites (Sunderland-Groves & Mboh 2009). Furthermore, 55% of night nests were constructed on the ground and 45% in trees. Significantly more arboreal nests were constructed in the wet season (69%), vs. the dry season (19%). Nest site reuse was common (35%), but not related to season (Sunderland-Groves & Mboh 2009). In 2012-2013, analyses of fresh and recent gorilla feeding found on trails showed that the most commonly eaten plant parts were pith (78.94%), fruits (7.11%) leaves (6.59%) and bark (6.47%) (Ikfuingei 2013). Gorillas feed on bark throughout the year (Ikfuingei 2013).

Documented behaviours

Table 7. Behaviours documented for Kagwene Gorilla Sanctuary

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. (2024) 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 (Kiribou et al. 2024).

Table 8. Estimated past and projected climatological characteristics in Kagwene Gorilla Sanctuary

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]	23.5	24.7	24.3	24.8	25.8
Annual precipitation [mm]	2406	2512	2547	2526	2481
Max no. consecutive dry days (per year)	43.5	39.4	41.3	40.6	44.4
No. days with heavy precipitation (per year)	5.1	5.3	5.4	5.7	6.9

Table 9. Projected exposure of apes to extreme climate impact events in Kagwene Gorilla Sanctuary

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	5	0.97	4	0.76	3.5	0.7	7	0.75
Drought	0	0	0	0	0	0	0	0
Heatwave	0.5	50	1.5	100	1	100	4	100
River flood	0.75	0	2.5	1.07	1.5	1.41	3	0.75
Tropical cyclone	0	0	0	0	0	0	0	0
Wildfire	30	0.7	30	0.7	29	0.7	29	0.7

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  Precipitation anomaly in Kagwene Gorilla Sanctuary

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  Temperature anomaly in Kagwene Gorilla Sanctuary

References

Bergl, R. A., & Vigilant, L. (2007). Genetic analysis reveals population structure and recent migration within the highly fragmented range of the Cross River gorilla (Gorilla gorilla diehli). Molecular Ecology, 16(3), 501-516. doi:10.1111/j.1365-294x.2006.03159.x

Ikfuingei, R. (2013). Annual Report of Cross River Gorilla Ecological Monitoring at the Kagwene Gorilla Sanctuary, Cameroon Progress Report for July 2012 – June 2013. An unpublished report submitted to the Wildlife Conservation Society, the U.S. Fish & Wildlife Service, the World Wide Fund for Nature, and the Cameroon Ministry of Forestry and Wildlife. Edits; Andrew Fowler.

Sunderland-Groves, J. L., Ekinde, A., & Mboh, H. (2009). Nesting Behavior of Gorilla gorilla diehli at Kagwene Mountain, Cameroon: Implications for Assessing Group Size and Density. International Journal of Primatology, 30(2), 253-266. doi:10.1007/s10764-009-9340-7

Kiribou, R., Tehoda, P., Chukwu, O., Bempah, G., Kühl, H. S., Ferreira, J., …, & Heinicke, S. (2024). Exposure of African ape sites to climate change impacts. PLOS Climate, 3(2), e0000345. doi:10.1371/journal.pclm.0000345

Page created by: APES Atlas Team Date: 2022-04-04