Bumbuna Dam Catchment Area
Summary
- Western chimpanzees (Pan troglodytes verus) are present in Bumbuna Dam Catchment Area.
- It has been estimated that 388 individuals occur at the site.
- The chimpanzee population trend is decreasing.
- This site has a total size of 2,981 km².
- Key threats to chimpanzees include displacement due to a large hydroelectric project, hunting, slash-and-burn agriculture, logging, and mining.
- The Bumbuna Conservation Area was established within the catchment area to protect some of the biodiversity. In addition, Loma Mountains National Park was established to offset the environmental impacts of the Bumbuna dam.
- The area features Sierra Leone’s first hydroelectric power plant, which has been operational since 2009.
Site characteristics
Situated in the central part of the country, the site contains Sierra Leone’s first hydroelectric dam, supplied by the Seli river (Thompson 2010). The power plant has been in operation since 2009, and current plans of the project involve the construction of a second dam 30 km upstream from Bumbuna, at Yiben. The site is located at the base of the Sula Mountains and it is characterized by a forest savanna mosaic. In addition to the Western chimpanzee, the area hosts other endangered species, including pygmy hippopotamus (Choeropsis liberiensis), red colobus (Piliocolobus badius), and black-and-white colobus monkeys (Ganas-Sawaray et al. 2018).
Table 1: Basic site information for Bumbuna Dam Catchment Area
| Area | 2,981 km² |
| Coordinates | 9.07 N, -11.72 W |
| Designation | None |
| Habitat types | Subtropical/Tropical Swamp Forest, Subtropical/Tropical Moist Lowland Forest, Savanna, Water Storage Areas |
Ape status
Local communities have reported that the chimpanzee population is decreasing in the area (Ganas-Swaray et al. 2018). Furthermore, surveys conducted between 2006 and 2018 indicate a population decline in the Bumbuna Conservation Area (Ganas-Swaray et al. 2018). Based on survey data collected in 2017-2018, it was predicted that the entire catchment area hosts approximately 388 chimpanzees (Ganas-Swaray et al. 2018). The 2017-2018 survey was complemented by recce surveys, camera trapping, and genetic analysis (Ganas-Swaray et al. 2018).
Table 2: Great ape population estimates in Bumbuna Dam Catchment Area
| Species | Year | Abundance estimate (95% confidence interval) | Density estimate (per km²) | Encounter rate (nests/km) | Area | Method | Source | Comments | A.P.E.S. database ID |
|---|---|---|---|---|---|---|---|---|---|
| Pan troglodytes verus | 2006 | 33-58 | 0.44-3.6 | Home range of 4 chimpanzee communities (i.e., not the entire catchment area) | Unknown | Nippon Koei UK 2007 as cited by Brncic et al. 2010 | At least four communities present in the area | ||
| Pan troglodytes verus | 2017-2018 | 30 (12-72) | 0.13 (0.06-0.32) | Bumbuna Conservation Unit, and areas surrounding Bumbuna power plant and Yiben reservoir | Line transects (Distance), index survey | Ganas-Swaray et al. 2018 | Line transect survey effort: 79.5 km, reconnaissance survey, presence of 7 chimpanzee groups was confirmed |
Threats
The Bumbuna hydroelectric project represents a major threat to the chimpanzee population in the area. The planned flooding of the inundation area will completely, or almost completely, reduce the home ranges of three chimpanzee groups, and four other groups ranging close the boundaries of the inundation area are also likely to be adversely affected (Ganas-Swaray et al. 2018). The hydroelectric project also indirectly impacts chimpanzees. The displacement of some chimpanzee groups into the home ranges of other groups may lead to fatalities, due to the territorial nature of chimpanzees (Ganas-Swaray et al. 2018). Displaced chimpanzees may also come into conflict with humans due to competition for the same resources (Ganas-Swaray et al. 2018). Thus, in combination with the current rates of habitat loss and hunting, the development of the project puts an immense pressure on the chimpanzee population (Ganas-Swaray et al. 2018; Nippon Koei 2005).
Table 3: Threats to great apes in Bumbuna Dam Catchment Area
| Category | Specific threats | Threat level | Quantified severity | Description | Year of threat |
|---|---|---|---|---|---|
| 1. Residential & commercial development | 1.1 Housing & urban areas | Present | Villages are present in the area (Ganas-Swaray et al. 2018) | Ongoing (2018) | |
| 2. Agriculture & aquaculture | 2.1 Annual & perennial non-timber crops | High | Slash-and-burn agriculture (Ganas-Swaray et al. 2018, MoEWR 2010) | Ongoing (2018) | |
| 2.3 Livestock farming & ranching | High | Presence of livestock in the area (Ganas-Swaray et al. 2018) | Ongoing (2018) | ||
| 3. Energy production & mining | 3.2 Mining & quarrying | Present | Artisanal gold mining (Ganas-Swaray et al. 2018, Nippon Koei 2005) | Ongoing (2018) | |
| 4. Transportation & service corridors | 4.1 Roads & railroads | High | Footpaths, logging roads, and abandoned motor roads (Ganas-Swaray et al. 2018) | Ongoing (2018) | |
| 5. Biological resource use | 5.1 Hunting & collecting terrestrial animals | High | Hunting signs present (e.g., gun shells, snares, lookout platforms); in addition, interview data revealed that chimpanzees are hunted in the area (Ganas-Swaray et al. 2018) | Ongoing (2018) | |
| 5.3 Logging & wood harvesting | Present | Signs of logging, forest in the area is highly fragmented (Ganas-Swaray et al. 2018) | Ongoing (2018) | ||
| 5.4 Fishing & harvesting aquatic resources | Present | Fishing in the area (Ganas-Swaray et al. 2018) | Ongoing (2018) | ||
| 6. Human intrusions & disturbance | Unknown | ||||
| 7. Natural system modifications | 7.2 Dams & water management/use | High | Displacement of chimpanzees due to flooding of inundation area (Ganas-Swaray et al. 2018) | Ongoing (2018) | |
| 8. Invasive & other problematic species, genes, diseases | Unknown | ||||
| 9. Pollution | Absent | ||||
| 10. Geological Events | Absent | ||||
| 11. Climate change & severe weather | Unknown | ||||
| 12. Other options | Absent |
Conservation activities
The Bumbuna Conservation Area (BCA) is a small protected area (3,532 ha) that was established in 2008 with the aim of conserving some of the biodiversity in the reservoir area (MoEWR 2010; Ganas-Swaray et al. 2018). However, the BCA was deemed insufficient to compensate for the adverse environmental impacts, and as an additional offset, the Loma Mountain Non-Hunting Forest Reserve was upgraded to national park, which is now called the Loma Mountains National Park (MoEWR 2010). Furthermore, there is a lack of conservation activities in the area (Ganas-Swaray et al. 2018).
Table 4: Conservation activities in Bumbuna Dam Catchment Area
| Category | Specific activity | Description | Year of activity |
|---|---|---|---|
| 1. Residential & commercial development | Not reported | ||
| 2. Agriculture & aquaculture | Not reported | ||
| 3. Energy production & mining | Not reported | ||
| 4. Transportation & service corridors | Not reported | ||
| 5. Biological resource use | Not reported | ||
| 6. Human intrusions & 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 | Not reported | ||
| 11. Habitat Protection | 11.2. Legally protect primate habitat | Bumbuna Conservation Area was established in 2008, however the number of chimpanzees has declined in the area due to habitat loss (Ganas-Swaray et al. 2018) | Ongoing (2018) |
| 12. Species Management | Not reported | ||
| 13. Livelihood; Economic & Other Incentives | Not reported |
Impediments
Table 5: Impediments reported for Bumbuna Dam Catchment Area
| Impediment | Source |
|---|---|
| Not reported |
Research activities
No information on research activities has been documented.
Documented behaviours
Table 6: Great ape behaviors reported for Bumbuna Dam Catchment Area
| Behavior | Source |
|---|---|
| Not reported |
Relevant datasets
References
Thompson, F. 2010. Sierra Leone's Hydro-Power Dam Lighting Up Freetown. Voice of America. Online: www.voanews.com
Ganas–Swaray, J., Arandjelovic, M., Casado, N., Campbell, G., Garriga, R., Serckx, A. 2018. Primate and large mammal targeted surveys, Phase II Bumbuna Hydroelectric Dam, Sierra Leone: Priority species. Final Report. Online: www.selihydropower.sl
Brncic, T.M., Amarasekaran,B. & McKenna,A. 2010. Final Report of the Sierra Leone National Chimpanzee Census Project. Tacugama Chimpanzee Sanctuary, Freetown, Sierra Leone.
Nippon Koei UK, BMT Cordah, Environmental Foundation for Africa. 2005. Bumbuna Hydroelectric Project Environmental Impact Assessment. Vol. 1: Executive Summary, 44 pp; Vol. 2: Environmental Impact Assessment, 299 pp; Vol. 3: Appendices, 364 pp.
Ministry of Energy and Water Resources (MoEWR). 2010. Bumbuna Hydroelectric Environmental and Social Management Project (ESMP).
Page completed by: A.P.E.S. Wiki Team Date: 02/09/2019