Greater Mahale Ecosystem
East Africa > Tanzania > Greater Mahale Ecosystem
Summary
- Eastern chimpanzees (Pan troglodytes schweinfurthii) are present in the Greater Mahale Ecosystem.
- It has been estimated that 2,600 individuals occur in the site.
- The chimpanzee population trend is decreasing.
- The site has a total size of 20,000 km².
- Key threats to chimpanzees include human settlements in important habitat, logging and charcoal production, fires, expansion of agriculture and herding, and poaching.
- Conservation activities have focused on anti-poaching patrols and presence of researchers, and providing fuel-efficient ovens.
- The site holds approximately 90% of the chimpanzee population in Tanzania.
Site characteristics
Located in western Tanzania, the Greater Mahale Ecosystem includes the Mahale Mountains National Park and its surrounding natural habitat. In addition to the eastern chimpanzee, other species of conservation concern that occur in the area include red colobus monkeys, elephants, lions, sables, and the endemic bird Kungwe apalis (WCS). A total of 1,939 mammal, bird, reptile, amphibian and plant species have been recorded at the site, of which 15 species are endemic to the Albertine Rift and 28 species are threatened (CR, EN, VU) under the IUCN Red List (WCS).
Table 1. Basic site information for Greater Mahale Ecosystem
| Area | 20,000 km² |
| Coordinates | |
| Designation | Unclassified |
| Habitat types | Subtropical/tropical montane forest, subtropical/tropical high altitude grassland |
IUCN habitat categories Site designations
Ape status
The WCS Albertine Rift Program conducted surveys of the Greater Mahale Ecosystem in the mid 2000s with Jane Goodall Institute (JGI), to estimate chimpanzee numbers for the area and assess other biodiversity WCS).
Table 2. Ape population estimates in Greater Mahale Ecosystem
| 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 schweinfurthii | 2005 | 2,600 | Greater Mahale Ecosystem | Extrapolation of suitable habitat based on satellite imagery and densities for different areas | Plumptre et al. 2010 |
Threats
In Tanzania, 90% of the country’s chimpanzees are found in the Greater Mahale Ecosystem, where suitable habitat is being lost and fragmented by the expansion of human settlements, conversion of land for agriculture, logging, and cattle herding (Chitayat et al. 2021). Chimpanzees in savanna-woodland mosaics, such as in the Greater Mahale Ecosystem, already live at relatively low densities, highlighting the need to identify and protect areas critical for chimpanzee conservation (Chitaya et al. 2021).
Table 3. Threats to apes in Greater Mahale Ecosystem
| Category | Specific threats | Threat level | Quantified severity | Description | Year of threat |
|---|---|---|---|---|---|
| 1. Residential & commercial development | 1.1 Housing & urban areas | Present, but threat severity unknown | People settling in the area tend to locate near water sources. As a result, small riverine strips of forest, critical for chimpanzees and the endemic Kungwe apalis, are disappearing (WCS n.d.) | Ongoing (2021) | |
| 2. Agriculture & aquaculture | 2.1 Annual & perennial non-timber crops | High | Conversion of chimpanzee habitat into agricultural land (GMERC n.d.). | Ongoing (2021) | |
| 2.3 Livestock farming & ranching | High | Cattle herding (Chitaya et al. 2021). | Ongoing (2021) | ||
| 3. Energy production & mining | Unknown | ||||
| 4. Transportation & service corridors | Unknown | ||||
| 5. Biological resource use | 5.1 Hunting & collecting terrestrial animals | Present, but threat severity unknown | Injuries caused by snares (GMERC). | Ongoing (2021) | |
| 5.3 Logging & wood harvesting | High | Clearing the forest for charcoal production (GMERC). | Ongoing (2021) | ||
| 6. Human intrusion & disturbance | 6.2 War, civil unrest & military exercises | Settlement of refugees from the wars in Burundi and Democratic Republic of Congo in the landscape has led to loss of habitat (WCS). | Unknown | ||
| 7. Natural system modifications | 7.1 Fire & fire suppression | High | Fires ignited by humans, contributing to habitat loss (WCS, GMERC). | Ongoing (2021) | |
| 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 |
Conservation activities
Government-led patrols are conducted in partnership with the Jane Goodall Institute to fight illegal activities, such as poaching and herding (GMERC).
Table 4. Conservation activities in Greater Mahale Ecosystem
| 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 | 5.6. Conduct regular anti-poaching patrols | GMERC organise and sponsor patrols to combat illegal activities since 2009. | Ongoing (2021) |
| 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 | Not reported | ||
| 11. Habitat Protection | Not reported | ||
| 12. Species Management | Not reported | ||
| 13. Livelihood; Economic & Other Incentives | 13.2. Provide non-monetary benefits to local communities for sustainably managing their forest and its wildlife (e.g. better education, infrastructure development) | Providing fuel efficient ovens GMERC. | Ongoing (2021) |
| 13.3. Run research project and ensure permanent human presence at site | Research is regularly conducted at the site GMERC. | Ongoing (2021) |
Conservation activities list (Junker et al. 2017)
Challenges
Table 5. Challenges reported for Greater Mahale Ecosystem
| Challenge | Source |
|---|---|
| Not reported |
Research activities
The Greater Mahale Ecosystem Research and Conservation group cover several topics in their research, such as chimpanzee behavioral ecology, bioacoustics, environmental and biodiversity monitoring, as well as research on yellow baboons and red-tailed monkeys (GMERC n.d.).
Documented behaviours
Table 6. Ape behaviors reported for Greater Mahale Ecosystem
| Behavior | Source |
|---|---|
| Not reported |
External links
Greater Mahale Ecosystem Research and Conservation
Greater Mahale Ecosystem WCS
Greater Mahale Ecosystem Frankfurt Zoological Society
Relevant datasets
References
Chitayat AB, Wich SA, Lewis M, Stewart FA, Piel AK (2021) Ecological correlates of chimpanzee (Pan troglodytes schweinfurthii) density in Mahale Mountains National Park, Tanzania. PLoS ONE 16(2): e0246628. https://doi.org/10.1371/journal.pone.0246628
GMERC (n.d.). Conservation. https://www.gmerc.org/conservation
WCS. (n.d.). Greater Mahale Ecosystem. https://albertinerift.wcs.org/Wild-Places/Greater-Mahale-Ecosystem.aspx
Plumptre AJ, Rose R, Nangendo G, Williamson E a., Didier K, Hart J, et al. Eastern Chimpanzee (Pan troglodytes schweinfurthii) Status Survey and Conservation Action Plan 2010–2020. Gland, Switzerland; 2010.
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