Tiwai Island

West Africa > Sierra Leone > Tiwai Island

Summary

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• Western chimpanzees (Pan troglodytes verus) are present in Tiwai Island.
• The population size is unknown.
• The chimpanzee population trend is unknown.
• This site has a total size of 12 km².
• Key threats to chimpanzees are habitat disturbance and hunting.
• Ecotourism and research activities are the main components of the conservation work carried out at the site.

Site characteristics

Tiwai island is located in the Moa River, to the north of Gola Rainforest National Park’s western block. Tiwai Island was declared a wildlife sanctuary in 1987 and it is managed by an administrative committee representing government, local communities, environmental organizations, and academic institutions (Klop et al. 2008). Over 700 plant species and 170 bird species have been identified on the island (Klop et al. 2008). The island has a remarkable concentration of primate species (11 in total), and is also home to the endemic pygmy hippopotamus, and hundreds of bird species.

Table 1. Basic site information for Tiwai Island

Area	12 km²
Coordinates	7.54, -11.35
Designation	Wildlife sanctuary
Habitat types	Subtropical/tropical moist lowland forest, subtropical/tropical swamp, permanent rivers/streams/creeks

IUCN habitat categories Site designations

Ape status

The site was surveyed in 2009, but abundance estimates are not publicly available (Brncic et al. 2010).

Table 2. Ape population estimates in Tiwai Island

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 verus	1988			Present	Tiwai Island	Line transects (Distance)	Whitesides et al. 1988	sighting of one group
Pan troglodytes verus	1994			Present	Tiwai Island	Line transects (Distance)	Fimbel 1994	22 sightings of individual chimpanzees
Pan troglodytes verus	2006-2007			present	Tiwai Island	Line transects (Distance)	Klop et al. 2008	Only presence confirmed

Threats

Farms were routinely established until 1982, when research activities started on the island, and the number of farm plots was limited (Fimbel 1994). Hunting intensity was also high on the island previous to the commencement of research activities (Oates 1999; Fimbel 1994). Research and conservation activities were disrupted during the years of civil war (Oates 1999) but resumed in 2004.

Table 3. Threats to great apes in Tiwai Island

Category	Specific threats	Threat level	Quantified severity	Description	Year of threat
1. Residential & commercial development		Absent
2. Agriculture & aquaculture	2.1 Annual & perennial non-timber crops	Low		Farming activities largely stopped in the 1980s (Klop et al. 2008, Fimbel 1994), but limited forest-product harvesting is permitted under current management (Tiwai Island Wildlife Sanctuary 2019)	Ongoing (2019)
3. Energy production & mining		Absent
4. Transportation & service corridors		Absent
5. Biological resource use	5.1 Hunting & collecting terrestrial animals	Present		Hunting on the island was banned when research activities began (Fimbel 1994), but might still be ongoing (Lincoln et al. 2016)	Ongoing (2016)
6. Human intrusions & disturbance	6.2 War, civil unrest & military exercises	Low		Conservation and research activities came to a halt during the 10 years of civil war in Sierra Leone (Lindsell et al. 2011, Oates 1999)	1991-2001
7. Natural system modifications		Absent
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

IUCN Threats list

Conservation activities

Starting as a research site in the 1980s (Oates 1999), the island continues to rely on research and tourism as the key components of conservation efforts. Tiwai Island is Sierra Leone’s first community conservation program. Tourist facilities and a research center are present at the site.

Table 4. Conservation activities in Tiwai Island

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	The site was designated as wildlife sanctuary in 1987 (Tiwai Island Wildlife Sanctuary 2019)	Ongoing (2019)
12. Species Management	Not reported
13. Livelihood; Economic & Other Incentives	13.3. Run research project and ensure permanent human presence at site	Research center at the site administered by Njala university, Hunter College, and the university of Miami (Tiwai Island Wildlife Sanctuary 2019)	Ongoing (2019)
	13.4. Run tourist projects and ensure permanent human presence at site	Tourist facilities are present in the island (Klop et al. 2008)	Ongoing (2008)

Conservation activities list (Junker et al. 2017)

Challenges

Table 5. Challenges reported for Tiwai Island

Challenge	Source
Not reported

Research activities

Ecological research began in the early 1980s, focusing on the behavioral ecology of olive colobus monkeys (Klop et al. 2008).

Documented behaviours

Table 6. Great ape behaviors reported for Tiwai Island

Behavior	Source
Nut cracking	Whitesides 1985

References

Brncic TM, Amarasekaran B & McKenna A. 2010. Final Report of the Sierra Leone National Chimpanzee Census Project. Tacugama Chimpanzee Sanctuary, Freetown, Sierra Leone.
Fimbel C. 1994. The relative use of abandoned farm clearings and old forest habitats by primates and a forest antelope at Tiwai, Sierra Leone, West Africa. Biological Conservation 70. 277-286.
Klop E, Lindsell JA & Siaka A. 2008. Biodiversity of Gola Forest, Sierra Leone. Unpublished Report. Royal Society for the Protection of Birds, Sandy, UK, and Conservation Society of Sierra Leone, Freetown, Sierra Leone.
Lincoln R. Larson, April L. Conway, Sonia M. Hernandez and John P. Carroll (2016) Human-wildlife Conflict, Conservation Attitudes, and a Potential Role for Citizen Science in Sierra Leone, Africa. Conservation & Society, Vol. 14, No. 3, pp. 205-217.
Lindsell, J. A., Klop, E. and Siaka, A. (2011) The impact of civil war on forest wildlife in West Africa: mammals in Gola Forest, Sierra Leone. Oryx 45:69–77.
Oates JF. 1999. Myth and Reality in the Rain Forest: How Conservation Strategies Are Failing in West Africa. University of California Press, Berkeley, CA. pp. 59-90.
Tiwai Island Wildlife Sanctuary. 2019. http://www.tiwaiisland.org/Site/research/guidelines/
Tiwai Island Wildlife Sanctuary, official website: http://www.tiwaiisland.org/Site/research/
Whitesides GH. 1985. Nut cracking by wild chimpanzees in Sierra Leone, West Africa. Primates 26: 91. https://doi.org/10.1007/BF02389050
Whitesides GH et al. 1988. Estimating Primate Densities from Transects in a West African Rain Forest: A Comparison of Techniques. Journal of Animal Ecology, Vol. 57, No. 2, pp. 345-367

Page completed by: A.P.E.S. Wiki Team Date: 02/09/2019