Guinea-Bissau Nationwide
West Africa > Guinea-Bissau > Guinea-Bissau Nationwide
Summary
- Western chimpanzees (Pan troglodytes verus) are present in Guinea-Bissau.
- It has been estimated that 1,908 (CI: 923-6,121) individuals occur in Guinea-Bissau.
- The chimpanzee population trend is unknown.
- This site has a total size of 36,125 km².
- No conservation interventions were reported that were implemented at the national level.
- Guinea-Bissau has designated 34 protected areas, which account for 16% and 10% of the terrestrial and marine national territory, respectively.
Site characteristics
Guinea-Bissau (36,125 km²) is located within the Guinean forest-savannah mosaic ecoregion, which separates the Guinean moist forests in the south and the West Sudanian savanna in the north (12.1775473, -14.8490914) (Olson et al., 2001). The climate is characterized by a hot wet season (June-October) and a hot dry season (November-May) (Bersacola et al. 2018). During wet season, the average monthly rainfall is 298.2 mm (World Bank, 2018b). During the rest of the year, rain is almost absent. The lowest and highest annual temperatures are during December-January (25°C) and May (29°C). More humid forest is covering the south and drier savannah-riparian forest mosaics is found in the east (Bersacola et al., 2018). Guinea-Bissau contains 34 PAs, which account for 16% and 10% of the terrestrial and marine national territory (UNEP-WCMC & IUCN, 2018). Most Protected areas are managed by the Institute for Biodiversity and Protected Areas (IBAP). After chimpanzees were erroneously considered to be extinct in Guinea-Bissau (Lee et al. 1988), recent field surveys confirmed, that Guinea-Bissau represents the western-most limit of the endangered West African Chimpanzee Pan troglodytes verus (Sousa et al. 2005).
Table 1: Basic site information for Guinea-Bissau
| Area | 36,125 km² |
| Coordinates | 12.04 N, -15.02 W |
| Designation | Not applicable |
| Habitat types | Moist Savanna, Subtropical/Tropical Moist Lowland Forest, Subtropical/Tropical Mangrove, Forest Vegetation Above High Tide Level, Subtropical/Tropical Heavily Degraded Former Forest, Plantations |
IUCN habitat categories Site designations
Ape status
Information concerning chimpanzee population status remain scarce (Torres et al. 2010). In 1996, Gippoliti et al. 2003 estimated chimpanzee numbers between 600 and 1000 individuals, but recent surveys suggest higher numbers. Chimpanzees are distributed in Guinea-Bissau across the south of the Corubal River. In two protected areas, Cantanhez National Park and Cufada Lagoons Natural Park, chimpanzee occurrence was confirmed (Casanova and Sousa 2007; Brugière et al. 2009). In Lagoas de Cufada Natural Park, 137 individuals and a nest density of 0.22 nest builders per km² were estimated (Carvalho, Marques & Vicente 2013). In the Boé region, estimates range from 700 individuals (Serra, Silva & Lopes 2007) to 1465-4415 individuals (Francisco & Wenceslau 2014). In the Cantanhez Region (i.e., Cantanhez Forest NP and surrounding areas like Cacine and Catio), the population size was estimated between 376 and 2,632 individuals (Torres et al. 2010). Within three key forests in central Cantanhez, 281 individuals and a density of 1.1-6.18 weaned individuals/km² was estimated (depending on assumption made for nest reuse in palm trees, Sousa et al. 2011). Recent research suggests that at least 12 chimpanzee communities occur in Cantanhez Forest NP and research is ongoing by Kimberley Hockings and colleagues to assess population numbers (Hockings in prep.). Based on the modelled density distribution of western chimpanzees across their geographic range Heinicke et al. (2019) estimated 1,908 (CI: 923-6,121) individuals in Guinea-Bissau. The recent population trend for Guinea-Bissau is unknown. The total area of suitable habitat for chimpanzees was estimated to be 752 km² large (approximately 28% of the Cantanhez Region, Torres et al. 2010). Comparisons of habitat estimates for 1986, 1994 and 2003 revealed a decrease in suitable habitat for chimpanzees between 1986 and 2003 by 270 km² (approximately 30% of the suitable habitat area available in 1986, Torres et al. 2010).
Table 2: Great ape population estimates in Guinea-Bissau
| 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 | 1996 | 600-1,000 | Nationwide | Informed guess | Gippoliti et al. 2003 | This estimate is now considered an underestimate (Goedmakers & Hockings pers. com.) | |||
| Pan troglodytes verus | 2015 | 1,908 (923-6,121) | Nationwide | Model estimate | Heinicke et al. 2019 | Based on density distribution predicted for geographic range of western chimpanzees using models and transect survey data |
Threats
Due to high levels of exploitation, loss of habitat and habitat quality as a result of human activities, chimpanzee populations in Guinea-Bissau have probably experienced a significant population reduction in the past 20 to 30 years (IUCN 2011).
General Threats on a national level:
• Habitat destruction and fragmentation (due to agriculture, bush-fires, etc.) (IUCN & Chimbo 2016)
• Mining and related habitat destruction and influx of newcomers and pollution (Dias et al. 2019, Francisco & Wenceslau 2014; IUCN & Chimbo 2016).
• Even though chimpanzees are rarely hunted, retaliatory killings occur when there are aggressive interactions between humans and chimpanzees foraging on cultivated foods (Hockings & Sousa 2013). There is also an illegal trade pet trade (Casanova & Sousa 2006, Born Free Foundation 2019). There is also camera trap evidence of snare injuries on chimpanzees (Hockings, Bersacola, Bessa, Ramon unpublished data).
• Population growth; especially immigration may be a problem as immigrants do not necessarily respect local customs that respect nature (IUCN & Chimbo 2016; Francisco & Wenceslau 2014)
• Increased mobility and improved access to chimpanzee habitat (bicycles, motorcycles etc.) (Carvalho et al. 2013).
Conservation activities
Chimbo Foundation works on community-based protection in the whole sector of Boé, an important chimpanzee habitat (IUCN & Chimbo 2016). The ”Instituto da Biodiversidade e das Areas Protegidas (IBAP)” implements conservation measurements such as law enforcement, livelihood improvement, and awareness creation. However, conservation interventions that were implemented at the national level were not reported.
Impediments
Table 5: Impediments reported for Guinea-Bissau
| Impediment | Source |
|---|---|
| Lack of law enforcement | IUCN & Chimbo 2016 |
| Lack of financial means | Torres et al. 2010 |
| Lack of human resources | Carvalho et al. 2013 |
Research activities
Geographical research gaps for chimpanzees in Guinea-Bissau are limited to areas north of the Corubal river in the Bafata region and around Canjadude in Boé (Bersacola et al. 2018). Within Guinea-Bissau, research on primates mainly focused on areas south of the Corubal river, coinciding with the region with highest forest cover (Tombali) and where most of the chimpanzee population in Guinea-Bissau occur (Boé, Tombali and Quinara regions). There are ongoing research efforts to monitor and collect behavioural data on chimpanzee communities in Cantanhez Forest NP (Hockings & Sousa 2012; Hockings & Sousa 2013; Bessa, Sousa & Hockings 2015; Bersacola et al. 2018; Vieira et al 2019; Bersacola 2019 (PhD thesis); Bessa in prep (PhD thesis)). Research has been carried out in co-operation with national and local authorities, establishing a system for the systematic monitoring and management (Casanova and Sousa, 2007). As part of a Darwin funded project led by Kimberley Hockings (University of Exeter) a biodiversity monitoring project is set up across Cantanhez with IBAP as a project partner.
Relevant datasets
References
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Page completed by: A.P.E.S. Wiki Team, Kimberley Hockings, Elena Bersacola, Joana Bessa & Marina Ramon Date: 03/12/2019