Wonga-Wongué

Central Africa > Gabon > Wonga-Wongué

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Summary

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• Central chimpanzees (Pan troglodytes troglodytes) & western lowland gorillas (Gorilla gorilla gorilla) are present in Wonga-Wongué.
• The population sizes are unknown.
• The great ape population trend is unknown.
• The site has a total size of 3,965.8 km².
• Key threats are not reported.
• Conservation activities are not reported.

Site characteristics

Wonga-Wongué is located in western Gabon, on the Atlantic coast. Habitats vary from mangrove wetlands and beaches to open grasslands and tropical forest (Mills et al. 2018). The site comprises a wildlife reserve and two hunting concessions (Ramsar 2016). In addition to chimpanzees and gorillas, other wildlife species found at the site include elephants, buffalos, hippos, and a wide diversity of waterbirds, predominantly Pelecanus onocrotalus (Ramsar 2016). The site was designated as a Ramsar Site for its international importance as a wetland in 1986.

Table 1. Basic site information for Wonga-Wongué

Species	Pan troglodytes troglodytes, Gorilla gorilla gorilla
Area	3,965.816 km²
Coordinates	Lat: -0.541739 , Lon: 9.460716
Type of site	Protected area
Habitat types	Wetlands (lakes, rivers, streams, bogs, marshes), Subtropical/tropical moist lowland, Marine coastal/supratidal
Type of governance

Types of sites Governance types Habitat types

Ape status

Table 2. Ape population estimates reported for Wonga-Wongué

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
Pan troglodytes troglodytes & Gorilla gorilla gorilla						Wonga-Wongué

Sampling methods Analytical frameworks

Threats

Utilization of the land is forbidden in the area designated as presidential reserve; in the surrounding areas logging occurs, but this does not constitute a big threat yet (Ramsar 2016). Tourism also occurs in the surroundings, with the main activities consisting of wildlife viewing and beach recreation (Ramsar 2016). Human population density is relatively low (0.2 people km-2), and 59 villages are located within 10 km of the reserve’s southwest and southeast borders (Mills et al. 2018). The reserve seems to be well protected; e.g., no elephants were poached within the site from 2014 to 2016 (Mills et al. 2018).

Conservation activities

Grassland covers 15% of the reserve (Mills et al. 2018). The Gabon Parks Agency (ANPN) prescribed burns are conducted annually during the long-dry season to maintain the grasslands, which would otherwise be overtaken by forest encroachment (Mills et al. 2018).

Challenges

Table 5. Challenges reported for Wonga-Wongué

Challenges	Specific challenges	Source	Year(s)
	Not reported

Challenges

Enablers

Table 6. Enablers reported for Wonga-Wongué

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

Documented behaviours

Table 7. Behaviours documented for Wonga-Wongué

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. subm. 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 (see Kiribou et al. subm. for details).

Table 8. Estimated past and projected climatological characteristics in Wonga-Wongué

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]	26.2	27.2	27.1	27.4	28.3
Annual precipitation [mm]	2920	3108	3014	3146	3065
Max no. consecutive dry days (per year)	68.2	39.9	33.5	39.2	32.4
No. days with heavy precipitation (per year)	6.2	12.3	11.9	10.9	12.2

Table 9. Projected exposure of apes to extreme climate impact events in Wonga-Wongué

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	3	0.07	2.5	0.04	3	0.06	5.5	0.08
Drought	0	0	0	0	0	0	0	0
Heatwave	15	72.12	14.5	89.76	17	89.58	18	88.22
River flood	2.25	0.75	4.5	2.1	3.75	2.81	7.5	1.68
Tropical cyclone	0	0	0	0	0	0	0	0
Wildfire	30	0.58	30	0.57	29	0.58	29	0.56

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  Precipitation anomaly in Wonga-Wongué

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  Temperature anomaly in Wonga-Wongué

External links

Ramsar

References

Mills, E. C., Poulsen, J. R., Fay, J. M., Morkel, P., Clark, C. J., Meier, A., ... & White, L. J. (2018). Forest elephant movement and habitat use in a tropical forest-grassland mosaic in Gabon. PloS one, 13(7), e0199387.

Page created by: APES Atlas Team Date: 2022-01-10