Population Assessment of Monkeys in an Area of Increasing Hunting Pressure on Bioko Island, Equatorial Guinea

Elizabeth M Sinclair, Purdue University


Primates on Bioko Island, Equatorial Guinea, are experiencing an increase in bushmeat hunting pressure, which could lead to extinctions of endemic species. The objective of this study was to evaluate how the presence of shotgun hunting pressure may be affecting the abundance of 4 species of primates adjacent to a new road that bisects the largest protected area, Gran Caldera Southern Highlands Scientific Reserve (GCSR) on Bioko Island. Data derived from distance sampling, quadratic habitat assessment, and hunter presence observation, was used to estimate the abundance of primates in three areas with varying levels of hunting pressure while considering the basic habitat and terrain. Subsequent data, collected by other investigations, also indicate that hunting in this region was on the rise. In this study, 388 primate clusters were encountered over 248 km along 9 transect lines (340.8 hours of observations spent on trails). Overall, results indicated that for all four species of primates (Bioko red-eared guenon (Cercopithecus erythrotis erythrotis), Bioko drill (Mandrillus leucophaeus) golden-bellied crowned guenon (Cercopithecus pogonias pogonias) and Stampfli’s putty-nosed guenon ( Cercopithecus nictitans martini)), the lowest abundance (0.58 groups/km) corresponded to the region with the highest hunting intensity (0.56 signs/km) and the highest abundance (2.29 clusters/km) corresponded to the region with the lowest hunting intensity (0.15 signs/km). Thus this study demonstrates that hunting pressure was negatively correlated with primate abundance. These results highlight the need for active protection of monkeys in the GCSH and provide baseline data for the formulation of management recommendations for the future conservation of the endangered primates on Bioko Island.




Honarvar, Purdue University.

Subject Area

Wildlife Conservation|Biology|Ecology

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