Mapping suitable habitat for Nigeria-Cameroon chimpanzees in Kom-Wum Forest Reserve, North-Western Cameroon

Great apes lose suitable habitats required for their reproduction and survival due to human activities across their distribution range in Africa. Little is known about habitat suitability of the Nigeria-Cameroon chimpanzee [Pan troglodytes ellioti (Matschie, 1914)], particularly for populations inhabiting forest reserves in North-West Cameroon. To address this knowledge gap, we employed a common species distribution model (MaxEnt) to map and predict suitable habitats for the Nigeria-Cameroon chimpanzee in Kom-Wum Forest Reserve, North-West Cameroon, based on environmental factors that potentially affect habitat suitability. We related these environmental factors to a dataset of chimpanzee occurrence points recorded during line transect and reconnaissance (recce) surveys in the forest reserve and surrounding forests.  Up to 91% of the study area is unsuitable for chimpanzees. Suitable habitats only represented 9% of the study area, with a high proportion of highly suitable habitats located outside the forest reserve. Elevation, secondary forests density, distance to villages and primary forests density were the most important predictors of habitat suitability for the Nigeria-Cameroon chimpanzee. The probability of chimpanzee occurrence increased with elevation, secondary forest density and distance from villages and roads. Our study provides evidence that suitable chimpanzee habitat in the reserve is degraded, suggesting that efforts to maintain protected areas are insufficient. The reserve management plan needs to be improved to conserve the remaining suitable habitat and to avoid local extinction of this endangered subspecies.

Future simulated landscape predicts habitat loss for the Golden Langur (Trachypithecus geei): A range level analysis for an endangered primate

Trachypithecus geei Khajuria, 1956 or Golden langur are an endangered colobine primate species that are distributed in the transboundary region of Bhutan and India. The species is severely threatened because of increasing habitat fragmentation and isolation across its entire range, especially the populations in Assam, India. The distribution range of the species has not been updated for the last two decades, nor is there any proper evaluation of the habitat requirements for the species. Therefore, we mapped the habitat suitability for the species across its entire distribution and projected its habitat suitability on the simulated landscape for the future (2031). The results indicate that out of the total range extent (66,320 km²), only 12,265 km² (18.49%) is suitable for the species at present, which will further be reduced to 8884 km² by the year 2031, indicating major range contraction. These suitable habitats are largely scattered and fragmented in southern range of the species. Among the predictors used, the distance to evergreen and deciduous broadleaf forest was the strongest predictor out of the 35 used for model building. Moreover, land use and land cover were found to be more informative than the climatic variables. Much of the suitable habitats of the species are located outside the protected area network in the landscape. Therefore, we identified landscape configurations and suitable habitat areas for the future conservation and monitoring of Golden Langur in the protected areas of its range.