Connectivity among subpopulations is vital for the persistence of small and fragmented populations. For
management interventions to be effective conservation planners have to make the critical distinction
between structural connectivity (based on landscape structure) and functional connectivity (which
considers both landscape structure and organism‐specific behavioral attributes) which can differ
considerably within a given context. We assessed spatial and temporal changes in structural and
functional connectivity of the Cross River gorilla Gorilla gorilla diehli (CRG) population in a 12,000 km2
landscape in the Nigeria‐Cameroon border region over a 23‐year period, comparing two periods: 1987–
2000 and 2000–2010. Despite substantial forest connections between occupied areas, genetic evidence
shows that only limited dispersal occurs among CRG subpopulations. We used remotely sensed land‐
cover data and simulated human pressure (using a spatially explicit agent‐based model) to assess
human impact on connectivity of the CRG population. We calculated cost‐weighted distances between
areas occupied by gorillas as measures of connectivity (structural based on land‐cover only, functional
based on both land‐cover and simulated human pressure). Whereas structural connectivity decreased by
5% over the 23‐year period, functional connectivity decreased by 11%, with both decreasing more during
the latter compared to the earlier period. Our results highlight the increasing threat of isolation of CRG
subpopulations due to human disturbance, and provide insight into how increasing human influence
may lead to functional isolation of wildlife populations despite habitat continuity, a pressing and
common issue in tropical Africa often not accounted for when deciding management interventions.
In addition to quantifying threats to connectivity, our study provides crucial evidence for management
authorities to identify actions that are more likely to be effective for conservation of species in human‐
dominated landscapes. Our approach can be easily applied to other species, regions, and scales. Am. J.
Primatol. 76:978–988, 2014.