Short-term trends in great ape density in a community-based conservation area in the eastern Democratic Republic of the Congo

The forests of eastern Democratic Republic of the Congo (DRC) constitute a biodiversity hotspot and provide habitat to two globally threatened great apes, the Grauer's gorilla Gorilla beringei graueri and eastern chimpanzee Pan troglodytes schweinfurthii.
Community-based conservation activities may provide protection to these primates and their environment, supplementing the role of protected areas.
We look at spatiotemporal trends in the ape populations that inhabit a community forest, the Nkuba Conservation Area (NCA), as trends in wildlife abundances and distributions may provide a first tentative measure of conservation impact. In the absence of a single systematic approach to gauge conservation effectiveness, we explore both temporal changes in ape abundances and spatial distributions as lines of evidence.
Using line transect data, we estimate that between 1000 and 2200 apes, with comparable numbers of gorillas and chimpanzees, live in the NCA.
In contrast to elsewhere in eastern DRC, we found no evidence of a declining ape population or shift in their distribution after the establishment of the NCA (~2012–2013). Spatial models revealed the presence of ape hotspots that remained spatially stable across study years (2013–2020).
Practical implication. That apes in the NCA do not experience rapid declines is a cautious but optimistic first sign of the conservation potential of the NCA and its associated intended (i.e. conservation activities) and unintended (e.g. researcher presence) protection interventions.