It is unclear whether the remarkable recovery of mountain gorillas (Gorilla beringei) in the Virunga Mountains, East Africa, that followed decades of intensive conservation efforts is indicative of positive trends in abundance and distribution of other large mammals (meso and megaherbivores). Positive population trends are particularly relevant for globally threatened elephants Loxodonta sp., as conservation and research efforts have predominantly focused on populations that range in lowland savanna ecosystems rather than the smaller but ecologically and genetically unique populations found in Virungas’ montane ecosystems. We used marked pellet group counts in dung clearance plots to determine the density/abundance and distribution of three meso (buffalo, black-fronted duiker, bushbuck) and one mega (elephant) herbivores in Volcanoes National Park (VNP; covering part of the Virunga Mountains), Rwanda, in July–September 2008 and 2021. We estimated that elephants and duiker populations saw a minor increase between 2008 and 2021 while densities of buffalo and bushbuck increased substantially over the course of the past decade. Accompanying, we found no evidence of substantial distributional shifts for elephants but observed increases in densities of the other species in the southwestern parts of VNP. Overall, density estimates for all species were much higher in both 2008 and 2021 than in a previous survey in 2004, which suggests that meso and megaherbivores have largely recovered from a steep decline in numbers towards the end of the 20th century, possibly benefitting from the same protection efforts that benefitted mountain gorillas.

In 2008 and 2021, we conducted large mammal dung counts during multiple sampling rounds at square plots (size pending species) located along transects parallel to elevational gradients across Volcanoes National Park, Rwanda.