Diversity and diel activity patterns of terrestrial mammals in the Nkuba Conservation Area, Democratic Republic of the Congo

Abstract

The Congo basin forests have vast conservation potential but because of their inaccessibility and periodic insecurity there is little formal protection or ecological research occurring there. Community-based conservation efforts in the unprotected forest corridor separating Kahuzi-Biega and Maiko National Parks in eastern Democratic Republic of the Congo aim to protect a unique forest ecosystem and facilitate the development of ecological research. To support this process, we obtained baseline data on the occurrence of terrestrial mammals in the Nkuba Conservation Area by conducting camera-trap (2014–2018) and transect (2013–2018) surveys. From camera-trap images we also extracted diel activity patterns and estimated overlap in these patterns between selected pairs of species. We identified 29 mammal species weighing > 1 kg using camera traps and 22 species in transect surveys, with a total of 33 mammal species, of which seven are categorized as threatened on the IUCN Red List. Among this mammalian community, we recorded nocturnal and diurnal species with short core activity periods, and several cathemeral species with long activity periods, with various degrees of temporal separation of diel activity between species. The presence of threatened species, including the Critically Endangered Grauer's gorilla Gorilla beringei graueri, suggests that the Nkuba Conservation Area harbours a forest community that requires continuous monitoring, further research and investment in protection from the ongoing deforestation and resource exploitation occurring in the surrounding region.

Status of terrestrial mammals in the Yangambi Landscape, Democratic Republic of the Congo

“…Despite the low colonization probability observed at the community level, persistence probabilities for species with high detection rates were p > 0.5 for C. emini , P. monticola , C. dorsalis and A. africanus , indicating stability for a few resilient species that are highly preferred by hunters and wildmeat consumers. Although abundance at the community level is amongst the lowest recorded with camera traps in the Congo Basin, the relative abundance index for these four species lies within the range recorded in Nkuba Conservation Area, in a neighbouring province of the Democratic Republic of the Congo (van der Hoek et al, 2023). None of the most abundant species exhibited significant avoidance of hunting trails, suggesting these highly resilient species do not avoid areas frequented by hunters.…”

“…Our assessment also confirms the depletion suggested for the Yangambi landscape based on the knowledge of hunters (van Vliet et al, 2018). The landscape has a lower mean estimated community occupancy and species richness than other conservation areas in the Congo Basin (Bruce et al, 2018; Hedwig et al, 2018; Orban et al, 2018; Bessone et al, 2020; Nakashima et al, 2020; van der Hoek et al, 2023). The species profile was characterized by the high representation of four species ( C. emini , A. africanus, P. monticola and C. dorsalis ) that are known to be common and highly resilient to hunting.…”

“…Although the use of camera traps has expanded globally, there is a disproportionate lack of published camera trap-based research from Central Africa, with the exception of Gabon, and particularly outside strictly protected areas (Agha et al, 2018). In the Democratic Republic of the Congo, the largest Central African country, there has been an increase in camera-trap assessments since 2020 (Bessone et al, 2020; Alempijevic et al, 2021; Mencia et al, 2021; van der Hoek et al, 2023), but there has been only one published study looking at the terrestrial mammal community as a whole, within Nkuba Conservation Area (van der Hoek et al, 2023).…”

Anthropogenic Pressures on Gorillas: A Case of Grauer’s Gorillas in Maiko National Park, the Democratic Republic of Congo

“…As a consequence, the lowland eastern gorilla (Gorilla beringei graueri syn. Grauer's gorillas) remains one of the most critically endangered gorilla subspecies [7,8].…”