Distribution and conservation status of the golden monkeyCercopithecus mitis kandtiin Rwanda

Abstract

Habitat loss and fragmentation are major threats to primate populations globally. The Endangered golden monkey Cercopithecus mitis kandti is only found in two small forest fragments: the Virunga massif in Rwanda, Uganda and the Democratic Republic of the Congo, and the Gishwati Forest in Rwanda. Little is known about the abundance and distribution of this subspecies, or threats to its survival. During 2007–2018, we collected data along 893.7 km of line transects and 354.2 km of recce trails in Volcanoes National Park and in Gishwati–Mukura National Park to estimate golden monkey density and examine any threats. In Volcanoes National Park, golden monkeys were found almost exclusively in the bamboo zone, and in Gishwati–Mukura National Park they occurred only in the remnant tropical montane Gishwati Forest. In Volcanoes National Park, density was estimated to be 7.89 (95% CI: 3.85–16.19), 5.41 (2.64–11.08), and 5.47 (3.68–8.14) groups per km2 in 2007, 2011 and 2017–2018, respectively. This corresponds to a total of 4,331 individuals (95% CI: 2,723–5,938) in 2007, 4,487 (2,903–6,071) in 2011 and 4,626 (4,165–5,088) in 2017–2018. In Gishwati Forest, group density averaged 1.98 (95% CI: 1.27–3.16) per km2, corresponding to 172 (95% CI: 154–190) individuals in 2017–2018. Survey results from Volcanoes National Park suggest that the golden monkey population has been stable during 2007–2018. Limited habitat, illegal activities such as harvesting of bamboo and firewood, and the presence of feral dogs, threaten the golden monkey in Rwanda and require continued monitoring. The development of a conservation action plan is a priority to protect this species.

High flexibility in diet and ranging patterns in two golden monkey (Cercopithecus mitis kandti) populations in Rwanda

“…The considerably larger monthly home ranges found in the Gishwati group G, and the fact that it only included 30 individuals, may indicate that the bamboo habitat has a higher carrying capacity than the mixed forest from Gishwati. Indeed, previous studies suggest that the bamboo zone of the Virunga massif supports higher monkey densities than the Gishwati forest (Tuyisingize et al, 2021;Twinomugisha & Chapman, 2006).…”

“…It is classified as Endangered by the World Conservation Union (IUCN) due to its small population size and decreasing remaining habitat (Butynski & de Jong, 2020). In the Virunga massif, golden monkeys range primarily in the bamboo forest where fruit trees are rare (Aveling, 1984; Tuyisingize et al, 2021; Tuyisingize, 2017; Twinomugisha et al, 2007); bamboo accounts for the majority of their diet (Tuyisingize, 2016; Twinomugisha et al, 2007), while fruits represent a small component compared to other Cercopithecus mitis populations (Chapman & Cords, Gautier‐Hion, et al, 2002). The Gishwati population ranges in tropical montane forest dominated by fruiting trees and a few bamboo stands (Tuyisingize et al, 2021; Twinomugisha & Chapman, 2006).…”

“…In the Virunga massif, golden monkeys range primarily in the bamboo forest where fruit trees are rare (Aveling, 1984; Tuyisingize et al, 2021; Tuyisingize, 2017; Twinomugisha et al, 2007); bamboo accounts for the majority of their diet (Tuyisingize, 2016; Twinomugisha et al, 2007), while fruits represent a small component compared to other Cercopithecus mitis populations (Chapman & Cords, Gautier‐Hion, et al, 2002). The Gishwati population ranges in tropical montane forest dominated by fruiting trees and a few bamboo stands (Tuyisingize et al, 2021; Twinomugisha & Chapman, 2006). Our knowledge of golden monkey seasonal and spatial variation in diet and ranging pattern is given these differences still limited.…”

Food availability influences birth seasonality at a small spatial scale in endangered golden monkeys (Cercopithecus mitis kandti)

“…Golden monkeys in VNP are found almost exclusively in the bamboo zone (Aveling, 1984;Tuyisingize, 2016;Tuyisingize et al, 2022;Twinomugisha & Chapman, 2006). The Gishwati forest is located approximately 26 km from the southernmost border of VNP at an elevation of 2200-2500 m ASL and covers $16 km 2 of afromontane mixed forest with a few small bamboo patches (Figure 1).…”

“…Interestingly, bamboo growth also varies at a small spatial scale, with high elevation bamboo from the southern sector of VNP producing shoots mostly during the early rainy season, and lower-elevation bamboo located farther north producing bamboo shoots mostly during the late rainy season (van der Hoek et al, 2019). As golden monkeys from VNP occur throughout the bamboo altitudinal range, from 2540 to 3100 m (Tuyisingize et al, 2022), we expect bamboo phenology to affect the timing of golden monkey reproduction.…”