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Roads affect wildlife in a variety of negative ways. Road ecology studies have mostly concentrated on areas in the northern hemisphere despite the potentially greater impact of roads on biodiversity in tropical habitats. Here, we examine 4 years (January 2016–December 2019) of opportunistic observations of mammalian roadkill along a road intersecting Jozani-Chwaka Bay National Park, Unguja, Zanzibar. In particular, we assess the impact of collisions on the population of an endemic primate, the Endangered Zanzibar red colobusPiliocolobus kirkii. Primates accounted for the majority of roadkill in this dataset. Monthly rainfall was not associated with roadkill frequency for mammals generally, nor for the Zanzibar red colobus. No single age–sex class of colobus was found dead more often than expected given their occurrence in the local population. The overall effect of roadkill on colobus populations in habitats fragmented by roads is unknown given the lack of accurate, long-term life history data for this species. Our findings suggest that mortality from collisions with vehicles in some groups of colobus is within the range of mortality rates other primates experience under natural predation. Unlike natural predators, however, vehicles do not kill selectively, so their impact on populations may differ. Although a comparison with historical accounts suggests that the installation of speedbumps along the road near the Park's entrance has led to a significant decrease in colobus roadkill, further actions to mitigate the impact of the road could bring substantial conservation benefits.

We present the first systematic assessment of the population, demography and distribution of the Endangered Zanzibar red colobus Piliocolobus kirkii, in Unguja in the Zanzibar archipelago, based on a survey effort of 4,725 hours. We estimate the total population comprises 5,862 individuals in 342 groups (mean group size 17.12); 3.4 times the mean of all previous estimates. We calculated a total area of occupancy of 376 km2, with 4,042 individuals living within protected areas. Mean group sizes were significantly higher within protected areas (20.57) than outside (12.80). The number of adult females was 3,179 (54.21%), with a mean of 9.29 per group, and the number of adult males was 932 (15.89%), with a mean of 2.71 per group, giving a ratio of 3.31 adult females to adult males. This ratio was significantly lower outside protected areas. The total number of infants was 958 (16.34%), with a mean of 2.80 per group, and the number of subadults/juveniles was 793 (13.52%), with a mean of 2.32 per group, giving ratios of 0.30 infants to adult females, and 0.25 subadults/juveniles to adult females. The results indicate that P. kirkii is resilient and thriving far better than assumed. However, recruitment is low and the population may be in decline, with individuals outside protected areas most at risk. We tentatively support the categorization of P. kirkii as Endangered on the IUCN Red List, argue for greater protected area status for southern Uzi, Vundwe and Mchamgamle, and discuss conservation implications for this charismatic flagship species.

Habitat loss and fragmentation, hunting pressure, and human–wildlife conflict threaten the survival of primates across Africa. Particularly dramatic forest losses have occurred outside protected areas in the Guinean forest–savannah transition zone. Using the Boé region, Guinea-Bissau, as a case study, we investigated whether and how this rapidly humanized mosaic of wooded savannah, gallery forests and cropland could sustain viable primate populations. We conducted line transect surveys and reconnaissance (recce) walks to assess populations of one Critically Endangered (chimpanzeePan troglodytes verus), one Endangered (Temminck's red colobusPiliocolobus badius temminckii), one Vulnerable (king colobusColobus polykomos), and one Near Threatened (sooty mangabeyCercocebus atys) arboreal primates across a 104 km2section of Boé in the dry season of 2016. Using the standing crop nest count method we estimated a relatively high chimpanzee density (0.77 individuals per km2, 95% CI 0.45–1.34). An assessment of habitat selection showed that chimpanzees prefer semi-dense forest and fallow fields with remnant old trees for nesting, and locations close to rivers. The other primates studied occurred in extremely low densities and were largely restricted to gallery forests. Our results indicate a need for immediate action to ensure the long-term survival of the primate community in the human-dominated landscape of Boé. Our recommendations include action to maintain hunting pressure at a low level, restoring and protecting gallery forests, introducing incentives for farmers for forest protection and primate-friendly practices, and extending the conservation programme to all arboreal primates in the region.

The diurnal primate community of the Korup area of south-west Cameroon is rich in species and high in endemism. Two years monitoring in the Support Zone around Korup National Park have shown that, although all species of the original community are still present, Preuss' red colobus and drill, which were considered to be threatened in the early 1990s, have declined further and are probably facing local extinction. Densities of the crowned monkey also seem to have declined. Only mona and putty-nosed monkeys have an expanded distribution, and densities that are within the range of those reported from previous studies in the region. Although hunting is the most important cause of these declines, logging also appears to be having a detrimental effect. In logged forest group densities of chimpanzee, red-capped mangabey, mona monkey and red-eared monkey decreased between the two survey years, whilst remaining constant or increasing in unlogged forest. The frequency of associations of guenon species did not differ between logged and unlogged study sites, but encounters of associations of all four guenon species were only found in unlogged forest. We strongly recommend enforcement of anti-poaching activities inside the Korup National Park, and establishment of wildlife management in the Support Zone, as only a combined strategy can successfully guarantee the persistence of the wildlife of the region.

The Zanzibar red colobus Procolobus kirkii is one of Africa's most endangered primates, with only c. 1500–2000 individuals remaining in the wild. The authors made preliminary surveys of three areas where this monkey was translocated or introduced in the 1970s and 1980s. It appears that only one of these releases was successful. A total of 67 animals were caught and translocated or introduced (including four that died during the process). Thirteen to 20 years later, 62–70 red colobus were located at the three sites; i. e. there had been no net gain in colobus numbers as a result of the translocations and introduction. One attempt apparently failed because of insufficient habitat, and another perhaps because of insufficient numbers ofcolobus or an imbalance in the age and sex composition of animals released. The one successful translocation involved moving a fairly large number of monkeys (36) into a forest with a relatively high diversity of tree species. In light of these findings, the authors recommend that far more attention be given to protecting the monkeys and their habitat where they currently exist, rather than spend time and money on translocations that are as likely to fail as to succeed.

The Magombera Forest in Tanzania contains the most viable population of the endangered Uhehe red colobus monkey, three other primates, and rare and endemic plants and animals. In 1980 almost half of the Magombera Forest Reserve was surrendered for settlement in exchange for the southern part being incorporated into the Selous Game Reserve. Due to an oversight, the southern part was not legally annexed into the Selous and now the Kilombero Sugar Company has claimed a portion of it. The forest is currently in good condition and offers the best opportunity to conserve the Uhehe red colobus. The author recommends a number of measures to save the forest and its wildlife and to ensure that the needs of the local people are met.

Two endangered monkeys, the Tana crested mangabey and the Tana red colobus, survive only in a small area of the Tana river in northern Kenya. The Government has now created a small reserve to protect them on land given up voluntarily by the local people. But the threat of a large irrigation project upstream could still jeopardise their survival. Mr Mkunga is Warden of the new reserve. © 1977, Fauna and Flora International. All rights reserved.

There are five, perhaps only four, monkey species in The Gambia and all are under threat. The main problems are habitat destruction, hunting of crop raiders and illegal capture for medical research. The information presented here was collected during a long-term study from March 1978 to September 1983 on the socio-ecology of the red colobus monkey in the Abuko Nature Reserve. Further information was collected during brief periods between February 1985 and April 1989 on the presence of monkeys in the forest parks. It is not systematic nor extensive, but it indicates clearly that action is needed if monkeys are to remain as part of the country's wildlife. The most pressing need is for survey work to supply the information needed to work out a conservation plan.

The Tanzania-Zambia railway now bisects the Magombera Forest Reserve in Tanzania, and as a result the most viable surviving population of the rare endemic Iringa red colobus is seriously threatened. The railway has facilitated tree-felling, settlement and cultivation, and the colobus habitat is already seriously damaged. The authors conducted a survey of the forest in 1979, and recommended that the southern part, which has a viable colobus population, be included in the neighbouring Selous Game Reserve, thus giving that part the stronger protection of a game reserve, and that the local people be compensated by the release to them of a small area of the Selous.