The Influence of Hunting on Antipredator Behavior in Central African Monkeys and Duikers

Many animals can adjust their behavioral strategies to reduce predation risk. We investigated whether rain forest monkeys and duikers alter their antipredatory behavior in response to hunting by humans in southwestern Gabon. We compared monkey and duiker responses to human observers in an area where hunting is prohibited, to those in a nearby area where hunting pressure is moderate but spatially variable. The results of our study indicate that monkeys become more secretive when hunted, commencing alarm calls only when at a certain distance (typically > 50 m) from humans. We found no difference in monkey group size between hunted and no-hunting areas. In no-hunting areas, duikers often freeze in response to approaching observers, but in hunted areas they abandon this strategy and rapidly flee from humans. Duikers also whistle more often in areas where they are hunted frequently. Our findings have at least two important implications. First, behavioral observations of monkeys and duikers may be useful in gauging local hunting intensity in African rain forests. Second, duiker densities are likely to be overestimated in hunted areas, where they more readily flee and whistle, and underestimated in no-hunting areas, where they rely on freezing behavior to avoid detection. Because behavioral adaptations to hunting vary both among species and localities, these differences should be considered when attempting to derive population-density estimates for forest wildlife.     

The effects of mowing and agricultural landscape management on population movements of the common quail

Aim Information on the movements of bird populations in extensive landscapes is needed to assess environmental effects and conservation strategies over appropriate temporal and spatial scales. The common quail (Coturnix coturnix) is a game bird that breeds mainly in dense cereal crops. These crops cover huge areas of the Iberian Peninsula. The aim of this work is to relate cereal mowing, which causes rapid and massive habitat loss for the common quail, to population movements of the species during its breeding season. Location Spain, southern Europe. Methods We used ring recoveries to analyse, using circular statistics, the orientation of movements by male common quails in the northern half of Spain. Forward stepwise multiple regressions were applied to correlate (1) the Julian day of cereal harvesting at 770 locations with the respective latitude, longitude and elevation, and (2) the number of hunted birds with hunting pressure, breeding densities and mean mowing date by province. Finally, data concerning the number of quails hunted at the end of the breeding season were compared by province and year using two‐way ANOVA. Results Our results show that during the breeding season in the northern half of Spain, male quails orient their movements towards higher areas, and mainly to the northern Castilian Plateau. These are the areas of Spain where cereals are harvested latest. Moreover, records show that the number of quails hunted is significantly higher in these areas than in other areas of the country, independently of hunting pressure and breeding densities, and it is extremely high in the northern Castilian Plateau. Main conclusions Cereal mowing combined with some Spanish geographical characteristics acts as a funnel, forcing quail populations to concentrate in certain areas of Spain at the end of the breeding season. This implies that the number of quails hunted in these areas may be high, and that they therefore constitute priority conservation areas.     

Correlates with the distribution and abundance of endangered Sclater's monkeys (Cercopithecus sclateri) in southern Nigeria

A distribution survey of the endangered Sclater's monkey ( Cercopithecus sclateri ) was conducted over a wide area in southern Nigeria using forest surveys and hunter interviews. Sclater's monkey, Nigeria's only endemic primate species, is restricted to a land area of about 28,500 km² in the densely human-populated, oil-producing region of southern Nigeria. Results indicate that this species is not as rare as previously thought; we confirmed its presence in 27 formerly unknown sites. Based on encounter-rate and distribution data, Sclater's monkey is one of the two most abundant diurnal primate taxa across its range. However, the species primarily occupies isolated and degraded forest fragments. Although hunting is widespread, selective hunting of larger-bodied primate taxa offers some respite for the smaller Sclater's monkey. We encountered this species more frequently in forests with relatively high hunting pressure, possibly indicating competitive release in the heavily hunted forests of southern Nigeria. Long-term persistence of Sclater's monkey, which has no official protection throughout its range, depends on the willingness of hunters to target smaller-bodied wildlife (effort-profit trade-off), local bushmeat demand and protection of key forest fragments and the few larger forests in the region.     

Effects of hunting on guianan forest game birds

To assess the effect of on-going and of previous or near by hunting pressure on game birds in a neotropical rain forest (French Guiana), I compared species abundances between six hunted and disturbed areas, seven non-hunted and pristine areas and eight intermediate areas, undisturbed and not currently hunted, but formerly hunted or close to current hunting areas. I recorded all birds detected within 100 m-wide strip transects, walked at random through every forest type all day long. The frequency of records per 10 h and flock sizes on each transect were averaged over all surveys in each study site (N = 3025 h). Censused groups included terrestrial (tinamous, woodquails, curassow and trumpeter) and arboreal species (guans, macaws, parrots, toucans), but not waterbirds. The abundance of all game birds was higher in non-hunted than in hunted areas, though not always significantly for secretive understorey species (tinamous, guans, wood-quail) or canopy frugivores (parrots, macaws, toucans). The Black Curassow and Gray-winged Trumpeter exhibited the highest and most consistent increases (7–10-fold) and more so between intermediate and non-hunted sites than between hunted and intermediate sites. The mean flock size also increased along the hunting gradient, especially in flocking species (macaws, parrots, trumpeter). Low reproductive rates and/or seasonal movements may explain that hunting pressure could still be felt after hunting has ceased or when it persists only away from a given area. Such a persistent effect would affect some populations in small protected areas.     

Hunting of Mammals Reduces Seed Removal and Dispersal of the Afrotropical Tree Antrocaryon klaineanum (Anacardiaceae)

Throughout the tropics, mammalian seed dispersers are being driven to local extinction by intense hunting pressure, generating concern not only about the loss of these species, but also about the consequences for the plants they disperse. We compared two rain forest sites in Cameroon—one with heavy hunting pressure and one protected from hunting—to appraise the loss of mammalian seed dispersers and to assess the impact of this loss on seed removal and seed dispersal of Antrocaryon klaineanum (Anacardiaceae), a mammal-dispersed tree. Surveys of arboreal frugivores indicate that three of the five monkey species, as well as chimpanzee and gorilla, have been extirpated from the hunted forest. Diaspore counts underneath A. klaineanum adults (six trees per site) indicate that seed removal is severely reduced in the hunted forest. Finally, genetic maternity exclusion analysis (using 3–7 nuclear microsatellite loci) of maternally inherited endocarp tissue from diaspores collected under the canopies of 12 fruiting "mother" trees (six trees per site) revealed that seed dispersal in the hunted forest is also greatly reduced. In the hunted forest with reduced mammal dispersal agents, only 1 of the 53 assayed endocarps (2%) did not match the mother and was determined to be from a dispersed diaspore. By contrast, in the protected forest, 20 of the 48 assayed endocarps (42%) were from dispersed diaspores. This study provides strong evidence that loss of dispersal agents can lead to reduced seed removal and loss of seed dispersal, disrupting the seed dispersal cycle.     

Illegal hunting and law enforcement during a period of economic decline in Zimbabwe: A case study of northern Gonarezhou National Park and adjacent areas

Illegal hunting of wildlife, or top-down harvesting, is a major issue in today's society, particularly in tropical ecosystems. There has been widespread concern about increasing illegal hunting of wildlife in most conservation areas in Zimbabwe following the political instability and economic decline the country faced since 2000. In this study, we focused on the northern Gonarezhou National Park (GNP), a large and unfenced protected area, and adjacent communal areas in southern Zimbabwe. We hypothesised that illegal hunting activities would (1) be perceived to have increased due to economic collapse and (2) vary with law enforcement efforts. A total of 236 local residents from eight villages adjacent to the northern GNP were interviewed using semi-structured questionnaires from December 2010 to May 2011, and law enforcement data for northern GNP between 2000 and 2010 were retrieved from the park law enforcement database. A total of 26 animal species were reportedly hunted. Bushmeat consumption and the need for local trade to raise income were reported as the main reasons behind illegal hunting. Contrary to the first hypothesis, the majority of respondents (n = 156, 66%) reported that illegal hunting activities had declined between 2000 and 2010 largely due to increased park protection as also supported by law enforcement data. A total of 22 animal species were recorded as having been illegally hunted in northern GNP. The number of illegal hunters arrested declined with increased law enforcement efforts although the number of wire snares recovered and hunting dogs shot appeared to increase following increased law enforcement efforts. These results partly support the second hypothesis that illegal hunting activities would vary with law enforcement efforts.     

Lemurs in a complex landscape: mapping species density in subtropical dry forests of southwestern Madagascar using data at multiple levels

The study of southern dry forest lemurs has been largely restricted to small reserves; yet, the majority of the region's lemur populations reside outside protected areas. Lemur catta and Propithecus verreauxi occupy the same forests but have different dietary preferences. This study assessed L. catta and P. verreauxi population densities across a 3-km dry forest gradient (1,539?ha) in southern Madagascar. The study was designed to allow lemur densities to be related to particular forest types. A particular aim of this study was to collect lemur data in both protected and unprotected areas. Density estimates were calculated using point transect distance sampling in a study area that contained the Beza Mahafaly Special Reserve and the adjacent disturbed forests. The highest densities recorded for each species were in the protected area where the two species were most segregated in their distribution, with L. catta density highest in gallery forest type and P. verreauxi density highest in dry deciduous. Densities of both species varied widely outside the protected area, but P. verreauxi density was more uniform than was L. catta. Results of this study indicate that patterns of lemur density in protected areas are not representative of patterns in disturbed forests; this also suggests that we cannot fully understand the ecological constraints facing primate species by studying them only in protected areas. This research highlights the value of pairing the study of landscape-level patterns of species distribution with both local ground-level ecological interpretations and broad-scale satellite data; information from only one level may give an incomplete view of the community.     

Hunting,disturbance and roost persistence of bats in caves at Ankarana,northern Madagascar

Surveys and monitoring of 37 caves in and around the Ankarana Special Reserve, northern Madagascar, yielded evidence of hunting of bats and potential disturbance of bats by miners and tourists, and colony counts for several bat species of potential conservation concern. Colony size decreased by 95% and 14% for a colony of Hipposideros commersoni and a colony of Eidolon dupreanum, respectively, when recent evidence of hunting occurred at those colonies and those declines are probably attributable to hunting. Evidence of hunting occurred commonly at the roosts of those species and most commonly at the roosts of Rousettus madagascariensis. Hunting of pteropodids was associated with high vulnerability of roosts to hunters, little forest buffer between the cave and open savannah and the absence of tombs in the cave. Roost sites of the hunted species persisted for at least several years and this regularity may facilitate hunting. This work supports the ranking of E. dupreanum, R. madagascariensis and H. commersoni as species of conservation concern. Managers should consider the impact of tourist visits on bats and of increasing access to caves for tourism. Conservation efforts for the hunted species should also seek to protect vulnerable and unprotected cave roosts.     

Report on the distribution,population, and ecology of the yunnan snub-nosed monkey (Rhinopithecus bieti)

The Yunnan snub-nosed monkey (Rhinopithecus bieti), an endangered species in China, has received more protection in theory than in practice. Therefore it is on the very verge of extinction. The population of the species was estimated less than 2,000 individuals spread in 19 distinct groups. It was confirmed that the monkey was confined to the Yunling Mountain System, the area between the Yangtze River (Changjiang, aka Jinshajiang) to the east and the Mekong River (Lancangjiang) to the west. We further concluded that a lowland belt to the east, about 100 km long and 20 – 30 km wide was not suitable habitat for the monkeys, and appeared to serve as the natural ecogeologic barrier for the species. Our results indicated that the southern limit of the distribution was at Longma (26°14′N), and that the northern limit of the distribution was at Xiaochangdu (29°20′N). The distribution area of the species was substantially smaller than previously estimated. There were substantial ecological differences between the southern and northern parts of the species range. The monkey was found only in fir-larch forest.     

Distribution patterns of flora and fauna in southern Chilean Coastal rain forests: Integrating Natural History and GIS

Knowledge of species richness centers is necessary for the design of conservation areas. In this study, we present a GIS analysis of two years of field data on animal and plant diversity distributions in evergreen, coastal rain forests of southern Chile (39°30′–41°25′ S). Despite their high endemism, these forests have remained largely unprotected. Field records were complemented with data from museum collections and scientific literature. We used selected environmental variables (evapotranspiration, altitude) and, in some cases, forest types as predictors of species distributions. Our study focused on the distribution of forest bryophytes, vascular plants, soil invertebrates, amphibians and birds. We generated distributional maps for each taxa based on their field records in the study area, complemented by natural history information, except in the case of bryophytes and soil invertebrates. In general, species richness was lower at 600 m elevation or above for all the taxa studied. Species richness tends to increase in the northern sector of the study area. We observed a greater richness of vascular plants near rivers and streams, and noted important floristic differences between west and east-facing slopes of the Coastal Range, with more species in the oriental side. Because species in high altitude forests are not a subset of those found at lower elevations, we propose that conservation strategies should prioritize the protection of the entire altitudinal gradient of the southern Coastal Range, especially in the more diverse oriental and northern sectors.     

Bushmeat hunting changes regeneration of African rainforests

To assess ecological consequences of bushmeat hunting in African lowland rainforests, we compared paired sites, with high and low hunting pressure, in three areas of southeastern Nigeria. In hunted sites, populations of important seed dispersers—both small and large primates (including the Cross River gorilla, Gorilla gorilla diehli)—were drastically reduced. Large rodents were more abundant in hunted sites, even though they are hunted. Hunted and protected sites had similar mature tree communities dominated by primate-dispersed species. In protected sites, seedling communities were similar in composition to the mature trees, but in hunted sites species with other dispersal modes dominated among seedlings. Seedlings emerging 1 year after clearing of all vegetation in experimental plots showed a similar pattern to the standing seedlings. This study thus verifies the transforming effects of bushmeat hunting on plant communities of tropical forests and is one of the first studies to do so for the African continent.     

Ungulate relative abundance in hunted and non-hunted sites in Calakmul Forest (Southern Mexico)

The relative abundance of an ungulate community in hunted and non-hunted areas was studied in Calakmul, a tropical forest in southern Mexico that includes a 723,815 ha Biosphere Reserve where no hunting is allowed and communal lands where hunting activity does take place. Tapir, white-lipped peccary (WLP), collared peccary, two species of brocket deer and white-tailed deer were the focal species. Relative abundance of ungulates was obtained by counting tracks along transects in three hunted sites and in the southern core area of the Calakmul Biosphere Reserve, a enforced part of the protected area of 350,000 ha where no hunting has been-permitted since 1989. A total of 1708 ungulates tracks were obtained along 206.1 km (n = 90 transects) divided among the four sites. Relative abundance of the species was estimated from the track encounter rate (TER) calculated as the number of tracks per species encountered per km of transect. No significant differences in brocket deer and collared peccary TER was found among hunted and non-hunted areas. TER for WLP was significant higher in the non-hunted area, while TER for white-tailed deer and tapir was significant higher in hunted sites. Hunting activity affected the ungulate species in Calakmul differently. Brocket deer, white-tailed deer and collared peccary are more resistant species toward the hunting pressure than the WLP, who needs an immediate protection plan throughout Calakmul. Hunting areas are important habitat refuges for tapir populations and they should be protected in these areas.

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Resumen La abundancia relativa de seis especies de ungulados fue obtenida a través de conteos de huellas a lo largo de transectos en tres sitios con cacería y en la parte sur de la Reserva de la Biosfera de Calakmul, una área de alrededor de 350,000 ha donde la cacería ha sido prohibida desde 1989. Tapir, pecarí de labios blancos, pecarí de collar, dos especies de venados temazates y el venado cola blanca fueron las especies estudiadas. Un total de 1708 huellas de ungulados fueron obtenidos a lo largo de 206.1 km (90 transectos) divididos en los cuatro sitios. La abundancia relativa de las especies fue estimada por medio de la tasa de encuentro de huellas (TEH) calculado como el número de huellas encontradas por km de transecto recorrido. La TEH de los venados temazates y el pecarí de collar fue similar entre las áreas con cacería y sin cacería. La TEH para el pecarí de labios blancos fue significativamente mayor en el área sin cacería, mientras que la TEH del venado cola blanca y el tapir fueron significativamente mayor en los sitios con cacería. La actividad de cacería afecta a las especies de ungulados diferente en la región de Calakmul. Los venados temazates, el venado cola blanca y el pecarí de collar están resistiendo mejor la presión de cacería que el pecarí de labios blancos quien necesita un plan inmediato de protección en toda el área. La evidencia sugiere que las áreas con cacería en este estudio son importantes para las poblaciones de tapir, y que se debe prestar atención a su protección en dichas áreas.

     

Demographic Structure of Zanzibar Red Colobus Populations in Unprotected Coral Rag and Mangrove Forests

More than half of the global population of the endangered Zanzibar red colobus (Procolobus kirkii) live outside the single major protected area on Zanzibar Island. We present data on the 2 largest, discrete subpopulations living in unprotected areas at extremes of the species’ range. We compare the size and structure of 11 groups, specifically 6 core groups inhabiting interior, mature forest with 5 peripheral groups living in disturbed/degraded edge habitats. Groups living in southern mangrove forest—a species-poor but more productive and less seasonal habitat than coral rag thicket—had larger group sizes and more heterogeneous age structure, were more stable, and had higher rates of infant survival than did groups in northern coral rag. Group size ranged from 5.5 ± 1.6 SD (the smallest reported for this species) in edge coral rag to 31.2 + 1.9 SD in core mangroves. Edge groups were significantly smaller than core groups in northern coral rag while in the south, where all groups had access to mangroves, we found no significant difference in mean group size between edge and core areas. Groups using mangroves exhibited frequent social play, an indicator of habitat quality, and had a higher ratio of births per female per year. We suggest that mangroves are an important refuge and possibly source habitat for Zanzibar red colobus. We urge the conservation of mangrove and remaining coral rag in the unprotected areas described here in an effort to sustain this endemic species throughout its range.     

Hunting pressure modulates the composition and size structure of terrestrial and arboreal vertebrates in Amazonian forests

Overhunting is a leading contemporary driver of tropical forest wildlife loss. The absence or extremely low densities of large-bodied vertebrates disrupts plant-animal mutualisms and consequently degrades key ecosystem services. Understanding patterns of defaunation is therefore crucial given that most tropical forests worldwide are now “half-empty”. Here we investigate changes in vertebrate community composition and size structure along a gradient of marked anthropogenic hunting pressure in the Médio Juruá region of western Brazilian Amazonia. Using a novel camera trapping grid design deployed both in the understorey and the forest canopy, we estimated the aggregate biomass of several functional groups of terrestrial and arboreal species at 28 sites along the hunting gradient. Generalized linear models (GLMs) identified hunting pressure as the most important driver of aggregate biomass for game, terrestrial, and arboreal species, as well as nocturnal rodents, frugivores, and granivores. Local hunting pressure affected vertebrate community structure as shown by both GLM and ordination analyses. The size structure of vertebrate fauna changed in heavily hunted areas due to population declines in large-bodied species and apparent compensatory increases in nocturnal rodents. Our study shows markedly altered vertebrate community structure even in remote but heavily settled areas of continuous primary forest. Depletion of frugivore and granivore populations, and concomitant density-compensation by seed predators, likely affect forest regeneration in persistently overhunted tropical forests. These findings contribute to a better understanding of how cascading effects induced by historical defaunation operate, informing wildlife management policy in tropical peri-urban, rural and wilderness areas.

     

Mapping Bushmeat Hunting Pressure in Central Africa

Hunting and trade of wild animals for their meat (bushmeat), especially mammals, is commonplace in tropical forests worldwide. In West and Central Africa, bushmeat extraction has increased substantially during recent decades. Currently, such levels of hunting pose a major threat to native wildlife. In this paper, we compiled published data on hunting offtake of mammals, from a number of studies conducted between 1990 and 2007 in Cameroon, Central African Republic, Democratic Republic of Congo, Equatorial Guinea, Gabon, and Republic of Congo. From these data sources, we estimated annual extraction rates of all hunted species and analyzed the relationship between environmental and anthropogenic variables surrounding each hunting rate and levels of bushmeat extraction. We defined hunting pressure as a function of bushmeat offtake and number of hunted species and confirm that hunting pressure is significantly correlated with road density, distance to protected areas and population density. These correlations are then used to map hunting pressure across the Congo Basin. We show that predicted risk areas show a patchy distribution throughout the study region and that many protected areas are located in high‐risk areas. We suggest that such a map can be used to identify areas of greatest impact of hunting to guide large‐scale conservation planning initiatives for central Africa.     

Possible Indirect Effects of Mammal Hunting on Dung Beetle Assemblages in Panama

Hunting often impacts rain forest mammal communities but little is known about its indirect effects on other taxa. We examined dung beetle assemblages using pitfall and flight-intercept traps at six rain forest sites in Panama that ranged in hunting intensity. Heavily hunted sites showed altered community composition, significantly fewer species (based on rarefaction), and lower abundances of dung beetles than did sites with little hunting. Our results suggest that intensive hunting affects nontarget forest taxa and is potentially altering ecosystem functioning.     

Does illegal hunting affect density and behaviour of African grassland birds? A case study on ostrich (Struthio camelus)

Widespread bushmeat hunting represents one of the major threats to many mammals and birds in Africa. We studied the influence of illegal bushmeat hunting on large grassland birds in the Serengeti National Park (SNP) and adjoining protected areas, by using the ostrich (Struthio camelus) as a case study. First, we documented illegal hunting of both small and large birds by using a questionnaire in the villages on the western and eastern side of the SNP. Second, we studied the effect of illegal hunting on density by driving 4,659 km of transects inside SNP and on the adjacent protected areas, where the data were analysed by DISTANCE sampling. Last, we used flight initiation distance (FID, i.e. the distance between an approaching predator (human) and prey when flight is started), to assess possible impacts on behaviour from illegal hunting. We found that people from the western side of the SNP admitted to hunting both small and large grassland birds, and collect ostrich feathers and eggs. Although the Maasai also hunted small birds, only ostrich feathers and eggs of the large grassland birds were used. Surprisingly, we found no significant differences in densities between the SNP and adjoining partially protected areas, but ostriches had longer FID to an approaching human outside the SNP. Currently illegal hunting does not appear to affect the ostrich population, but given the extensive use of birds for consumption more awareness educational programs accompanied by provision of agricultural incentives within the protected areas are needed.     

Comparing data of different survey methods for sustainable wildlife management in hunting areas: the case of Tarangire–Manyara ecosystem,northern Tanzania

Cost–benefit considerations of wildlife monitoring are essential, particularly, in areas outside national park boundaries, where resources for conducting wildlife censuses are scarce, but that, at the same time, are subject to high pressure for wildlife utilization, such as hunting. Large mammal survey data from various sources were collated and analyzed to investigate which methods are best suited for monitoring purposes at low cost in the Tarangire–Manyara ecosystem, northern Tanzania. Our results indicate that primary data (from aerial and road transects counts) that involve direct species observations, although sometimes very expensive, are required for establishing the status of the target species in terms of density or population size. Concomitantly, secondary data from various sources, such as interviews, hunting quota, and damage reports, obtained over wide areas and over longer periods of time, can provide important information on presence/absence and distribution of species within an area. In addition, the study revealed that hunting quotas set did not correlate with species abundance/numbers from the primary data surveys for most of the large mammals hunted within the ecosystem. For a better conservation and management of wildlife, in particular with respect to the forthcoming formation of Wildlife Management Areas, we propose an integrated approach to wildlife monitoring using primary and secondary data sources through the involvement of local people’s knowledge.     

Patterns of climate‐induced density shifts of species: poleward shifts faster in northern boreal birds than in southern birds

Climate change has been shown to cause poleward range shifts of species. These shifts are typically demonstrated using presence–absence data, which can mask the potential changes in the abundance of species. Moreover, changes in the mean centre of weighted density of species are seldom examined, and comparisons between these two methods are even rarer. Here, we studied the change in the mean weighted latitude of density (MWLD) of 94 bird species in Finland, northern Europe, using data covering a north–south gradient of over 1000 km from the 1970s to the 2010s. The MWLD shifted northward on average 1.26 km yr^?1, and this shift was significantly stronger in northern species compared to southern species. These shifts can be related to climate warming during the study period, because the annual temperature had increased more in northern Finland (by 1.7 °C) than in southern Finland (by 1.4 °C), although direct causal links cannot be shown. Density shifts of species distributed over the whole country did not differ from shifts in species situated on the edge of the species range in southern and northern species. This means that density shifts occur both in the core and on the edge of species distribution. The species‐specific comparison of MWLD values with corresponding changes in the mean weighted latitude using presence–absence atlas data (MWL) revealed that the MWLD moved more slowly than the MWL in the atlas data in the southern species examined, but more rapidly in the northern species. Our findings highlight that population densities are also moving rapidly towards the poles and the use of presence–absence data can mask the shift of population densities. We encourage use of abundance data in studies considering the effects of climate change on biodiversity.     

Roadless wilderness area determines forest elephant movements in the Congo Basin

A dramatic expansion of road building is underway in the Congo Basin fuelled by private enterprise, international aid, and government aspirations. Among the great wilderness areas on earth, the Congo Basin is outstanding for its high biodiversity, particularly mobile megafauna including forest elephants (Loxodonta africana cyclotis). The abundance of many mammal species in the Basin increases with distance from roads due to hunting pressure, but the impacts of road proliferation on the movements of individuals are unknown. We investigated the ranging behaviour of forest elephants in relation to roads and roadless wilderness by fitting GPS telemetry collars onto a sample of 28 forest elephants living in six priority conservation areas. We show that the size of roadless wilderness is a strong determinant of home range size in this species. Though our study sites included the largest wilderness areas in central African forests, none of 4 home range metrics we calculated, including core area, tended toward an asymptote with increasing wilderness size, suggesting that uninhibited ranging in forest elephants no longer exists. Furthermore we show that roads outside protected areas which are not protected from hunting are a formidable barrier to movement while roads inside protected areas are not. Only 1 elephant from our sample crossed an unprotected road. During crossings her mean speed increased 14-fold compared to normal movements. Forest elephants are increasingly confined and constrained by roads across the Congo Basin which is reducing effective habitat availability and isolating populations, significantly threatening long term conservation efforts. If the current road development trajectory continues, forest wildernesses and the forest elephants they contain will collapse.