Tropical drylands are characterized by extreme environmental conditions that, coupled with anthropogenic habitat degradation, can limit the occurrence of native species. Species that are most sensitive to these pressures may be prone to disappear in the context of climate change. In this study, we evaluated the influence of environmental and anthropogenic variables on the occurrence of large mammals and birds at the Tatacoa Desert, an arid region in central Colombia. We tested the relationship between the magnitude of the species’ responses to environmental, human-related variables and to body mass, and percentage of carnivory. Overall, we found a positive association between forest cover and the occupancy of the largest mammals (> 8kg), negative associations between solar radiation and human footprint with individual species occupancy, and a positive association of species occupancy with distance to touristic sites. Our results suggest that the largest and/or more carnivore species may be affected positively by forest cover and negatively by intense solar radiation highlighting the consequences of the increasing process of desertification on large mammals and birds at the upper Magdalena River basin of Colombia under the current scenario of global climate change.

In this study we provide the first comprehensive camera-trap assessment of terrestrial mammals in the Yangambi landscape, comprising the Yangambi Biosphere Reserve and a logging concession in the Democratic Republic of the Congo. The terrestrial mammal community in this area exhibits lower occupancy and species richness compared to other conservation areas in the Congo Basin. The community is dominated by four species: Emin's pouched rat Cricetomys emini (1.3 kg), African brush-tailed porcupine Atherurus africanus (2.8 kg), blue duiker Philantomba monticola (5 kg) and bay duiker Cephalophus dorsalis (12 kg), which are known to be highly resilient. Large ungulates and medium-sized carnivores have particularly low abundances. Our study also confirmed the presence of four species categorized as threatened on the IUCN Red List: the chimpanzee Pan troglodytes, giant ground pangolin Smutsia gigantea, black-bellied pangolin Phataginus tetradactyla and white-bellied pangolin Phataginus tricuspis. Our findings highlight the need to consider wildlife conservation at the landscape level, including the logging concession, where species showed higher occupancy levels compared to the Biosphere Reserve, and highlighting the need for planning infrastructure construction and developing mitigation schemes, reducing forest degradation from logging and developing permanent cash crop agriculture. Landscape-level conservation will only be possible if a collaborative management model steered by local communities is developed with the participation of all constituencies.

The IUCN now recognizes the savannah Loxodonta africana and forest Loxodonta cyclotis elephants to be separate species. Despite ecological, behavioural and morphological differences, and different habitat ranges, genetic studies confirm that the two species and hybrids coexist in forest–savannah ecotones. However, the hybrid phenotypes have not yet been described. In this survey we examined whether the phenotypes of the two species and of hybrids can be distinguished. In the first step, we used a machine learning algorithm (K-nearest neighbours) to compare 296 reference images of African elephants from five forest areas and six savannah areas where hybrids have not been recorded, confirming that six morphological criteria can be used to distinguish the species with more than 90% confidence. In the second step, we analysed 1,408 videos of elephants from 14 camera traps in Sebitoli, in Kibale National Park, Uganda, part of the main hybridization area. We used a multiple correspondence analysis and a species assignment key, highlighting the presence of three categories of phenotypes. Compared to the savannah and forest phenotypes (36.8 and 12.1%, respectively), the intermediate phenotypes, which could include hybrids, were more frequent (51.1%). Further studies combining morphology and genetics of the same individuals will be necessary to refine this species assignment key to characterize phenotypes confidently. This non-invasive, fast and inexpensive phenotypical-based method could be a valuable tool for conservation programmes.

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.

The introduction of mammal predators has been a major cause of species extinctions on oceanic islands. Eradication is only possible or cost-effective at early stages of invasion, before introduced species become abundant and widespread. Although prevention, early detection and rapid response are the best management strategies, most oceanic islands lack systems for detecting, responding to and monitoring introduced species. Wildlife managers require reliable information on introduced species to guide, assess and adjust management actions. Thus, a large-scale and long-term monitoring programme is needed to evaluate the management of introduced species and the protection of native wildlife. Here, we evaluate camera trapping as a survey technique for detecting and monitoring introduced small and medium-sized terrestrial mammals on an oceanic island, Terceira (Azores). Producing an inventory of introduced mammals on this island required a sampling effort of 465 camera-trap days and cost EUR 2,133. We estimated abundance and population trends by using photographic capture rates as a population index. We also used presence/absence data from camera-trap surveys to calculate detection probability, estimated occupancy rate and the sampling effort needed to determine species absence. Although camera trapping requires large initial funding, this is offset by the relatively low effort for fieldwork. Our findings demonstrate that camera trapping is an efficient survey technique for detecting and monitoring introduced species on oceanic islands. We conclude by proposing guidelines for designing monitoring programmes for introduced species.

The Sulawesi civet Macrogalidia musschenbroekii is endemic to the Indonesian island of Sulawesi, where it is the largest mammalian predator. Limited field data means that little is known about the species’ distribution, habitat preferences, conservation status and needs, but it is believed to depend on primary forest. We conducted camera-trap surveys across the forests of North Sulawesi, including in two of its main protected areas: Bogani Nani Wartabone National Park and Tangkoko Nature Reserve. From 148 camera trap stations and 10,371 trap nights, Sulawesi civets were recorded 17 times at 12 stations, and in almost equal numbers in primary forest, secondary forest and farmland, including the first photographic records from both the National Park and Nature Reserve. We also collected data on the Malay civet Viverra tangalunga, an introduced species of Viverridae and potential competitor. Our records (n = 21) revealed that it is established in secondary forest; it only co-occurred twice with the Sulawesi civet. With a lapse of > 20 years since the last field record of the Sulawesi civet, our findings offer new insight into its status and new enthusiasm within the provincial government for its conservation, which has led to an extension of camera-trap research into neighbouring Gorontalo province.

The random encounter model, a method for estimating animal density using camera traps without the need for individual recognition, has been developed over the past decade. A key assumption of this model is that cameras are placed randomly in relation to animal movements, requiring that cameras are not set only at sites thought to have high animal traffic. The aim of this study was to define a correction factor that allows the random encounter model to be applied in photo-trapping surveys in which cameras are placed along tracks to maximize capture probability. Our hypothesis was that applying such a correction factor would compensate for the different rates at which lynxes use tracks and the surrounding area, and should thus improve the estimates obtained with the random encounter model. We tested this using data from a well-known Iberian lynx Lynx pardinus population. Firstly, we estimated Iberian lynx densities using a traditional camera-trapping design followed by spatially explicit capture–recapture analyses. We estimated the differential use rate for tracks vs the surrounding area using data from a lynx equipped with a GPS collar, and subsequently calculated the correction factor. As expected, the random encounter model overestimated densities by 378%. However, the application of the correction factor improved the estimate and reduced the error to 16%. Although there are limitations to the application of the correction factor, the corrected random encounter model shows potential for density estimation of species for which individual identification is not possible.

Despite the efforts invested in their conservation, the status of many threatened carnivores in key conservation landscapes remains unknown. The dhole Cuon alpinus is an Endangered social carnivore whose geographical range has contracted by c. 80% since the early 20th century. North-east India is a critical link between South Asian and South-east Asian dhole populations. In this study we compiled presence records of dholes across north-east India, from multiple sources. We also conducted camera-trap surveys in one part of this region, Dampa Tiger Reserve in the state of Mizoram. We examined the influence of ecological and management factors on fine-scale site-use by dholes in Dampa Tiger Reserve, showing a positive association of dhole site-use with sambar Rusa unicolor encounters, distance to the forest boundary and presence of forest department personnel, underscoring the importance of prey and protection. Our findings also highlight the need for targeted, multi-scale assessments of dhole ecology across other sites in north-east India.

Wildlife is an essential component of all ecosystems. Most places in the globe do not have local, timely information on which species are present or how their populations are changing. With the arrival of new technologies, camera traps have become a popular way to collect wildlife data. However, data collection has increased at a much faster rate than the development of tools to manage, process and analyse these data. Without these tools, wildlife managers and other stakeholders have little information to effectively manage, understand and monitor wildlife populations. We identify four barriers that are hindering the widespread use of camera trap data for conservation. We propose specific solutions to remove these barriers integrated in a modern technology platform called Wildlife Insights. We present an architecture for this platform and describe its main components. We recognize and discuss the potential risks of publishing shared biodiversity data and a framework to mitigate those risks. Finally, we discuss a strategy to ensure platforms like Wildlife Insights are sustainable and have an enduring impact on the conservation of wildlife.

The Cerros del Sira in Peru is known to hold a diverse composition of endemic birds, amphibians and plants as a result of its geographical isolation, yet its mammalian community remains poorly known. There is increasing awareness of the threats to high-elevation species but studying them is often hindered by rugged terrain. We present the first camera-trap study of the mammal community of the Cerros del Sira. We used 45 camera traps placed at regular elevational intervals over 800–1,920 m, detecting 34 medium-sized and large mammal species. Eight are listed as threatened on the IUCN Red List, three are categorized as Data Deficient and one is yet to be assessed. Although other authors have reported that the upper elevations of the Cerros del Sira are free from hunting, we found evidence of hunting activity occurring above 1,400 m, and inside the core protected area. In addition to this direct evidence of hunting, recent information has identified significant amounts of canopy loss in the northern reaches of the core zone. Despite widespread ecological degradation in the surrounding lowlands, the high-elevation areas of the Cerros del Sira still maintain a unique assemblage of lowland and highland tropical rainforest mammals. It has been assumed that the Cerros del Sira and other similar remote locations are safe from disturbance and protected by their isolation but we suggest this is an increasingly dangerous assumption to make, and secure protection strategies need to be developed.

Deciduous dipterocarp forests throughout Asia provide crucial habitat for several globally threatened species. During the dry season water availability in these forests is primarily limited to perennial rivers and waterholes. Such water sources form an essential part of these dry forests and are used by multiple species, including large mammals and birds, but little is known regarding how waterhole characteristics affect wildlife use. We investigated waterhole utilization by six globally threatened dry forest specialists: banteng Bos javanicus, Eld's deer Rucervus eldii, giant ibis Thaumatibis gigantea, green peafowl Pavo muticus, lesser adjutant Leptoptilos javanicus and Asian woolly-necked stork Ciconia episcopus. We camera-trapped 54 waterholes in Srepok Wildlife Sanctuary, eastern Cambodia, during the dry season of December 2015–June 2016. We measured nine waterhole and landscape characteristics, including indicators of human disturbance. Waterhole depth (measured every 2 weeks) and the area of water at the start of the dry season were the main environmental factors influencing waterhole use. Additionally, waterholes further from villages were more frequently used than those nearer. Our study reaffirmed the importance of waterholes in supporting globally threatened species, especially large grazers, which are critical for maintaining these dry forest ecosystems. The results also suggested that artificially enlarging and deepening selected waterholes, particularly those further from human disturbance, could enhance available habitat for a range of species, including grazers. However, this would need to be conducted in coordination with patrolling activities to ensure waterholes are not targets for illegal hunting, which is a problem throughout South-east Asian protected areas.

Transfrontier wildlife corridors can be successful conservation tools, connecting protected areas and reducing the impact of habitat fragmentation on mobile species. Urban wildlife corridors have been proposed as a potential mitigation tool to facilitate the passage of elephants through towns without causing conflict with urban communities. However, because such corridors are typically narrow and close to human development, wildlife (particularly large mammals) may be less likely to use them. We used remote-sensor camera traps and global positioning system collars to identify the movement patterns of African elephants Loxondonta africana through narrow, urban corridors in Botswana. The corridors were in three types of human-dominated land-use designations with varying levels of human activity: agricultural, industrial and open-space recreational land. We found that elephants used the corridors within all three land-use designations and we identified, using a model selection approach, that season, time of day and rainfall were important factors in determining the presence of elephants in the corridors. Elephants moved more slowly through the narrow corridors compared with their movement patterns through broader, wide-ranging corridors. Our results indicate that urban wildlife corridors are useful for facilitating elephants to pass through urban areas.

Rigorous population studies on many small carnivores are lacking in India. Presence-absence models with habitat covariates were applied to estimate seasonal occupancy and abundance of nine small-carnivore species from camera-trap data in Mudumalai Tiger Reserve (2010 and 2011). We deployed 25 camera-trap stations in the deciduous forest, 21 in the semi-evergreen forest and 26 in the dry thorn forest. In total, 7380 trap-nights yielded 448 photographs of small carnivores: jungle cat (n = 72), leopard cat (n = 6), rusty-spotted cat (n = 11), small Indian civet (n = 89), common palm civet (n = 37), brown palm civet (n = 20), stripe-necked mongoose (n = 66), ruddy mongoose (n = 96) and Indian grey mongoose (n = 51). In the dry season, rusty-spotted cat was the rarest carnivore with an average abundance (λmean) of 0.24 ± 0.26, while ruddy mongoose was the most abundant (λmean = 0.90 ± 0.40). In the wet season, leopard cat was the rarest species (λmean = 0.048 ± 0.041) while grey mongoose was the most abundant (λmean = 0.68 ± 0.35). Abundance of jungle cat, common palm civet, ruddy mongoose and grey mongoose increased in the dry thorn forest whereas in the dry season abundance of small Indian civet decreased in this forest type. Abundance of leopard cat and small Indian civet was not influenced by habitat in the wet season. Deciduous forest was positively associated with abundance of rusty-spotted cat. Deciduous and semi-evergreen forests had a positive effect on abundance of stripe-necked mongoose while the latter was a positive predictor of abundance and occupancy for brown palm civet. Improved modelling approaches can account for the spatio-temporal variation in habitat use of small carnivores occupying specialized niches in heterogeneous tropical forests of southern India.

Baird's tapir Tapirus bairdii is categorized as Endangered on the IUCN Red List and is considered rare and locally extirpated from most of its historic range in Costa Rica. We conducted camera-trap and track surveys at 38 forested sites in and around the San Juan–La Selva Biological Corridor in the Northern Zone of Costa Rica. Cameras were set along established game trails and natural funnels and operated for 14–38 days per site. Additionally, we documented tapir tracks at many sites. We used survey photographs and track presence to create detection histories to estimate the habitat and survey-specific variables that influence the probability of detection and the probability of occurrence of Baird's tapir. The two major protected areas within and adjacent to the corridor were most positively associated with tapir occurrence, and forest cover and native and exotic tree plantations were also positively associated with tapirs’ use of sites. Although the Baird's tapir is rare, our findings suggest that it is more resilient and better able to use available habitat in the fragmented corridor than previously thought. This is most likely a consequence of increased forest cover from reforestation and tree plantations and limited hunting pressure. Given its charismatic nature we recommend that Baird's tapir could be used as a flagship species for the San Juan–La Selva Biological Corridor, to raise local awareness about conservation and increase economic growth from ecotourism.

The Amazonian moist forest, which covers most of French Guiana, is one of the core habitats for the lowland tapir Tapirus terrestris. Tapirs are hunted in French Guiana, although a law introduced in 2011 restricts hunting to one animal per person per hunting trip. We carried out camera-trap surveys in the Nouragues Nature Reserve for 4 years, with the goal of estimating tapir densities in undisturbed conditions and determining sustainable harvest levels for tapirs in French Guiana. We analysed our data with a Bayesian spatially explicit capture–recapture model, with parameter sharing across surveys to improve estimates, and used the model to calculate derived parameters such as maximum sustainable harvest levels. Density estimates for all four surveys were similar and the model indicated a difference in encounter rates for the two camera models used but no difference in encounter rates or home range sizes for males and females or between years. Based on the calculated density of 0.32 tapir km−2 we estimated sustainable harvest levels at 0.009 tapir km−2. Comparing this value to hunting surveys from 11 sites between 1999 and 2006, we found that hunting levels were unsustainable in at least seven villages. We conclude that even the new restrictive hunting law will not prevent overhunting of tapirs in certain areas and thus stronger regulations are needed. However, because of the remoteness of tapir habitat in many parts of French Guiana tapirs are not immediately threatened in the country as a whole.

Methods that accurately estimate animal abundance or density are crucial for wildlife management. Although numerous techniques are available, there have been few comparisons of the precision and cost-effectiveness of different approaches. We assess the precision and cost of three methods for estimating densities of the Endangered Grevy's zebra Equus grevyi. We compare distance sampling and photographic capture–recapture, and a new technique, the random encounter model (REM) that uses camera-trap encounter rates to estimate density. All three methods provide comparable density estimates for Grevy's zebra and are preferable to the common practice of raw counts. Photographic capture–recapture is the most precise and line-transect distance sampling the least precise. Line transects and photographic capture–recapture surveys are cost-effective in the first year and REM is most cost-effective in the long-term. The methods used here for Grevy's zebra may be applied to other rangeland ungulates. We suggest that for single species monitoring programmes in which individuals can be identified, photographic capture–recapture surveys may be the preferred method for estimating wildlife abundances. When encounter rates are low, distance sampling lacks the precision of the other methods but its cost advantage may make it appropriate for long-term or multi-species monitoring programmes. The REM is an efficient and precise method of estimating densities but has high initial equipment costs. We believe REM has the potential to work well for many species but it requires independent estimates of animal movements and group size.

To prevent seed losses from predation, plants have developed protective strategies. Seeds may utilize chemical or structural defences to deter predators. Mucuna holtonii (Fabaceae) has large seeds containing a toxic amino acid, L-dopa, and covered with a hard seed coat. Our study assessed the effectiveness of chemical and mechanical seed defences against vertebrate and invertebrate seed predators within Estación Biológica La Selva, Costa Rica. Pre-dispersal insect and fungus attack of M. holtonii seeds was low (95.7% of 1493 seeds were undamaged). Camera traps monitoring 90 marked M. holtonii seeds showed that the collared peccary (Pecari tajacu) consumed 98.6% of 69 removed seeds over 16 d. Field experiments involving 100 seeds with intact and 100 with opened seed coats found that only opened seeds had endosperm removed by Sericomyrmex amabilis ants (0.5–100% of endosperm removed). Shade-house experiments showed that seeds with high amounts of endosperm removed by ants resulted in low germination success and low seedling biomass production. Although M. holtonii seeds are rich in L-dopa, this compound is not an effective chemical defence against mammals that possess foregut fermentation. The seed coat of M. holtonii is an effective structural defence against invertebrate seed predators, preventing endosperm removal and enhancing seedling survival.

We studied the habitat use, activity patterns and use of mineral licks by five species of Amazonian ungulate using data from four 60-d camera trap surveys at two different sites in the lowland rain forest of Madre de Dios, Peru. Camera traps were set out in two regular grids with 40 and 43 camera stations covering an area of 50 and 65 km2, as well as at five mineral licks. Using occupancy analysis we tested the hypothesis that species are spatially separated. The results showed that the grey brocket deer (Mazama gouazoubira) occurred almost exclusively in terra firme forests, and that the white-lipped peccary (Tayassu pecari) used floodplain forest more frequently during some surveys. All other species showed no habitat preference and we did not find any spatial avoidance of species. The white-lipped peccary, the collared peccary (Pecari tajacu) as well as the grey brocket deer were strictly diurnal while the lowland tapir (Tapirus terrestris) was nocturnal. The red brocket deer (Mazama americana) was active day and night. The tapir was the species with the highest number of visits to mineral licks (average 52.8 visits per 100 d) followed by the white-lipped peccary (average 16.1 visits per 100 d) and the red brocket deer (average 17.1 visits per 100 d). The collared peccary was only recorded on three occasions and the grey brocket deer was never seen at a lick. Our results suggest that resource partitioning takes place mainly at the diet level and less at a spatial level; however, differences in small-scale habitat use are still possible.

We used capture-recapture analyses to estimate the density of a tiger Panthera tigris population in the tropical forests of Huai Kha Khaeng Wildlife Sanctuary, Thailand, from photographic capture histories of 15 distinct individuals. The closure test results (z = 0.39, P = 0.65) provided some evidence in support of the demographic closure assumption. Fit of eight plausible closed models to the data indicated more support for model Mh, which incorporates individual heterogeneity in capture probabilities. This model generated an average capture probability = 0.42 and an abundance estimate of = 19 (9.65) tigers. The sampled area of = 477.2 (58.24) km2 yielded a density estimate of = 3.98 (0.51) tigers per 100 km2. Huai Kha Khaeng Wildlife Sanctuary could therefore hold 113 tigers and the entire Western Forest Complex c. 720 tigers. Although based on field protocols that constrained us to use sub-optimal analyses, this estimated tiger density is comparable to tiger densities in Indian reserves that support moderate prey abundances. However, tiger densities in well-protected Indian reserves with high prey abundances are three times higher. If given adequate protection we believe that the Western Forest Complex of Thailand could potentially harbour >2,000 wild tigers, highlighting its importance for global tiger conservation. The monitoring approaches we recommend here would be useful for managing this tiger population.

We used remote cameras to obtain information on an elusive species and to examine the effects of different camera trapping methodologies on abundance estimates. We determined activity pattern, trail use, trap success, and density of ocelot Leopardus pardalis in seven camera-trap surveys across two habitat types in western Belize: tropical broad-leaf rainforest and tropical pine forest. Ocelots in the rainforest were active mostly at night, in particular immediately after sunset, and they travelled on low-use roads (especially in the wet season) and high-use roads (especially in the dry season) more than established and newly cut trails. Trap success was relatively high in the rainforest (2.11–6.20 captures per 100 trap nights) and low in the pine forest (0.13–0.15 captures per 100 trap nights). Camera trapping combined with mark-recapture statistics gave densities of 25.82–25.88 per 100 km2 in the broad-leaf versus 2.31–3.80 per 100 km2 in the pine forest. Density estimates increased when animals repeatedly captured at the same camera (zero-distance moved animals) were included in the buffer size analysis. Density estimates were significantly negatively correlated with distance between cameras. We provide information on ocelot population status from an unstudied portion of its range and advise that camera trap methodologies be standardized to permit comparisons across sites.