Pangolins in global camera trap data: Implications for ecological monitoring

A comparison of the sampling effectiveness of acoustic recorder, camera trap and point count methods in sampling nocturnal birds in Afrotropical landscapes

Conservation decisions for bird diversity in the Afrotropics are often based on ecological studies utilizing diurnal bird species likely owing to difficulties associated with sampling nocturnal birds. It is therefore important to compare the sampling effectiveness of some of the available techniques that can be used in nocturnal bird surveys to guide future long-term survey efforts. Thus, we compared the sampling effectiveness of point count, acoustic recorder and camera trap for estimating nocturnal bird species richness and also across habitat types. We surveyed 20 points that were spaced at least 500 m apart in November and December 2021 in the Amurum Forest Reserve and its surroundings in Jos-Nigeria. At each point, we used two camera traps, one at the ground and the other at 2.0 m. We also used one acoustic recorder as well as a 15-min point count during each survey at each point. We encountered 11 nocturnal bird species, primarily nightjars but also owls. While we did not encounter any species with the camera traps, all 11 species were recorded using the acoustic recorder. All species except for Ketupa lacteaus were recorded in point count. Eight species were recorded in the gallery, seven in rocky and nine in savannah. Species richness and estimation using the acoustic recorder and point count were similar across habitat types. We conclude that either point count or acoustic recorders are useful for nocturnal bird surveys in Afrotropical environments. However, the choice of methods should be based on the research questions as some questions may be better answered by a specific method or even a combination of both.

Monitoring Endangered and Rare Wildlife in the Field: A Foundation Deep Learning Model Integrating Human Knowledge for Incremental Recognition with Few Data and Low Cost

Intelligent monitoring of endangered and rare wildlife is important for biodiversity conservation. In practical monitoring, few animal data are available to train recognition algorithms. The system must, therefore, achieve high accuracy with limited resources. Simultaneously, zoologists expect the system to be able to discover unknown species to make significant discoveries. To date, none of the current algorithms have these abilities. Therefore, this paper proposed a KI-CLIP method. Firstly, by first introducing CLIP, a foundation deep learning model that has not yet been applied in animal fields, the powerful recognition capability with few training resources is exploited with an additional shallow network. Secondly, inspired by the single-image recognition abilities of zoologists, we incorporate easily accessible expert description texts to improve performance with few samples. Finally, a simple incremental learning module is designed to detect unknown species. We conducted extensive comparative experiments, ablation experiments, and case studies on 12 datasets containing real data. The results validate the effectiveness of KI-CLIP, which can be trained on multiple real scenarios in seconds, achieving in our study over 90% recognition accuracy with only 8 training samples, and over 97% with 16 training samples. In conclusion, KI-CLIP is suitable for practical animal monitoring.

Extending the conservation impact of great ape research: Flagship species sites facilitate biodiversity assessments and land preservation

To inform regional conservation planning, we assessed mammalian and avian biodiversity in the Djéké Triangle, which is an intact forest with long-term research and tourism focused on western lowland gorillas (Gorilla gorilla gorilla). This critical region serves as a conservation conduit between the Nouabalé-Ndoki National Park (NNNP) in the Republic of Congo and the Dzanga-Ndoki National Park in Central African Republic. Wildlife inventories were conducted to determine if biodiversity in the Djéké Triangle (initially part of a logging concession) was equivalent to the NNNP. Camera traps (CTs) were deployed to estimate species richness, relative abundance, naïve occupancy, and activity patterns of medium-to-large species in mixed species and monodominant Gilbertiodendron forests that comprise the majority of regional terra firma. Species inventories were collected from CTs positioned on a grid and at termite nests throughout the Djéké Triangle and compared to CTs placed in the Goualougo Triangle located within the NNNP. From 10,534 camera days at 65 locations, we identified 34 mammal and 16 bird species. Allaying concerns of wildlife depletion, metrics of species richness in the Djéké Triangle surpassed those of the Goualougo Triangle. Many species were observed to occur across habitats, while others showed habitat specificity, with termite mounds indicated as an important microhabitat feature. Our comparisons of animal activity budgets in different habitat types provide important reference information for other populations and contexts. In conclusion, this study provided empirical evidence of the high conservation value of this region that contributed to increasing the protected status of the Djéké Triangle.

Mammalian predator and prey responses to recreation and land use across multiple scales provide limited support for the human shield hypothesis

Outdoor recreation is widespread, with uncertain effects on wildlife. The human shield hypothesis (HSH) suggests that recreation could have differential effects on predators and prey, with predator avoidance of humans creating a spatial refuge 'shielding' prey from people. The generality of the HSH remains to be tested across larger scales, wherein human shielding may prove generalizable, or diminish with variability in ecological contexts. We combined data from 446 camera traps and 79,279 sampling days across 10 landscapes spanning 15,840 km2 in western Canada. We used hierarchical models to quantify the influence of recreation and landscape disturbance (roads, logging) on ungulate prey (moose, mule deer and elk) and carnivore (wolf, grizzly bear, cougar and black bear) site use. We found limited support for the HSH and strong responses to recreation at local but not larger spatial scales. Only mule deer showed positive but weak landscape-level responses to recreation. Elk were positively associated with local recreation while moose and mule deer responses were negative, contrary to HSH predictions. Mule deer showed a more complex interaction between recreation and land-use disturbance, with more negative responses to recreation at lower road density or higher logged areas. Contrary to HSH predictions, carnivores did not avoid recreation and grizzly bear site use was positively associated. We also tested the effects of roads and logging on temporal activity overlap between mule deer and recreation, expecting deer to minimize interaction with humans by partitioning time in areas subject to more habitat disturbance. However, temporal overlap between people and deer increased with road density. Our findings highlight the complex ecological patterns that emerge at macroecological scales. There is a need for expanded monitoring of human and wildlife use of recreation areas, particularly multi-scale and -species approaches to studying the interacting effects of recreation and land-use change on wildlife.

Camera trapping expands the view into global biodiversity and its change

Growing threats to biodiversity demand timely, detailed information on species occurrence, diversity and abundance at large scales. Camera traps (CTs), combined with computer vision models, provide an efficient method to survey species of certain taxa with high spatio-temporal resolution. We test the potential of CTs to close biodiversity knowledge gaps by comparing CT records of terrestrial mammals and birds from the recently released Wildlife Insights platform to publicly available occurrences from many observation types in the Global Biodiversity Information Facility. In locations with CTs, we found they sampled a greater number of days (mean = 133 versus 57 days) and documented additional species (mean increase of 1% of expected mammals). For species with CT data, we found CTs provided novel documentation of their ranges (93% of mammals and 48% of birds). Countries with the largest boost in data coverage were in the historically underrepresented southern hemisphere. Although embargoes increase data providers' willingness to share data, they cause a lag in data availability. Our work shows that the continued collection and mobilization of CT data, especially when combined with data sharing that supports attribution and privacy, has the potential to offer a critical lens into biodiversity. This article is part of the theme issue 'Detecting and attributing the causes of biodiversity change: needs, gaps and solutions'.

Adapting camera-trap placement based on animal behavior for rapid detection: A focus on the Endangered, white-bellied pangolin (Phataginus tricuspis)

Pangolin species are notoriously difficult to detect and monitor in the wild and, as a result, commonly used survey techniques fall short in gathering sufficient data to draw confident conclusions on pangolin populations, conservation status, and natural history. The white-bellied pangolin is a semiarboreal species that may be poorly detected in general mammal surveys even with modern techniques such as camera-trapping. As a result, population status information is often derived from hunting, market, and trafficking data. There is therefore a crucial need to improve camera-trap survey methods to reliably detect this species in its natural environment. Here, we test the influence of camera-trap placement strategy on the detectability of the white-bellied pangolin by comparing estimates from targeted ground-viewing camera-trapping and a novel log-viewing placement strategy adapted from local hunters' knowledge. Our results suggest that (1) deploying camera-traps to detect animals walking along logs is an effective strategy for recording several forest species, including the white-bellied pangolin, and (2) that camera-traps targeting logs are more efficient at detecting white-bellied pangolins than camera-traps viewing the ground (>100% increase in detection probability). We also found moderate evidence that there is a relationship between the white-bellied pangolin occurrence at our locality and elevation and weak evidence of an association with distance to the nearest river. Our results suggest an effective new monitoring approach allowing consistent detection of the white-bellied pangolin with moderate survey effort. This highlights the importance of harnessing local knowledge to guide the design of monitoring protocols for cryptic species.

Pangolin hunting and trafficking in the forest–savannah transition area of Cameroon

Pangolins have long been hunted for food and for their scales, but information on local hunting strategies in African range countries and the patterns of pangolin trafficking around sourcing areas is limited. Such knowledge is vital to inform monitoring approaches and conservation interventions. We administered questionnaires to 367 people from 20 villages around two national parks in Cameroon to gain insights into local hunting practices, and trading and trafficking patterns. We found that tracking was the preferred method of hunting pangolins. Trapping was also used, and setting traps on fallen logs and near burrows improved the likelihood of catching pangolins. The white-bellied pangolin Phataginus tricuspis was the most traded species, and the giant pangolin Smutsia gigantea was the most sought after. We found no evidence of trade in the black-bellied pangolin Phataginus tetradactyla. Most respondents stated that pangolin prices had increased over the last 5 years, and scarcity of pangolins was the primary reason given for this increase. We identified a pangolin scale trafficking network operating from rural communities to neighbouring cities. Although most respondents recognized that hunting pangolins is illegal, c. 30% indicated that they were engaged in pangolin hunting.

Targeting burrows improves detection in giant pangolin Smutsia gigantea camera-trap surveys

The Endangered giant pangolin Smutsia gigantea is rare and elusive across its Central African range. Because of its solitary and nocturnal nature, the species is difficult to study and so its ecology is little known. Pangolins are considered the most trafficked mammals in the world. Therefore, confirming presence accurately and monitoring trends in distribution and abundance are essential to inform and prioritize conservation efforts. Camera traps are popular tools for surveying rare and cryptic species. However, non-targeted camera-trap surveys yield low camera-trapping rates for pangolins. Here we use camera-trap data from surveys conducted within three protected areas in Uganda to test whether targeted placement of cameras improves giant pangolin detection probability in occupancy models. The results indicate that giant pangolin detection probability is highest when camera traps are targeted on burrows. The median number of days from camera deployment to first giant pangolin detection event was 12, with the majority of events captured within 32 days from deployment. The median interval between giant pangolin events at a camera-trap site was 33 days. We demonstrate that camera-trap surveys can be designed to improve the detection of giant pangolins and we outline a set of recommendations to maximize the effectiveness of efforts to survey and monitor the species.

Giant pangolin and white-bellied pangolin observations from a World Heritage site

Pangolins are one of the most threatened mammal groups, as a result of habitat loss and exploitation for their meat, scales, and other body parts. However, there is a lack of quantitative data on pangolin populations; their behaviour and ecology make them challenging to survey. We undertook systematic camera-trap surveys of the 5260 km2 World Heritage Dja Faunal Reserve, Cameroon, sampling 305 sites in eight grids over 28,277 camera-trap days. We recorded 768 images of giant pangolin in 99 independent detections at 57 sites (RAI = 0.35), and 2282 images in 355 detections (RAI = 1.26) of white-bellied pangolin at 137 sites. Ground-dwelling giant pangolins were largely confined to the core of the Reserve. Semi-arboreal white-bellied pangolins were predominantly distributed in the northeast, east and south of the Reserve. Lower occupancy in the west and northwest could partly be due to pressures from human settlements around the Hydromekin Dam and Sud-Cameroun Hévéa rubber plantation. Our study suggests that at the ground-level the two species do not spatially segregate, and both were active throughout the night. We found high diel activity overlap, although there was a significant difference in activity peak times. There was also evidence of white-bellied pangolin possibly exhibiting fine-scale behavioural avoidance of giant pangolin.

Camera trap data reveal the habitat associations, activity patterns and population density of Indian pangolin (Manis crassicaudata) in Maduru Oya National Park, Sri Lanka

The Indian pangolin (Manis crassicaudata) is a solitary, medium–sized mammal native to South Asia. In this study we used camera trap data recorded during a meso–mammal survey conducted from January 2019 to January 2021 to assess the occupancy, habitat associations, population density and activity patterns of Indian pangolins in Maduru Oya National Park (MONP), Sri Lanka. The preferred habitat of the species was dry–mixed forest with an occupancy probability of 0.42 ± 0.19. Occupancy modeling revealed the association of the species with the forested habitats of the park with rich canopy cover, high NDVI scores and abundant termite mounds. Activity of this pangolin was highly nocturnal, reaching a peak after midnight. We observed a considerable spatiotemporal overlap in Indian pangolin activity and human activity, possibly increasing hunting pressure on the species. We estimated occupancy and abundance–based population density (0.73 ± 0.21 indiv./km2) using the random encounter model for the first time in the study area. These findings could be useful for conservation and management decisions concerning the survival and vital habitats of one of the most trafficked mammals in the world, the Indian pangolin.

Biological richness of Gunung Slamet, Central Java, and the need for its protection

Designating protected areas remains a core strategy in biodiversity conservation. Despite high endemism, montane forests across the island of Java are under-represented in Indonesia's protected area network. Here, we document the montane biodiversity of Gunung Slamet, an isolated volcano in Central Java, and provide evidence to support its increased protection. During September–December 2018, we surveyed multiple sites for birds, primates, terrestrial mammals, reptiles, amphibians and vegetation. Survey methods included transects, camera traps and targeted searches at six sites, at altitudes of 970–2,512 m. We used species distribution models for birds and mammals of conservation concern to identify priority areas for protection. We recorded 99 bird species (13 globally threatened), 15 mammals (five globally threatened) and 17 reptiles and amphibians (two endemic). Our species distribution models showed considerable cross-taxon congruence between important areas on Slamet's upper slopes, generally above 1,800 m. Particularly important were records of the endemic subspecies of the Endangered Javan laughingthrush Garrulax rufifrons slamatensis, not recorded in the wild since 1925, the Endangered Javan gibbon Hylobates moloch and Javan surili Presbytis comata, and the Vulnerable Javan lutung Trachypithecus auratus and Javan leopard Panthera pardus melas. Recent forest loss has been modest, at least 280 km2 of continuous forest remain above 800 m, and our surveys show that forest habitats are in good condition. However, the mountain is widely used by trappers and hunters. Given its importance for biodiversity conservation, we discuss different options for improving the protection status of Gunung Slamet, including designation as a National Park or Essential Ecosystem.

Methods for Monitoring Large Terrestrial Animals in the Wild

Reliable information about wildlife is absolutely important for making informed management decisions. The issues with the effectiveness of the control and monitoring of both large and small wild animals are relevant to assess and protect the world’s biodiversity. Monitoring becomes part of the methods in wildlife ecology for observation, assessment, and forecasting of the human environment. World practice reveals the potential of the joint application of both proven traditional and modern technologies using specialized equipment to organize environmental control and management processes. Monitoring large terrestrial animals require an individual approach due to their low density and larger habitat. Elk/moose are such animals. This work aims to evaluate the methods for monitoring large wild animals, suitable for controlling the number of elk/moose in the framework of nature conservation activities. Using different models allows determining the population size without affecting the animals and without significant financial costs. Although, the accuracy of each model is determined by its postulates implementation and initial conditions that need statistical data. Depending on the geographical, climatic, and economic conditions in each territory, it is possible to use different tools and equipment (e.g., cameras, GPS sensors, and unmanned aerial vehicles), a flexible variation of which will allow reaching the golden mean between the desires and capabilities of researchers.

Effects of scent lure on camera trap detections vary across mammalian predator and prey species

Camera traps are a unique survey tool used to monitor a wide variety of mammal species. Camera trap (CT) data can be used to estimate animal distribution, density, and behaviour. Attractants, such as scent lures, are often used in an effort to increase CT detections; however, the degree which the effects of attractants vary across species is not well understood. We investigated the effects of scent lure on mammal detections by comparing detection rates between 404 lured and 440 unlured CT stations sampled in Alberta, Canada over 120 day survey periods between February and August in 2015 and 2016. We used zero-inflated negative binomial generalized linear mixed models to test the effect of lure on detection rates for a) all mammals, b) six functional groups (all predator species, all prey, large carnivores, small carnivores, small mammals, ungulates), and c) four varied species of management interest (fisher, Pekania pennanti; gray wolf, Canis lupus; moose, Alces alces; and Richardson’s ground squirrel; Urocitellus richardsonii). Mammals were detected at 800 of the 844 CTs, with nearly equal numbers of total detections at CTs with (7110) and without (7530) lure, and variable effects of lure on groups and individual species. Scent lure significantly increased detections of predators as a group, including large and small carnivore sub-groups and fisher specifically, but not of gray wolf. There was no effect of scent lure on detections of prey species, including the small mammal and ungulate sub-groups and moose and Richardson’s ground squirrel specifically. We recommend that researchers explicitly consider the variable effects of scent lure on CT detections across species when designing, interpreting, or comparing multi-species surveys. Additional research is needed to further quantify variation in species responses to scent lures and other attractants, and to elucidate the effect of attractants on community-level inferences from camera trap surveys.

Estimating occupancy of Chinese pangolin (Manis pentadactyla) in a protected and non-protected area of Nepal

Chinese pangolin is the world's most heavily trafficked small mammal for luxury food and traditional medicine. Although their populations are declining worldwide, it is difficult to monitor their population status because of its rarity and nocturnal behavior. We used site occupancy (presence/absence) sampling of pangolin sign (i.e., active burrows) in a protected (Gaurishankar Conservation Area) and non-protected area (Ramechhap District) of central Nepal with multiple environmental covariates to understand factors that may influence occupancy of Chinese pangolin. The average Chinese pangolin occupancy and detection probabilities were Ψ ^  ± SE = 0.77 ± 0.08; p ^  ± SE = 0.27 ± 0.05, respectively. The detection probabilities of Chinese pangolin were higher in PA ( p ^  ± SE = 0.33 ± 0.03) than compared to non-PA ( p ^  ± SE = 0.25 ± 0.04). The most important covariates for Chinese pangolin detectability were red soil (97%), food source (97.6%), distance to road (97.9%), and protected area (97%) and with respect to occupancy was elevation (97.9%). We recommended use of remote cameras and potentially GPS collar surveys to further investigate habitat use and site occupancy at regular intervals to provide more reliable conservation assessments.

Record of a 10-year old European Wildcat Felis silvestris silvestris Schreber, 1777 (Mammalia: Carnivora: Felidae) from Mt. Etna, Sicily, Italy

Longevity data for wild felids are lacking in the literature.  Here we report a camera trap recapture of a European Wildcat Felis silvestris at Mt. Etna in Sicily, Italy after nine years.  This individual was clearly identifiable as its tail ended with a white ring rather than the typical black ring and had a unique shape of the dorsal stripe.  At first capture on 26 May 2009, this cat was assessed as an adult, so that the likely minimum age of this individual at the time of recapture on 10 June 2018 must have been be at least 10 years.  This finding represents the oldest known European Wildcat in the wild and provides insight into age structure in wildcat populations.