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1: Camera-trap spacing and the spatial closure assumption. Black circles represent camera-trap stations, coloured shapes represent animal movement patterns. For occupancy and N-mixture analysis, only one station should be within the home range of the target species (species A and B). For spatial capture recapture, multiple stations should be within the home range of the target species (species C).
Source publication
Cost-efficient repeatable methods to track biodiversity changes are important for forest and wildlife managers to improve management practices and target conservation efforts at the local scale.
The aim of this user’s guide is to provide practitioners step-by-step instructions for biodiversity assessment and monitoring of tropical forest mammals us...
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Husodo T, Febrianto P, Megantara EN, Shanida SS, Pujianto MP. 2019. Diversity of mammals in forest patches of Cisokan, Cianjur, West Java, Indonesia. Biodiversitas 20: 1281-1288. Most species on Java, Indonesia are ecologically associated with or dependent on forests, the island's high deforestation rates are a major threat to its species. Until no...
Citations
... We compared the canopy cover and understory vegetation densities at scatter and provisioning sites using photographs of the vegetation, following the methods of Abrams et al. (2018). For this, we took photographs of the vegetation at a 0.5 m height in four cardinal and four intercardinal directions in front of a red tarpaulin placed at a 5 m distance, after monitoring the carcass or at the end of the field experiment, which was before the start of the vegetation period (Niedballa et al., 2022). ...
Vertebrate scavengers provide essential ecosystem services such as accelerating carrion decomposition by consuming carcasses, exposing tissues to microbial and invertebrate decomposers, and recycling nutrients back into the ecosystem. Some scavengers do not consume carcasses on site but rather scatter their remains in the surroundings, which might have important implications for nutrient transport, forensic investigations and the spread of diseases such as African Swine Fever. However, only a few studies have investigated and measured the scatter distances. Using wild boar (Sus scrofa) carcasses and limbs, we monitored scavenging behavior and measured scatter distances of mammals. We placed 20 carcasses (up to 25 kg) and 21 separate limbs equipped with very high frequency (VHF) transmitters and monitored scavenger activity using camera traps in a mountainous region in southeast Germany. Except for one carcass, all other carcasses and limbs were scattered. We measured 72 scatter distances (of 89 scattering events; mean = 232 m, maximum = 1250 m), of which 75% were dispersed up to 407 m. Scavengers moved scattered pieces into denser vegetation compared to the half-open vegetation at provisioning sites. Red foxes (Vulpes vulpes) were the most common scavenger species, contributing to 72 scattering events (58 measured scatter distances). Our results provide evidence of scatter distances farther than previously assumed and have far-reaching implications for disease management or forensic investigations , as the broader surroundings of carcasses must be included in search efforts to remove infectious material or relevant body parts for forensic analysis.
... The canvas method was employed to assess understory transparency [25]. An orange waterproof canvas measuring 1.5 m × 1 m was placed 10 m from the plot's center. ...
Simple Summary
The Lower Tumen River basin habitat at the Sino-North Korean border is crucial for reestablishing Amur leopards in the Korean Peninsula, where they once thrived. However, except for the Jingxin–Dapanling (JD) and Mijiang (MJ) corridors, most areas have become impassable due to human activities and urbanization. In this study, we evaluated the effectiveness of the MJ corridor by analyzing the species abundance, forest structure, landscape features, and disturbance factors. Our findings indicate that leopard activity is predominantly concentrated in the northern part of the corridor, with little to no presence in the middle and southern regions near the North Korean border. Human disturbances, forest structure, and infrastructural obstacles seem to impede the movement of leopards. To ensure the resurgence of the leopard population in the Korean Peninsula, it is imperative to mitigate or eliminate the impacts of these hindrances. This entails reducing human disturbances, enhancing forest structure, and removing infrastructural barriers. Such efforts are vital to facilitate the revival of the Amur leopards in their former range in the Korean Peninsula.
Abstract
The interconnected forest regions along the lower Tumen River, at the Sino-North Korean border, provide critical habitats and corridors for the critically endangered Amur Leopard (Panthera pardus orientalis). In this region, there are two promising corridors for leopard movement between China and North Korea: the Jingxin–Dapanling (JD) and Mijiang (MJ) corridors. Past studies have confirmed the functionality of the JD corridor, but leopards’ utilization of the MJ corridor has not yet been established or confirmed. In this study, we assessed the functionality of the MJ corridor. The study area was monitored using camera traps between May 2019 and July 2021. We also analyzed 33 environmental and vegetation factors affecting leopard survival and analyzed leopard movement. In the Mijiang area, the Amur leopard was mainly active in the region adjacent to the Northeast China Tiger and Leopard National Park and did not venture into area near the North Korean border. The complex forest structure allowed leopards to move into the Mijiang area. However, the high intensity of human disturbance and manufactured physical barriers restricted further southward movement. Therefore, human-induced disturbances such as grazing, mining, farming, logging, and infrastructure development must be halted and reversed to make the Mijiang region a functional corridor for the Amur leopard to reach the North Korean forest. This necessitates inter-governmental and international cooperation and is essential for the long-term survival of the Amur leopard.
... We used two non-facing camera-traps at each station, mounted on trees approximately 30-40 cm from the ground. For details on the methodology and study design please see Abrams et al. (2018). In total, we set 103 cameratrap stations across Bidoup -Nui Ba NP. ...
The Annamite striped rabbit Nesolagus timminsi is a little-known and Endangered lagomorph endemic to the Annamites ecoregion of Vietnam and Laos. The species’ known distribution extends from the northern to central Annamites. Here, we report the first records of the species from the southern Annamites. We recorded camera-trap photographs of Annamite striped rabbit in Bidoup – Nui Ba National Park, located in Lam Dong province, Vietnam. The photographs represent the first records of the species from the southern Annamites, and a significant southern range extension. We discuss the implications of this finding for Annamite striped rabbit conservation.
... Cameratrap data were managed using the package camtrapR (Niedballa, Sollmann, Courtiol, & Wilting, 2016). We excluded arboreal species from our final species list, as these species are unlikely to be reliably detected by camera-traps placed at ground-level (Abrams et al., 2018). We also removed rodents and squirrels, given the difficulty of identifying these mammals to species level using camera-trap images alone, and all domestic animals. ...
... Leaf litter values were averaged to give a single value for each station. For a detailed explanation of the microhabitat assessment, see Abrams et al. (2018). ...
Aim
Unsustainable hunting is leading to widespread defaunation across the tropics. To mitigate against this threat with limited conservation resources, stakeholders must make decisions on where to focus anti‐poaching activities. Identifying priority areas in a robust way allows decision‐makers to target areas of conservation importance, therefore maximizing the impact of conservation interventions.
Location
Annamite mountains, Vietnam and Laos.
Methods
We conducted systematic landscape‐scale surveys across five study sites (four protected areas, one unprotected area) using camera‐trapping and leech‐derived environmental DNA. We analysed detections within a Bayesian multispecies occupancy framework to evaluate species responses to environmental and anthropogenic influences. Species responses were then used to predict occurrence to unsampled regions. We used predicted species richness maps and occurrence of endemic species to identify areas of conservation importance for targeted conservation interventions.
Results
Analyses showed that habitat‐based covariates were uninformative. Our final model therefore incorporated three anthropogenic covariates as well as elevation, which reflects both ecological and anthropogenic factors. Conservation‐priority species tended to found in areas that are more remote now or have been less accessible in the past, and at higher elevations. Predicted species richness was low and broadly similar across the sites, but slightly higher in the more remote site. Occupancy of the three endemic species showed a similar trend.
Main conclusion
Identifying spatial patterns of biodiversity in heavily defaunated landscapes may require novel methodological and analytical approaches. Our results indicate that to build robust prediction maps it is beneficial to sample over large spatial scales, use multiple detection methods to increase detections for rare species, include anthropogenic covariates that capture different aspects of hunting pressure and analyse data within a Bayesian multispecies framework. Our models further suggest that more remote areas should be prioritized for anti‐poaching efforts to prevent the loss of rare and endemic species.
... The cameras were set 20-30 cm from the ground to maximize the probability of detecting chevrotain. Camera-traps that are set too high have been shown to consistently under-record small and medium-sized mammals 32 . The cameras were programmed to take a three-photograph burst after being triggered, with no delay period between photographic events. ...
In an age of mass extinctions, confirming the survival of lost species provides rare second chances for biodiversity conservation. The silver-backed chevrotain Tragulus versicolor, a diminutive species of ungulate known only from Vietnam, has been lost to science for almost three decades. Here, we provide evidence that the silver-backed chevrotain still exists and the first photographs of the species in the wild, and urge immediate conservation actions to ensure its survival. Interviews with local people and camera-trap surveys have led to the first scientifically confirmed sightings of the silver-backed chevrotain for more than 25 years. The news that this species is not extinct is tempered by major threats of habitat loss and poaching in the region.
... Finally, canopy closure values were averaged across the five rasters to give a single mean canopy closure value for each camera-trap station. Detailed information on canopy data collection protocols can be found in Abrams et al. 77 Canopy closure values are given as a percentage, with higher values indicating a more intact canopy, and more structurally intact forest. The canopy closure values show that the sites in Malaysian Borneo are more degraded than the sites in the Annamites (x ̅ Borneo = 0.77 ± 0.2, x ̅ Annamites = 0.83 ± 0.05). ...
Habitat degradation and hunting have caused the widespread loss of larger vertebrate species (defaunation) from tropical biodiversity hotspots. However, these defaunation drivers impact vertebrate biodiversity in different ways and, therefore, require different conservation interventions. We conducted landscape-scale camera-trap surveys across six study sites in Southeast Asia to assess how moderate degradation and intensive, indiscriminate hunting differentially impact tropical terrestrial mammals and birds. We found that functional extinction rates were higher in hunted compared to degraded sites. Species found in both sites had lower occupancies in the hunted sites. Canopy closure was the main predictor of occurrence in the degraded sites, while village density primarily influenced occurrence in the hunted sites. Our findings suggest that intensive, indiscriminate hunting may be a more immediate threat than moderate habitat degradation for tropical faunal communities, and that conservation stakeholders should focus as much on overhunting as on habitat conservation to address the defaunation crisis.
... Today, numerous methods are used to gather detections of mammals, all of which are time-and labour-intensive. Camera trapping has proven to be the most labour-efficient method (Roberts, 2011) and now plays an important role in wildlife management, allowing researchers to record a wide range of species in remote terrain over long time periods (Abrams et al., 2018;Burton et al., 2015;Trolliet, Vermeulen, Huynen, & Hambuckers, 2014). With the increased use of camera-trapping surveys, the methods for processing and statistically analysing the data have also advanced (Burton et al., 2015;MacKenzie et al., 2006). ...
... Factors that affect the ecological state (presence/absence) are related to habitat, while factors that affect the detection state (detection/non-detection) can be related to both habitat and survey conditions (survey method, effort, etc.) with a distance of 1.5 km between cluster centres. Each station consisted of two Reconyx PC850 white-flash camera traps (a total of 128 camera traps) facing each other, operating 24 hr/day and left in the forest for a minimum of 60 days (for details, see Abrams et al., 2018). Two types of leeches, tiger and brown leeches were collected concurrent to camera trapping. ...
Invertebrate‐derived DNA (iDNA), in combination with high throughput sequencing, has been proposed as a cost‐efficient and powerful tool to survey vertebrate species. Previous studies, however, have only provided evidence that vertebrates can be detected using iDNA, but have not taken the next step of placing these detection events within a statistical framework that allows for robust biodiversity assessments.
Here, we compare concurrent iDNA and camera‐trap surveys. Leeches were repeatedly collected in close vicinity to 64 camera‐trap stations in Sabah, Malaysian Borneo. We analyse iDNA‐derived mammalian detection events in a modern occupancy model that accounts for imperfect detection and compare the results with those from occupancy models parameterised with camera‐trap‐derived detection events. We also combine leech‐iDNA and camera‐trap data in a single occupancy model.
We found consistent estimates of occupancy probabilities produced by our camera‐trap and leech datasets. This indicates that the metabarcoding of leech‐iDNA method provides reasonable estimates of occupancy and may be a suitable method for studying and monitoring mammal species in tropical rainforests. However, we also show that a more extensive collection of leeches would be needed to assess mammal biodiversity with a robustness similar to that of camera traps. As certain taxa were only detected in leeches, we see great potential in complementing camera‐trap studies with the iDNA approach, as long as the collection of leeches follows a robust and standardised sampling scheme.
Synthesis and applications. Here, we describe an approach to analyse detection records of mammals derived from leech samples using an occupancy framework that accounts for leech‐specific factors influencing the detection probability. We further combined camera trap and leech data, which lead to increased confidence in occupancy estimates. Our approach is not restricted to the processing of leech samples, but can be used for the analysis of other invertebrate DNA and environmental DNA data. Our study is the first step to shift the application of invertebrate DNA studies from opportunistic ad‐hoc collections to the systematic surveys required for long‐term management of wildlife populations.
... Today, numerous methods are used to gather detections of mammals, all of which are time-and labour-intensive. Camera trapping has proven to be the most labour-efficient method (Roberts, 2011) and now plays an important role in wildlife management, allowing researchers to record a wide range of species in remote terrain over long time periods (Abrams et al., 2018;Burton et al., 2015;Trolliet, Vermeulen, Huynen, & Hambuckers, 2014). With the increased use of camera-trapping surveys, the methods for processing and statistically analysing the data have also advanced (Burton et al., 2015;MacKenzie et al., 2006). ...
... Factors that affect the ecological state (presence/absence) are related to habitat, while factors that affect the detection state (detection/non-detection) can be related to both habitat and survey conditions (survey method, effort, etc.) with a distance of 1.5 km between cluster centres. Each station consisted of two Reconyx PC850 white-flash camera traps (a total of 128 camera traps) facing each other, operating 24 hr/day and left in the forest for a minimum of 60 days (for details, see Abrams et al., 2018). Two types of leeches, tiger and brown leeches were collected concurrent to camera trapping. ...
Invertebrate-derived DNA (iDNA), in combination with high throughput sequencing, has been proposed as a cost-efficient and powerful tool to survey vertebrate species. Previous studies, however, have only provided evidence that vertebrates can be detected using iDNA, but have not taken the next step of placing these detection events within a statistical framework that allows for robust biodiversity assessments. Here, we compare concurrent iDNA and camera-trap surveys. Leeches were repeatedly collected in close vicinity to 64 camera-trap stations in Sabah, Malaysian Borneo. We analyze iDNA-derived mammalian detection events in a modern occupancy model that accounts for imperfect detection and compare the results with those from occupancy models parameterized with camera-trap-derived detection events. We also combine leech-iDNA and camera-trap data in a single occupancy model. We found consistent estimates of occupancy probabilities produced by our camera-trap and leech datasets. This indicates that the metabarcoding of leech-iDNA method provides reasonable estimates of occupancy and can be a suitable method for studying and monitoring mammal species in tropical rainforests. However, we also show that a more extensive collection of leeches would be needed to assess mammal biodiversity with a similar robustness as with camera traps. As certain taxa were only detected in leeches, we see great potential in complementing camera-trap studies with the iDNA approach, as long as the collection of leeches follows a similar robust and standardized sampling scheme. Synthesis and applications: The approach we describe here is not restricted to the processing of leech samples, but can be used for the analysis of other iDNA and environmental DNA (eDNA) data. Our study is the first step to shift the application of e/iDNA studies from opportunistic ad-hoc collections to systematic surveys required for long-term wildlife populations and biodiversity monitoring programs.
The maned wolf (Chrysocyon brachyurus) is a vulnerable and ubiquitous species endemic to South America. Their
populations are declining due to habitat loss as a consequence of agricultural expansion and exposure to anthropic
threats such as road-kills, illegal hunting and diseases. In Argentina, there is a lack of information about
its accurate distribution because its populations are sparse and the specimens are very difficult to observe due to
its cryptic and lonely behavior, low population density, and type of habitat. In this article, we describe the results
of the application of the environmental DNA methodology to carry out indirect monitoring of maned wolf
specimens. The data obtained show that this technique is effective in detecting specimens of this mammal, which
was verified through direct monitoring. This information represents an adjustment of the methods that can be
applied in large-scale monitoring to study the structure and distribution of the maned wolf populations, as well as
to obtain genetic data about this species, to design optimal conservation plans to preserve it in Argentina.
This Report is a Gap Analysis Assessment for Nakai-Nam Theun National Park, Central Lao PDR.
