Camera Trap Sites Research Articles

People or predators? Comparing habitat‐dependent effects of hunting and large carnivores on the abundance of North America's top mesocarnivore

Variation in animal abundance is shaped by scale‐dependent habitat, competition, and anthropogenic influences. Coyotes Canis latrans have dramatically increased in abundance while expanding their range over the past 100 years. Management goals typically seek to lower coyote populations to reduce their threats to humans, pets, livestock and sensitive prey. Despite their outsized ecological and social roles in the Americas, the factors affecting coyote abundance across their range remain unclear. We fit Royle–Nichols abundance models at two spatial scales in a Bayesian hierarchical framework to three years of data from 4587 camera trap sites arranged in 254 arrays across the contiguous USA to assess how habitat, large carnivores, anthropogenic development and hunting regulations affect coyote abundance. Coyote abundance was highest in southwestern USA and lowest in the northeast. Abundance responded to some factors as expected, including positive (soft mast, agriculture, grass/shrub habitat, urban–natural edge) and negative (latitude and forest cover) relationships. Colonization date had a negative relationship, suggesting coyote populations have not reached carrying capacity in recently colonized regions. Several relationships were scale‐dependent, including urban development, which was negative at local (100‐m) scales but positive at larger (5‐km) scales. Large carnivore effects were habitat‐dependent, with sometimes opposing relationships manifesting across variation in forest cover and urban development. Coyote abundance was higher where human hunting was permitted, and this relationship was strongest at local scales. These results, including a national map of coyote abundance, update ecological understanding of coyotes and can inform coyote management at local and landscape scales. These findings expand results from local studies suggesting that directly hunting coyotes does not decrease their abundance and may actually increase it. Ongoing large carnivore recoveries globally will likely affect subordinate carnivore abundance, but not in universally negative ways, and our work demonstrates how such effects can be habitat and scale dependent.

Wildlife resilience in an urban landscape: understanding land-use impacts in Cape Town

AbstractUrbanisation is rapidly transforming and fragmenting natural habitats, disrupting ecosystems and negatively impacting biodiversity. The City of Cape Town (CoCT) is situated in a global biodiversity hotspot, but sustained anthropogenic activities have resulted in the local extirpation of most medium and large mammals. A recent survey of mammals within urban protected areas of CoCT revealed that a few, mostly medium-sized generalist species, persist. It is uncertain which native mammal species, if any, inhabit the unprotected green belts and parks in suburban and urban areas of the city. A total of 37 camera trap sites were established along four transects for a period of four months between 31 January and 31 May 2022. A total of 12 terrestrial mammal species were detected, nine of which were wild native mammals and three domestic species. Most detections were in natural habitat followed by suburban, with urban areas having the lowest detection rate of wildlife. Single season hierarchical multi-species occupancy models revealed that tree cover had a significant positive effect on both community and individual species occupancy. Contrary to our predictions, neither human population density nor the extent of the impervious surface at sites significantly affected occupancy. Cape grysbok (Raphicerus melanotis) were significantly more likely to occur at sites with a higher proportion of impervious surfaces supporting other recent research, which showed this species together with water mongoose (Atilax paludinosus) and Cape porcupine (Hystrix africaeaustralis) are one of only a few native mammals that appear to persist and may even thrive in human-modified landscapes. Our findings underscore the complexity of urban biodiversity conservation and the species-specific responses to environmental factors, emphasising the importance of tree cover in urban wildlife management.

Detection rates and diel activity patterns of four understudied felids from Borneo.

Carnivore guilds are charismatic and have vital and irreplaceable roles in their native ecosystems, yet many of these species are threatened and remain understudied. Borneo is a biodiversity hotspot that hosts a rich diversity of endemic wildlife but is threatened by deforestation and habitat loss. Using cameras placed by the Smithsonian Institution in Sabah, Borneo, we assessed the detection rates and diel activity patterns of the native felid species. Across 51 camera trap sites between 2016 and 2019, felids were detected 55 times across a combined 9958 trap nights, including 20 independent detection events for Sunda leopard cats, 15 for Sunda clouded leopards, 12 for Borneo bay cats, and 5 for marbled cats, with no detections of flat-headed cats. Collectively, this demonstrates the challenge of sampling cryptic species that have declined due to habitat loss and conflict with humans. Despite this, we show that Borneo bay cats and marbled cats exhibited different diel activity patterns than Sunda cloud leopards, suggesting the smaller species use temporal displacement to avoid competition and predation. Sunda leopard cats exhibited broadly similar activity patterns to Sunda clouded leopard, potentially because the two species typically occupy different dietary and habitat niches. These results demonstrate the importance of devoting future research towards monitoring these species and understanding the mechanisms by which they co-exist.

The fishing cat: New insights on distribution in the northern sector of Chitwan National Park, Nepal

Fishing cat Prionailurus viverrinus (Bennett, 1833) is an elusive and medium-sized feline species with distinguished marking patterns on their head and body separating them from other feline species. Despite being distributed widely among diverse geographic locations, their abundance has declined due to significant habitat loss and human disturbances. There exists a substantial research gap regarding their abundance and distribution in Nepal. In this article, we presented the updated documentation of the fishing cat distribution in the northern sector of Chitwan National Park through our species-focused camera trapping survey. The study was carried out between April and May 2021 with a total of 130 camera trap nights. We obtained images of fishing cats from three camera trap sites, less than one kilometer of aerial distance from the human settlements, indicating that the species could also be extensively using human-dominated landscapes within and around the parts of CNP. Our research also found that fishing cats are residing close to the Rapti riverbed where seasonal shallow water holes are more common, allowing them to hunt their prey easily.

Status assessment of a recently reintroduced eurasian lynx (Lynx lynx) population in the Palatinate Forest, South-West Germany

To reinforce Eurasian lynx populations in central Europe, 20 lynx from Slovakia and Switzerland were translocated to the Palatinate Forest between 2016 and 2020. Using a systematic camera trapping array consisting of 80 camera trapping sites in a 1,000 km² study area located in the centre of the approximately 1,800 km² Palatinate Forest, we aim to describe the status of the population in the final stages of the reintroduction project in winter and spring 2019/20 and 2020/21. We also use our data to provide a first estimate of population density of the newly established population. With an estimate of 0.52 independent individuals per 100 km², population density in the Palatinate Forest was still significantly lower than the densities of well-established reintroduced populations. The number of independent individuals detected in the study area decreased from 15 individuals in 2019/20 to 11 individuals in 2020/21, thus significantly below the number of lynx translocated. The low abundance in the Palatinate Forest can be explained by the dispersal of several individuals to the Vosges (France), which, together with the Palatinate Forest, form a continuous area of suitable lynx habitat of approximately 8,000 km². Our results may thus reflect the status of a young population that can expand over a potentially large area. Nevertheless, in light of the low population density, we strongly recommend a synchronized and harmonized transboundary monitoring program to keep track of the development of this important Franco-German lynx population. In case population density remains low, supportive measures need to be considered.

Range expansion of a declining forest species, the Western Gray Squirrel (Sciurus griseus), into semiarid woodland

Abstract Globally, animals that are range-restricted are frequently becoming species of conservation concern, in part due to competitive exclusion by phylogenetically and ecologically similar species that are more tolerant of human disturbance. However, climate and land use changes to natural landscapes can create pockets of refugia for range-restricted species. Western gray squirrels (Sciurus griseus) are native to the west coast of North America, principally California and western Oregon. Over the past several decades, Western Gray Squirrel populations have declined in human-dominated areas, with increased competition from introduced congeneric species native to eastern North America cited as a primary driver. Despite declines in their established range west of the Pacific Crest in western North America, western gray squirrels are extending their range into the Great Basin, where they were not historically found. Using a network of remote camera traps deployed across the Sierra Nevada–Great Basin ecotone in northwestern Nevada, we detected western gray squirrels across 16 of 100 camera-trapping sites. The majority of detections were located in piñon–juniper woodland, a land cover type not previously occupied by this species. Occupancy modeling revealed that western gray squirrels were equally likely to occur in piñon–juniper woodland compared to mature pine forest that they occupy elsewhere in their range. A species distribution model parameterized with historical gray squirrel observations (pre-1950), indicated increased climatic suitability for the species on the eastern side of the Sierra Nevada in recent decades, which may have facilitated this range expansion. Our findings reveal the potential for species declining in their historical range to colonize novel habitats that become increasingly suitable as a result of human-driven changes to ecosystems.

Cheetah spatiotemporal overlap with other large carnivores and prey at camera-trap sites: do they fit the niche-complementarity hypothesis?

In guilds, such as the large predators, species compete over multiple resources that are both consumable and non-consumable. The niche complementary hypothesis states that competitors can overlap in resource use if there is low overlap for at least one shared resource. In Africa, cheetah, Acinonyx jubatus, compete with other large carnivores across space, time and prey and are known to be subordinate; however, rarely has the entire guild been considered when assessing resource partitioning by cheetah. Using camera-trap data from four areas sampled over 4 years, we compared spatial and temporal overlap between cheetah and other large carnivores. Moreover, we estimated short-term avoidance of sites by cheetah after another large carnivore had visited. We show that cheetah align with the niche complementary hypothesis to avoid other large carnivores. Cheetah experienced high overlap with African wild dog, Lycaon pictus, activity patterns but avoided sites that were used frequently by them. The inverse was observed for lion, Panthera leo, and spotted hyena, Crocuta crocuta, with cheetah avoiding them across time but not space. Cheetah experienced moderate overlap with leopard, Panthera pardus, across both space and time, with only possible short-term avoidance occurring. Finally, cheetah exhibited high levels of spatial and temporal overlap with preferred prey species, suggesting a novel demonstration of the trade-off between resource acquisition and predator avoidance. Our results showcase the importance of taking multiple scales and resource axes into consideration when determining species abilities to co-exist and provides tools for managers working in highly managed systems.

Conservation planning in national parks may benefit from site occupancy and detection estimates of native animal species

Protected areas are the best strategy to conserve native biodiversity around the world. In Southeast Asia, most of the pristine tropical forest habitats are limited to terrestrial protected areas such as national parks and wildlife reserves. Endau Rompin National Park (ERNP) is one of undisturbed biodiversity-hotspots in the southern region of Peninsular Malaysia but surrounded by industrial oil palm plantations and threatened by habitat fragmentation. To date, little is known about the distribution and habitat requirement of wildlife, including those conservation priority species in the ERNP. This study aims to investigate the mammal distribution in the ERNP by estimating the probability of occurrence of a species among sampled sites. At 24 camera-trapping sites, we used passive infrared camera traps to detect the forest wildlife. We estimated wildlife occupancy by using single-season occupancy analysis while considering of imperfect detection and relating it to stand- and landscape-level variables. We detected 26 species of native wild animals in the study area including several conservation priority species such as Asian elephant, Asian tapir, and Malayan tiger. The site occupancy of conservation-priority species attests to ERNP's status as an important regional biodiversity hotspot. The detection probabilities of wildlife species were highly sensitive to specific ecological variables at stand- and landscape-level. Our data indicated that tree canopy cover, forest edges, adjacent human settlements, and riparian habitats (e.g., stream and river) are crucial for the persistence of the native wildlife species. Our results suggest that pristine forest habitat such as those typical to the ERNP are critical for wildlife conservation. We suggest that the stand- and landscape-level ecological variables are considered in the conservation planning to protect the forest biodiversity and ecological integrity of the national park and other terrestrial protected areas in the tropics.

Direct and indirect landscape-scale pathways structure carnivore communities in an agro-prairie ecosystem

Abstract Many carnivore populations have experienced substantial declines and are at increased risk of extinction, mainly due to negative interactions with humans and biological traits that make them susceptible to habitat loss and fragmentation, often driven by agricultural expansion. Carnivore community richness is likely influenced by many direct and indirect factors, though it is unclear how carnivore communities are structured in prairie landscapes that are considered one of the most imperiled ecosystems worldwide. Our goal was to identify landscape-scale effects driving carnivore community richness in a contemporary agro-prairie ecosystem. We used 3 years of presence data (2018–2020) from camera-trap sites (n = 381) distributed across western Kansas, United States and developed a structural equation model (SEM) to test a priori hypotheses explaining carnivore richness. Measures of water availability, native prairie, and agriculture—as well as sampling effort (i.e., days cameras were active)—were all positively associated with carnivore richness. Additionally, our index of rabbit abundances at sites had a direct positive effect on our measure of carnivore richness. Our SEM explained 42% of the variance in carnivore richness (χ2 = 8.76, d.f. = 21, P = 0.99) in this human-dominated landscape. Our results suggest that carnivore communities in agro-prairie landscapes are structured through multiple direct and indirect landscape-scale pathways. Contemporary agro-prairie mosaics may act as filters for the agricultural tolerance of carnivores, with species more vulnerable to native prairie loss becoming locally extirpated.

Using heterogeneous camera-trapping sites to obtain the first density estimates for the transboundary Eurasian lynx (Lynx lynx) population in the Dinaric Mountains

Estimating abundance of wild animal populations is crucial for their management and conservation. While spatial capture-recapture models are becoming increasingly common to assess the densities of elusive species, recent studies have indicated potential bias that can be introduced by unaccounted spatial variation of detectability. We used camera-trapping data collected in collaboration with local hunters from a transnational population survey of the Eurasian lynx (Lynx lynx) in Slovenia and Croatia, to provide the first density estimate for the threatened Eurasian lynx population in the Northern Dinaric Mountains. Population density was 0.83 (95% CI: 0.60–1.16) lynx/100 km2, which is comparable to other reintroduced Eurasian lynx populations in Europe. Furthermore, we showed that baseline detection rate was influenced by the type of site used, as well as by sex of the individual and local behavioural response. Scent-marking sites had on average a 1.6- and 2.5-times higher baseline detection rate compared to roads and other locations, respectively. Scent-marking behaviour is common for several mammals, and selecting sites that attracts the targeted species is used to increase detection rates, especially for rare and cryptic species. But we show that the use of different location types for camera trapping can bias density estimates if not homogenously distributed across the surveyed area. This highlights the importance of incorporating not only individual characteristics (e.g., sex), but also information on the type of site used in camera trapping surveys into estimates of population densities.

Disentangling vertebrate spatio-temporal responses to anthropogenic disturbances: evidence from a protected area in central Myanmar

AbstractUrbanization of natural landscapes and increasing human populations have brought people and our companion animals into closer contact with wildlife, even within protected areas. To provide guidance for human–wildlife coexistence, it is therefore critical to understand the effects of anthropogenic disturbances and how well native wildlife species survive in human-dominated landscapes. We investigated the spatio-temporal responses of 10 vertebrate taxa, with an emphasis on the Endangered Eld's deer Rucervus eldii thamin, to anthropogenic disturbances in Shwesettaw Wildlife Sanctuary, Myanmar. We quantified anthropogenic disturbances as distance from human settlements, distance from a highway, and the presence of people and free-ranging dogs Canis familiaris. Anthropogenic disturbances had stronger negative impacts on the detection of native wildlife species than on occupancy. Eld's deer avoided areas close to human settlements and showed low diel activity overlap with both people and dogs, although we found a positive association with human presence at the camera-trap sites. Five species exhibited lower diel activity overlap with people in the rainy season when human activity is the highest in our study area. All studied wildlife species shifted to nocturnal activity or did not show any clear activity pattern during the cool-dry season when the presence of dogs increased. The ecological and conservation impacts of dogs are underestimated in South-east Asia, particularly in Myanmar, and this case study highlights the impacts of dogs on the temporal use of habitat by wildlife and the need for better practices in the management of dogs within protected areas.

Spatio-Temporal Niche of Sympatric Tufted Deer (Elaphodus cephalophus) and Sambar (Rusa unicolor) Based on Camera Traps in the Gongga Mountain National Nature Reserve, China.

Simple SummaryThe broad adoption of camera traps in wildlife monitoring leads to a better understanding of the distribution and activity patterns of wild animals. In this study, two endangered wild animals distributed in the Gongga Mountain National Nature Reserve, the tufted deer (Elaphodus cephalophus) and sambar (Rusa unicolor), were investigated for habitat suitability and rhythm activity patterns based on 9-year (2012–2021) camera-trap data. The results revealed that the suitable range of the major environmental factors and the distribution range of tufted deer in the reserve were greater than those of sambar. The daily activity peaks in tufted deer and sambar were both at dusk and dawn, but sambar stayed active during the evening.Clarifying the distribution pattern and overlapping relationship of sympatric relative species in the spatio-temporal niche is of great significance to the basic theory of community ecology and integrated management of multi-species habitats in the same landscape. In this study, based on a 9-year dataset (2012–2021) from 493 camera-trap sites in the Gongga Mountain National Nature Reserve, we analyzed the habitat distributions and activity patterns of tufted deer (Elaphodus cephalophus) and sambar (Rusa unicolor). (1) Combined with 235 and 153 valid presence sites of tufted deer and sambar, the MaxEnt model was used to analyze the distribution of the two species based on 11 ecological factors. The distribution areas of the two species were 1038.40 km2 and 692.67 km2, respectively, with an overlapping area of 656.67 km2. Additionally, the overlap indexes Schoener’s D (D) and Hellinger’s-based I (I) were 0.703 and 0.930, respectively. (2) Based on 10,437 and 5203 independent captures of tufted deer and sambar, their daily activity rhythms were calculated by using the kernel density estimation. The results showed that the daily activity peak in the two species appeared at dawn and dusk; however, the activity peak in tufted deer at dawn and dusk was later and earlier than sambar, respectively. Our findings revealed the spatio-temporal niche relationship between tufted deer and sambar, contributing to a further understanding of the coexistence mechanism and providing scientific information for effective wild animal conservation in the reserve and other areas in the southeastern edge of the Qinghai–Tibetan Plateau.

Estimating arboreality and the effects of forest structure on tropical tree‐dwelling mesomammals using arboreal camera traps

AbstractTropical forests are the most species‐rich biomes in the world but suffer high rates of logging and conversion. Tropical tree‐dwelling (arboreal and semi‐arboreal) mesomammals reliant on old‐growth forest structures are especially vulnerable. The degree of behavioral arboreality of semi‐arboreal mammals can be related to forest structure and perceived terrestrial threats. Paired arboreal and terrestrial camera traps are a promising new method for estimating the arboreality of cryptic and nocturnal species. Our study aimed to (1) model the effects of forest structure and anthropogenic disturbance on the detection and occurrence of arboreal and semi‐arboreal mesomammals and (2) evaluate differences in occurrence and detection between paired arboreal and terrestrial camera trap sites for semi‐arboreal mammals while estimating the degree of arboreality. We set 20 terrestrial and arboreal camera trap pairs in eastern Cat Tien National Park (Nam Cat Tien), Vietnam, from June 2019 to September 2020. We evaluated the effects of forest structure and proximity to roads on nine arboreal mesomammal species using single‐season occupancy models. We used multi‐scale occupancy modeling to estimate the degree of arboreality for four semi‐arboreal mammals. All models were fit using hierarchical Bayesian modeling and compared using WAIC. We detected most arboreal and terrestrial mesomammal species currently known to inhabit Nam Cat Tien, including rare and cryptic species. Canopy connectivity and other mature forest characteristics were important for explaining the detection and occurrence of highly arboreal species, while the effect of a tree and focal limb characteristics on detection was species‐specific. All semi‐arboreal species had a greater probability of terrestrial station use than arboreal, suggesting a greater vulnerability to terrestrial threats, though the degree of arboreality varied by species. Using one sampling method underestimated occupancy for most semi‐arboreal species. Multi‐method sampling designs with multi‐scale occupancy modeling can improve estimates of species distribution and habitat use for guiding management and conservation decisions.

Population size, density, and ranging behaviour in a key leopard population in the Western Cape, South Africa.

Globally, leopards are the most widespread large felid. However, mounting anthropogenic threats are rapidly reducing viable leopard populations and their range. Despite the clear pressures facing this species, there is a dearth of robust and reliable population and density estimates for leopards across their range, which is particularly important in landscapes that consist of protected and non-protected areas. We conducted a camera trapping survey between 2017 and 2018 in the Western Cape, South Africa to estimate the occupancy, density, and population size of a leopard population. Leopards were recorded at 95% of camera trapping sites, which resulted in a high occupancy that showed no significant variation between seasons, habitat types, or along an altitudinal gradient. Our results indicated a low leopard density in the study area, with an estimated 1.53 leopards/100 km2 in summer and 1.62 leopards/100 km2 in winter. Mean leopard population size was therefore estimated at 107 and 113 individuals in the winter and summer respectively. Leopard activity centres for female ranges were centred in the core study area and could be predicted with good certainty, while males appeared to move out of the study area during winter which resulted in a higher uncertainty in locations of activity centres. Interestingly, livestock depredation events in the surrounding farmlands were significantly higher in winter, which coincides with male leopards moving outside the core protected area into the surrounding farmlands. To reduce livestock losses and retaliatory leopard killings, we suggest that human-carnivore conflict mitigation measures be intensely monitored during the winter months in the study area. We also suggest that future leopard conservation efforts should focus on privately-owned land as these non-protected areas contain the majority of the remaining suitable leopard habitat and may provide important dispersal corridors and buffer zones on which the long-term sustainability of leopard populations depends.

Trends in Habitat Use between Sympatric Sika Deer and Japanese Serow as Revealed by Camera Traps

In response to severe vegetation degradation caused by sika deer in Japan, it is important to understand the habitat use trends of the sika deer and sympatric Japanese serows to promote the management and conservation of both species and their habitats. This study used camera traps to examine the trends of habitat use of the two sympatric ungulates in the Kuraiyama Experimental Forest (KEF) at Gifu University. We set camera traps at 20 sites and evaluated the number of individuals photographed for three years. Additionally, we surveyed several environmental factors around the camera trap sites to determine the relationship between species prevalence and habitat features. Both species were photographed at all sites, and some habitat use trends were observed. The deer used the west side of the valley, whereas the serows used the east, with clearer trends further observed in summer. Both ungulates avoided snow cover in winter and used steeper slopes and ridges in several seasons. With the current increase in the deer population, niche overlap between the two species may occur in the common place preferred by both species; therefore, careful monitoring of their relationships and their changes should be continued in the future.

Carnivore coexistence facilitated by spatial and dietary partitioning and fine‐scale behavioural avoidance in a semi‐arid ecosystem

AbstractSympatric carnivores compete for similar resources which may lead to dominant species influencing the ecology of subordinate ones. However, carnivores often make use of coevolutionary strategies which enable them to minimise competition with dominant competitors and thus facilitate coexistence. We used camera trapping and scat analysis to investigate the potential competition between leopards (Panthera pardus) and caracals (Caracal caracal) along spatial, temporal and dietary axes to determine the mechanisms of their coexistence in the Cederberg, South Africa. Our results showed that both carnivores co‐occurred at 39.73% of camera trapping sites, but spatial overlap based on Pianka's index was relatively low. We found a high overlap in daily activity patterns between these carnivore species both during winter and summer. Leopards and caracals exhibited fine‐scale behavioural avoidance of one another, with time‐to‐encounters between interspecific competitors being significantly larger compared to intraspecific competitors. The two carnivores had a relatively high diet overlap, although this was largely due to one prey species, namely rock hyrax (Procavia capensis), which appears to be an important shared prey item. However, we did find evidence of dietary niche segregation, as leopards consumed larger prey compared to caracals. Our study suggests that carnivore coexistence in the Cederberg is facilitated by a combination of population‐level partitioning in space‐use and dietary habits, as well as fine‐scale behavioural avoidance at the individual level to reduce interference competition. This study provides insights into the competition and coexistence mechanisms between sympatric carnivores and broadens our understanding of these ecological processes in carnivore guild systems.

Camera trap surveys can reveal the dynamics of deer “hotspots” in Ireland.

Systematic camera trap surveys are important for gathering information on terrestrial wildlife. Such surveys reveal distributions, abundances, and behaviours that can inform conservation and wildlife management by providing evidence of animal presence at known locations and times. However, in Ireland, international-standard camera trap surveys have not been undertaken to inform the management of large terrestrial wildlife. Through participation in a continent-wide initiative (Snapshot Europe) with a shared methodology, we undertook Ireland’s first systematic camera trap survey for large mammals over a two-month period in 2021 in a known deer “hotspot” - central Wicklow, Ireland. We captured eight wild mammal species from 19 forest camera trap sites. Sika (Cervus nippon) or sika-red deer hybrids (Cervus nippon × Cervuselaphus) were detected at all sites and comprised 92% of all independent camera trap events of wild mammals. Sika (and hybrid) events occurred at an average rate of 1.1 events per site per day. Females were more often detected than males (male:female = 1:1.42). We also noted that most females were not accompanied by juveniles (female:juvenile = 1:0.31). Overall, we demonstrate the efficacy of even this exploratory survey for revealing wildlife dynamics and generating data for science-informed management and conservation. We recommend that further surveys should be carried out across Ireland to achieve minimum international standards for monitoring terrestrial wildlife.

Mountain refugia limit anthropogenic suppression in a re-established felid population: the case of the Magaliesberg leopard population in South Africa

Although highly adaptable, leopards incur substantial mortality in human-modified landscapes and generally subsist at lower densities than in protected areas. Leopard populations are difficult to enumerate across any landscapes, though there have been strides to improve upon this, particularly in South Africa. This study aimed to determine the population density of leopards in the Magaliesberg mountain range of the North West province in 2015 and provided a longitudinal comparison of these camera-trapping sites. It appraises the efficacy of interventions aimed at improving the status quo of zero leopards found during a prior survey in 2011. Such interventions included a moratorium on sport hunting of the species, and the reintroduction of four individuals, two of each sex, into this area. Camera trapping over 10 months detected seven unique individuals, including one juvenile and six adults, consisting of four males and three females, half of which were previously reintroduced or progeny thereof. A Bayesian capture-recapture abundance model indicated a population of 5–7 individuals occurring within 1 480 km2 of available habitat, yielding a density estimate of 0.34–0.47 adult leopards per 100 km2, which is a relatively low estimate, likely due to population suppression from anthropogenic pressures surrounding the site (i.e., snaring). This study demonstrates that large carnivore populations can recolonise their former range via targeted interventions within topographical refugia.

Ravines as conservation strongholds for small wildcats under pressure from free-ranging dogs and cats in Mediterranean landscapes of Chile

ABSTRACT The Chilean Mediterranean ecosystem is threatened by anthropogenic pressures, such as habitat loss by intensive agriculture and urban sprawl. Abandoned dogs (Canis lupus familiaris) and cats (Felis silvestris catus) pose conservation challenges for Chilean wildlife including the pampas cat (Leopardus colocolo) and the güiña (Leopardus guigna). We used camera trap data to investigate influences of natural and anthropogenic landscape features on spatiotemporal trends of these species. We also used co-occurrence modeling and kernel density estimation to investigate spatial and temporal patterns overlap of wildcats, free-ranging (FR) dogs, and FR-cats. FR-dogs showed the highest detection and site use probabilities, while güiñas had the lowest across 80 camera trap sites. Top models showed no spatial avoidance between species and co-occurrence of wildcats was positively influenced by forest habitat. However, FR-dogs negatively affected detection of wildcats. Ravines surrounded by forest positively influenced güiña and pampas cat detection probabilities when dominant species were not present. FR-dogs and wildcats had significantly different temporal activity patterns and low overlap coefficients, while wildcats and FR-cats showed high overlap in activity patterns. We suggest changing current policies to control domestic animals and strategic planning in agricultural areas of central Chile to better conserve native wildcat species.

Poaching Threatens the Establishment of a Lynx Population, Highlighting the Need for a Centralized Judiciary Approach

Illegal hunting represents a major threat to the conservation of predators, but its impact remains difficult to assess as there are strong incentives to conceal this criminal activity. Attributing declines of carnivores to poaching is therefore an important conservation challenge. We present a case study of the Eurasian lynx (Lynx lynx) in the Swiss Alps (Valais) where the current distribution range is smaller than in the recent past and population density is by ≥80% lower than in the adjacent Swiss Prealps. We tested four hypotheses to explain this lower density: (1) a too low density of camera-traps deployed for lynx surveys in Valais compared to the Prealps (methodological artifact); (2) less favorable environmental conditions around the camera-trap sites; (3) lower densities of the main prey; and (4) poaching. We estimated lynx and ungulate densities and environmental conditions at trail camera sites and could clearly reject the first three hypotheses because: (1) the survey protocol was similarly effective; (2) environmental conditions around the trapping sites in Valais were even more favorable for lynx detection than in the Prealps; and (3) prey supply was even larger in Valais. Concerning hypothesis 4, we discovered a network of illegal lynx traps (neck snares) in the main immigration corridor into Valais from the thriving adjacent lynx population in the Prealps, suggesting intense local poaching. Our findings substantiate the suspicions of long-lasting lynx poaching as a threat to the establishment and survival of the Valais population. The fact that instances of poaching were publicly known since 1995 but remained unabated for at least two decades, until the first conviction occurred, questions the commitment of local authorities to address this case of wildlife crime. Our study demonstrates the need for inquiries about poaching of top predators to be carried out at the highest levels of jurisdiction to avoid any risk of collusion between law enforcement agents and poachers.