Applications of non-intrusive methods to study the sand cat: a field study in the Sahara Desert

Surveys based on indirect signs and camera trapping are two non-invasive methods extensively used for monitoring elusive mammals. Both approaches can be useful to obtain key information on wildlife in remote areas, since they may allow for the logistically viable design of optimal field frameworks. The sand cat (Felis margarita) is a feline that inhabits the Sahara Desert, the Arabian Peninsula, and western Asian deserts. Its basic ecology is poorly known and the status and impacts of threats are difficult to assess. Some local population declines have been detected, and more research is needed. Based on field surveys carried out in the Atlantic Sahara, we have evaluated the applications of both methods to study this species. Our results show that (a) camera trapping provided reliable data on several key aspects of its ecology, (b) walking surveys to collect feces for molecular data failed completely, and (c) for footprints, identification problems and the marked effects of the absence of optimal substrates and the prevalence of wind are relevant handicaps. Beyond this evaluation, we provide for the first time some key aspects of the ecology of sand cats in the Sahara Desert, including habitat selection, density, diel activity, and predator–prey relationships.

Occupancy data improves parameter precision in spatial capture–recapture models

Population size is one of the basic demographic parameters for species management and conservation. Among different estimation methods, spatially explicit capture–recapture (SCR) models allow the estimation of population density in a framework that has been greatly developed in recent years. The use of automated detection devices, such as camera traps, has impressively extended SCR studies for individually identifiable species. However, its application to unmarked/partially marked species remains challenging, and no specific method has been widely used. We fitted an SCR‐integrated model (SCR‐IM) to stone marten Martes foina data, a species for which only some individuals are individually recognizable by natural marks, and estimate population size based on integration of three submodels: (1) individual capture histories from live capture and transponder tagging; (2) detection/nondetection or “occupancy” data using camera traps in a bigger area to extend the geographic scope of capture–recapture data; and (3) telemetry data from a set of tagged individuals. We estimated a stone marten density of 0.352 (SD: 0.081) individuals/km². We simulated four dilution scenarios of occupancy data to study the variation in the coefficient of variation in population size estimates. We also used simulations with similar characteristics as the stone marten case study, comparing the accuracy and precision obtained from SCR‐IM and SCR, to understand how submodels' integration affects the posterior distributions of estimated parameters. Based on our simulations, we found that population size estimates using SCR‐IM are more accurate and precise. In our stone marten case study, the SCR‐IM density estimation increased the precision by 37% when compared to the standard SCR model as regards to the coefficient of variation. This model has high potential to be used for species in which individual recognition by natural markings is not possible, therefore limiting the need to rely on invasive sampling procedures.

Understanding conflict and co-existence among Spiti Bhot community and large carnivores in high Himalaya: The case of Himalayan wolves

The wolves in the Hindukush–Himalayan region belong to one of the most basal lineages of Canis lupus, yet little is known about their ecology and behavior. In this study, we determine wolf movement and analyze diet patterns in contrast with studies from within its distribution range. We determine conflict perception and identify hotspots using ecological, social, and remotely sensed information. Wolf diet (n = 283 scats) constituted mostly of domestic prey (79%), while wild prey constituted 17.8% of the wolf diet. Interview-based questionnaire surveys revealed that 55% of the respondents claimed to have seen wolves. Over 98% of the respondents claimed wolves as a possible threat to various livestock in the study area. Marginal response curves through the MaxEnt model showed that wolf hotspots were positive in response to their density of location, landuse-landcover, village population, village density, and depredation. Comparisons between scat- and questionnaire-based depredation data showed that the perceived levels of depredation by wolves differed significantly from the actual proportion of livestock prey species consumed by wolves (χ2 = 99.64, p-value < 0.0001). Wolf conflict hotspots showed a very high conflict zone area of 36 km2, high conflict zone of 62 km2, medium conflict zone of 196 km2, and low conflict zone of 3,636 km2. Future conflict mitigation strategies may focus on such areas primarily to reduce livestock losses and enhance conservation outcomes. Negative perceptions toward wolves can be managed through a holistic conservation action plan in concert with the existing snow leopard conservation program alongside local traditions that do not hinder livelihood security.

A pilot study of the use of dry dog food as an alternative attractant in mesocarnivore studies

Dry dog food is a potential attractant for carnivores, but it is scarcely used in mesocarnivore studies. We tested its efficiency by placing 50 independent sampling stations consisting in trios of camera traps baited with either dry dog food and valerian extract and a control without any attractant. We obtained 84 independent contacts including 39 mesocarnivore sightings in 150 camera-night samples. Community composition estimates were affected by attractants: diversity was higher and dominance smaller when using dry dog food than when using valerian extract. Dry dog food elicited three times more contacts than control cameras (mean ± SE = 0.48 ± 0.04 vs 0.15 ± 0.02 contacts/camera). Our results suggest the potential efficiency of dry dog food as an alternative attractant, either alone or used in combination with other traditional inedible baits in mesocarnivore studies.

Spatio-temporal ecology of a carnivore community in middle atlas, NW of Morocco

In species that live in sympatry, some dimensions of their ecological niche can overlap, but coexistence is possible thanks to segregation strategies, being the differential use of space and time one of the most frequent. Through a pioneer study in North-West Africa based on a camera-trapping survey, we studied ecology features of a carnivores' community in the Middle Atlas Mountains, Morocco. We focused on how species shared (or not) the territory and their activity patterns. Camera trapping detected five carnivorous species: African golden wolf (Canis lupaster), red fox (Vulpes vulpes), domestic dog (Canis lupus familiaris), genet (Genetta genetta) and African wildcat (Felis lybica lybica). Generalized Linear Models confirmed different habitat selection patterns between these species. The presence of a small protected area or prey availability apparently were not determinant factors in the abundance of these species. Spatial segregation patterns were observed between the red fox with the domestic dog and between the red fox with the genet. Kernel density estimates showed strong temporal segregation of red fox and African golden wolf with regard to domestic dog, and suggested avoidance mechanisms for the triad red fox, genet and African golden wolf. Despite the influence of interspecific competition in the assembly of the community, human pressure was apparently the most relevant factor related with the spatio-temporal segregation in this territory.

Optimising camera trap height and model increases detection and individual identification rates for a small mammal, the numbat (Myrmecobius fasciatus)

Camera traps are widely used to collect data for wildlife management, but species-specific testing is crucial. We conducted three trials to optimise camera traps for detecting numbats (Myrmecobius fasciatus), a 500–700-g mammal. We compared detection rates from (1) Reconyx PC900 camera traps installed at heights ranging from 10–45cm, and (2) Reconyx PC900, Swift 3C standard and wide-angle camera traps with differing detection zone widths. Finally, we compared elevated, downward-angled time-lapse cameras installed at heights ranging from 1–2m to obtain dorsal images for individual numbat identification. Camera traps set at 25cm had the highest detection rates but missed 40% of known events. During model comparison, Swift 3C wide-angle camera traps recorded 89%, Swift 3C standard 51%, and Reconyx PC900 37% of known events. The number of suitable images from elevated, downward-angled cameras, depicting dorsal fur patterns, increased with increasing camera height. The use of well regarded camera trap brands and generic recommendations for set-up techniques cannot replace rigorous, species-specific testing. For numbat detection, we recommend the Swift 3C wide-angle model installed at 25-cm height. For individual numbat identification, elevated, downward-angled time-lapse cameras were useful; however, more research is needed to optimise this technique.

Ecological traits and the spatial structure of competitive coexistence among carnivores

Competition is a widespread interaction among carnivores, ultimately manifested through one or more dimensions of the species' ecological niche. One of the most explicit manifestations of competitive interactions regards spatial displacement. Its interpretation under a theoretical context provides an important tool to deepen our understanding of biological systems and communities, but also for wildlife management and conservation. We used Bayesian multispecies occupancy models on camera-trapping data from multiple sites in Southwestern Europe (SWE) to investigate competitive interactions within a carnivore guild, and to evaluate how species' ecological traits are shaping coexistence patterns. Seventeen out of 26 pairwise interactions departed from a hypothesis of independent occurrence, with spatial association being twice as frequent as avoidance. Association behaviors were only detected among mesocarnivores, while avoidance mainly involved mesocarnivores avoiding the apex predator (n = 4) and mesocarnivore-only interactions (n = 2). Body mass ratios, defined as the dominant over the subordinate species body mass, revealed an important negative effect ( β ^ = - 0.38 ; C I 95 = - 0.81 t o - 0.06 ) on co-occurrence probability, and support that spatially explicit competitive interactions are mostly expressed by larger species able to dominate over smaller ones, with a threshold in body mass ratios of ~4, above which local-scale intraguild coexistence is unlikely. We found a weak relationship between pairwise trophic niche overlap and the probability of coexistence ( β ^ = - 0.19 ; C I 95 = - 0.58 t o 0.21 ), suggesting that competition for feeding resources may not be a key driver of competition, at least at the scale of our analysis. Despite local-scale avoidance, regional-scale coexistence appears to be maintained by the spatial structuring of the competitive environment. We provide evidence that SWE ecosystems consist of spatially structured competitive environments, and propose that coexistence among near-sized species is likely achieved through the interplay of "facultative" and "behavioral" character displacements. Factors influencing carnivore coexistence likely include context-dependent density and trait-mediated effects, which should be carefully considered for a sound understanding of the mechanisms regulating these communities.

Hybridization between Felis silvestris silvestris and Felis silvestris catus in two contrasted environments in France

European wildcat (Felis silvestris silvestris) populations are fragmented throughout most of the whole range of the subspecies and may be threatened by hybridization with the domestic cat F.s. catus. The underlying ecological processes promoting hybridization remain largely unknown. In France, wildcats are mainly present in the northeast and signs of their presence in the Pyrenees have been recently provided. However, no studies have been carried out in the French Pyrenees to assess their exposure to hybridization. We compared two local populations of wildcats, one living in a continuous forest habitat in the French Pyrenees, the other living in a highly fragmented forest-agricultural landscape in northeastern France to get insights into the variability of hybridization rates. Strong evidence of hybridization was detected in northeastern France and not in the Pyrenees. Close kin in the Pyrenees were not found in the same geographic location contrary to what was previously reported for females in the northeastern wildcat population. The two wildcat populations were significantly differentiated (F ST = 0.072) to an extent close to what has been reported (F ST = 0.103) between the Iberian population, from which the Pyrenean population may originate, and the German population, which is connected to the northeastern population. The genetic diversity of the Pyrenean wildcats was lower than that of northeastern wildcat populations in France and in other parts of Europe. The lower hybridization in the Pyrenees may result from the continuity of natural forest habitats. Further investigations should focus on linking landscape features to hybridization rates working on local populations.

Improving mesocarnivore detectability with lures in camera-trapping studies

Context Camera trapping is commonly employed for studying carnivores because it provides better data than do other methods, and with lower costs. Increasing the probability of detecting the target species can reduce parameter uncertainty and survey effort required to estimate density and occurrence. Different methods, including attractants and baits, can be used to increase detectability. However, their efficacy has rarely been quantitatively assessed. Aims To quantify the efficacy of scent and bait attractants to increase the detection probability of mesocarnivores by camera trapping. Methods We tested two scent lures, valerian extract (Val) and lynx urine (LU), their combination (Val–LU), and a non-reward bait (i.e. not accessible to the animal), raw chicken, as carnivore attractants in two protected areas of central Spain. We used camera-trapping records under an occupancy-modelling framework to estimate attractant-specific detection probabilities for six mesocarnivore species, and quantified their effects by comparing these estimates with the baseline (i.e. no attractant) detectability. Key results The weekly detection probability of four mesocarnivore species (red fox, Vulpes vulpes, stone marten, Martes foina, common genet, Genetta genetta, and Eurasian badger, Meles meles) significantly increased when Val–LU (between 0.11 ± 0.07 and 0.67 ± 0.05) or chicken (between 0.31 ± 0.02 and 0.77 ± 0.22) were used as attractant, when compared with baseline detectability (between 0.01 ± 0.02 and 0.29 ± 0.05). Although rarely, wildcats (Felis silvestris) were mostly detected with Val–LU. The probability of detecting a species after k sampling occasions (7 days each) where it was present was highly improved with both Val–LU and chicken for all species (e.g. from 0.20 to 0.98 after four sampling occasions with chicken for the stone marten). Both attractants reduced the sampling time required to ascertain that a species was absent to between 42% and 15% of baseline values. Conclusions The tested attractants greatly improved the detectability of most Iberian mesocarnivores. Although chicken was preferable for some species such as stone marten, Val–LU is most efficient for detecting the whole mesocarnivore community, including rare species such as wildcats. Implications Attractant selection in studies using non-invasive detection methods must be supported by quantitative assessment of the detection probability associated to each attractant. Researchers must choose those attractants best fitting target species and study aims.

Effectiveness of different types of hair traps for brown bear research and monitoring

Non-invasive sampling by hair-trapping is increasingly used worldwide in wildlife research. Despite this rise and the potential of hair samples for ecology and conservation studies, the relative performance of hair collection devices has been rarely tested. Here, we compare the effectiveness of five types of hair traps for brown bears Ursus arctos in the Carpathian Mountains (SE Poland) and test the effects of trap type, season, number of days elapsed since trap installation and trap features on the trapping success in order to provide recommendations for optimal sampling in future studies. The trap types were corral, path-trap, "smola"(beechwood tar) tree-trap, turpentine tree-trap and natural rub. In 2010, we collected 858 hair samples during 2330 inspections of 175 hair traps and found that the most effective traps were smola tree-traps (mean percentage of successful inspections ± SD: 30.2% ± 26.0) and natural rubs (50.8% ± 16.7). Based on this finding, over the following 2 years we focused on 24 smola tree-traps and eight natural rubs. During this long-term survey (2010-2012, 969 inspections, 1322 samples collected) the trapping success increased with time and smola tree-traps achieved similar effectiveness to natural rubs (45.5% ± 29.7 and 45.9 ± 23.4, respectively). We show that when baiting smola tree-traps ten weeks prior to research or monitoring, sampling effectiveness can reach up to 30%. Taking into account the logistical and methodological constraints associated with detecting and using natural rubs for a proper survey design, we recommend using smola tree-traps baited in advance for hair sampling in wildlife studies.

Estimating carnivore community structures

Obtaining reliable estimates of the structure of carnivore communities is of paramount importance because of their ecological roles, ecosystem services and impact on biodiversity conservation, but they are still scarce. This information is key for carnivore management: to build support for and acceptance of management decisions and policies it is crucial that those decisions are based on robust and high quality information. Here, we combined camera and live-trapping surveys, as well as telemetry data, with spatially-explicit Bayesian models to show the usefulness of an integrated multi-method and multi-model approach to monitor carnivore community structures. Our methods account for imperfect detection and effectively deal with species with non-recognizable individuals. In our Mediterranean study system, the terrestrial carnivore community was dominated by red foxes (0.410 individuals/km²); Egyptian mongooses, feral cats and stone martens were similarly abundant (0.252, 0.249 and 0.240 individuals/km², respectively), whereas badgers and common genets were the least common (0.130 and 0.087 individuals/km², respectively). The precision of density estimates improved by incorporating multiple covariates, device operation, and accounting for the removal of individuals. The approach presented here has substantial implications for decision-making since it allows, for instance, the evaluation, in a standard and comparable way, of community responses to interventions.

An evaluation of hair-snaring devices for small-bodied carnivores in southwest China

Human population growth is a major threat to the biodiversity of mammals in China. Rapid development of infrastructure, pollution, and poor enforcement of environmental laws in China have altered the landscape and accelerated the extinction rates of mammals. To maintain biodiversity and conserve the mammals of China, it is essential to develop monitoring protocols for species of concern that are efficient, cost-effective, and current. It is now common practice for ecologists to survey mammals of interest using noninvasive sampling methods. These sampling techniques are affordable, require no handling of the target animals, and generally yield large samples. In China, such sampling methods have rarely been used and evaluated. For this study, we recorded the behavior of masked palm civets ( Paguma larvata ) and Siberian weasels ( Mustela sibirica ) to determine their relative preference for using different hair-snaring devices and evaluated the effectiveness of each device at collecting hair. Our goal was to determine which genetic sampling method(s) should be used to study masked palm civets and Siberian weasels in the future in Southwest China. In March–June of 2014, we monitored 13 hair-snare stations throughout the Main Valley of Laohegou Nature Reserve, Sichuan Province, China. Genetic analysis revealed that we collected 373 hair samples from civets and 47 hair samples from weasels over 104 and 26 sessions, respectively. Both civets and weasels seemed to prefer lure sticks to ground cubbies; however, the latter were more effective at collecting civet hair. Although glue sheets from lure sticks collected large samples of guard hair (> 10), no device in its current design was consistently effective at collecting weasel hair. We suggest researchers in Southwest China use ground cubbies as described in this study to collect hair from masked palm civets and test other cubby designs (e.g., longer gun brushes or smaller in size) for collecting hair from Siberian weasels.

人口增长是中国哺乳动物多样性危机的主要根源之一。在中国，基础建设的快速发展、环境污染，加之环境执法力度不足造成了哺乳动物的栖息地的退化，加速了动物的灭绝速率。为了维持生物多样性水平和保护中国的哺乳动物，有必要针对受关注的物种开发有效、低成本且通用的监测方法。现在，非损伤性取样方法正被生态学家普遍应用于哺乳动物的调查中。这些调查技术在成本上易于接受，不需要接触目标动物，并且通常可以得到大量可靠的样本。在中国，非损伤性取样方法的应用和评估还较少。本研究中，我们在四川省老河沟自然保护区评估了花面狸和黄鼬对毛发陷阱的访问偏好及陷阱收集动物毛发的有效性；目标是选出有效地遗传取样方法用于将来对花面狸和黄鼬的研究。从2014年3月到6月，我们在保护区主要山谷内设置了13个毛发陷阱站，在收集野生动物的毛发同时使用红外相机记录动物访问陷阱站时的行为。我们发现，相比于设置在地面的小室陷阱，花面狸和黄鼬都更喜欢访问直立的木桩陷阱，但是，小室陷阱能够更有效地收集花面狸的毛发。尽管固定有粘性薄片的木桩 陷阱能够少量收集带有直针毛的毛发（>10根）,但是我们评估的毛发陷阱都不能有效地收集黄鼬的 毛发。根据研究，我们建议研究人员在中国西南可以应用固定有枪刷的小室陷阱（如本研究中所评估的）收集花面狸的毛发，而用更长的枪刷，或者更小的小室陷阱，并固定粘性薄片收集黄鼬的毛发。

Strong spatial segregation between wildcats and domestic cats may explain low hybridization rates on the Iberian Peninsula

The European wildcat (Felis silvestris silvestris) is an endangered felid impacted by genetic introgression with the domestic cat (Felis silvestris catus). The problem of hybridization has had different effects in different areas. In non-Mediterranean regions pure forms of wildcats became almost extinct, while in Mediterranean regions genetic introgression is a rare phenomenon. The study of the potential factors that prevent the gene flow in areas of lower hybridization may be key to wildcat conservation. We studied the population size and spatial segregation of wildcats and domestic cats in a typical Mediterranean area of ancient sympatry, where no evidence of hybridization had been detected by genetic studies. Camera trapping of wild-living cats and walking surveys of stray cats in villages were used for capture-recapture estimations of abundance and spatial segregation. Results showed (i) a low density of wildcats and no apparent presence of putative hybrids; (ii) a very low abundance of feral cats in spite of the widespread and large population sources of domestic cats inhabiting villages; (iii) strong spatial segregation between wildcats and domestic/feral cats; and (iv) no relationship between the size of the potential population sources and the abundance of feral cats. Hence, domestic cats were limited in their ability to become integrated into the local habitat of wildcats. Ecological barriers (habitat preferences, food limitations, intra-specific and intra-guild competition, predation) may explain the severe divergences of hybridization impact observed at a biogeographic level. This has a direct effect on key conservation strategies for wildcats (i.e., control of domestic cats).

Best bait for your buck: bait preference for camera trapping north Australian mammals

Critical evaluations of bait attractiveness for camera trapping wildlife are scant even though use of the most attractive bait should improve detection of cryptic, threatened species. We aimed to determine the most attractive bait for camera trapping the northern hopping-mouse (Notomys aquilo) and sympatric mammals. We also tested the effectiveness of overhead camera trap orientation in identifying individual northern quolls (Dasyurus hallucatus) as this could be used to define a camera trap event for analysis purposes. Using white-flash camera traps, the attractiveness of four baits (peanut butter with oats, corn, sesame oil and sunflower kernels) and a control were compared for N. aquilo, D. hallucatus, the northern brown bandicoot (Isoodon macrourus) and the agile wallaby (Notamacropus agilis). Spot patterns of D. hallucatus were compared to determine the visitation rate of individuals. Peanut butter– and sesame oil–based baits were significantly more attractive to D. hallucatus, while I. macrourus strongly preferred the peanut butter bait. Bait type did not affect the mean number of events for N. aquilo or N. agilis. The consistently identifiable images of individual D. hallucatus were used to determine the optimal event delineator of 15 min. The improved techniques for camera trapping D. hallucatus should be valuable for future capture–recapture studies of this species. Camera trapping is a viable replacement for the ineffective method of indexing the abundance of N. aquilo using indirect signs.