Hair Snares Research Articles

Evaluation of nutria (Myocastor coypus) detection methods in Maryland, USA

Nutria (Myocaster coypus), invasive, semi-aquatic rodents native to South America, were introduced into Maryland near Blackwater National Wildlife Refuge (BNWR) in 1943. Irruptive population growth, expansion, and destructive feeding habits resulted in the destruction of thousands of acres of emergent marshes at and surrounding BNWR. In 2002, a partnership of federal, state and private entities initiated an eradication campaign to protect remaining wetlands from further damage and facilitate the restoration of coastal wetlands throughout the Chesapeake Bay region. Program staff removed nearly 14,000 nutria from five infested watersheds in a systematic trapping and hunting program between 2002 and 2014. As part of ongoing surveillance activities, the Chesapeake Bay Nutria Eradication Project uses a variety of tools to detect and remove nutria. Project staff developed a floating raft, or monitoring platform, to determine site occupancy. These platforms are placed along waterways and checked periodically for evidence of nutria visitation. We evaluated the effectiveness of monitoring platforms and three associated detection methods: hair snares, presence of scat, and trail cameras. Our objectives were to (1) determine if platform placement on land or water influenced nutria visitation rates, (2) determine if the presence of hair snares influenced visitation rates, and (3) determine method-specific detection probabilities. Our analyses indicated that platforms placed on land were 1.5–3.0 times more likely to be visited than those placed in water and that platforms without snares were an estimated 1.7–3.7 times more likely to be visited than those with snares. Although the presence of snares appears to have discouraged visitation, seasonal variation may confound interpretation of these results. Scat was the least effective method of determining nutria visitation, while hair snares were as effective as cameras. Estimated detection probabilities provided by occupancy modeling were 0.73 for hair snares, 0.71 for cameras and 0.40 for scat. We recommend the use of hair snares on monitoring platforms as they are the most cost-effective and reliable detection method available at this time. Future research should focus on determining the cause for the observed decrease in nutria visits after snares were applied.

Habitat associations in a recolonizing, low‐density black bear population

AbstractAmerican black bears are closely associated with forest habitat. They were nearly extirpated from the Central Interior Highlands, United States, in the early twentieth century, but have recolonized this part of the range since the 1960s. Due to lower population densities (as a result of recent recolonization), we hypothesized that bears in this region would show strong associations with forest habitat at both the home range and landscape scale. To test this, we analyzed hair snare and GPS telemetry data from five sampling grids with a combined spatial capture–recapture and resource selection function model to investigate individual space use within home ranges and landscape scale variation in density of black bears in the southern Missouri part of the Interior Highlands. We performed a linear discriminant analysis to identify habitat correlates of black bear density. We found that at the home range level, bears selected for more forested habitat and steeper slopes. Black bear density varied among sampling grids from 0.842 to 10.248 individuals/100 km2 which is at the low end of the spectrum of reported black bear densities. There were no clear habitat correlates for among‐grid variation in density, but in the three higher‐density grids, density declined with increasing forest cover and increasing distance from human settlements. This suggests that the bear populations benefited from more heterogeneous habitat and that rural settlements may represent food resources. Exploiting these anthropogenic resources could be facilitated by the fact that bears in our study were not hunted and were viewed as a novelty rather than a nuisance, which may lead to low perceived risk from anthropogenic sources. Our results highlight the need to interpret habitat associations of American black bears not only at local scales but also in the landscape context.

Spatial Capture–Recapture: A Promising Method for Analyzing Data Collected Using Artificial Cover Objects

Abstract Spatial capture–recapture (SCR) is a relatively recent development in ecological statistics that provides a spatial context for estimating abundance and space use patterns, and improves inference about absolute population density. SCR has been applied to individual encounter data collected noninvasively using methods such as camera traps, hair snares, and scat surveys. Despite the widespread use of capture-based surveys to monitor amphibians and reptiles, there are few applications of SCR in the herpetological literature. We demonstrate the utility of the application of SCR for studies of reptiles and amphibians by analyzing capture–recapture data from Red-Backed Salamanders, Plethodon cinereus, collected using artificial cover boards. Using SCR to analyze spatial encounter histories of marked individuals, we found evidence that density differed little among four sites within the same forest (on average, 1.59 salamanders/m2) and that salamander detection probability peaked in early October (Julia...

Effects of sampling scale on American black bear spatial genetic structure

Abstract: Sampling bias can lead to erroneous interpretations of spatial genetic structure that can subsequently impact conservation efforts and management decisions. Genetic sampling of rare and elusive species can be challenging and, by necessity, samples are often collected opportunistically from multiple sources that could differ in spatial dispersion and timing of collection. Here we quantified the effects of timing of sample collection and sampling methods on spatial and temporal variability in sample dispersion and measures of American black bear (Ursus americanus) local spatial genetic structure. Hair (N = 890) and tissue (N = 1,017) samples were collected from Michigan's Northern Lower Peninsula (USA) during the summer using non-invasive (hair snares) and autumn harvest methods during 2003, 2005, and 2009. Point pattern analyses of sample dispersion revealed that sample density did not differ significantly between seasons or among years. Measures of spatial genetic structure (i.e., spatial autoc...

Accounting for behavioural response to capture when estimating population size from hair snare studies with missing data

Summary Hair snares have become an established method for obtaining mark‐recapture data for population size estimation of Ursids and have recently been used to study other species including other carnivores, small mammals and ungulates. However, bias due to a behavioural response to capture in the presence of missing data has only recently been recognized and no statistical methodology exists to accommodate it. In a hair snare mark‐recapture experiment, data can be missing if animals encounter a hair snare without leaving a hair sample, poor‐quality samples are not genotyped, a fraction of all samples collected are genotyped due to cost considerations (subsampling) and/or not all genotyped hair samples provide an individual identification. These are all common features of hair snare mark‐recapture experiments. Here, we present methodology that accounts for a behavioural response to capture in the presence of missing data from (i) subsampling and (ii) failure of hair samples to produce an individual identification. Four subprocesses are modelled–animal capture, hair deposition, researcher subsampling and DNA amplification with key parameters estimated from functions of the number of hair samples left by individuals at traps. We assess the properties of this methodology (bias and interval coverage) via simulation and then apply this methodology to a previously published data set. Our methodology removes bias and provides nominal interval coverage of population size for the simulation scenarios considered. In the example data set, we find that removing 75% of the hair samples leads to a 40% lower estimate of population size. Our methodology corrects about half of this bias and we identify a second source of bias that has not previously been reported associated with differential trap visitation rates among individuals within trapping occasions. Our methodology will allow researchers to reliably estimate the size of a closed population in the presence of a behavioural response to capture and missing data for a subset of missing data scenarios. It also provides a framework for understanding this generally unrecognized problem and for further extension to handle other missing data scenarios.

Trap Array Configuration Influences Estimates and Precision of Black Bear Density and Abundance

Spatial capture-recapture (SCR) models have advanced our ability to estimate population density for wide ranging animals by explicitly incorporating individual movement. Though these models are more robust to various spatial sampling designs, few studies have empirically tested different large-scale trap configurations using SCR models. We investigated how extent of trap coverage and trap spacing affects precision and accuracy of SCR parameters, implementing models using the R package secr. We tested two trapping scenarios, one spatially extensive and one intensive, using black bear (Ursus americanus) DNA data from hair snare arrays in south-central Missouri, USA. We also examined the influence that adding a second, lower barbed-wire strand to snares had on quantity and spatial distribution of detections. We simulated trapping data to test bias in density estimates of each configuration under a range of density and detection parameter values. Field data showed that using multiple arrays with intensive snare coverage produced more detections of more individuals than extensive coverage. Consequently, density and detection parameters were more precise for the intensive design. Density was estimated as 1.7 bears per 100 km2 and was 5.5 times greater than that under extensive sampling. Abundance was 279 (95% CI = 193–406) bears in the 16,812 km2 study area. Excluding detections from the lower strand resulted in the loss of 35 detections, 14 unique bears, and the largest recorded movement between snares. All simulations showed low bias for density under both configurations. Results demonstrated that in low density populations with non-uniform distribution of population density, optimizing the tradeoff among snare spacing, coverage, and sample size is of critical importance to estimating parameters with high precision and accuracy. With limited resources, allocating available traps to multiple arrays with intensive trap spacing increased the amount of information needed to inform parameters with high precision.

Complementary use of motion-activated cameras and unbaited wire snares for DNA sampling reveals diel and seasonal activity patterns of brown bears (Ursus arctos) foraging on adult sockeye salmon (Oncorhynchus nerka)

The seasonal and diel movements of predators to take advantage of shifts in prey availability are fundamental elements of their foraging ecology, and also have consequences for the prey populations. In this study, we used complementary noninvasive techniques (motion-activated cameras and hair snares) to investigate seasonal and diel activity of brown bears (Ursus arctos L., 1758) along six proximate streams supporting spawning populations of sockeye salmon (Oncorhynchus nerka (Walbaum in Artedi, 1792)) in southwestern Alaska. Camera records over 3 years showed a rapid increase in bear activity around the time salmon arrived in the streams, with differences among streams corresponding to differences in salmon phenology. Bears were active throughout the day and night, but there were clear crepuscular peaks when camera data were pooled. When wire snares (to collect hair samples) were paired with cameras, the data showed similar seasonal patterns, but each technique detected bears missed by the other. Roughly equal numbers of bears left hair but no camera image, and images but no hair, at paired sites. Taken together, the results indicated a close correspondence between bear activity and salmon timing, differences in diel timing among streams, and the complementarity of data obtained by motion-activated cameras and hair snares.

Chesapeake Bay Nutria Eradication Project: Update 2009-2014

Feral nutria were established near Blackwater National Wildlife Refuge (BNWR) in Dorchester County Maryland in 1943 after a failed attempt to create a fur industry. As the population expanded in number and distribution, natural resource managers began to notice an accelerating trend in wetland loss in the areas most heavily infested by nutria. By the late 1980s, an estimated 35,000 nutria occupied BNWR, which had seen approximately 5,000 acres of emergent marsh converted to shallow open water habitats and mudflats. Exclusion studies in the 1990s demonstrated a direct link between nutria and marsh loss, and by 2000 officials had procured funding to initiate an eradication feasibility study. This paper provides a historical overview of the eradication campaign that has been underway since 2002. The Chesapeake Bay Nutria Eradication Project (CBNEP) is a cooperative partnership between the U.S. Fish and Wildlife Service, USDA Wildlife Services program, and numerous state and non-governmental organizations. The CBNEP employs an adaptive management strategy utilizing systematic trapping carried out by salaried wildlife specialists to eliminate nutria from infested watersheds. We present a phased approach that allows us to continually expand the eradication zone and maintain nutria-free areas with a relatively small staff. Through an active research and development program, we have innovated new tools and techniques for trapping and detecting nutria including: floating trap sets, attractants, decoys, remote triggered cameras, detection platforms, hair snares, and Judas nutria. To date, we have reduced nutria populations to near-zero densities across 250,000 acres of emergent marsh. Based on extensive surveys, remaining populations should be removed by the end of 2014. Following a 2-year verification/biosecurity protocol, we hope to have nutria eradicated from the Delmarva Peninsula by 2017.

Efficiency of hair snares and camera traps to survey mesocarnivore populations

Mammalian carnivore communities affect entire ecosystem functioning and structure. However, their large spatial requirements, preferred habitats, low densities, and elusive behavior deem them difficult to study. In recent years, noninvasive techniques have become much more common as they can be used to monitor multiple carnivore species across large areas at a relatively modest cost. Hair snares have the potential to fulfill such requirements, but have rarely been tested in Europe. Our objective was to quantitatively assess the effectiveness of hair snares for surveying mesocarnivores in the Iberian Peninsula (Southwestern Europe), by comparison with camera-trapping. We used an occupancy modeling framework to assess method-specific detectability and occupancy estimates and hypothesized that detection probabilities would be influenced by season, sampling method, and habitat-related variables. A total of 163 hair samples were collected, of which 136 potentially belonged to mesocarnivores. Genetic identification success varied with diagnostic method: 25.2 % using mitochondrial CR, and 9.9 % using the IRBP nuclear gene. Naïve occupancy estimates were, in average, 5.3 ± 1.2 times higher with camera-trapping than with hair-snaring, and method-specific detection probabilities revealed that camera traps were, in average, 6.7 ± 1.1 times more effective in detecting target species. Overall, few site-specific covariates revealed significant effects on mesocarnivore detectability. Camera traps were a more efficient method for detecting mesocarnivores and estimating their occurrence when compared to hair snares. To improve hair snares' low detection probabilities, we suggest increasing the number of sampling occasions and the frequency at which hair snares are checked. With some refinements to increase detection rates and the success of genetic identification, hair-snaring methods may be valuable for providing deeper insights into population parameters, attained through adequate analysis of genetic information, that is not possible with camera traps.

Spatially explicit models for inference about density in unmarked or partially marked populations

Recently developed spatial capture-recapture (SCR) models represent a major advance over traditional capture-recapture (CR) models because they yield explicit estimates of animal density instead of population size within an unknown area. Furthermore, unlike nonspatial CR methods, SCR models account for heterogeneity in capture probability arising from the juxtaposition of animal activity centers and sample locations. Although the utility of SCR methods is gaining recognition, the requirement that all individuals can be uniquely identified excludes their use in many contexts. In this paper, we develop models for situations in which individual recognition is not possible, thereby allowing SCR concepts to be applied in studies of unmarked or partially marked populations. The data required for our model are spatially referenced counts made on one or more sample occasions at a collection of closely spaced sample units such that individuals can be encountered at multiple locations. Our approach includes a spatial point process for the animal activity centers and uses the spatial correlation in counts as information about the number and location of the activity centers. Camera-traps, hair snares, track plates, sound recordings, and even point counts can yield spatially correlated count data, and thus our model is widely applicable. A simulation study demonstrated that while the posterior mean exhibits frequentist bias on the order of 5-10% in small samples, the posterior mode is an accurate point estimator as long as adequate spatial correlation is present. Marking a subset of the population substantially increases posterior precision and is recommended whenever possible. We applied our model to avian point count data collected on an unmarked population of the northern parula (Parula americana) and obtained a density estimate (posterior mode) of 0.38 (95% CI: 0.19-1.64) birds/ha. Our paper challenges sampling and analytical conventions in ecology by demonstrating that neither spatial independence nor individual recognition is needed to estimate population density - rather, spatial dependence can be informative about individual distribution and density.

Varying effort in capture–recapture studies

Summary The standard spatial capture–recapture design for sampling animal populations uses a fixed array of detectors, each operated for the same time. However, methods are needed to deal with the unbalanced data that may result from unevenness of effort due to logistical constraints, partial equipment failure or pooling of data for analysis. We describe adjustments for varying effort for three types of data each with a different probability distribution for the number of observations per individual per detector per sampling occasion. A linear adjustment to the expected count is appropriate for Poisson‐distributed counts (e.g. faeces per searched quadrat). A linear adjustment on the hazard scale is appropriate for binary (Bernoulli‐distributed) observations at either traps or binary proximity detectors (e.g. automatic cameras). Data pooled from varying numbers of binary detectors have a binomial distribution; adjustment is achieved by varying the size parameter of the binomial. We compared a hazard‐based adjustment to a more conventional covariate approach in simulations of one temporal and one spatial scenario for varying effort. The hazard‐based approach was the more parsimonious and appeared more resistant to bias and confounding. We analysed a dataset comprising DNA identifications of female grizzly bears Ursus arctos sampled asynchronously with hair snares in British Columbia in 2007. Adjustment for variation in sampling interval had negligible effect on density estimates, but unmasked an apparent decline in detection probability over the season. Duration‐dependent decay in sample quality is an alternative explanation for the decline that could be included in future models. Allowing for known variation in effort ensures that estimates of detection probability relate to a consistent unit of effort and improves the fit of detection models. Failure to account for varying effort may result in confounding between effort and density variation in time or space. Adjustment for effort allows rigorous analysis of unbalanced data with little extra cost in terms of precision or processing time. We suggest it should become routine in capture–recapture analyses. The methods have been made available in the R package secr.

Assessing the efficacy of hair snares as a method for noninvasive sampling of Neotropical felids

Hair snares have been used in North and Central America for a long time in assessment and monitoring studies of several mammalian species. This method can provide a cheap, suitable, and efficient way to monitor mammals because it combines characteristics that are not present in most alternative techniques. However, despite their usefulness, hair snares are rarely used in other parts of the world. The aim of our study was to evaluate the effectiveness of hair snares and three scent lures (cinnamon, catnip, and vanilla) in the detection of felids in one of the largest remnants of the Brazilian Atlantic Forest. We performed tests with six captive felid species - Panthera onca (Linnaeus, 1758), Leopardus pardalis (Linnaeus, 1758), L. tigrinus (Schreber, 1775), L. wiedii (Schinz, 1821), Puma concolor (Linnaeus, 1771), and P. yagouaroundi (É. Geoffroy Saint-Hilaire, 1803) - to examine their responses to the attractants, and to correlate those with lure efficiency in the field. The field tests were conducted at the Parque Estadual Pico do Marumbi, state of Paraná, Brazil. Hair traps were placed on seven transects. There were equal numbers of traps with each scent lure, for a total of 1,551 trap-days. In captivity, vanilla provided the greatest response, yet no felids were detected in the field with any of the tested lures, although other species were recorded. Based on the sampling of non-target species, and the comparison with similar studies elsewhere, this study points to a possible caveat of this method when rare species or small populations are concerned. Meanwhile, we believe that improved hair snares could provide important results with several species in the location tested and others.

How Does Spatial Study Design Influence Density Estimates from Spatial Capture-Recapture Models?

When estimating population density from data collected on non-invasive detector arrays, recently developed spatial capture-recapture (SCR) models present an advance over non-spatial models by accounting for individual movement. While these models should be more robust to changes in trapping designs, they have not been well tested. Here we investigate how the spatial arrangement and size of the trapping array influence parameter estimates for SCR models. We analysed black bear data collected with 123 hair snares with an SCR model accounting for differences in detection and movement between sexes and across the trapping occasions. To see how the size of the trap array and trap dispersion influence parameter estimates, we repeated analysis for data from subsets of traps: 50% chosen at random, 50% in the centre of the array and 20% in the South of the array. Additionally, we simulated and analysed data under a suite of trap designs and home range sizes. In the black bear study, we found that results were similar across trap arrays, except when only 20% of the array was used. Black bear density was approximately 10 individuals per 100 km2. Our simulation study showed that SCR models performed well as long as the extent of the trap array was similar to or larger than the extent of individual movement during the study period, and movement was at least half the distance between traps. SCR models performed well across a range of spatial trap setups and animal movements. Contrary to non-spatial capture-recapture models, they do not require the trapping grid to cover an area several times the average home range of the studied species. This renders SCR models more appropriate for the study of wide-ranging mammals and more flexible to design studies targeting multiple species.

Comparison of the effectivity of different snare types for collecting and retaining hair from Eurasian Lynx (Lynx lynx)

Genetic methods are increasingly being used as noninvasive tools to survey populations of wild animals. One challenge of these methods is the sampling of genetic material from the target species. Genetic material of various predators, such as bears, canids, and felids, has been successfully obtained from both hair trapped in snares and scat. However, there is currently no standard procedure for sampling genetic material from the Eurasian Lynx (Lynx lynx). We tested established and newly developed hair snares in two near-natural lynx enclosures in the Bavarian Forest National Park. All snares consisted of a wooden post; they differed in the type of material attached to the post for snaring hair: carpet (velour with 40 nails), wildcat (spruce wood with 2–3 mm deep, horizontal and diagonal ridges), wire brush, doormat, or rubber bands (250 g of rubber bands wrapped around the post). We determined the acceptance of the hair snares by the animals by observing their behavior with the aid of video cameras. The number of rubbing events on the different trap types did not significantly differ, but the rubbing duration was longer for the doormat hair snare. The wire brush hair snare collected the highest total amount of hair and — beside the carpet — the highest amount of hair per unit of time. Almost all hair trapped on the wire brush snare were retained during a 2-week exposure to the elements outside of the enclosures. The results of our study may hold for other felid species with hair characteristics similar to those of lynx.

Genetic tagging reveals a significant impact of poison baiting on an invasive species

AbstractGlobally, invasive predators are major pests of agriculture and biodiversity and are the focus of comprehensive control programs. Because these species are typically elusive, wary of traps, and occur at low densities, their fundamental population dynamics are difficult to determine and quantitative evaluations of control programs are rarely conducted. Noninvasive DNA analysis has the potential to resolve this long‐standing limitation to pest management. We carried out a landscape‐scale experiment to quantify reduction in the abundance of a red fox (Vulpes vulpes) population when baited with sodium fluoroacetate (1080) poison (the most widely used method of fox control in Australia). We collected fox hairs with hair snares during 4 4‐day sessions over the course of 6 months at a site in semi‐arid Western Australia. The first session took place in late summer just prior to when juvenile foxes typically disperse, and the final session followed aerial baiting with 1080 poison. We obtained consensus microsatellite genotypes from 196 samples, and used them to conduct both spatially explicit and open model capture–recapture analysis. Twenty‐eight percent of trap nights yielded hair samples suitable for identification of individual foxes, which is more than an order of magnitude greater than trapping rates reported with conventional techniques. Fox density changed little during 3 pre‐baiting sessions and averaged 0.73 foxes/km2 (±0.33 SE), which is less than most previous trap‐based estimates for Australian foxes. Density dropped significantly in response to baiting to 0.004 foxes/km2. Prior to baiting, the apparent survival of foxes remained static (0.72 ± 0.14 SE), but in response to baiting it dropped precipitously and was effectively zero. This experiment provides the first quantitative assessment of the effectiveness of 1080 poison baiting for reducing fox density, and in this case demonstrates it to be a highly effective method for culling foxes from a region. Further, it demonstrates that noninvasive DNA analysis will provide significantly more data than conventional trapping methods. This method is likely to provide greater precision and accuracy than conventional methods and therefore result in more robust evaluations of management strategies for the fox in Australia, and for cryptic species elsewhere. © 2011 The Wildlife Society.

Bobcats Exhibit Low Detection Rates at Hair Collection Stations in East Texas

We evaluated the detection rate for hair snare sampling for bobcats (Lynx rufus) using collocated hair snares and infrared-triggered cameras at 20 locations on private property in eastern Texas. Hair snare and camera stations were located together and included both visual and olfactory attractants. In 1,680 trap-nights we photographically documented 15 visits by bobcats but collected only one bobcat hair sample. Our observations suggested limited rubbing behavior by bobcats at hair snares and did not support any influence by sympatric carnivores (e.g., gray fox, Urocyon cinereoargenteus). Low rub frequency may limit the utility of these techniques for bobcats and we suggest that alternate techniques such as camera surveys or fecal DNA collection may be more suitable.

Evaluation of noninvasive genetic sampling methods for cougars in Yellowstone National Park

AbstractConventional methods for monitoring cougar, Puma concolor, populations involve capture, tagging, and radio‐collaring, but these methods are time‐consuming, expensive, and logistically challenging. For difficult‐to‐study species such as cougars, noninvasive genetic sampling (NGS) may be a useful alternative. The ability to identify individuals from samples collected through NGS methods provides many opportunities for developing population‐monitoring tools, but the utility of these survey methods is dependent upon collection of samples and accurate genotyping of those samples. In January 2003, we initiated a 3‐yr evaluation of NGS methods for cougars using a radio‐collared population in Yellowstone National Park (YNP), USA. Our goals were to: 1) determine which DNA collection method, hair snares or snow tracking, provided a better method for obtaining samples for genetic analysis, 2) evaluate reliability of the genetic data derived from hair samples collected in the field, and 3) evaluate the potential of NGS for demographic monitoring of cougar populations. Snow tracking yielded more hair samples and was more cost effective than snagging hair with rub pads. Samples collected from bed sites and natural hair snags (e.g., branch tips, thorn bushes) while snow tracking accurately identified and sexed 22 individuals (9 F, 13 M). The ratio of the count from snow tracking to the count from radio‐telemetry was 15:24 in winter 2004, 13:12 in 2005, and 22:29 for both years combined. Annual capture probabilities for obtaining DNA from snow tracking varied considerably between years for females (0.42 in 2004 and 0.88 in 2005) but were more consistent for males (0.77 in 2004 and 0.88 in 2005). Our results indicate that snow tracking can be an efficient, reliable NGS method for cougars in YNP and has potential for estimating demographic and genetic parameters of other carnivore populations in similar climates. © 2011 The Wildlife Society.

A Noninvasive Hair Sampling Technique to Obtain High Quality DNA from Elusive Small Mammals

Noninvasive genetic sampling approaches are becoming increasingly important to study wildlife populations. A number of studies have reported using noninvasive sampling techniques to investigate population genetics and demography of wild populations1. This approach has proven to be especially useful when dealing with rare or elusive species2. While a number of these methods have been developed to sample hair, feces and other biological material from carnivores and medium-sized mammals, they have largely remained untested in elusive small mammals. In this video, we present a novel, inexpensive and noninvasive hair snare targeted at an elusive small mammal, the American pika (Ochotona princeps). We describe the general set-up of the hair snare, which consists of strips of packing tape arranged in a web-like fashion and placed along travelling routes in the pikas’ habitat. We illustrate the efficiency of the snare at collecting a large quantity of hair that can then be collected and brought back to the lab. We then demonstrate the use of the DNA IQ system (Promega) to isolate DNA and showcase the utility of this method to amplify commonly used molecular markers including nuclear microsatellites, amplified fragment length polymorphisms (AFLPs), mitochondrial sequences (800bp) as well as a molecular sexing marker. Overall, we demonstrate the utility of this novel noninvasive hair snare as a sampling technique for wildlife population biologists. We anticipate that this approach will be applicable to a variety of small mammals, opening up areas of investigation within natural populations, while minimizing impact to study organisms.

A Noninvasive Hair Sampling Technique to Obtain High Quality DNA from Elusive Small Mammals

Noninvasive genetic sampling approaches are becoming increasingly important to study wildlife populations. A number of studies have reported using noninvasive sampling techniques to investigate population genetics and demography of wild populations1. This approach has proven to be especially useful when dealing with rare or elusive species2. While a number of these methods have been developed to sample hair, feces and other biological material from carnivores and medium-sized mammals, they have largely remained untested in elusive small mammals. In this video, we present a novel, inexpensive and noninvasive hair snare targeted at an elusive small mammal, the American pika (Ochotona princeps). We describe the general set-up of the hair snare, which consists of strips of packing tape arranged in a web-like fashion and placed along travelling routes in the pikas’ habitat. We illustrate the efficiency of the snare at collecting a large quantity of hair that can then be collected and brought back to the lab. We then demonstrate the use of the DNA IQ system (Promega) to isolate DNA and showcase the utility of this method to amplify commonly used molecular markers including nuclear microsatellites, amplified fragment length polymorphisms (AFLPs), mitochondrial sequences (800bp) as well as a molecular sexing marker. Overall, we demonstrate the utility of this novel noninvasive hair snare as a sampling technique for wildlife population biologists. We anticipate that this approach will be applicable to a variety of small mammals, opening up areas of investigation within natural populations, while minimizing impact to study organisms.

Hair-Snares: A Non-Invasive Method for Monitoring Felid Populations in the Selva Lacandona, Mexico

Non-invasive techniques such as hair snares have been used in conjunction with molecular methods to study species that occur at low densities and have elusive behavior, as an alternative to invasive methods such as trapping and hunting. This study was designed to evaluate the use of hair snares as a non-invasive method for the collection of felid and other mammalian samples in the tropical rainforest of the Selva Lacandona, Chiapas, Mexico. Hair snares were placed along transects in Montes Azules Biosphere Reserve for four months a year in 2005 and 2006. Hairs were selected based on morphological characteristics and identification of species was done based on a diagnostic portion of mtDNA cytochrome b region. A total of 389 hits on 888 hair-snare checks were recorded, representing a capture rate of 43%. The species identified included margay ( Leopardus wiedii, n=2), ocelot ( Leopardus pardalis, n=1), jaguarundi ( Puma yagouaroundi, n=1), gray fox ( Urocyon cinereoargenteus, n=1), tayra ( Eira barbara, n=3), coati ( Nasua narica, n=1), four-eyed opossum ( Metachirus nudicaudatus, n=6), and common opossum ( Didelphis marsupialis, n=16). The present study is the first to report the successful collection of hair samples from jaguarundi and margay in the wild and hair samples from ocelots in tropical areas. The deficit of information on carnivore populations in tropical rainforests is due mainly to the lack of appropriate methodologies that are reliable and cost-effective. This study supports the assumption that hair-snaring is viable and cost-effective in ecosystems such as the Selva Lacandona, particularly when monitoring carnivore populations that have wide geographic distributions and low densities.