Monitoring postrelease establishment and movement of animals is important in evaluating conservation translocations. We translocated 39 wild pine martens Martes martes (19 females, 20 males) from ...Scotland to Wales. We released them into forested areas with no conspecifics in 2015, followed by a second release in 2016, alongside the previously released animals. We used radio‐tracking to describe postrelease movement and habitat selection. Six martens (15%) were not re‐encountered during the tracking period, of which four undertook long‐distance dispersal. For the remaining individuals, we characterized two phases of movement, “exploration” followed by “settlement,” that differed between releases. In the first release, martens remained in exploration phase for a mean of 14.5 days (SE = 3.9 days) and settled at a mean distance of 8.7 km (SE = 1.8 km) from release sites, whereas martens released in year two, alongside resident conspecifics, traveled away from release sites at a faster rate, settling sooner, at a mean of 6.6 days (SE = 1.8 days), but further, at a mean distance of 14.0 km (SE = 1.7 km) from release sites. Animals released in year one did not exhibit habitat preferences overall but within forests they favored recently felled areas, whereas animals released in year two showed strong selection for forested habitat but did not discriminate between forest types. The presence of conspecifics appeared influential for settlement and site fidelity of translocated martens and was associated with more rapid but more distant dispersal of the later cohort. Releases of animals in close proximity appeared to promote site fidelity and rapid establishment of ranges in the recipient environment.
We translocated 39 wild pine martens Martes martes (19 females, 20 males) from Scotland to Wales. We released them into forested areas with no conspecifics in 2015, with a second release in 2016, alongside previously released animals. The presence of conspecifics appeared influential for settlement and site fidelity of translocated martens but was associated with more distant and more rapid dispersal of the later cohort. Releases of animals in close proximity appeared to promote site fidelity and rapid establishment of ranges in the recipient environment.
The family Mustelidae is the largest among the order Carnivora. While we know a great deal about certain species, there is still a lack of information about many mustelids.
We first investigated the ...International Union for Conservation of Nature (IUCN) Red List species‐level assessments for each mustelid species. Then, we undertook a systematic review of the scientific literature with the aim of identifying the primary threats and subthreats reported, and which species are most studied. Threats are defined by the IUCN as “the proximate human activities or processes that have impacted, are impacting, or may impact the status of the taxon”.
We analysed 1003 published articles. For each article, we collected year of publication, geographical zone of each study, species studied, and the threats and subthreats identified.
The majority of species (62%) were classified as Least Concern on the IUCN Red List, but 31 out of 63 species were found to be declining globally and only two species were increasing. The species studied and location of studies were biased, with 72% of studies undertaken in North America or Europe and focussing on very few species. A high proportion of species distributed predominantly in the tropics were categorised as declining, and threats linked with hunting, fishing, and logging were identified as the most common for mustelids by the IUCN Red List and in the scientific literature. Differences in the proportion of threats affecting each subfamily were also reported.
The nature of threats varies in different parts of the world and between species. It is essential to undertake more research with a strong focus towards species in highly biodiverse regions. A greater understanding of threats such as wildlife pet trade, emerging diseases, and climate change must also be central to prevent declines.
The family Mustelidae is the largest among the order Carnivora. While we know a great deal about certain species, there is still a lack of information about many mustelids. Here, we investigated the International Union for Conservation of Nature (IUCN) Red List species‐level assessments for each mustelid species. Then, we undertook a systematic review of the scientific literature with the aim of identifying the primary threats and subthreats reported, and which species are most studied. We found that 31 out of 63 species were found to be declining globally and only two species were increasing. A high proportion of species distributed predominantly in the tropics were categorised as declining, and threats linked with hunting, fishing, and logging were identified as the most common for mustelids by the IUCN Red List and in the scientific literature. Most studies (72%) took place in North America or Europe and focused on very few species. It is therefore essential to undertake more research with a strong focus towards species in highly biodiverse regions. A greater understanding of threats such as wildlife pet trade, emerging diseases, and climate change must also be central to prevent declines.
After historical declines in population sizes and ranges, we compare and contrast the recent history and contemporary variation in the status of Great Britain's eight native mammalian carnivore ...species from the 1960s to 2017.
Wildcat Felis silvestris conservation status is unfavourable and is masked by hybridisation with domestic cats Felis catus. Red foxes Vulpes vulpes remain widespread but are currently declining. European otter Lutra lutra, European pine marten Martes martes and European polecat Mustela putorius populations are characterised by rapid recovery. Otters have almost completely recolonised Great Britain, polecats have expanded their range throughout southern Britain from refugia in Wales and pine martens have expanded their range from the Scottish Highlands. European badgers Meles meles have generally increased in population density. Status assessments of stoats Mustela erminea and weasels Mustela nivalis are data‐deficient but available evidence suggests that stoats may have increased while weasels may have declined.
Anthropogenic processes influencing carnivore status include legal protections, habitat quality, reintroductions, predator control, pollutants, hybridisation and diseases and their associated control practices. Population effects of contaminants, such as anticoagulant rodenticides, remain poorly characterised. The widespread interface with domestic and feral cats makes the wildcat's situation precarious. Recent declines in rabbit Oryctolagus cuniculus populations are a concern, given that several carnivore species depend on them as food.
We conclude that, with the exception of the wildcat, the status of Great Britain's mammalian carnivores has markedly improved since the 1960s. Better understanding of the social aspects of interactions between humans and expanding predator populations is needed if conflict is to be avoided and long‐term co‐existence with people is to be possible.
The European polecat (Mustela putorius) is a mammalian predator which occurs across much of Europe east to the Ural Mountains. In Great Britain, following years of persecution the range of the ...European polecat contracted and by the early 1900s was restricted to unmanaged forests of central Wales. The European polecat has recently undergone a population increase due to legal protection and its range now overlaps that of feral domestic ferrets (Mustela putorius furo). During this range expansion, European polecats hybridized with feral domestic ferrets producing viable offspring. Here, we carry out population-level whole-genome sequencing on 8 domestic ferrets, 19 British European polecats, and 15 European polecats from the European mainland. We used a range of population genomics methods to examine the data, including phylogenetics, phylogenetic graphs, model-based clustering, phylogenetic invariants, ABBA-BABA tests, topology weighting, and Fst. We found high degrees of genome introgression in British polecats outside their previous stronghold, even in those individuals phenotyped as "pure" polecats. These polecats ranged from presumed F1 hybrids (gamma = 0.53) to individuals that were much less introgressed (gamma = 0.2). We quantify this introgression and find introgressed genes containing Fst outliers associated with cognitive function and sight.
Monitoring small mustelids like weasels
Mustela nivalis
and stoats
M. erminea
is challenging as they are rarely seen, leave scant field signs and display avoidance behaviour towards traps and ...monitoring devices. The Irish stoat
M. erminea hibernica
is a subspecies endemic to Ireland and the Isle of Man, and despite being widespread in Ireland, no information exists on its population status due to the difficulty of detection. We compared the efficacy of two camera trap methods to detect Irish stoats in counties Mayo and Galway, Republic of Ireland. Firstly, the ‘Mostela’ (a modified camera trapping device comprising a camera trap and a tracking tunnel inside a wooden box) and secondly, an external camera trap deployed outside the box. We used a single-season occupancy model to estimate the probability of detection and occupancy of Irish stoat using these two methods at 12 sites. Both methods detected stoats, at 17% of sites inside the Mostela and 33% of sites on the external camera, although this non-agreement was not statistically significant. Detection probabilities were low, with wide and largely overlapping confidence intervals for both methods. Occupancy probabilities were relatively low, and the occupancy probability for the external camera was very close to the naïve occupancy estimate. We evaluate the potential applicability of both methods for future work to assess the population and conservation status of this little-studied species.
As a result of legal protection and population recovery, European polecats (Mustela putorius) in Great Britain are expanding into areas associated with greater usage of second-generation ...anticoagulant rodenticides (SGARs). We analysed polecat livers collected from road casualties from 2013 to 2016 for residues of five SGARs. We related variation in residues to polecat traits and potential exposure pathways, by analysing stable isotopes of carbon (δ13C) and nitrogen (δ15N) in their whiskers. 54 of 68 (79%) polecats had detectable residues of at least one SGAR. Bromadiolone (71%) was the most frequently detected compound, followed by difenacoum (53%) and brodifacoum (35%). Applying historical limits of detection to allow comparison between these new data and previous assessments, we show that in the 25 years from 1992 to 2016 inclusive, the rate of detection of SGARs in polecats in Britain has increased by a factor of 1.7. The probability of SGAR detection was positively related to increasing values of δ15N, suggesting that polecats feeding at a higher trophic level were more likely to be exposed. Total concentrations of SGARs in polecats with detectable residues were higher in polecats collected in arable compared to pastoral habitats, and in the west compared to the east of Britain. The number of compounds detected and total concentrations of SGARs increased with polecat age. There was no evidence of regional or seasonal variation in the probability of detecting SGARs, suggesting that the current risk of exposure to SGARs does not vary seasonally and has increased (from that in the 1990s) throughout the polecat's range. We recommend quantification of current practices in rodenticide usage, particularly in the light of recent regulatory changes, to enable assessment and mitigation of the risks of secondary exposure to rodenticides in non-target wildlife.
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•79% of European polecats in England and Wales were exposed to rodenticides.•1.7-fold increase in detection of rodenticides in polecats since the 1990s.•71% polecats had residues of bromadiolone, 53% difenacoum, 35% brodifacoum.•Enriched nitrogen isotope signatures were positively related to rodenticide detection.•Liver rodenticide concentrations were higher in arable than pastoral habitats.
79% of polecats in Great Britain were found to have been exposed to rodenticides from 2013 to 2016 and exposure has increased by a factor of 1.7 since the 1990s.
Monitoring rare and elusive species is critical in guiding appropriate conservation management measures. Mammalian carnivores are challenging to monitor directly, due to their generally nocturnal and ...solitary lifestyle, and relatively large home ranges. The European mink
Mustela lutreola
is a critically endangered, small, semi-aquatic carnivore and is one of the most threatened mammal species in Europe. In northern Spain, the European mink population is monitored regionally using different methods and approaches, making assessment of national population status difficult. There is an urgent need to 1) assess the efficacy of survey methods and 2) identify a standard monitoring methodology that can be deployed rapidly and inexpensively over large areas of the mink’s range. We deployed four methods—camera trapping, hair tubes, live trapping, and environmental DNA (eDNA) from water samples—to compare the probability of detecting European mink when present at 25 sampling sites within five 10 × 10 km
2
, and the economic cost and time required for each method. All four methods successfully detected European mink but the probability of detection varied by method. Camera trapping and hair tubes had the highest probability of detection; however, eDNA and live trapping detected mink in one 10 × 10 km
2
where the latter two methods did not. For future European mink monitoring programs, we recommend a combination of at least two methods and suggest that camera traps or hair tubes are combined with live trapping or eDNA (depending on the scale and aims of the study), to gather critical information on distribution, occupancy and conservation status.
The Western polecat
has a widespread European distribution and is currently listed as Least Concern by the
. Reports are increasing of polecat population declines in several countries, although a ...paucity of data means population trends are poorly understood. This paper reviews and summarises information on the polecat’s status and range-wide population trends. Information and opinion were gathered for 34 countries, from individuals and organisations studying polecats and from reviewing the literature and national Red Lists. Where trends were identified, the polecat population is known or suspected to be declining in 20 countries, reported to be stable in five countries, stable or increasing in one country, and increasing in two countries. For many countries, data are so limited in quantity or spatial scale, or at risk of bias, that trends could not be identified or confidence in trend assessments is low. The main drivers of polecat decline are poorly understood, but might include habitat degradation; changes in prey availability; competition with invasive carnivores; poisoning; conflict with human interests; harvesting and killing of polecats; and hybridisation. Robust survey methods and systematic monitoring programmes are urgently needed to gather up-to-date data on polecat population trends across the species’ range.
The marbled polecat (
Vormela peregusna
) is a small mustelid that occurs from the Balkans to Mongolia and is listed as vulnerable under the International Union for Conservation of Nature's (IUCN) ...Red List. There are currently no efficient methods to monitor populations at a broad scale and most records come from opportunistic sightings. However, the elusive nature and unique pelage of the species often results in a lot of interest when sighted, with observations regularly being shared on social media platforms. Such records from social media can provide an extensive source of freely available information that could be used to inform the species’ distribution. In this study, we systematically collected marbled polecat records from five social media platforms by using a manual and automated search targeting the western range of the species. We identified 131 unique marbled polecat sightings originating mostly from Facebook, Instagram and Twitter. The records confirmed the species’ presence in 92 50-km grid cells within the study area and outperformed other sources, such as GBIF and scientific literature searches. The combination of all three datasets resulted in 133 presence points, which was sufficient enough to perform further habitat suitability modelling and reliable alpha hull range estimates. The social media search was well suited to clarify broad distribution patterns of marbled polecat, but did not detect the species in areas where its presence was most uncertain. The results of the modelling work, however, can be used to target further dedicated survey work for the species. The framework used in this study can be applied to provide more detailed information on distribution and occurrence patterns for other rare or under-studied species.
Many methods are available to gather data on wildlife population parameters, such as population abundance and density, yet few have been compared or validated. We compared the efficacy of three ...survey methods (live trapping, hair tubes and scats) for estimating abundance and population density of the European pine marten
(Martes martes)
in Galloway Forest, Scotland. We evaluated these methods by, firstly, comparing the accuracy of the population estimate derived from each method, and, secondly, comparing the financial cost of each method. Molecular analysis of samples from all three methods was used to determine sex and individual genotype. Population abundance estimates were derived from capture-recapture programme Capwire. The non-invasive methods (hair tubes and scats combined) detected 81% of known individuals, although hair tubes and scats performed poorly alone, detecting 48% and 52% of individuals, respectively. Live trapping was the individual method that detected the most individuals (77%). Hair tubes were the most expensive method, both in financial cost and personnel hours, whilst scat sampling was the cheapest method. There was a highly significant association between the sex of the animal and the total number of detections by method. The population abundance estimate from all methods combined was 32 (95% CI 31–35) and the population density estimate was 0.27 martens/km
2
. This study indicates that a combined sampling approach comprising hair tubes and scats maximises the number of detections and provides a viable alternative to invasive live trapping.
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