Spatio-temporal population genetics of the Danish pine marten (Martes martes)

A spatio-temporal study of genetic variation in the Danish pine marten ( Martes martes ) populations from the Jutland peninsula and from the island of Sealand was performed using 11 microsatellite markers. Samples obtained from 1892 to 2003 were subdivided into historical (prior to 1970) and recent (from 1970) groups. As compared with the historical samples, there was a significant loss of genetic variation in the recent Jutland population, but not in Sealand. Effective population sizes were estimated using Bayesian-based software (TMVP). Historical effective population sizes were 5897 (90% highest probability density, HPD, limits: 1502–6849) in Jutland and 1300 (90% HPD limits: 224–5929) in Sealand, whereas recent effective population sizes were 14.7 (90% HPD limits: 10.9–23.5) in Jutland and 802 (90% HPD limits: 51.8–5510) in Sealand. Significant genetic differentiation ( F _ST) was found between the two historical samples, between the two recent samples, and between the historical and the recent sample in Jutland; whereas the F _ST value between the historical and the recent sample in Sealand was not significant. The significant genetic differentiation between the historical and the recent samples indicates changes in the genetic compositions over time, and the higher F _ST values between the two recent samples, as compared with the two historical samples, indicates that the populations in Sealand and Jutland have drifted apart within a short time span. No deviation from Hardy–Weinberg equilibrium was found within populations, indicating no further substructuring.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 93 , 457–464.     

Socio-spatial ecology of pine marten (Martes martes) in conifer forests,Ireland

Understanding the social organisation and spacing patterns of wildlife populations is an important aspect of conservation management and applied science. The present study investigated the spatial ecology of pine marten (Martes martes) inhabiting conifer forests in Ireland, the largest habitat resource available for the species. It represented the first study of pine marten spacing patterns in Irish conifer forests. Pine marten (n?=?7; five males and two females) were live-trapped and radio-tracked for between 4 and 10 months from March 2008 to March 2009. Mean annual home-range estimates (95 % fixed kernel) for males (150.7 ha) were generally larger than those of females (90.2 ha). There was considerable inter-seasonal overlap in home ranges (approx 85 %) with less inter-sexual (12.0 %) or intra-sexual (11.8 %) overlap, although the sample size of individuals for comparison was small. Pine marten home ranges were stable from season to season. Core ranges varied in size from 10.6 to 104.1 ha, and as a mean percentage of home-range area were 22.9 and 42.5 % for males and females, respectively. In terms of forest management, potential under occupancy of available space by pine marten and vulnerability of very small core ranges to clear felling practices needs further research to determine any impacts on individuals and populations.     

Inbreeding affects fecundity of American mink (Neovison vison) in Danish farm mink

Inbreeding is an increasing problem in farmed mink, because of limited exchange of individuals between farms. In this study, genetic relatedness within seven American mink (Neovison vison) colour strains originating from 13 different mink farms in Denmark was analysed using 21 polymorphic microsatellite loci. We detected large differences in the level of relatedness (range 0.017-0.520) within colour strains. Moreover, a very strong and highly significant negative correlation between the level of relatedness and fecundity was observed (r = 0.536, P < 0.001) [Correction added after online publication on 9 March 2011: r(2) has been changed to r]. To our knowledge, this is the first time that such a correlation has been demonstrated for commercially farmed mink.     

Scent marking and social relationships in pine martens (Martes martes)

Scent marking was studied in pine martens (Martes martes) in female-female and male-female pairs. Results show that agonistically dominant individuals generally had higher scent marking frequencies. However, environmental familiarity can modify the social relationship, whatever the previous social experiences, and, consequently, marking activity. Despite important intra-and interindividual variations, the subjects appeared to react to physical and social modifications by an increased marking rate. One factor affecting marking activity in both novel and established pairs was the activity level of the conspecific partner. the data support the hypothesis that pine martens react in the same way to physical and social modifications, but with different response levels. The discussion focuses on possible functions of scent marking. © 1993 Wiley-Liss, Inc.     

Hybridization between escaped domestic and wild American mink (Neovison vison)

The release of domesticated organisms into natural populations may adversely affect these populations through predation, resource competition, and the introduction of disease. Additionally, the potential for hybridization between wild and domestic conspecifics is of great concern because it can alter the evolutionary integrity of the affected populations. Wild American mink ( Neovison vison ) populations may be threatened not only by competition for resources with domestic mink originating from farms, but by breeding with such escapees. Using 10 microsatellite loci, we genotyped mink from Ontario, Canada, sampled from two farms, two putatively mixed populations in regions surrounding the mink farms, and two wild populations with no recent history of mink farming. Using individual-based Bayesian population assignment, we identified four population clusters, including one wild, and three domestic populations. The latter were not clustered by farm but rather by distinct line-bred colour phases. Population clustering also identified domestic and hybrid mink in the free-ranging populations. Nearly two-thirds of the mink sampled in the two putatively mixed populations (78% and 43%) were either farm escapees or descendants of escapees. Principal components analysis of allele frequencies supported our Bayesian assignment results. The power of our assignment test was assessed using simulated hybrid genotypes which suggested that our overall correct classification rate was 96.2%. The overwhelming presence of domestic animals and their hybridization with mink in natural populations is of great concern for the future sustainability of wild mink populations.     

Linking habitat characteristics with genetic diversity of the European pine marten (Martes martes) in France

Although typically considered as a forest specialist species, the European pine marten (Martes martes) is an example of a number of species that have recently been found to also live in fragmented landscapes. Considering that habitat fragmentation and loss is a major threat to the persistence of mammal species in such landscapes, we investigated the association between habitat characteristics and genetic diversity across four pine marten populations occupying contrasting landscapes in France with different degrees of forest availability and fragmentation. Bayesian and multivariate clustering methods evidenced the presence of three genetic clusters and isolation by distance between populations was found at the national scale. We found an overall moderate level of genetic variability, but no evidence of a bottleneck or deficit in heterozygosity in any of the populations. No pattern of isolation by distance was found within the populations, except in the one located in the Pyrenean Mountains which appeared partly isolated from other continental populations and also showed a lower level of genetic diversity. No obvious association between the pattern of genetic variability and the pattern of forested habitat characteristics was found. We discuss the possibility that pine martens show greater behavioural plasticity than typically expected allowing them to adapt to different habitat types.     

Range expansion of the pine marten (Martes martes) in an agricultural landscape matrix (NW Italy)

Habitat segregation is considered to favour the coexistence of sympatric pine martens Martes martes and stone martens M. foina, the latter being displaced to agricultural and urbanised areas. Subsequent to the report of pine martens in cultivated areas of the western River Po plain (NW Italy), we reviewed all available information on the presence of this species in plain areas of northern Italy and, for two study areas, applied a non-invasive PCR-RFLP method for the identification of Martes species from faecal mtDNA.A total of 24 pine marten records were collected, grouped in the western part of the River Po plain. The number of records showed an exponential increase from 1988 to 2007, the percentage of woods in a 10 km² wide circular plot surrounding the location of records being inversely correlated to its distance from the 300 m a.s.l. contour line. In the two study areas, 36 out of 119 “marten-like” faeces were assigned to the pine marten, whilst none belonged to the stone marten. In the best monitored area, the pine marten was present almost constantly.Our results suggest that the pine marten is expanding its range to include cultivated areas which were previously considered a prerogative of the more synanthropic stone marten.     

First record of Skrjabingylus petrowi (Nematode: Metastrongyloidea) in a pine marten Martes martes from Ireland

We report the first record of the parasitic nematode Skrjabingylus petrowi in Ireland, the fifth record of S. petrowi outside Russia. Twenty-three of the nematodes were removed from the skull of a male road kill pine marten Martes martes from Co. Tipperary. The spicule lengths measured in the male nematodes removed ranged from 410 to 500 μm, which is in agreement with the range of 410 to 605 μm previously recorded for S. petrowi. This investigation presents further evidence that anatomical measurements are required for the accurate diagnosis of Skrjabingylus spp. and that S. petrowi has a host preference for Martes spp.     

Parasitic helminths of free-ranging mink (Neovison vison mink) from southern Florida

Five free-ranging mink, Neovison vison mink, from in or near the Fakahatchee Strand Preserve State Park, Collier County, Florida (26 degrees 00'N, 81 degrees 25'W), were examined for parasitic helminths. Nine species of helminths were identified (2 trematodes, 5 nematodes, and 2 acanthocephalans). The most prevalent parasites were Molineus patens (4 of 5 mink), mean intensity 173 (range, 12-342); Strongyloides sp. (4 of 5), mean intensity 48 (range, 1-170); Macracanthorhynchus ingens (immature) (4 of 5), mean intensity 2.5 (range, 1-4); and Alaria mustelae (3 of 5), mean intensity 59.3 (range, 11-127). Polymorphus brevis and Dirofilaria lutrae are reported from the mink for the first time.     

Exclusion of candidate genes for coat colour phenotypes of the American mink (Neovison vison)

In a previous project, we screened the American mink Bacterial Artificial Chromosome library, CHORI‐231, for genes potentially involved in various coat colour phenotypes in the American mink. Subsequently, we 454 sequenced the inserts containing these genes and developed microsatellite markers for each of these genes. Here, we describe a lack of association between three different ‘roan‐type' phenotypes represented by Cross, Stardust and Cinnamon in American mink and six different genes that we considered to be potentially linked to these phenotypes. Thus, c‐KIT (HUGO‐approved symbol KIT), ATOH‐1 (HUGO‐approved symbol ATOH1) and POMC were excluded as potential candidates for these three phenotypes. In addition, MITF and SLC24A5 were excluded for Cross and Cinnamon, and KITL (HUGO‐approved symbol KITLG) for Cross and Stardust. Although most of these genes have been implicated as the cause of similar phenotypes in other mammals, including horses, pigs, cows, dogs, cats, mice and humans, they do not appear to be responsible for comparable phenotypes found in American mink.     

Muskrat (Ondatra zibethicus) decline after the expansion of American mink (Neovison vison) in Poland

Field survey data in Central Poland revealed that the proportion of sites inhabited by muskrats decreased from 44% to 7% over one decade. This corresponded to the decline in hunting bags of muskrat over the whole of Poland. The largest hunting harvest of muskrat was recorded in 1987/1988 (66,416 individuals), the smallest in 2007/2008 (4,567 individuals). The decline in hunting bags occurred in all regions analysed; however, it was most rapid in the north and north-east. Before the expansion of mink, which started in northern Poland at the beginning of the 1980s, muskrat densities in particular regions depended on the availability of aquatic habitats. A comparison of hunting bags of muskrat and American mink in years 2002–2008 indicated a significant negative correlation between the numbers of these two species harvested in seven regions of Poland. The negative correlation between numbers of muskrat and mink suggests that mink predation is one of the most important factors in the decline of the muskrat population in Poland.     

Albinism in the American mink (Neovison vison) is associated with a tyrosinase nonsense mutation

Albino phenotypes are documented in various species including the American mink. In other species the albino phenotypes are associated with tyrosinase (TYR) gene mutations; therefore TYR was considered the candidate gene for albinism in mink. Four microsatellite markers were chosen in the predicted region of the TYR gene. Genotypes at the markers Mvi6025 and Mvi6034 were found to be associated with the albino phenotype within an extended half-sib family. A BAC clone containing Mvi6034 was mapped to chromosome 7q1.1-q1.3 by fluorescent in situ hybridization. Subsequent analysis of genomic TYR sequences from wild-type and albino mink samples identified a nonsense mutation in exon 1, which converts a TGT codon encoding cysteine to a TGA stop codon (c.138T>A, p.C46X; EU627590). The mutation truncates more than 90% of the normal gene product including the putative catalytic domains. The results indicate that the nonsense mutation is responsible for the albino phenotype in the American mink.     

Effect of felling on red fox (Vulpes vulpes) and pine marten (Martes martes) diets in transitional mixed forest in Belarus

In transitional mixed forests in northern and central Belarus the influence of intensified felling on the diets of red foxes Vulpes vulpes L. and pine martens Martes martes L. was investigated in two model forested terrains with sandy and clay top-grounds. A total of 1904 scats of red foxes and 1624 scats of pine martens were analysed over two periods differed by logging rate. When logging rate was conservative, red fox and pine marten diets were found to be similar, but under heavy logging feeding of the predator species shifted. In both model woodlands we found the same pronounced dietary trend of higher consumption of rodents, first of all, Microtus voles. The dietary changes were well related to the registered increase in Microtus vole numbers and total number of rodents in felling areas. The increased preying on rodents caused lower consumption of other food items, particularly medium-sized mammals (year-round) or/and birds or/and fruits (in the warm season) or/and mammalian carrion (in the cold season). In the conditions of intensified felling the food niches of the red fox and pine marten diverged mostly because of the great difference in the species structure of rodents consumed. Red foxes turned to preying on Microtus voles more frequently, but less on bank voles Myodes glareolus; while pine martens increased their taking of Microtus voles, continued foraging for bank voles and began taking slightly more of Apodemus mice. Before heavy logging dietary similarity between the red fox and pine marten was high and did not vary considerably through seasons and study areas, whereas after felling was intensified their diet overlap became lower.     

Spring and summer food habits and habitat use of the Europena pine marten (Martes martes) on the island of Micorca, Spain

The food habits and habitat use of pine marten ( Martes martes L.) on the Balearic Island of Mincorca were studied from March-August 1990. In a 28.2 km² area, a series of hiking trails/forest roads were used to collect pine marten faeces bi-monthly and study te species' differential use of habitats. A total of 28 different food items were identified in 723 faeces. Small mammals were the most important food overall, constituting 34% of the volume During March-April, small mammals were the principal food consumed (63% of volume), followed by birds (19%). In May-June, birds were the main food (40%), then small mammals. Plant material and insects were the most important foods in July-August, both made up 68% of the pine marten diet. The abundance of certain foods and the degree of difficulty in obtaining them appear to be important factors that govern pine marten food selection in Minorca. Habitat use was studied along 12 routes totalling 32.6 km. Pine marten showed preference in March-April for Coastal Shrubland habitat, while during May-June they were found most in the Upland Pine type. During July-August, the Upland Pine and Open Pine habitats were most frequented by pine marten. According to bimonthly food habits data, habitat use seems largely determined by the abundance and availability of their prey items in the available habitat types. Martens may concentrate hunting efforts in areas different from when they are not hunting. The Minorcan pine marten differs from continental populations in its wide use of shrublands, in addition to forests.     

Tiletamine-zolazepam-xylazine immobilization of American marten (Martes americana)

The effectiveness of tiletamine-zolazepam (Telazol) and xylazine as an immobilizing combination for American martens (Martes americana) was evaluated. Fifteen martens were intramuscularly injected on 19 occasions using a 3:2 mixture of tiletamine-zolazepam (3.2+/-0.6 mg/kg [mean +/- SD]) and xylazine (2.1+/-0.4 mg/kg) at Pictured Rocks National Lakeshore, Michigan (USA) during May to October 2002-2003. Mean induction time was 2.5+/-1.8 min; mean recovery time was 70.8+/-31.9 min. There was no relation between the amount (mg/kg) of tiletamine-zolazepam-xylazine injected and induction (r(2)=0.08, P=0.26). However, there was an inverse relation (r(2)=0.28, P<0.01) between dosage and time to first effect of immobilants. Time to recovery increased (r(2)=0.21, P=0.05) with increased dosage. Mean heart rate, respiratory rate, and body temperature declined through 10 min postinduction (P<0.05). No mortality occurred and no short-term adverse effects were observed in recaptured individuals. In conclusion, a 3:2 mixture of tiletamine-zolazepam/xylazine is a safe and effective immobilizing agent for martens when conducting non-surgical field procedures. Immobilizing martens with 4.2 mg/kg tiletamine-zolazepam and 2.8 mg/kg xylazine should provide < or =30 min of handling time and allow full recovery in about 70 min.     

Fur snagging as a method of evaluating the presence and abundance of a small carnivore, the pine marten (Martes martes)

The pine marten Martes martes was once considered one of Ireland's rarest carnivores, but is now recolonizing many of the areas where it was once extirpated. It is important to monitor its population expansion so that conservation management decisions can be made regarding the status of this species. In this study, we investigate the use of fur snagging devices as a method of estimating pine marten presence and abundance in lowland and upland broadleaf woodland. We investigated whether these devices reliably detected presence, and how quickly. It was found that hair traps functioned very well in detecting pine martens on all survey transects and was essential in their detection in the most isolated site. A survey length of 6 days was sufficient to detect pine marten in all survey sites, with most detections occurring within the first 4 days. The hair traps functioned equally well as scat location for detecting pine marten and had the added advantage of there being no confusion as to the origin of the sample. Live trapping was used to verify the estimates of relative abundance from hair traps. There was a trend for the number of hair samples per site and the number of times animals were trapped per site to be positively correlated, although this was not significant. Hair traps do provide a real alternative for the monitoring of pine martens in both lowland and upland broadleaf woodlands, overcoming many of the disadvantages associated with scat location.