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Cabria M.T.,University of the Basque Country | Cabria M.T.,University of Liege | Michaux J.R.,University of Liege | Gomez-Moliner B.J.,University of the Basque Country | And 6 more authors.
Molecular Ecology | Year: 2011

Human-mediated global change will probably increase the rates of natural hybridization and genetic introgression between closely related species, and this will have major implications for conservation of the taxa involved. In this study, we analyse both mitochondrial and nuclear data to characterize ongoing hybridization and genetic introgression between two sympatric sister species of mustelids, the endangered European mink (Mustela lutreola) and the more abundant polecat (M. putorius). A total of 317 European mink, 114 polecats and 15 putative hybrid individuals were collected from different localities in Europe and genotyped with 13 microsatellite nuclear markers. Recently developed Bayesian methods for assigning individuals to populations and identifying admixture proportions were applied to the genetic data. To identify the direction of hybridization, we additionally sequenced mtDNA and Y chromosomes from 78 individuals and 29 males respectively. We found that both hybridization and genetic introgression occurred at low levels (3% and 0.9% respectively) and indicated that hybridization is asymmetric, as only pure polecat males mate with pure European mink females. Furthermore, backcrossing and genetic introgression was detected only from female first-generation (F1) hybrids of European mink to polecats. This latter result implies that Haldane's rule may apply. Our results suggest that hybridization and genetic introgression between the two species should be considered a rather uncommon event. However, the current low densities of European mink might be changing this trend. © 2011 Blackwell Publishing Ltd. Source

Nagl A.,University of Veterinary Medicine Vienna | Kneidinger N.,University of Veterinary Medicine Vienna | Kiik K.,University of Tartu | Lindeberg H.,Natural Resources Institute Finland | And 3 more authors.
Theriogenology | Year: 2015

This study examined the reproductive physiology of female European mink (Mustela lutreola) to augment the available information on estrus, ovulation, and pregnancy with the long-term goal of supporting ex situ breeding management of this highly endangered species. Fecal reproductive hormone metabolites were measured using EIAs for estrogen and 20-oxo-pregnane metabolites. Seasonal hormone profiles were established. A comparison of hormone fluctuations in pregnant and nonpregnant females showed that both estrogen and 20-oxo-pregnane metabolites were significantly elevated during gestation, which is 42 days in length. Delayed implantation or embryonic diapause does not occur in this species. Litter size was correlated with 20-oxo-pregnane levels but not with estrogen concentrations. During lactation, 20-oxo-pregnane metabolite levels remained higher than in nonpregnant females. The breeding season was characterized by peaks in vaginal cornified cells and fecal estrogen metabolite levels. Up to four peaks in estrogen levels were identified and confirmed that European mink are seasonally polyestrous. The results of 20-oxo-pregnane measurements indicated that hCG can be applied to induce ovulation. With the establishment of this noninvasive method, we present a new tool to support population management of this species. © 2015 Elsevier Inc. Source

Leimann A.,University of Tartu | Knuuttila A.,Haartman Institute | Maran T.,Species Conservation Laboratory | Maran T.,Estonian University of Life Sciences | And 2 more authors.
Virus Research | Year: 2015

Aleutian mink disease virus (AMDV) causes a severe disease called Aleutian disease (AD). AMDV infects primarily mustelids, but also other mammal species. Recent evidence suggests that AMDV may also affect humans. To examine AMDV in different wild animals and in farmed mink in Estonia, we collected 203 blood samples from eight mammal species in 2007-2010, of which 152 were from species living in the wild (American mink, European mink, pine marten, polecat, raccoon dog, badger, otter, and stone marten) and 51 were from farmed mink. AMDV was tested by PCR amplification of NS1 and VP2 gene fragments, and was only detected in 4 free-ranging (14.8%) and 11 farmed (21.6%) American mink. No other species was positive for AMDV. In addition, the VP2 gene fragment was sequenced for 14 farmed mink isolates from Finland for which NS1 sequences were already publicly available. None of the four Estonian AMDV isolates found in free-ranging mink had identical sequences with farmed mink. In fact, isolates from free-ranging and farmed mink belonged to different clades, suggesting that the analyzed virus isolates circulating in nature are not from escapees of current farms.Two global phylogenies were built: one based on NS1 (336. bp, 151 taxa from nine countries); the other based on a combined NS1-VP2 dataset (871. bp, 40 taxa from six countries). AMDV genotypes did not cluster according to their geographic origin, suggesting that transport of farm mink from multiple source farms has been intense. Nevertheless, one subclade in both phylogenies was comprised solely of isolates from farmed mink, while several subclades comprised isolates only from free-ranging mink, indicating that some isolates may circulate more in the wild and others among farm animals. © 2015 Elsevier B.V. Source

Podra M.,Tallinn University | Maran T.,Tallinn University | Maran T.,Species Conservation Laboratory | Sidorovich V.E.,National Academy of Sciences of Belarus | And 2 more authors.
European Journal of Wildlife Research | Year: 2013

As part of a conservation initiative, we released captive-bred individuals of European mink (Mustela lutreola) onto a Baltic island 'sanctuary', Hiiumaa (Estonia), and investigated the development of their diet in the wild. Fifty-four animals out of the 172 released were equipped with radio collars and tracked in 2000-2003 intensively after release. Based on the analysis of the contents of 564 collected scats, we monitored how the diet of released individuals changed after release and how this was affected by habitat and by season. Diet changed as they adapted to the wild: some prey consumed immediately after release were later substituted with prey more typical of wild European mink elsewhere. The mink's tendency to take typical prey increased (crayfish, 3; fish, 1. 5; and small mammals, 2 times), while the proportion of atypical prey decreased more than five times in 60 days after release. Once established in the wild, the composition of the diet and its variation between seasons, habitats or weather conditions were similar to that reported elsewhere for wild European mink. There is no indication therefore that the components of the diet provided in captivity persisted in the wild after the adaptation period. We suggest that the adaptation of released carnivores to natural prey merits more attention in reintroduction projects. © 2012 Springer-Verlag. Source

Remm L.,University of Tartu | Lohmus A.,University of Tartu | Maran T.,Estonian University of Life Sciences | Maran T.,Species Conservation Laboratory
ORYX | Year: 2015

Conservation of charismatic vertebrates in modern landscapes often includes habitat engineering, which is well supported by the public but lacks a consideration of wider conservation consequences. We analysed a pond management project for an introduced island population of captive-bred, Critically Endangered European mink Mustela lutreola. Ponds were excavated near watercourses in hydrologically impoverished forests to support the main prey of the mink (brown frogs Rana temporaria and Rana arvalis). A comparison of these ponds with other, natural, water bodies revealed that the (re)constructed ponds could reduce food shortages for the mink. Moreover, the ponds provided habitat for macroinvertebrates that were uncommon in the managed forests in the study area, including some species of conservation concern. The cost-effectiveness of the management of charismatic species can be increased by explicitly including wider conservation targets at both the planning and assessment stages. © 2014 Fauna & Flora International. Source

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