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Cabria M.T.,University of the Basque Country | Cabria M.T.,University of Liège | Michaux J.R.,University of Liège | 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.


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.


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.


Kiik K.,University of Tartu | Maran T.,Species Conservation Laboratory | Maran T.,Tallinn University | Nagl A.,University of Veterinary Medicine Vienna | And 2 more authors.
Zoo Biology | Year: 2013

High among-individual variation in mating success often causes problems in conservation breeding programs. This is also the case for critically endangered European mink and may jeopardize the long-term maintenance of the species' genetic diversity under the European mink EEP Program. In this study, breeding success of wild and captive born European minks at Tallinn Zoological Garden are compared, and the mating behavior of the males is analyzed. Results show that wild born males successfully mate significantly more often than captive born males (89% and 35%, respectively). On the basis of an extensive record of mating attempts, both male aggressiveness and passivity are identified as primary causes of the observed mating failures. All other potential determinants have only a minor role. Mating success as well as a male's aggressiveness and passivity are shown to depend more strongly on the male than the female partner. We did not find any evidence that the behavior of an individual is dependent on the identity of its partner. We suggest that aggressiveness and passivity are two expressions of abnormal behavior brought about by growing up in captivity: the same individuals are likely to display both aggressive and passive behavior. The results point to the need to study and modify maintenance conditions and management procedures of mink to reduce the negative impact of the captive environment on the long-term goals of the program. © 2013 Wiley Periodicals, Inc.


Kiik K.,University of Tartu | Maran T.,Species Conservation Laboratory | Maran T.,Estonian University of Life Sciences | Kneidinger N.,University of Veterinary Medicine Vienna | Tammaru T.,University of Tartu
Applied Animal Behaviour Science | Year: 2016

In litter-bearing mammals, the environment and social interactions during early life often have a substantial effect on future behaviour of the animal. Most information though derives from lab rodents, pets or farm animals while comparable data are scarce for non-domesticated species, and endangered carnivores in particular. In this study, we focused on social behaviour of juvenile European mink, with the practical aim to provide information for enhancing the ex-situ breeding programme of this critically endangered species. As the first step, we compiled a detailed ethogram of social behaviour observed among the European mink cubs. For the 13 captive born litters available, we then systematically recorded the relative duration of different types of behaviour during a two months period. The behaviour of the captive cubs was found to be diverse, containing all elements characteristic of congeneric mustelids, with no indication of litters deviating from the typical pattern. In all broods, a considerable and approximately equal share of time was allocated to social play, a suggested indicator of positive welfare. Aggressive behaviour of the mother towards her offspring was minimal when the cubs were young and, increased only with the litter dispersal period approaching. Bites between the cubs during play fighting did not increase with the age of the juveniles. We found no evidence that captive environment adversely affects the behaviour of the juveniles during the first months of their life. © 2016 Elsevier B.V.


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.


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.


Harrington L.A.,University of Oxford | Podra M.,Estonian University of Life Sciences | Macdonald D.W.,University of Oxford | Maran T.,Estonian University of Life Sciences | Maran T.,Species Conservation Laboratory
Endangered Species Research | Year: 2014

Naïve captive-bred animals often make excessive movements when released into the wild, which may increase vulnerability to predation, take animals into unsuitable habitat and/or increase the probability of conflict with humans. We analysed the post-release movements of captive-bred European mink Mustela lutreola reintroduced to Hiiumaa Island, Estonia. We tested the effect of pre-release enclosure type, sex, generations in captivity, pregnancy and age on post-release movements, investigated the settlement process and explored the relationship between post-release movements and survival. We found no effect of enclosures on post-release movements in the first 2 wk following release (except that individuals from large naturalistic enclosures spent less time close to water than did animals from standard zoo enclosures) but some evidence of a slight effect at 1 mo post-release. Males moved further at 3 d (but not 2 wk) postrelease than did females, and juveniles appeared to move further in the first 3 d post-release than did 1 yr olds. We were unable to detect a relationship between post-release movements and survival. The largest known cause of mortality was predation, but it was not clear why mink were vulnerable to predation, and the locational data presented here were unable to shed light on this issue. Individual variation also made it difficult to define patterns. These are common problems in reintroductions, and we suggest that in future releases of captive-bred animals, more detailed post-release behavioural observations and investigation of personality types might be insightful. © Inter-Research 2014.

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