The detrimental impact of invasive, non-native species on biodiversity conservation and ecosystem function is widely recognised. The invasion of predatory species can have particularly deleterious consequences on native species in the invaded range and there is an increasing awareness of, and necessity for, management action to minimise these impacts. There is a growing body of literature identifying the impacts of invasive species and priorities for conservation action. However, there is a noticeable gap between the rising scientific output regarding invasive species control and conservation measures, and the management action required to implement recommendations. The American mink (Neovison vison, hereafter mink) has been a recent focus of invasive species research and management. Mink are semi-aquatic mustelids and generalist predators and were introduced to countries around the world for fur farming. Feral populations have established across the introduced range with devastating consequences for native species, particularly birds and mammals. In the UK, mink are held partly responsible for the decline in water voles (Arvicola amphibius) and in Scotland in particular, breeding seabirds are significantly impacted by mink predation. Control of mink in North East Scotland has proven successful using an adaptive management, community-based approach but there is currently no equivalent project in the complex, coastal landscape of west Scotland. This study aimed to provide information that could refine and further develop management plans for mink in north and west Scotland by acquiring a better understanding of the ecology of mink in Scotland to inform the implementation of control. Mink were distributed across all but the far north of Scotland. There was spatial and temporal variation in the pattern and rate of their expansion which was attributed to landscape heterogeneity. In northwest Scotland, availability of suitable habitat was restricted to the coastline and consequently, the availability of prey was hypothesised to be limited to coastal areas. Indeed, the diet of mink in northwest Scotland had a greater input from marine resources than those in southwest Scotland, where habitat availability and, therefore, terrestrial food resources, extended inland. Landscape features were shown to affect the direction of colonisation, with mountains restricting and valleys facilitating dispersal. Population genetic studies confirmed that mink dispersal in northwest and northeast Scotland was limited by mountain barriers. Additionally, populations in northwest Scotland were likely to have originated from southwest Scotland. These results suggest that mink control should be primarily focussed in coastal habitats in west Scotland and that the risk of reinvasion from relatively close populations in northeast Scotland is minimal. Volunteer involvement in conservation projects is being accepted increasingly as a cost-effective way to gather ecological information and implement conservation over large spatial scales. The landscape of west Scotland, particularly in northern areas, is complex, remote and sparsely populated by humans which consequently creates challenges for executing mink control. Ecotourism boat operators were concerned about the presence of mink and their effect on local wildlife in coastal areas and were willing to volunteer in mink management. Consequently ecotourism boat operators could provide a key link between management recommendations and implementation. This study combined methodologies from ecological modelling, population genetics, chemical analyses and social science to address questions regarding invasive species management. This holistic approach has resulted in a thorough overview of the distribution and ecology of an invasive species as well as recommendations for management action and implementation that will be applicable to a range of invasive species.

Thesis (Ph. D.)--Columbia University, 1956. / eContent provider-neutral record in process. Description based on print version record.

Thesis (Ph. D.)--University of Washington, 1996. / Vita. Includes bibliographical references (leaves [133]-144).

Thesis (Ph. D.)--Columbia University, 1956.

Polybrominated diphenyl ethers (PBDEs) are a class of brominated flame retardants that are recognized as global environmental contaminants and a potential health risk. They have been shown to elicit neurodevelopmental toxicity through disruption of the cholinergic neurotransmitter system in rodent models, but the effects of environmentally relevant exposures in wildlife species are unknown. The objective of this study was to assess the effects of the commercial pentabrominated diphenyl ether mixture DE-71 on cholinergic parameters in captive mink (Mustela vison) following dietary exposure of adult females and in utero, lactational and dietary exposure of their offspring. Adult females were fed diets containing 0, 0.1, 0.5 or 2.5 μg/g DE-71 from four weeks prior to breeding through weaning of their kits at six weeks of age. A portion of the weaned kits were maintained on their respective diets through 27 weeks of age. Cholinergic neurochemical biomarkers, including muscarinic acetylcholine receptor (mAChR) and nicotinic acetylcholine receptor (mAChR) binding, cholinesterase (ChE) activity and acetylcholine (ACh) concentration, were assayed in the cerebral cortex, and ChE activity measured in the plasma. Results indicated no significant effects of DE-71 on cholinergic parameters in the cerebral cortex, but a 3-fold increase in ChE activity in the plasma of adult females in the 2.5 μg/g DE-71 group. There were also no direct effects of DE-71 on mAChR or mAChR binding or ChE activity in the enzyme and receptor fractions from the whole brain of untreated mink following in vitro exposure to 0-23.6 nM DE-71. This study demonstrated that environmentally relevant exposures to DE-71 did not affect key parameters of the cholinergic neurotransmitter system in the brain of captive mink.

No description available.

Loss of biodiversity is a growing problem and hence conservation of species is becoming increasingly important. In this dissertation conservation issues related to the critically endangered European mink (Mustela lutreola) are examined in situ (in the wild) and ex situ (in captivity) on both an individual and community level. It also contains fundamental research as conservation contexts often allow for conclusions beyond applied biology. Individual behavioural differences, e.g. personality, can impact fitness and are hence relevant for conservation. Paper I thus experimentally explores the structure, expression and plasticity of personality in captive European minks. Thereafter paper II investigates if personality affects survival of reintroduced captive-bred animals and if spatiotemporal conditions affects the relationship between personality and survival. Paper III experimentally explores individual dietary specialism and learning in relation to novel prey as this could also impact survival. One of the main threats to the European mink is displacement by the invasive American mink (Neovison vison) wherefore management of American mink is important for European mink conservation. Paper IV hence analyses survey data to study whether native otters and red foxes can suppress American mink populations in north-eastern Europe. In the results three personality trait domains were identified in the European mink: boldness, exploration and sociability. The domains were repeatable but plastic between the non-breeding and breeding season. Reintroduced personality-tested animals survived longer if they were bolder but the effect of exploration was either positive or negative depending on spatiotemporal conditions. This is not only interesting for conservation but provides new insights on how individual behavioural differences could be maintained over evolutionary time. Whilst exploration is likely to be maintained by fluctuating selection pressures, the mechanism seem to vary with domain. The feeding experiments revealed diet choices similar to those found in wild individuals as there were both generalists and different types of specialists. Still, individuals differed in learning time towards novel but natural prey, suggesting that reintroduced animals might differ in their ability to find food after release. This could affect survival also and be related to personality. Survey data revealed that American mink abundances were suppressed by those of red foxes. Previous studies show that foxes are suppressed by lynx, and the abundance pattern of mink in relation to red fox found here indicate the existence of a predator cascade as mink were most abundant where lynx were abundant and vice versa. In several regions in the study area population dynamics indicated either exploitation or interference competition as probable mechanisms whereby foxes suppress minks. However, in many regions there were no relationships between dynamics. This could be due to that exploitation and interference competition might occur simultaneously and thus cancel each other out in the dynamics. Overall this thesis shows the importance of considering individual traits in conservation efforts, and also provides knowledge on the structure, plasticity and evolution of personality. As American mink was suppressed by foxes, management efforts might be most beneficial for species impacted by the mink if they to a larger extent are undertaken in areas with low fox abundances. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Submitted. Paper 3: Submitted. Paper 4: Manuscript.</p>

The presence of inflammation in the progression of fatty liver disease induced by fasting was determined in mink. Tumour necrosis factor alpha (TNF-?), and monocyte chemoattractant protein 1 (MCP-1) liver mRNA levels were quantified by real-time PCR. Mink fasted for 5 and 7 days had significantly higher levels of TNF-? and MCP-1 liver mRNA, compared to mink fasted for 0, 1, and 3 days. Mink fasted for 7 days, but re-fed for 28 days had the lowest mRNA levels of both TNF-?, and MCP-1 demonstrating the liver’s ability to restore homeostasis post-fasting. TNF-? mRNA levels were correlated with MCP-1 liver mRNA and liver fat percent. To confirm the physical presence of inflammation, slides stained with haematoxylin and eosin were analyzed for bile ducts resulting in no significant differences. Results indicate that elevated MCP-1 and TNF-? expression are associated with fasting induced fatty liver in mink.

The aim of my thesis was to evaluate two methods of monitoring of the American mink and polecat, monitoring with live traps and by floating rafts. While the first method is commonly used in our country, where the second method is the pilot project here, but it has been used in the UK successfully. Observation was from August to November in 2008 and from April to November in 2009. Observation took place in the area near PP Černíč near Dačice, where were chosen 4 different habitats. All detected tracks of Mustelids found on rafts were from the American mink. It corresponds with captures, where were captured also only minks and no polecat. Occupation of rafts was higher in 2008 than in 2009 because of the eradication of mink in November 2008. In both years the highest occupancy rate in rafts was in September and the lowest in October. There were differences between habitats and number of captured minks and tracks. In compare between rafts and traps, rafts were more successful method.

Semi-aquatic mammals have evolved to forage in both aquatic and terrestrial environments, and they generally lack locomotor specialisation for either. Having relatively unspecialised adaptations, some semi-aquatic species are generalist foragers, and their activity and diving patterns provide insight into constraints on their foraging behaviour. The recent miniaturisation and improved accuracy of logging devices allow remote data collection from small (<1kg), shallow-diving species. The development of analytical methods has lagged behind technological advances (and techniques developed for fully aquatic animals do not account for the variability of behaviour typical of semi-aquatic animals and their switching between terrestrial and aquatic environments). I applied and developed novel analytical techniques to identify activities and diving patterns of a semi-aquatic mustelid, the American mink (Neovison vison), fitted with Time-Depth Recorders (TDRs). Using a hidden Markov model (HMM) algorithm allowed me to classify dives into three states to identify clustering, and describe sequential diving patterns by mink. TDRs were used to determine active/inactive periods on the basis of rapid TDR temperature changes, and this method was validated empirically. Having developed this methodology, I applied it to 18 datasets collected from 14 mink in lowland England. Terrestrial activity of mink was positively related to ambient temperature (across both sexes), however aquatic activity, especially diving, appeared to be more influenced by daylight than by temperature. Mink showed intersexual differences, with males being more nocturnal and more active on land, and females more diurnal, and more persistent in diving. There was considerable variability between sexes and individuals. This is the first study to use HMM to classify the dives of a semi-aquatic animal, and the first to use TDR temperature records to identify mammalian activity patterns. These methods will be generally applicable to animals that make rapid transitions between environments and have thus far been difficult to study.