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1. The American mink Neogale vison is an invasive alien species in Europe that threatens endemic biodiversity and can transmit zoonotic diseases, including the SARS-CoV-2 virus. The last attempt to map the geographic range of this species in Europe, at continental scale, dates back to 2007. 2. We aimed to update the distribution map of the feral American mink and assess its temporal trends. The information we collected was critically analysed with the aim of improving future monitoring protocols and data collection. 3. We gathered and standardised data from 34 databases, covering 32 countries. Through 3 five-year periods from 2007 to 2021, changes in range size, hunting bags and capture statistics were analysed. We also reviewed the current situation of mink farming in the different European countries and recorded population control schemes. 4. The American mink is now widespread in the Baltic States, France, Germany, Iceland, Ireland, Poland, Scandinavia, Spain and the UK. The species is reported to be absent in some areas (e.g. parts of the UK, Iceland and Norway). Data are deficient for several countries, mainly in south-eastern Europe. These findings indicate that, during the last 15 years, the species has continued to spread across the continent, increasing its potential extent of occurrence in most countries. Our effort to collect and harmonise data across international borders highlighted information gaps and heterogeneity in data quality. 5. Updated distribution data on the species provided here will aid risk assessment and risk management policies. These actions require a coordinated effort for population monitoring at continental level. Monitoring effort and data collection should be intensified in south-eastern Europe to improve data on the current distribution of this invasive species.

Biotic interactions are expected to influence species’ responses to climate change, but they are usually not included when predicting future range shifts. We assessed the importance of biotic interactions to understand future consequences of climate and land use change for biodiversity using as a model system the brown bear (Ursus arctos) in Europe. By including biotic interactions using the spatial variation of energy contribution and habitat models of each food species, we showed that the use of biotic factors considerably improves our understanding of the distribution of brown bears. Predicted future range shifts, which included changes in the distribution of food species, varied greatly when considering various scenarios of change in biotic factors, warning about future indirect climate change effects. Our study confirmed that advancing our understanding of ecological networks of species interactions will improve future scenarios of biodiversity change, which is key for conserving biodiversity and ecosystem services.

In semi-arid environments, the effects of irregularly distributed rainfall, flow regulation and water inter-basin transfer enhance the spread of non-native fish to the detriment of native communities. In the River Segura, since the 1980s the number of non-native fish species has progressively increased, also because of the building of water transfer facility connecting the rivers Segura and Tajo. With the aim of highlighting how man-driven changes in the diversity of fish communities affect the diet of top-predators, we compared Eurasian otter Lutra lutra diet in the span of 20 years, i.e. 1997–98 vs. 2016–19. As habitat quality affects the condition of Andalusian barbel Luciobarbus sclateri, the most widespread native fish, we also compared the size of preyed barbels to point out whether human activities may have lowered their profitability to otters. Fish and introduced red swamp crayfish Procambarus clarkii formed the bulk of otter diet in both study periods. In 2016–19 the contribution of non-native species to otter diet increased significantly, both for crayfish and fish, which included ten non-native species. Otter feeding habits faithfully mirrored the variation in the composition of the fish community and confirmed the importance of crayfish as alternative-to-fish prey in the Iberian Peninsula. The average length of preyed barbels was significantly lower in the second study period, consistently with a decline in barbel profitability for otters.

Connectivity, in the sense of the persistence of movements between habitat patches, is key to maintain endangered populations and has to be evaluated in management plans. In practice, connectivity is difficult to quantify especially for rare and elusive species. Here, we use spatial capture-recapture (SCR) models with an ecological detection distance to identify barriers to movement. We focused on the transnational critically endangered Pyrenean brown bear (Ursus arctos) population, which is distributed over Spain, France and Andorra and is divided into two main cores areas following translocations. We integrate structured monitoring from camera traps and hair snags with opportunistic data gathered after depredation events. While structured monitoring focuses on areas of regular bear presence, the integration of opportunistic data allows us to obtain information in a wider range of habitat, which is especially important for ecological inference. By estimating a resistance parameter from encounter data, we show that the road network impedes movements, leading to smaller home ranges with increasing road density. Although the quantitative effect of roads is context-dependent (i.e. varying according to landscape configuration), our model predicts that a brown bear with a home range located in an area with relatively high road density (8.29km/km2) has a home range size reduced by 1.4-fold for males and 1.6-fold for females compared to a brown bear with a home range located in an area with low road density (1.38km/km2). When assessing connectivity, spatial capture-recapture modeling offers an alternative to the use of experts’ opinion when telemetry data are not available.

Mammals usually adjust behavioral patterns when exposed to disturbances. Elusiveness and low-risk time selection may reduce their stress in periods of highest risk. In Europe, brown bears (Ursus arctos) coexist with humans in densely populated and modified landscapes and, consequently, are exposed to human-caused disturbances during the daytime hours. Furthermore, intraspecific interactions might also influence their behavioral responses, especially during the mating season. Activity patterns of several large carnivores have been thoroughly studied; however, research is scarce for relocated populations. Here, we report the activity patterns in the reintroduced brown bear population in the Pyrenees. We expected the bears to reduce their activity depending on the type and level of disturbances. We analyzed individual behavior of both sexes (males, solitary females, and females with offspring) and age groups (adults and subadults) using camera-trap surveys under different types of intraspecific and anthropogenic disturbances. In general, bears were more active during the night (2200–0600 h) and avoided peaks of human activity (1000–1800 h). Furthermore, with the increasing nocturnal disturbance of adult males during the mating season, females with offspring and subadults were more active during daylight. This suggests that vulnerable individuals showed high tolerance for human presence. These results contribute to improve our knowledge of how a threatened and relocated bear population behaves in a human-modified landscape of southern Europe. Further research on this population will be crucial to establish optimal management interventions during translocations, and the prevention of human-bear encounters and conflicts.

Detection probability is an important input when studying and managing species. It reduces the miscalculations of the estimates of occupancy, population abundances and their trends inherent to the imperfect detection during sampling. However, detection probability may vary in relation to environmental and biological factors, such as the presence of other species of similar ecological niche. We used a two-species single-season occupancy model to analyse the detection probability of the native Eurasian otter Lutra lutra and the invasive American mink Neovison vison in the northeast of the Iberian Peninsula and to test for potential differences in their detection when co-occurring and when not. Despite the known behavioural change of American mink towards a more terrestrial diet and a more diurnal activity pattern in the presence of Eurasian otter, their detectability did not vary when both species co-occurred versus when they did not. However, we observed seasonal differences in the probability of detection. Specifically, the probability of detection was higher in winter for both species. Furthermore, Eurasian otter was more often detected in sites with clay substrate, whereas American mink in sites with clay and rocks. These results indicate that the effectiveness of monitoring of Eurasian otter and American mink remains independent of the species co-occurrence. Yet, seasonal variations in the detection should be taken into account when monitoring.

This datasheet on Neovison vison covers Identity, Overview, Distribution, Dispersal, Diagnosis, Biology & Ecology, Natural Enemies, Impacts, Uses, Prevention/Control, Further Information.

Estimating the size of small populations of large mammals can be achieved via censuses, or complete counts, of recognizable individuals detected over a time period: minimum detected (population) size (MDS). However, as a population grows larger and its spatial distribution expands, the risk of under-estimating population size using MDS rapidly increases because the assumption of perfect detection of all individuals in the population is violated. The need to report uncertainty around population size estimates consequently becomes crucial. We explored these biases using the monitoring framework of the critically endangered Pyrenean brown bear that was close to extinction in the mid-1990s, with only five individuals remaining, but was subsequently bolstered by the introduction of 11 bears from Slovenia. Each year since 1996, the abundance of the population has been assessed using MDS and minimum retained (population) size (MRS), which corresponded to a reassessment of the MDS in the light of the new information collected in subsequent years (e.g., adding bears which were not detected the previous years but detected the current year). We used Pollock’s closed robust design (PCRD) capture-recapture models applied to the cross-border non-invasive sampling data from France, Spain and Andorra to provide the first published annual abundance and temporal trend estimates of the Pyrenean brown bear population since 2008. Annual population size increased fivefold between 2008 and 2020, going from 13 to 66 individuals. PCRD estimates were globally close to MRS counts and had reasonably narrow associated 95% Credibility Intervals. Even in cases where sampling effort is large compared to population size, the PCRD estimates of population size can diverge from the MDS counts. We report individual heterogeneity in detection that might stem from intraspecific home range size variation that result in individuals that move the most being most likely to be detected. We also found that cubs had a higher mortality rate than adults and subadults, because of infanticide by males, predation, maternal death, or abandonment. Overall, the PCRD capture-recapture modelling approach provides estimates of abundance and demographic rates of the Pyrenean brown bear population, together with associated uncertainty, while minimizing bias due to inter-individual heterogeneity in detection probabilities. We strongly encourage wildlife ecologists and managers to use robust approaches when researching large mammal populations. Such information is vital for informing management decision-making and assessing population conservation status.

53 pages, 10 figures, 20 tables, This paper provides an overview of the last 40 years of use, and in many cases abuse, of the natural resources in Catalonia, a country that is representative of European countries in general, and especially those in the Mediterranean region. It analyses the use of natural resources made by mining, agriculture, livestock, logging, fishing, nature tourism, and energy production and consumption. This use results in an ecological footprint, i.e., the productive land and sea surface required to generate the consumed resources and absorb the resulting waste, which is about seven times the amount available, a very high number but very similar to other European countries. This overexploitation of natural resources has a huge impact on land and its different forms of cover, air, and water. For the last 25 years, forests and urban areas have each gained almost 3% more of the territory at the expense of agricultural land; those municipalities bordering the sea have increased their number of inhabitants and activity, and although they only occupy 6.7% of the total surface area, they account for 43.3% of the population; air quality has stabilized since the turn of the century, and there has been some improvement in the state of aquatic ecosystems, but still only 36% are in good condition, while the remainder have suffered morphological changes and different forms of nonpoint source pollution; meanwhile the biodiversity of flora and fauna remains still under threat. Environmental policies do not go far enough so there is a need for revision of the legislation related to environmental impact and the protection of natural areas, flora, and fauna. The promotion of environmental research must be accompanied by environmental education to foster a society which is more knowledgeable, has more control and influence over the decisions that deeply affect it. Indeed, nature conservation goes hand in hand with other social and economic challenges that require a more sustainable vision. Today’s problems with nature derive from the current economic model, which is environmentally unsustainable in that it does not take into account environmental impacts. Lastly, we propose a series of reasonable and feasible priority measures and actions related to each use made of the country’s natural resources, to the impacts they have had, and to their management, in the hope that these can contribute to improving the conservation and management of the environment and biodiversity and move towards sustainability, This research was funded by the Institut d’Estudis Catalans (IEC). With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)

Simple Summary Invasive species are widely recognized to negatively affect native species through both direct and indirect interactions. When diet overlap between the native and invasive species increases, their competitive interaction is expected to increase too. This in turn may lead to displacement of one of the species. However, the specific mechanisms of the diet displacement are still unclear. In this study, we analysed the diet and diet overlap between the critically endangered European mink and the invasive American mink during the invasion process of the latter species by means of stable isotope analyses. We found a significant diet overlap between the native and invasive mink when they co-occur, an important individual variation of diet, and no significant change of diet of the native species in response to the arrival of the invasive mink. These results suggest significant competitive pressure imposed on the native European mink by the invasive American mink. As such, urgent implementation of control measures of invasive species is needed to ensure the viability and conservation of endangered European mink populations. Abstract The pressure elicited by invasive species on native species significantly increases with the increase of the overlap of their ecological niches. Still, the specific mechanisms of the trophic displacement of native species during the invasion process are unclear. The effects of the invasive American mink (Neovison vison) on the critically endangered European mink (Mustela lutreola) was assessed by analyses of diet and niche overlap during the invasion process. To do this, the isotopic composition (δ13C and δ15N) of both species of mink and their four main types of prey was analysed. Significant trophic overlap between the native European mink and invasive American mink was found when they coexisted in sympatry. Furthermore, both mink species were characterised by significant individual variation in diet and no obvious change in diet of the native species in response to the arrival of the introduced species was observed. High niche overlap registered between both species in sympatry with no displacement in diet of the native mink in response to the arrival of the invasive mink is expected to have important consequences for the viability and conservation of the native mink populations, as it suggests high competitive pressure.

Coexistence of humans and large carnivores is a major challenge for conservation and management, especially in human‐modified landscapes. Ongoing recovery of some large carnivore populations is good conservation news, but it also brings about increased levels of conflict with humans. Compensation payments and preventive measures are used worldwide as part of conservation programmes with the aim of reducing such conflicts and improving public attitude towards large carnivores. However, understanding the drivers triggering conflicts is a conservation priority, which helps prevent and reduce damages. Here, we have analysed the spatio‐temporal patterns of brown bear Ursus arctos damages to apiaries, crops and livestock in the two small, isolated and endangered bear populations in northern Spain. The increase in the number of damages varied in parallel with the increase in bear numbers, which is probably a primary cause determining the occurrence on damages. Damages also varied among years, seasons and bear populations and seemed to mainly depend on the local availability of natural food items, weather conditions and the availability of apiaries and livestock. Fluctuating availability of food items may explain the frequency of conflicts, which is yet another call to apply preventive measures in carnivore damage to human property in seasons and years when natural food availability is lower than usual. Understanding and preventing damage is in turn essential to mitigate conflicts where humans and large carnivores share the same landscape., During this research, V.P., A.O., R.G.G. and A.Z.A. were financially supported by the Excellence Project CGL2017‐82782‐P financed by the Spanish Ministry of Science, Innovation and Universities, the Agencia Estatal de Investigación (AEI) and the Fondo Europeo de Desarrollo Regional (FEDER, EU). V.P. was also funded by a GRUPIN research grant from the Regional Government of Asturias (Ref.: IDI/2018/000151). G.B. was financially supported by a collaboration contract with the MUSE – Museo delle Scienze of Trento (Italy). M.M.D. was financially supported by the Spanish Ramon y Cajal grant RYC‐2014‐16263.

The publisher regret that the presentation of Figure 3 in the original version of the above article was incorrectly presented. The data in the image were inadvertently omitted during publication process.

V.P. was fnancially supported by (1) the Excellence Project CGL2017-82782-P financed by the Spanish Ministry of Science, Innovation and Universities, the Agencia Estatal de Investigación (AEI) and the Fondo Europeo de Desarrollo Regional (FEDER, EU), and (2) Modalidad Grupos de Investigación Consolidados, Principado de Asturias (IDI/2018/000151). M.M.D. was fnancially supported by the Spanish Ramon y Cajal grant RYC-2014-16263. N.S., C.B. and A.G. were partly supported by the National Centre for Research and Development (GLOBE POL-NOR/198352/85/2013) and the National Science Centre in Poland (DEC-2013/08/M/NZ9/00469; 2016/22/Z/NZ8/00121; 2017/25/N/NZ8/02861). E.R., J.N., A.F., N.S., and C.B. were supported by the Agencia Estatal de Investigación from the Ministry of Economy, Industry and Competitiveness, Spain (project CGL2017-83045-R AEI/FEDER EU, co-fnanced with FEDER)., Bombieri, G., Naves, J., Penteriani, V., Selva, N., Fernández-Gil, A., López-Bao, J.V., Ambarli, H., Bautista, C., Bespalova, T., Bobrov, V., Bolshakov, V., Bondarchuk, S., Camarra, J.J., Chiriac, S., Ciucci, P., Dutsov, A., Dykyy, I., Fedriani, J.M., García-Rodríguez, A., Garrote, P.J., Gashev, S., Groff, C., Gutleb, B., Haring, M., Härkönen, S., Huber, D., Kaboli, M., Kalinkin, Y., Karamanlidis, A.A., Karpin, V., Kastrikin, V., Khlyap, L., Khoetsky, P., Kojola, I., Kozlow, Y., Korolev, A., Korytin, N., Kozsheechkin, V., Krofel, M., Kurhinen, J., Kuznetsova, I., Larin, E., Levykh, A., Mamontov, V., Männil, P., Melovski, D., Mertzanis, Y., Meydus, A., Mohammadi, A., Norberg, H., Palazón, S., Pătrașcu, L.M., Pavlova, K., Pedrini, P., Quenette, P.Y., Revilla, E., Rigg, R., Rozhkov, Y., Russo, L.F., Rykov, A., Saburova, L., Sahlén, V., Saveljev, A.P., Seryodkin, I.V., Shelekhov, A., Shishikin, A., Shkvyria, M., Sidorovich, V., Sopin, V., Støen, O., Stofik, J., Swenson, J.E., Tirski, D., Vasin, A., Wabakken, P., Yarushina, L., Zwijacz-Kozica, T., Delgado, M.M.

The mitigation of conflicts associated with large carnivore damage to livestock and agriculture is pivotal to their conservation. We evaluate current programs to compensate and prevent large carnivore damage in 27 European countries and the factors related to the economic costs of these programs. Overall, high compensation costs are associated with free-ranging livestock (68% of total costs) and with national economic wealth. Contrary to general belief, the return of large carnivores does not always translate into higher compensation costs. We identify a tendency towards prioritizing compensation over prevention; only a few wealthy countries pay the majority of the money allocated for prevention programs to adapt husbandry practices to the presence of large carnivores. We conclude that programs mainly focused on paying large compensation amounts will often fail to build tolerance towards predators. To mitigate conflicts and optimize the cost-effectiveness of publicly funded measures, responsible agencies should be proactive, focus on prevention-based policies and periodically evaluate the effectiveness of compensation and prevention programs in an adaptive manner. With this purpose and to identify further solutions for conflict mitigation, we call for a pan-European database of damage occurrence, management actions and associated costs.

The European mink is a critically endangered mustelid with only three declining and isolated populations. Based on particular interpretation of genetic studies, the origin of SW population (France and Spain) and its conservation measures were recently questioned, and considered an example of managed relocation. The four published genetic studies show similar results, revealing a bottleneck structure. The SW population was probably established by very few individuals, which can be explained by dispersal of some-long distance migrants or by human introduction. The historical records evidence a long-distance dispersal capacity of the species and the temporal trend expansion in SW Europe is spatially collated with the idea of an expanding population. On contrast, most support for the introduction hypothesis comes from critics to other hypotheses, while it lacks of structure to stand on its own as hypothesis: no ecological barrier preventing natural expansion identified, no reports or reasons for captivity breeding or translocation programs, and lacks of supporting documents among others. Arguing shifting baseline syndrome in European mink conservation has weak basis and can result perilously misleading for a species in the brink of extinction.

The American mink (Neovison vison) is a semi-aquatic mustelid from North America that is considered an invasive species in many countries. Due to its reported damage to native species, efforts are often undertaken to eradicate or control these mink populations. The aims of this study were to describe the demographic structures of three mink populations subjected to different culling intensities, to detect possible variations in these structures caused by trapping and to identify possible efficient indicators of trapping efforts. From 1998 to 2011, a total of 1306 American mink collected during official culling operations in three different Spanish areas were submitted for study. We sexed the carcasses and removed a canine tooth from each animal during the post-mortem procedures. The incremental cementum lines of the teeth were used for age estimation. No evidence of age structure changes was detected in any population. The proportion of individuals in each sex and age class remained constant over time, suggesting that despite control efforts, the age structure remained stable over the study period. The population with the highest culling intensity has the highest sub-adult/adult ratio (1.51), and the catch per unit effort in this area was lower in the second part of the period, which is a possible indicator of reduced density. Age structure and sub-adult ratio might be useful indicators of successful trapping efforts. The results from this study could be useful for decision-making in conservation of native species and management of mink populations.

The European mink (Mustela lutreola) has undergone a dramatic decline and is one of the most endangered mammals in the world. The invasive American mink (Neovison vison) is considered the main factor for this decline. However, the American mink's introduction and the subsequent ecological concurrence of the two species cannot solely explain the decline or disappearance of the European mink. Aleutian mink disease virus (AMDV) is the main health problem in fur farming worldwide, causing varied clinical syndromes that depend on the viral strain and host factors. Infection with AMDV has been speculated to contribute to the decline of the European mink, but a detailed study has not been performed. To assess the potential effects of AMDV infection on the conservation of the European mink, we surveyed AMDV antibody in samples from 492 native European mink and 1,735 feral American mink collected over 16 yr. The antibody prevalence in European mink was 32%. There were no statistically significant differences in antibody prevalence between sexes, among years, or among weight classes. For recaptured European mink, incidence of seroconversion (negative to positive) was 0.46 cases per animal-year at risk. For positive animals, the incidence of conversion from positive to negative was 0.18 cases per animal-year at risk. In 1,735 feral American minks, the overall prevalence was 32.4% and varied among the six wild populations studied. Infection with AMDV appears to be endemic, distributed across the entire ranges of both species, and no effects on the population dynamics of either species were observed.

Age estimation of three mustelid species with similar body size was performed in Northern Spain. Canine samples of 1766 carcasses from 1661 American mink (Neovison vison), 54 European mink (Mustela lutreola), and 51 European polecats (Mustela putorius) were sectioned, and cementum annuli counts in tooth sections were used for age estimation. American mink samples consisted primarily of trap-captured animals from governmental control campaigns, whereas road casualties were the principal origin of European mink and European polecat carcasses. Individuals prior to their first breeding season (class 0+) represented approximately half of all animals, with no significant differences between species or causes of death. Differences in sub-adult percentages were observed between the pre- and post-reproductive period, with a high mortality during the dispersal-winter period in all three species. Frequencies of mortality of the sub-adult age class were 0.46, 0.50, and 0.55 for American mink, European mink, and European polecat, respectively. Survival rates of the American mink were higher than those of the native species. The oldest animals detected were 7+, 5+, and 3+ years old for the American mink, European mink, and European polecat, respectively. No differences were observed in mean age of animals found dead as road casualties in all three species or between captured American mink and road casualties. The information obtained is of high value for understanding the demographic processes of the populations and particularly for conservation and management decisions for these species.

The genetic characteristics of introduced populations have a relevant impact on their ability to establish and spread. The American mink (Neovison vison), native to North America, is an important invasive species in the Iberian Peninsula. Here, we used mitochondrial DNA sequences data to investigate the genetic diversity and phylogeographic structure of invasive versus native populations of this species. We also evaluated whether genetic diversity in invasive populations could be explained by the genetic characteristics of the native sources from which they derived. Phylogenetic analysis revealed two major lineages in the native range, which indicated a clear separation between western and eastern populations. On the contrary, we found no evidence of genetic structure in the invasive range. This was probably the result of the diverse origins of the released specimens and the rapid expansion and encounters of the introduced populations. We detected spatial mixing of both North American lineages in several sampling localities of the north central area of the Iberian Peninsula, giving rise to high levels of genetic diversity in some areas compared to North American populations. This could potentially lead to higher fitness of these individuals and thus increase the population viability and invasiveness of this species. These results point to the need to better study the populations in which lineages mix and, if necessary, intensify control efforts in them.

Wildlife damage to human property threatens human–wildlife coexistence. Conflicts arising from wildlife damage in intensively managed landscapes often undermine conservation efforts, making damage mitigation and compensation of special concern for wildlife conservation. However, the mechanisms underlying the occurrence of damage and claims at large scales are still poorly understood. Here, we investigated the patterns of damage caused by brown bears Ursus arctos and its ecological and socio-economic correlates at a continental scale. We compiled information about compensation schemes across 26 countries in Europe in 2005–2012 and analysed the variation in the number of compensated claims in relation to (i) bear abundance, (ii) forest availability, (iii) human land use, (iv) management practices and (v) indicators of economic wealth. Most European countries have a posteriori compensation schemes based on damage verification, which, in many cases, have operated for more than 30 years. On average, over 3200 claims of bear damage were compensated annually in Europe. The majority of claims were for damage to livestock (59%), distributed throughout the bear range, followed by damage to apiaries (21%) and agriculture (17%), mainly in Mediterranean and eastern European countries. The mean number of compensated claims per bear and year ranged from 0·1 in Estonia to 8·5 in Norway. This variation was not only due to the differences in compensation schemes; damage claims were less numerous in areas with supplementary feeding and with a high proportion of agricultural land. However, observed variation in compensated damage was not related to bear abundance. Synthesis and applications. Compensation schemes, management practices and human land use influence the number of claims for brown bear damage, while bear abundance does not. Policies that ignore this complexity and focus on a single factor, such as bear population size, may not be effective in reducing claims. To be effective, policies should be based on integrative schemes that prioritize damage prevention and make it a condition of payment of compensation that preventive measures are applied. Such integrative schemes should focus mitigation efforts in areas or populations where damage claims are more likely to occur. Similar studies using different species and continents might further improve our understanding of conflicts arising from wildlife damage., This study was funded by the National Science Center in Poland under agreement DEC‐2013/08/M/NZ9/00469. J.A. was funded by the project GLOBE POL‐NOR/198352/85/2013 under the Polish‐Norwegian Research Programme operated by the National Centre for Research and Development.

Large carnivores are keystone species in the ecosystems where they inhabit. Their loss may provoke an imbalance at several levels of the ecosystem. Conservation strategies for existing populations of large carnivores and restoration programmes of disappeared populations can help at maintaining the ecosystem balance and foster the perception links of humans with nature. The case of the restoration of the brown bear population in the Pyrenees during the last 20 years is a successful example of conservation measures carried out to assure the coexistence between this species and the local society, which economy is based on extensive livestock, beekeeping and tourism. In this chapter, I describe the role of large carnivores in mountain ecosystems and the context and development of the of the brown bear in the Catalan Pyrenees as an example of the challenges of large carnivore conservation in a rural context but a high influence from nearby urban areas.

Understanding changes over time in the distribution of interacting native and invasive species that may be symptomatic of competitive exclusion is critical to identify the need for and effectiveness of management interventions. Occupancy models greatly increase the robustness of inference that can be made from presence/absence data when species are imperfectly detected, and recent novel developments allow for the quantification of the strength of interaction between pairs of species. We used a two-species multi-season occupancy model to quantify the impact of the invasive American mink on the native European mink in Spain through the analysis of their co-occurrence pattern over twelve years (2000–2011) in the entire Spanish range of European mink distribution, where both species were detected by live trapping but American mink were culled. We detected a negative temporal trend in the rate of occupancy of European mink and a simultaneous positive trend in the occupancy of American mink. The species co-occurred less often than expected and the native mink was more likely to become extinct from sites occupied by the invasive species. Removal of American mink resulted in a high probability of local extinction where it co-occurred with the endemic mink, but the overall increase in the probability of occupancy over the last decade indicates that the ongoing management is failing to halt its spread. More intensive culling effort where both species co-exist as well as in adjacent areas where the invasive American mink is found at high densities is required in order to stop the decline of European mink.

An experimental release of the European mink (Mustela lutreola) was carried out in the Salburua wetland in North Spain between 2008 and 2010. A partial removal of feral American mink (Neovison vison) was done preceding the release. The survival and the cause of death of each of 27 captive-bred minks were studied during five months after release. Only 22 % of the minks (N = 6) survived during whole radio-tracking period. Predation was the most significant cause of mortality (76 %, N = 16). Seven European minks (33 % of mortality) were killed by another “mink-size” carnivore—the causes of death of these individuals were of particular interest to clarify possible impact of a few remained American mink to released European mink. We used three criteria to identify the exact causes of death of these seven minks: 1. Comparison of the distances of bite marks with the inter-canine distances of small carnivores, 2. Site descriptions and signs of predators and 3. Density of carnivores within the study area. None of the criteria taken separately allowed the complete identification of the predator species. Summing up the results of all three criteria, a male American mink was found to be the most likely predator of at least six released European minks (29 % of overall mortality and 38 % of predated minks). Our results show that the presence of American mink, even if the number is estimated to be low, may seriously limit the success of reinforcement or reintroduction of the European mink.

The American mink Neovison vison is an elusive mustelid that is monitored mostly through the detection of its field signs, namely, footprints and scats. In Europe, the American mink has been often monitored using the standard otter survey strategy developed specifically for the Eurasian otter Lutra lutra, requiring to walk transects of 600 m spaced at least 5 km apart. We tested whether the standard otter survey strategy was appropriate for surveying mink. We studied a high-density population of mink along a 9-km stretch of river between December 2004 and April 2005. Monthly surveys were conducted and scats and footprints were recorded within 100-m sections along the river. The results showed a monthly variation in signs recovery, with the months of December, January and February being the best ones for surveying. Transects of 600 m detected mink between 74 and 90 % of the times in all months, excluding March when detection was as low as 56 %. Taken all together, the results suggest that the standard otter survey strategy was adequate to detect mink, at least in this case where species density was high. The study also highlighted monthly differences in signs detection, suggesting that temporal variations should be taken into account when designing the sampling strategy and the length of the sampling units (transects). In the months immediately following the mating season (and possibly in lower-density mink populations), it may be advisable to increase the length of transects to increase detection of mink.

We studied the morphology of American mink Neovison vison in five out of the six introduced populations in Spain. The spatial and temporal variation of body weight (BW), body length (BL), tail length, hind-foot length and ear length were analysed. Temporal trends in BW and BL in relation to years since mink introduction were also analyzed. In addition, we tested the effect of sex, age (juvenile, subadult and adult) and age–sex interaction, on each parameter. Morphological parameters differed between populations, illustrating the high variability of body size of American mink in different environments, and the phenotypic plasticity of the species. Annual variations were synchronized between populations, suggesting a large-scale effect on all of them. BW and BL showed a decreasing trend in both males and females in relation to years since introduction. This decrease may be related to mink's diet. Differences in sex and age were found, pointing to sexual dimorphism in adults, subadults and juveniles. The dimorphism in non-adult individuals suggests that subadult males may have a competitive advantage from subadult females in feeding and/or hunting on bigger prey from an early age (resource partitioning hypothesis).

Loss of biodiversity due to biological invasions is one of the most critical issues our society is facing. American mink is one of the most nefarious invasive non-native species and has major consequences for diversity, ecosystems and economics. A project to evaluate the impact of American mink has been carried out in Catalonia since 2000 under the aegis of regional and national government and a European LIFE programme. In this study, we tested whether temporal variations in the relative abundance of native species were related to American mink. In addition, we compared the abundance of natives before and after mink arrival. Among the competitors spotted genet and European polecat, mink abundance and arrival had a significant negative effect on their populations. However, among black rat and fish prey only three native fish species had a negative temporal relation with the abundance of mink and three fish species showed a significant difference in their abundance before and after mink arrival. The effect of mink was significant among species with a higher niche overlap (polecat and genet versus mink). The persistence and coexistence of the alien and native species seems to depend on heterogeneity, in terms of the based on niche segregation among these species.

The effectiveness of culling campaigns to eradicate or limit populations of the alien, invasive American mink in Catalonia was studied by comparing the annual relative abundance of culled versus non-culled populations. We selected three populations that were culled under government campaigns and a fourth that served as a control and hence was left undisturbed (not culled). The study took place between 2002 and 2006 and annual relative abundances were estimated from trapping with bankside traps. The abundance of all four populations remained relatively stable throughout the study period. However, the annual relative abundance of the culled populations was lower than that of the non-culled population, which indicates that culling may have lowered the densities of mink, although eradication was not achieved. We also determined the potential distribution of the American mink in Catalonia by means of a habitat suitability model. The final aim was to assist in planning this species’ management. Almost all watercourses in Catalonia were identified as suitable for the American mink, with preferred areas located in the northeast. We recommend that the government and administrations promote culling campaigns focused on limiting the spread of the American mink as eradication is likely to be difficult to be achieved under the current situation. Target areas should be located on the edges of the American mink’s range and should be prioritized to limit the spread of this species to areas in which there are endangered native species.

Space use, intra-territorial habitat preferences, and factors affecting both were studied in an invading population of American mink, Mustela vison, in two rivers of a Mediterranean region of Spain. Average linear home range was 1.19 ± 0.73 km (±SD) and core area was 0.21 ± 0.08 km for resident males (n = 10); while for females (n =5) they were 0.54 ± 0.14 and 0.19 ± 0.11 km, respectively. Overlapping between the home ranges of residents was low. In no case their core areas overlapped. Home ranges were small in comparison to other study areas and in general the resident minks were territorial. Linear home range length was related to individual weight and to the river. Weight had a positive effect indicating a potential body condition effect, while river may be showing a habitat quality effect. Habitat preferences were positively affected by the abundance of helophytic vegetation and negatively by the presence of human activity. Helophytic vegetation offers both food and refuges, while human activity may represent a potential danger. Percentage of captures was higher inside the core areas and was slightly influenced positively by abundance of helophytic vegetation. All this information should be considered when designing and implementing measures to control the expansion of Amer- ican minks. We recommend keeping going with the trapping sessions but, given the results obtained, reducing the distance between traps down to 200 m to maximize capturability (i.e., about doubling the trapping effort), and, when available, placing them near helophytic vegetation. In the absence of helophytic vegetation, traps should be located near any kind of vegetation providing coverage for mink and far from human activity

Melero, Y., Palazon, S. and Gosalbez, J. 2008. Morphological adaptation of an invasive American mink population in Mediterranean areas of Spain. — Acta Zoologica (Stockholm) 89 : 47‐51 In this work we studied the morphology of an invasive population of American mink Mustela vison in Catalonia, Mediterranean Spain. Body weight, body length, tail length, hindfoot length and ear length were measured for four age‐sex classes: subadult male ( n = 17), subadult female ( n = 16), adult male ( n = 36) and adult female ( n = 10). A General Linear Mixed Model was used to test the effect of year, sex, age and age‐sex interaction, on each parameter. The morphological results differed from those of other introduced populations because of their different origin and their adaptation to different environments. Differences in sex and age were found, pointing to sexual dimorphism both in adults and subadults. The degree of dimorphism was lower than that of other populations, probably because of a lack of trophic niche separation between male and female mink because in the study area only small prey animals were available.

We examine the distribution of American mink Mustela vison in 28 European countries, and we review the impacts of this invasive species and the efforts made so far in controlling it. Our study reveals that, although mink farms are mostly concentrated in northern countries, mink are widely distributed across Europe, and that in some countries mink are apparently declining, although in most cases the causes are unknown. Countries for which the impact of mink on native species has been studied show that mink can have a significant effect on ground-nesting birds, rodents, amphibians and mustelids. The overall economic impact of feral mink seems to be relatively small but can be significant in specific regions. Recently, a number of eradication and local control projects have been carried out throughout Europe, indicating that these actions could be effective to protect native species. A consistent body of knowledge is starting to accumulate on issues concerning the American mink as an invasive alien species, but, as this review highlights, for most European countries there is currently a limited knowledge about its distribution or impacts. Taking all these observations together, we present some of the actions that have recently emerged as effective for dealing with this species and discuss which considerations may further encourage competent European authorities to take action to prevent and mitigate impacts of American mink.

[Background] The European mink (Mustela lutreola, L. 1761) is a critically endangered mustelid, which inhabits several main river drainages in Europe. Here, we assess the genetic variation of existing populations of this species, including new sampling sites and additional molecular markers (newly developed microsatellite loci specific to European mink) as compared to previous studies. Probabilistic analyses were used to examine genetic structure within and between existing populations, and to infer phylogeographic processes and past demography., [Results] According to both mitochondrial and nuclear microsatellite markers, Northeastern (Russia, Estonia and Belarus) and Southeastern (Romania) European populations showed the highest intraspecific diversity. In contrast, Western European (France and Spain) populations were the least polymorphic, featuring a unique mitochondrial DNA haplotype. The high differentiation values detected between Eastern and Western European populations could be the result of genetic drift in the latter due to population isolation and reduction. Genetic differences among populations were further supported by Bayesian clustering and two main groups were confirmed (Eastern vs. Western Europe) along with two contained subgroups at a more local scale (Northeastern vs. Southeastern Europe; France vs. Spain)., [Conclusions] Genetic data and performed analyses support a historical scenario of stable European mink populations, not affected by Quaternary climate oscillations in the Late Pleistocene, and posterior expansion events following river connections in both North- and Southeastern European populations. This suggests an eastern refuge during glacial maxima (as already proposed for boreal and continental species). In contrast, Western Europe was colonised more recently following either natural expansions or putative human introductions. Low levels of genetic diversity observed within each studied population suggest recent bottleneck events and stress the urgent need for conservation measures to counteract the demographic decline experienced by the European mink., This work was partially funded by three LIFE projects (“Conservación del visón europeo (Mustela lutreola) en “Castilla León” LIFE 00/NAT/E7229, La Rioja” LIFE 00/NAT/E7331 and “Álava” LIFE 00/NAT/E7335), and grants from the Diputación Foral de Álava and the University of the Basque Country (GIU 06/09) awarded to BJGM. The Basque Government (BG) also financed this study (project numbers IT317-10; IT575-13)., We acknowledge support of the publication fee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI).

This study describes the diet of European mink (Mustela lutreola) in Northern Spain. The diet was analysed from 105 European mink samples. Moreover, we collected other 37 faeces from a radiotracked European mink male. The European mink diet was based on small mammals (relative frequency of occurrences 36,9%), fish (30,6%) and birds (17,8%). The Levins index of trophic-niche width was 3,76. Wood mouse Apodemus sylvaticus was the most consumed small mammal and Cyprinids -mainly Barbus sp. was the most consumed fish. The average size and weight of consumed fish were 13,5 cm and 31,5 g, respectively and males consumed larger and heavier fish than females.

Recent advances in molecular scatology have allowed the development of reliable and non-invasive methods that can be applied in monitoring of small carnivores, without disturbance of the animals. Here a method is described that can be used to differentiate European mink Mustela lutreola, polecat M. putorius and American mink M. vison based on the analysis of DNA extracted from faeces. It consists of a nested PCR of a region of the mitochondrial D-loop followed by digestion of the resulting 240 bp amplicons with the restriction enzymes RsaI and MspI. The restriction patterns of both enzymes, when used together, are found to detect species-specific sequence variation. Two different haplotypes for European mink (AA, AB), another two for the polecat (AC, AD) and one for American mink (BC) can also be discriminated by this technique. Two new haplotypes for the mitocondrial D-loop of mustelids are described after DNA sequencing.

Human intervention is the main cause of the decline of the Critically Endangered European mink Mustela lutreola. In this study we analysed the main causes of direct human-caused mortality of the species in Spain. A total of 47 mortality records were obtained for the period 1950–1989, and 145 for 1990–2008. There was temporal variation in the cause of death, with trapping and shooting being the most common causes of mortality in 1950–1989 and road-kills in 1990–2008. In the case of road-kills there was variation related to road type. Males were more affected by road-kills than females, especially during the mating season when they range more widely. Our results indicate that there has been a change in human social behaviour and in people's awareness of the species, with a reduction in European mink captured and shot but an increase in mortality on roads.

Recent studies show that the availability of prey influences the ecology of otters by regulating breeding, carrying capacity and mortality. Mediterranean habitats experience extreme seasonal variation in water flow – a stress period can occur in summer when water flows and levels are low with long periods of drought, while torrential floods usually occur in autumn and spring. Reservoirs can affect this situation by further influencing water flow regimes and acting as a barrier. Our data show the close relationship between the amount of food (fish) available to otters and their use of a stretch of water and the otter density there. The adjustment of the number of individuals (and carrying capacity) in an area can be seen from their mortality, a decrease in their reproductive success, or migration. Our results are consistent with the hypothesis that otters are food-limited. Torrential rains, summer droughts and dams for water management have repercussions for otter populations in as much as they affect their prey-species. Barbels Barbus spp. and, secondarily, nases Chondrostoma spp. are shown to be important to otter ecology and breeding in Mediterranean Iberian rivers. The conservation and management of the otter in these habitats must not ignore the management of food sources. In order not to affect otter populations, the effect of the reservoirs and their dams also must be considered. The release and cessation of floodwater from reservoirs must be progressive and mimic more closely the flow regime of natural rivers.

The European mink Mustela lutreola is one of Europe’s most endangered carnivores, with few vulnerable populations remaining. Surprisingly, a recent phylogeny placed a single mink specimen within the polecat (M. putorius, M. eversmannii) group, suggesting a recent speciation and/or the effects of hybridization. The analysis has now been extended to a further 51 mink and polecats. As before, phylogenetic methods failed to resolve the relationships between the species. One haplotype (C11) was found in both species, and predominated in European mink from Spain and eastern Europe. The known M. lutreola fossils are of very young date, so either mink arose recently, or else the situation is confused by hybridization and a biased fossil recovery. The study highlights the dangers of using a single genetic marker in defining Evolutionarily Significant Units (ESUs). Polecats and European mink are clearly distinct in their morphology and ecology, and should still be considered as separate ESUs, but without further data it is difficult to define Management Units. Following the precautionary principle, we recommend that for the moment European mink in eastern Europe (Belarus, Estonia and Russia) and Spain should be managed separately.

Trophic relationships between invasive species in multiply invaded ecosystems may reduce food limitation relative to more pristine ecosystems and increase resilience to control. Here, we consider whether invasive predatory American mink Neovison vison are trophically subsidized by invasive crayfish. We collated data from the literature on density and home range size of mink populations in relation to the prevalence of crayfish in the diet of mink. We then tested the hypothesis that populations of an invasive predator reach higher densities and are more resilient to lethal control when they have access to super-abundant non-native prey, even in the absence of changes in density dependence, hence compensatory capacity. We found a strong positive relationship between the proportion of crayfish in mink diet and mink population density, and a negative relationship between the proportion of crayfish in mink diet and mink home range size, with crayfish contribution to mink diet reflecting their abundance in the ecosystem. We then explored the consequence of elevated mink density by simulating a hypothetical eradication program with a constant harvest in a Ricker model. We found that mink populations were more resilient to harvest in the presence of crayfish. As a result, the simulated number of mink harvested to achieve eradication increased by 500 % in the presence of abundant crayfish if carrying capacity increased by 630 %. This led to a threefold increase in time to eradication under a constant harvest and an approximately 20-fold increase in the cumulative management cost. Our results add to evidence of inter-specific positive interactions involving invasive species, and our simple model illustrates how this increases management cost.

Patterns of daily activity and the factors affecting it were studied in an invading Mediterranean population of American mink, Neovison vison, radiotracked in the northeast of Spain during the post breeding season (winter – half year). We distinguished between local activity, defined as active behaviour without spatial displacement, locomotion activity as active locomotion behaviour while foraging or travelling, and inactivity. We studied the effect of sex, age, daylight (nocturnal or diurnal), month, river flow and average rainfall on the activity of eight males and three females. Male mink presented more locomotion activity than females and subadult mink had more locomotion activity than adult mink. Average rainfall per day had a negative effect on locomotion, while daylight had no effect on either total activity or locomotion activity. Studied mink spent most of their time inactive in-den. These results are accordance with the patterns of activity shown by other native and invasive populations.

Les modifications de la distribution du vison d'Europe (Mustela lutreola) entre 1950 et 1999 sont decrites, avec 258 nouvelles donnees pour l'espece. Toutes les donnees proviennent du nord de l'Espagne (Pays basque, Rioja, Navarre, NO Aragon, NE Castilla-Leon) avec quelques-unes du sud de la Catalogne. Le type de donnees s'est modifie au cours du temps. La quantite d'animaux tues par l'homme a diminue alors que la mortalite due a la route a augmente. Entre 1980 et 1999, les visons ont ete trouves dans 99 carres UTM (10 x 10 km), et dans seulement 85 carres depuis 1990 (2,0 % et 1,8 % du territoire espagnol, respectivement). M.lutreola existe sous forme de trois noyaux de populations, plus ou moins connectes. On peut emettre deux hypotheses principales pour expliquer la repartition actuelle du vison d'Europe en Espagne; (1) M lutreola se trouve en Espagne depuis avant le XIX e siecle, au sein de son aire historique, et (2) M. lutreola a rejoint l'Espagne recemment (au cours du XX e siecle) a partir du SO de la France, par une extension au sud. Nos donnees semblent confirmer cette derniere hypothese. Meme si des visons d'Europe ont ete trouves dans des rivieres fortement polluees, ils evitent en general les eaux polluees. De plus, l'etablissement, a l'interieur de l'aire de repartition du vison d'Europe, d'une population de visons d'Amerique dans le nord de l'Espagne, et l'expansion de la grosse population de visons americains depuis le centre de l'Espagne, ainsi que la presence d'ADVirus chez plusieurs visons d'Europe constituent de serieuses menaces pour sa survie en Espagne.

Serious declines in populations of native European mink (Mustela lutreola) have occurred in Europe. One responsible factor may be infectious diseases introduced by exotic American mink (Mustela vison). In order to investigate a possible role for Aleutian mink disease parvovirus (ADV), we surveyed native riparian carnivores and feral American mink. When serum samples from 12 free-ranging European and 16 feral American mink were tested, antibodies to ADV were detected from three of nine European mink. ADV DNA was detected by polymerase chain reaction in whole cell DNA from four of seven carcasses; two American mink, one European mink and a Eurasian otter (Lutra lutra). Lesions typical of Aleutian disease were present in one of the American mink. A portion of the ADV VP2 capsid gene was sequenced and the results suggested that two sequence types of ADV were circulating in Spain, and that the Spanish ADVs differed from other described isolates from North America and Europe. Future conservation and restoration efforts should include measures to avoid introduction or spread of ADV infection to native animals.