Feeding plasticity and temporal behaviour of the alien American mink in Europe

Cathemerality: a key temporal niche

Given the marked variation in abiotic and biotic conditions between day and night, many species specialise their physical activity to being diurnal or nocturnal, and it was long thought that these strategies were commonly fairly fixed and invariant. The term 'cathemeral', was coined in 1987, when Tattersall noted activity in a Madagascan primate during the hours of both daylight and darkness. Initially thought to be rare, cathemerality is now known to be a quite widespread form of time partitioning amongst arthropods, fish, birds, and mammals. Herein we provide a synthesis of present understanding of cathemeral behaviour, arguing that it should routinely be included alongside diurnal and nocturnal strategies in schemes that distinguish and categorise species across taxa according to temporal niche. This synthesis is particularly timely because (i) the study of animal activity patterns is being revolutionised by new and improved technologies; (ii) it is becoming apparent that cathemerality covers a diverse range of obligate to facultative forms, each with their own common sets of functional traits, geographic ranges and evolutionary history; (iii) daytime and nighttime activity likely plays an important but currently neglected role in temporal niche partitioning and ecosystem functioning; and (iv) cathemerality may have an important role in the ability of species to adapt to human-mediated pressures.

Diet of Free Ranging American Mink (Neovison vison) in Denmark

Non-native American mink (Neovison vison) is a widely spread predator in Denmark. The feral population in mainland Denmark consists of captive-born mink that escaped from fur farms and wild mink born in nature, whereas the population on Bornholm is almost all wild-born mink. In this study, the diets of feral mink in mainland Denmark and on the island of Bornholm are analyzed. The aim of this study was to examine (1) whether the diet of the larger captive-born mink differs from that of the smaller wild-born mink, (2) assess the regional variations between the diets of mink in mainland Denmark and on Bornholm, and (3) investigate the seasonal variation in the diet composition of mink. The stomach contents of 364 mink (243 wild-born and 114 captive-born) culled in the years 2019-2022 were analyzed. Of these, 203 mink were from mainland Denmark, and 154 were from Bornholm. No significant differences were found between the diets of captive-born mink and wild-born mink or the mink found in mainland Denmark and on the island of Bornholm. Significantly more empty stomachs were found during spring than during the summer and autumn, suggesting a bottleneck in the diet during spring.

Wild Mesocarnivores as Reservoirs of Endoparasites Causing Important Zoonoses and Emerging Bridging Infections across Europe

Mesocarnivores are small- or mid-sized carnivore species that display a variety of ecologies and behaviours. In Europe, wild mesocarnivores are represented by the red fox (Vulpes vulpes), the golden jackal (Canis aureus), the European wildcat (Felis silvestris), the Mustelidae of the genera Meles, Martes, Mustela, Lutra, the invasive species of raccoon dog (Nyctereutes procyonoides), raccoons (Procyon lotor), and American mink (Neogale vison). These abundant animals thrive in various habitats and often develop their activity close to human settlements. Thus, they may play an important role in the introduction, maintenance, and transmission of major parasitic zoonoses and promote bridging infections with domestic animals. Against this background, this article reports and discusses some of the most important endoparasites of wild mesocarnivores living in Europe, on the basis of their actual role as reservoirs, spreaders, or sentinels. The data derived from epizootiological studies in different European countries, and the proven or speculated implications of the detected endoparasites in human and domestic animals' health, are discussed. Through older and recent literature review, the state-of-the-art knowledge on the occurrence and prevalence of the parasites under consideration is presented, showing further, warranted investigations and the need for surveillance and vigilance.

Distribution of introduced American mink in the Northern Apennine area (Central Italy)

The American mink Neovison vison is a widespread alien carnivore in Europe due to escapes from fur farms through this continent. Impacts by naturalized mink include competition with native species and predation of crayfish and small vertebrates. Therefore, an updated monitoring of mink distribution is required to design management plans. The American mink has been reported with an established population in North-Eastern Italy, in Sardinia, and two small nuclei respectively in the Central and in the Northern Apennine ridge. Available information for the latter dates back to early 1990s. In this note, we described the range expansion of the American mink population in the Northern Apennine ridge and we estimate the current distribution range and the extent of occurrence by using data collected from 2006 to 2021 through the Minimum Convex Polygon (MCP). We compared the current distribution range with that of 1990s. The American mink showed a remarkable range increase since its first escape in the Northern Apennines, thus requiring rapid actions to limit impacts on native biodiversity.

Value-conflicts in the conservation of a native species: a case study based on the endangered white-clawed crayfish in Europe

The future of the native European crayfish Austropotamobius pallipes depends on accurate conservation management. The goal of this paper is to attempt an investigation of the major ethical conflicts that can emerge in the conservation of this endangered crayfish threatened by invasive competitors, introduced diseases, and landscape alteration. To assess this issue, we will employ the Ethical Matrix, in a version explicitly tailored for its use in conservation. The filled Ethical Matrix will highlight several potential conflicts between values such as environmental protection, social and economic interests, animal welfare, cultural and aesthetic value, etc. We will discuss these conflicts, alongside some potential mitigating strategies present in the literature. We will stress in particular the need to take into account the ethical principle of fairness when assessing the economic and recreational value of invasive species, especially concerning the unfair distribution of costs. Moreover, we will assert the importance of conservation of A. pallipes both for its existence value and for its role as an umbrella and keystone species. Beyond its focus on A. pallipes, the Ethical Matrix here discussed might also provide insights on the value conflicts relative to analogous in situ conservation efforts involving a native species threatened by invasive alien competitors.

Graphic abstract