Eurasian Beaver Castor Fiber Research Articles

Beaver dams in Mediterranean ecosystems: trait‐specific effects on macroinvertebrates

AbstractAfter centuries of extinction due to human persecution, Eurasian beavers Castor fiber L. have been released to Southern Europe in the last decades. Being ecosystem engineers, beavers have attracted great attention regarding restoration of aquatic and terrestrial ecosystems. Nonetheless, the effects of the species on aquatic invertebrates known to date are not univocal and mostly refer to central European riverine systems. Here, we evaluated the effects of beaver presence on aquatic macroinvertebrates for the first time in a Mediterranean riverine ecosystem, by applying a sound control‐impact sampling design and controlling for seasonal variation in macroinvertebrate assemblage composition. A significant variation in response to season was evident for macroinvertebrate communities, revealing distinct assemblages during spring and summer. Furthermore, the presence of beavers was also identified as a significant driver of species composition, as samples near the beaver dam showed significant variation from control sites. Macroinvertebrate community traits changed according to the relative position to the beaver dam, as control sites featured on average higher abundances of taxa with higher values of bioindication score, larger size, lower adaptation to drag, and were less frequently of introduced origins. Yet, these differences were strongly taxon‐ and season‐specific in their intensity and direction. Differences across sites were mainly driven by the relative abundances of few taxa—including both alien species and high environmental quality indicators—such as those from genera Potamopyrgus, Baetis, Habrophlebia, Ephemerella, Leuctra, and Radix, which explained about 70% of the observed divergence among conditions. Our results indicate that beavers and their engineering activity may induce highly variable species‐specific responses in macroinvertebrates, thus possibly representing a driver of environmental heterogeneity along Mediterranean rivers, and that both bioindicators and alien species may exploit such heterogeneity.

Wolf diet in the Notecka Forest, western Poland

We assessed the diet composition of wolves inhabiting Notecka Forest (ca 1400 km2) in western Poland based on the analysis of scats (n = 261) collected in 2008–2021. The study revealed that wolves in this large forest tract, consisting mainly of pine monocultures, consumed primarily wild ungulates (95.2% of consumed biomass). The roe deer was the essential food item (47.8%), followed by the red deer Cervus elaphus (25.1%) and the wild boar Sus scrofa) (18.4%). Wolves supplemented their diet with medium‐sized wild mammals, mainly the European hare Lepus europaeus (2.8%) and the Eurasian beaver Castor fiber (1.9%). The food niche was narrow (B = 1.1), and there was no difference in food composition between the spring–summer and autumn–winter seasons. We emphasize the significance of the smallest European wild ruminant, roe deer, in the diet of wolves inhabiting Central European Plains.

Сучасна теріофауна лівобережжя Каньйонового Придністер’я

The article analyses the current state of the mammal fauna of part of Podolian Transnistria, which lies between the rivers Zbruch and Zolota Lypa (southern Ternopil Oblast, Ukraine). To designate the region, the publication uses a term from old Polish sources—Canyon Transnistria—which reflects the prevailing landform. The area of research in old faunal summaries is mentioned only as part of wider regions, such as Galicia, western Ukraine, or Ternopil Oblast. Over the past decades, the number of publications on the mammal fauna of this particular region has increased substantially, which makes it possible to make a summary overview. The modern mammal fauna of the region comprises 60 species belonging to 7 orders, 20 families, and 41 genera. Over the past 70 years, the mammal fauna of the studied region has undergone significant changes. Its dynamic component is almost 27%. It includes species of recent immigrants (Blyth’s pipistrelle Pipistrellus lepidus, mound-building mouse Mus spicilegus, muskrat Ondatra zibethicus), as well as two species that recovered their range (Eurasian beaver Castor fiber, wildcat Felis silvestris); the dynamic component also includes three extinct or probably extinct species—Geoffroy’s bat (Myotis emarginatus), Podolian ground squirrel (Spermophilus odessanus), and European rabbit (Oryctolagus cuniculus). A group of phantom species has been singled out, which are known only from single old finds, and modern studies of these species are far from sufficient to understand their status. It includes the lesser mouse-eared bat (Myotis oxygnathus), Nathusius’s pipistrelle (Pipistrellus nathusii), southern birch mouse (Sicista loriger), and Podolian mole rat (Spalax zemni). Such species as the long-eared bat (Plecotus austriacus) and the pygmy field mouse (Sylvaemus uralensis) appeared in the lists of the mammal fauna of the region due to changes in taxonomy. The rare component of the mammal fauna comprises 18 species (30%). The article provides a brief description of the current state of mammal populations in the region. Conservation recommendations are given for rare species.

Ecosystem engineers enter the city: Habitat characteristics influencing the distribution of Eurasian beavers Castor fiber in a human-transformed landscape

In recent decades, the population of the Eurasian beaver Castor fiber has increased significantly, and from near extinction the species has become widespread again over large part of its former range. However, the recovery of the beaver population is giving rise to increasing numbers of human-beaver conflicts in areas inhabited by humans. The key challenge of beaver population management is, therefore, to identify habitat characteristics that determine the presence of the species in the human-dominated landscape, including urban areas. Based on a large-scale inventory of beavers conducted in one of the most densely populated regions of Europe, we show that the factors enhancing habitat suitability for beavers at the landscape scale are the increasing cover of meadows and surface waters, and the total length of watercourses. Although beavers avoid built-up areas, 13% of all recorded sites were located in the most densely populated regions, and the local habitat features that favour the presence of beavers in an urban landscape are the increasing cover of forests, meadows and surface waters, the total length of watercourses and the total length of roads. This indicates that patches of natural or semi-natural vegetation persisting along watercourses located in the vicinity of communication routes constitute a habitat for beavers entering the most urbanized areas. The beaver is currently expanding into western and southern Europe, but the species’ future distribution will include highly transformed urban areas. To limit human-beaver conflicts, predictions of beaver distributions in human-dominated landscapes should be used in urban and landscape planning.

Should individual animals be given names in wildlife reintroductions?

AbstractIndividual animals are often given names by humans. For example, names are attributed to domestic animals to acknowledge their closeness to people, some research studies use names to identify differences between individuals in a study group, or zoos often use names to tell stories that attract public or media attention.Publicly naming individual animals can provide opportunities in conservation, but there are also risks. In this perspective we exemplify such opportunities and risks in the context of wildlife reintroductions. We draw on examples and observations from our experience researching Eurasian beaverCastor fiberreintroduction in England, to encourage careful thinking before publicly attributing a name to an individual in reintroduction projects.Naming individuals in reintroduction can: be a low‐cost engagement tool; help people relate to unfamiliar reintroduced species; encourage local ownership of reintroduction projects; enable an effective tool for communicating information about the species and ways to coexist; or support creative or cultural expression.Yet naming individuals in reintroduction could: risk misrepresentation of natural species characteristics; make it challenging to normalise the sense that the reintroduced species is a wild animal; unintentionally imply that humans have ownership or power over the animal; cause distraction from establishing viable populations due to focus on the individual; or result in human investment in individual animals, which may have influence on reintroduction outcomes if that animal later comes to harm or dies (naturally or otherwise).Synthesis and Applications. We argue there is more to the act of naming individuals than may first appear. If considering doing so, we call for careful thought about whether it is appropriate and how to go about it. While we intentionally refrain from concluding whether ‘to name or not to name’, we call for careful, informative, message framing that takes advantage of the opportunities and is prepared for future circumstances, when naming of individuals does take place.Read the freePlain Language Summaryfor this article on the Journal blog.

Eurasian beavers in Central Italy: perceptions in the local community

According to the IUCN guidelines, wildlife reintroduction should consider any impacts on humans within feasibility assessments. Eurasian beavers Castor fiber are recovering across their native range, due to protection laws and reintroductions. In Central Italy, a self-sustaining, naturalised population of Eurasian beavers has been identified in the last five years. A questionnaire to measure whether and how citizens in the local area perceive the presence of the beaver was administered to 1114 respondents. We observed a comprehensive awareness of the presence of the beaver in Italy and a high ability to distinguish it from non-native coypus Myocastor coypus (92.3%). We also recorded a general high knowledge of issues related to the presence of the beaver (i.e., potential effects on indigenous biodiversity). The majority (65.5%) of the surveyed population was in favour of reintroducing the beaver in Central Italy, and only 1.2% was firmly against it. The majority of interviewed people was against the removal of beavers from Central Italy (65.8%), whereas only 3.7% was in favor, citing fears of perceived impacts on the river, crops, and fish populations.

"Oops…a Beaver Again!" Eurasian Beaver Castor fiber Recorded by Citizen-Science in New Areas of Central and Southern Italy.

The Eurasian beaver Castor fiber was once present in the Palearctic, ranging from the western Iberian Peninsula to northwestern China. In the Middle Ages, this rodent underwent a severe decline in population due to habitat loss, hunting for fur and meat, and the demand for castoreum. At the beginning of 1900, the range of the Eurasian beaver was limited to scattered refugia in Eurasia. Since 1920, legal protection, reintroduction events, and natural spread triggered the recovery of the species in most of its original range. In March 2021, the presence of the Eurasian beaver in Central Italy (Tuscany and Umbria regions) was confirmed through camera trapping after the detection of unequivocal signs of presence (i.e., gnawed trunks). Recordings are located about 550 km south of the known range of this species, thus suggesting that the presence of beavers in Tuscany and Umbria might be due to a local unauthorised reintroduction. In this work, we also reported the presence of beavers in the Abruzzi region and in Southern Italy (Molise-Campania regions), over 380 km in a straight line south to the southernmost record of beaver presence in Central Italy.

Beyond beaver wetlands: The engineering activities of a semi-aquatic mammal mediate the species richness and abundance of terrestrial birds wintering in a temperate forest

The engineering activities of the Eurasian beaver Castor fiber have far-reaching effects on the components of an environment and therefore modify the functioning of the ecosystem. The wetlands thereby created are the most conspicuous effect of beaver activity and attract water-related species. However, there is some evidence suggesting that beavers influence not only aquatic ecosystems but also the terrestrial habitats adjacent to these wetlands and the organisms occurring there. Because the impact of beavers on terrestrial birds is still poorly understood, this study evaluates the assemblage of birds wintering on beaver sites (N = 65) and paired reference sites (N = 65) in temperate forests of central Europe. We investigated the correlations between beaver presence, parameters of wetland areas, terrestrial vegetation characteristics, distance from the water’s edge and bird species richness and abundance. We found a greater species richness and abundance of wintering birds on beaver sites than on watercourses unmodified by this ecosystem engineer (by 38% and 61%, respectively). Species richness and abundance were higher in the terrestrial habitats near the edges of beaver ponds, but for some species this tendency also held in forests growing at some distance from beaver wetlands. Greater species richness was related to beaver presence, but also increased with a more open canopy and greater forest floor diversity, whereas bird abundance was correlated only with canopy openness. The beaver sites attracted primary cavity nesters, secondary cavity nesters and frugivorous species. This study provides evidence that the engineering activities of beavers during the growing season have a delayed cascading effect on the richness and abundance of the bird assemblage in terrestrial habitats in winter. This indicates that beaver ecosystem engineering should be seen as having a potential for carry-over effects, in which the consequences of beaver activity become apparent in subsequent seasons. Birds are considered to be ecological indicators, so our results highlight the importance of beavers for the distribution of terrestrial organisms at the local scale, and therefore the functioning of ecosystems beyond the immediate wetland area.

Temporal Activity Patterns of the Eurasian Beaver and Coexisting Species in a Mediterranean Ecosystem.

Simple SummaryCompetition and predation are the main factors shaping interspecific coexistence in wildlife communities. Species reappearance and introductions may alter these dynamics. The Eurasian beaver Castor fiber is a widespread species in Europe, and it is part of the diet of many birds and mammalian carnivores of all sizes. Additionally, competition with other herbivorous mammals at feeding sites could occur. For this reason, we computed the overlap of activity rhythms among the recently reappeared Eurasian beaver and its potential predators (red fox Vulpes vulpes and grey wolf Canis lupus) and competitors (coypu Myocastor coypus) in Central Italy. The beaver was confirmed as a mostly crepuscular species, avoiding the bright moonlight nights and the activity of its predators, which is potentially shaped by the behaviour of their main prey.Analyses of temporal partitioning and overlaps in activity rhythms are pivotal to shed light on interspecific coexistence between similar species or prey and predators. In this work, we assessed the overlap of activity rhythms between the Eurasian beaver Castor fiber and its potential competitors and predators through camera trapping in an area in Central Italy. Interspecific overlaps of temporal activity patterns were estimated for the beavers, potential predators (the red fox Vulpes vulpes and the grey wolf Canis lupus), and a potential competitor, the coypu Myocastor coypus. The beavers showed a mostly crepuscular behaviour. Although high temporal overlap was observed between the Eurasian beavers and the red foxes and grey wolves, the activity of the beavers did not overlap with that of the predators. Accordingly, the beavers were more active on the darkest nights, i.e., avoiding bright moonlight.

Retention and loss of PIT tags and surgically implanted devices in the Eurasian beaver

BackgroundPassive integrated transponder devices (PIT tags) are a valuable tool for individual identification of animals. Similarly, the surgical implantation of transmitters and bio-loggers can provide useful data on animal location, physiology and behavior. However, to avoid unnecessary recapture and related stress of study animals, PIT tags and bio-loggers should function reliably for long periods of time. Here, we evaluated the retention of PIT tags, and of very high frequency (VHF) transmitters and bio-loggers that were either implanted subcutaneously or into the peritoneal cavity of Eurasian beavers (Castor fiber).ResultsOver a 21-year period, we implanted PIT tags in 456 individuals and failed to detect a PIT tag at recapture in 30 cases, consisting of 26 individuals (6% of individuals). In all instances, we were still able to identify the individual due to the presence of unique ear tag numbers and tail scars. Moreover, we implanted 6 VHFs, 36 body temperature loggers and 21 heart rate loggers in 28 individuals, and experienced frequent loss of temperature loggers (at least 6 of 23 recaptured beavers) and heart rate loggers (10 of 18 recaptured beavers). No VHFs were lost in 2 recaptured beavers.ConclusionsPossible causes for PIT tag loss (or non-detection) were incorrect implantation, migration of the tag within the body, a foreign body reaction leading to ejection, or malfunctioning of the tag. We speculate that logger loss was related to a foreign body reaction, and that loggers were either rejected through the incision wound or, in the case of temperature loggers, possibly adhered and encapsulated to intestines, and then engulfed by the gastro-intestinal tract and ejected. We discuss animal welfare implications and give recommendations for future studies implanting bio-loggers into wildlife.

Recovery in the melting pot: complex origins and restored genetic diversity in newly established Eurasian beaver (Rodentia: Castoridae) populations

Abstract Several larger vertebrate species have recovered from dramatic bottlenecks caused by overhunting and habitat destruction. One of the most notable comebacks concerns the Eurasian beaver (Castor fiber L.), which has increased its range by natural dispersal from both relict populations and populations established through translocations. Genetic methods have recently been used to study beavers at several locations. However, owing to a lack of reference samples from relict populations and alternative names of mitochondrial DNA haplotypes, the ancestry of re-established beaver populations remains obscure. Here, we focus on the genetic characterization of several newly established populations. Unlike previous studies, we also used microsatellite genotypes of reference samples from all relict populations. Our analysis was fully capable of tracing the origin of the nuclear and mitochondrial genome to relict populations. Although we confirmed an extraordinarily low genetic diversity in relict populations, our analysis showed restored diversity in newly established populations resulting from translocations. Recent expansions and stochastic effects have created a strong but complicated population structure, with neighbouring populations differing significantly in genetic composition. We conclude that this restored genetic diversity very likely contributes to the viability and ongoing expansion of the newly established populations.

Features of the Leningradsky region Priozersky district water reservoirs’ entomofauna

In order to monitor the aquatic entomofauna, insects were captured in various sections of the watercourse, both located near beaver settlements and located on reservoirs where beaver settlements and traces of their stay were not found. The data obtained during the study indicate that near the settlements of the Eurasian beaver (Castor fiber), the number of species of aquatic Coleoptera, Hemiptera, and dragonflies encountered is higher than at other collection stations. No significant differences in the number of entomofauna species were found for other taxa.

Renewed coexistence: learning from steering group stakeholders on a beaver reintroduction project in England

Species reintroductions are growing in popularity, and example motivations include supporting species populations or the restoration of ecosystem function. Interactions between humans and the reintroduced species are likely to occur post-reintroduction. Coexistence between humans and wildlife is adaptive and dynamic, in part requiring management of conflicts between humans and wildlife, or of conflicts between humans over wildlife management. We seek to learn from the experiences of steering group members in a Eurasian beaver (Castor fiber) project in England and identify how governance of coexistence with reintroduced species may differ from the governance of coexistence with species that are already present in the landscape. Using a qualitative thematic analysis of an online survey, we identify a series of lessons in six key areas: (1) project governance, (2) stakeholder engagement, (3) research and monitoring programme, (4) strategy to manage arising conflicts, (5) public engagement, and (6) broad perspectives on reintroduction trials. We advocate for reflective evaluation as an essential component of reintroduction projects to enable knowledge-sharing from experiences, leading to improved practices in the future. Reflecting on our analysis, we identify and define ‘Renewed Coexistence’—a new term that draws on pre-existing coexistence knowledge but identifies the unique elements that relate to governing coexistence with reintroduced species.

Staphylococcus aureus isolates from Eurasian Beavers (Castor fiber) carry a novel phage-borne bicomponent leukocidin related to the Panton-Valentine leukocidin

Staphylococcus aureus can be a harmless coloniser, but it can also cause severe infections in humans, livestock and wildlife. Regarding the latter, only few studies have been performed and knowledge on virulence factors is insufficient. The aim of the present study was to study S. aureus isolates from deceased wild beavers (Castor fiber). Seventeen isolates from eleven beavers, found in Germany and Austria, were investigated. Antimicrobial and biocide susceptibility tests were performed. Isolates were characterised using S. aureus-specific DNA microarrays, spa typing and whole-genome sequencing. From two isolates, prophages were induced by mitomycin C and studied by transmission electron microscopy. Four isolates belonged to clonal complex (CC) 8, CC12, and CC398. Twelve isolates belonged to CC1956 and one isolate was CC49. The CC49 and CC1956 isolates carried distinct lukF/S genes related to the Panton-Valentine leukocidin (PVL) from human isolates of S. aureus. These genes were located on related, but not identical, Siphovirus prophages. The beavers, from which those isolates originated, suffered from abscesses, purulent organ lesions and necrotising pneumonia, i.e., clinical manifestations resembling symptoms of severe PVL-associated disease in humans. It might thus be assumed that the “Beaver Leukocidin (BVL, lukF/S-BV)”-positive strains are beaver-specific pathogens, and further studies on their clinical role as well as on a possible transmissibility to other species, including humans, are warranted.

DISTRIBUTION AND GENETIC ANALYSIS OF WILD-LIVING EURASIAN BEAVERS IN CENTRAL ITALY

The presence of the Eurasian beaver Castor fiber L. has been recently confirmed with two separated populations in Tuscany (Central Italy) and probably represents the result of an unofficial release. In late spring and summer 2021, seven reliable records of Eurasian beaver have been collected in Umbria and other neighbouring regions, implying that the distribution of this large rodent is even wider than previously reported. In this short work, we updated the distribution of this protected species in Central Italy, by collecting and mapping all the confirmed occurrences. Beavers were proved to be present throughout the Tiber (Tevere) river basin in both provinces of Umbria, and another individual has been road-killed in the Marche region, near the border with Tuscany. Other single signs of presence occurred in Emilia Romagna and Latium. The only hair sample we were able to collect confirmed it as the Eurasian beaver species. No reliable evidence is available on the number of free-ranging beavers in Central Italy, and systematic monitoring is needed. Before any management and conservation action, further data are required concerning distribution range, potential origin, social perception, and the effects on the ecosystems.

Distribution patterns of the native Eurasian and the non-native North American beaver in Finland\u2014possible factors affecting the slow range expansion of the native species

Distribution patterns of species are affected by resource availability, dispersal, disturbance and population dynamics. The smaller population size and range of the native Eurasian beaver (Castor fiber) compared to the non-native North American beaver (Castor canadensis) in Finland raise questions on reasons for the slower range expansion of the native species. We compared the population growth rates and the spread of both species from their release sites. We also studied the factors possibly affecting the spread of the Eurasian beaver in South western Finland in more detail. We found that the North American beaver has spread longer distances than the Eurasian beaver, but we did not find evidence for movement barriers constraining the expansion rate of the native species. Lack of high-quality habitats does not seem to constrain the expansion to nearby areas either. Despite this, the Eurasian beaver population has grown to a high density close to its reintroduction site, and it has started to spread to novel areas only recently. We conclude that the expansion of the native beaver in Finland seems to be controlled by factors other than those related to barriers for movement: movement behavior and population dynamics, which require further investigation.

A non-invasive, DNA-based method for beaver species identification in Finland

For the ability to control an invasive species and to protect an ecologically similar native species it is essential to map the exact distributions of both species. This is difficult if the species are so morphologically similar that their identification in the field is almost impossible. In Finland, the invasive North American beaver Castor canadensis is spreading towards the range of the native Eurasian beaver Castor fiber and at present, these species are partly sympatric. Effective management of these morphologically similar species requires an efficient method for species identification, ideally one that is non-invasive. Non-invasive genetic methods are used in a wide variety of wildlife species, for example in the research of large carnivores. Feces are a good source of DNA for terrestrial animals, but for the semi-aquatic animals like beavers, feces are not the best option. However, environmental DNA (eDNA) has been successfully used to detect species non-invasively in aquatic and terrestrial environments. We developed a non-invasive, eDNA-based method to map the distribution of the beaver species in Finland and to investigate within-species genetic diversity. The eDNA was obtained from the feed remains (wood chips) from beaver forage sites. With the help of Citizen science, wood chip samples were collected from different parts of Finland. We used our eDNA method to identify the ranges of both beaver species. Additionally, the presence of Eurasian beavers in south-east Finland was proven for the first time. Our non-invasive eDNA method is an effective way to accurately identify the ranges of both beaver species and will allow for the control of the invasive North American beaver and conservation of the native Eurasian beaver in Finland.

Reappearance of the Eurasian beaver Castor fiber L. in Tuscany (Central Italy): the success of unauthorised releases?

Reappearance of the Eurasian beaver Castor fiber L. in Tuscany (Central Italy): the success of unauthorised releases?

The influence of Eurasian beaver Castor fiber activity on fish assemblages in small steppe rivers in Russia

The influence of Eurasian beaver Castor fiber activity on fish assemblages in small steppe rivers in Russia

Size is not everything: differing activity and foraging patterns between the sexes in a monomorphic mammal

Animals balance foraging with other activities, and activity patterns may differ between sexes due to differing physical requirements and reproductive investments. Sex-specific behavioural differences are common in sexually dimorphic mammals, but have received limited research attention in monomorphic mammals where the sexes are similar in body size. Eurasian beavers (Castor fiber) are obligate monogamous and monomorphic mammals and a good model species to study sex-specific differences. As females increase energy expenditure during reproduction, we hypothesized differing seasonal activity budgets, circadian activity rhythms and foraging patterns between male and reproducing female beavers. To test this hypothesis, we equipped adult beavers with VHF transmitters (N=41; 16 female, 25 male) and observed them throughout their active period at night from spring to late summer. Occurrence of their main activities (foraging, travelling and being in lodge) and use of food items (trees/shrubs, aquatic vegetation and herbs/grasses) were modelled to investigate sex-specific seasonal activity budgets and circadian activity rhythms. The sexes did not differ in time spent foraging across the season or night, but during spring, females resided more in the lodge and travelled less. Males and females both foraged on aquatic vegetation during spring, but females used this food source also during late summer, whereas males mostly foraged on trees/shrubs throughout the year. We conclude that seasonal activity budgets and foraging differ subtly between the sexes, which may relate to different energy budgets associated with reproduction and nutritional requirements. Such subtle seasonal behavioural adaptions may be vital for survival and reproduction of monomorphic species.Significance statementActivity budgets and foraging patterns of animals are key to their survival and may differ between males and females with different body sizes and physical requirements. In monomorphic species, where males and females have similar body sizes, fewer differences are expected, but may still be pronounced during certain times of the year. We modelled sex-specific seasonal activity budgets and circadian activity rhythms and use of food items in a monomorphic mammal, the Eurasian beaver. By treating season and time of day as a continuous variable rather than modelling differences within distinct predefined periods, we identified subtle sex-specific seasonal trends in activity budgets and use of food items.