Castor Fiber Research Articles

Antibodies against 12 infectious agents in free-ranging Eurasian beaver (Castor fiber L.) from the Czech Republic.

Antibodies against 12 infectious agents in free-ranging Eurasian beaver (Castor fiber L.) from the Czech Republic.

Susceptibility to Postbiotic Substances-Enterocins of the Strains Enterococcus thailandicus from Beavers (Castor fiber)

Eurasian beaver (Castor fiber) populations have been reintroduced to European countries, though this bears the risk of novel wildlife pathogen reservoir establishment. The species nova E. thailandicus was described first in Thailand as a food-derived strain. Later, this species was detected in the feces of pigs, poultry, sewage, and humans. In those studies, the potential risk posed by this species was evaluated. Against that background, the aim of this study was to investigate the susceptibility to postbiotic active substances (enterocins) against fecal E. thailandicus strains from beavers caught in Poland. The strains were identified with the use of 16S rRNA gene similarity sequencing. These six E. thailandicus strains with low-grade biofilm-forming abilities and two strains with the presence of the gelE virulence factor gene were susceptible to seven enterocins produced by non-autochthonous strains, mostly of the species E. faecium and E. durans. The inhibitory activity against the tested strains reached 25,600 AU/mL. Although the studied E. thailandicus strains did not show a strictly pathogenic character, their growth inhibition by postbiotics was identified as a novel elimination strategy.

The impact of beaver dams on distribution of waterborne Escherichia coli and turbidity in an agricultural landscape.

The impact of beaver dams on distribution of waterborne Escherichia coli and turbidity in an agricultural landscape.

Long-term dynamics, distribution, and protection of the Eurasian beaver Castor fiber in Poland

Long-term dynamics, distribution, and protection of the Eurasian beaver Castor fiber in Poland

Recolonisation or invasion? First insights into the origin of the newly established beaver populations in Bulgaria via eDNA

After a series of reintroductions (including unofficial releases) and natural recolonizations during the last decades, the Eurasian beaver (Castor fiber) is returning throughout Europe. However, it is hard to distinguish the species from its American relative, Castor canadensis, that has also been successfully introduced and is thriving in some parts of the continent as an invasive species. In this context, it is important to obtain genetic information for the newly recorded populations, in order to take appropriate management actions. The current paper presents results of the first genetic assay of five recently established beaver populations along the Danube River and two of its tributaries in Northern Bulgaria. The non-invasive method of eDNA sampling was applied. We found that all populations belong to Castor fiber and are of the haplotypes from the refugial populations in Norway and France. We hypothesise that they naturally spread from Romania, where reintroductions have been done using individuals from Bavaria, which were in turn translocated from Scandinavia, France, Russia and Poland.

ИДЕНТИФИКАЦИЯ ЖИРНОКИСЛОТНОГО СОСТАВА ТОПЛЕНЫХ ЖИРОВ

The purpose of the study is to determine the qualitative and quantitative composition of fatty acids in rendered fats obtained from derivatives of hibernating hunting animals by licensed extraction in the territory of the hunting grounds of the Kemerovo Region – Kuzbass. Animal production was carried out during the periods allowed for seizure under licenses for the corresponding animal species in the period from 2019 to 2022. The objects of research are mammals hibernating, primarily brown bear (Ursus arctos), common badger (Meles meles), marmot ( lat. Marmota) and river beaver (Castor fiber). Differences in raw fat of the listed animals were studied in terms of organoleptic (color, smell, appearance) and physicochemical parameters (fat, protein, moisture content, melting point). It is shown that the raw fat of a bear, badger, marmot and beaver differs in the content of fat, protein and moisture. In terms of "melting point", all fats can be classified as low-melting. The fat was rendered by the conductive method at a temperature of 85 ± 2 °C and a duration of 60 minutes. Qualitative indicators were determined in samples of rendered fats (solidification point, refractive index, acid, iodine, peroxide number). It was established that the refractive index can be a marker for the identification of rendered fats. The value of the iodine number indicates a high content of unsaturated fatty acids in rendered fats. The identification of the fatty acid composition was carried out by the chromatographic method with the quantitative determination of the groups of mono- and polyunsaturated fatty acids. From 16 to 27 fatty acids were identified in bear and badger fats, over 50 % of which are polyunsaturated.

Feeding preference of Eurasian beavers (Castor fiber) in the Lower Rhine region, Germany

Eurasian beavers (Castor fiber) have been successfully reintroduced into the wild in many European countries. Because of the growth of populations and the associated spread, more and more areas in nature are being occupied that have not previously been checked by humans with regard to their quality. One such area that has been taken over by beavers is the district of Kleve, North-Rhine Westphalia, Germany. In this study, the variables of habitat selection were analyzed. For this purpose, eight habitats occupied by beavers in the district of Kleve were analyzed. These included both artificial and natural water bodies, as well as nature reserves and non-protected areas. Seven of the eight habitats examined had sufficient biodiversity indices. The highest value was measured in a natural water body in a nature reserve (H = 2.51), and the lowest value was measured in an artificial, unprotected habitat (H = 0.15). Food choice preferences were consistent with observations from previous studies, indicating that all habitat requirements in relation to trees are met.

Eurasian Beaver (Castor Fiber) Reintroduction: A Nutrient Mitigation Solution for Lowland Chalk Streams?

Globally scarce and ecologically valuable, the lowland chalk streams of southern and eastern England experience extensive eutrophication pressures arising from intensive agriculture. Mitigation measures are required to restore natural chalk stream functioning and the reintroduction of the Eurasian beaver (Castor fiber) could provide a solution. Here, we investigated the impact upon chalk stream hydrochemistry of the reintroduction of beavers to a 6-ha enclosure on the headwaters of the River Glaven, Norfolk. Over a two-year period (March 2022 – May 2024), 190 river water samples were collected across control and impact sites displaying minor-to-major hydrological disturbance from beaver activity, with samples analysed for nitrate (NO3), phosphate (PO4), and dissolved organic carbon (DOC). Results revealed significant reductions in nutrient concentrations downstream of the beaver enclosure (NO3 = -43%; PO4 = -51%), as well as significantly lower concentrations relative to the agricultural control site (NO3 = -64%; PO4 = -86%). Conversely, DOC concentrations were significantly higher downstream of the enclosure (+ 94%) and compared to the control (+ 272%). Greater reductions in nitrate and phosphate during the summer (NO3 = -47%; PO4 = -61%) compared to winter (NO3 = -37%; PO4 = -38%) indicated biological assimilation within the beaver wetland as a likely causal mechanism, whilst lower dissolved oxygen concentrations within the beaver ponds indicated a role for denitrification in nitrate removal. Overall, these results demonstrate that beaver wetlands can significantly mitigate eutrophication risk in agriculturally impacted chalk streams and provides further evidence in support of their wider reintroduction to English catchments.

The impact of reintroduced Eurasian beaver (Castor fiber) dams on the upstream movement of brown trout (Salmo trutta) in upland areas of Great Britain.

The return of Eurasian beaver (Castor fiber) to large areas of Europe represents a conservation success with the current population estimated to be around 1.2 million individuals. Their reintroduction to many areas, including Great Britain, has in some cases been controversial. Despite numerous documented benefits to biodiversity, concerns relate to localised flooding, adverse impacts on land use and engineered structures (e.g. culvert blockage), disease transfer, and the influence of beaver habitat modifications on fisheries, particularly in relation to salmonids. This study investigated the impacts of a series of four beaver dams on the upstream movement of brown trout during the spawning period (October-December) at a field site in Scotland. The study site comprised two streams entering a common loch, one modified by a series of four beaver dams, the other remaining unaltered during the Study Period. Trout were captured using electric fishing, fyke nets and rod and line and were tagged with Passive Integrated Transponders (PIT) before release. PIT telemetry antennas were installed below and above each dam to establish successful passage of trout during the monitoring period that included trout spawning movements in 2015 (high flows) and 2016 (low flow). There was a distinct difference in passage success between years, with high flows (using prior rainfall as a proxy measure) and larger fish size being important positive predictors of upstream passage success. A combination of environmental (prior rainfall and water temperature) and biotic (fish size) factors influenced passage success with high flows being a significant covariate at all four dams in two models used to define trout passage dynamics (Weibull and exponential base models), providing the best explanatory variable for fish passage at two of the four dams. Survival analysis and associated modelling indicated that migratory delay was inversely related to previous passage success, whilst motivation was also a determinant of success, with greatest passage in highly motivated trout. Our findings indicate that given the right environmental and biotic factors, brown trout are adept at passing beaver dams, although under certain conditions, beaver dams can impede the movement of brown trout and the magnitude of impact is influenced by these factors. In particular, the barrier effects of beaver dams are exacerbated under low flow conditions, and this may become a greater challenge in the future due to shifting climatic conditions if periods of warmer and drier weather persist and coincide with peak migratory movements of fish.

Eurasian beaver ( Castor fiber ) mating behavior.

Eurasian beavers ( Castor fiber ) typically mate in the water at night, and observations of mating beavers are extremely scarce. As a result, little is known about their mating behavior. Here, I provide video documentation of beavers mating in the River Elbe during daylight, offering a unique opportunity to observe their mating behavior. The mating cycle consisted of: 1) a phase of self-grooming on land, 2) followed by the male pushing the female into the water and following her, and 3) copulation taking place in the water. This cycle was repeated several times throughout the same day. These observations contribute to our limited understanding of Eurasian beaver mating behavior.

Upinio bebro (Castor fiber) bebraviečių pasiskirstymo luobos ir guntino upėse tyrimas

River beaver’s (Castor fiber) lifestyle and ability to survive influence nature ecosystems. Beavers in their living environment raise the water level and thus flood areas of forest and land. This paper analyzes the results obtained from the assessment of river beaver habitats in two rivers with different water discharges. The study to determine the activity of beavers and their impact on the environment was carried out in October-November 2023. Active beaver sites were determined by fresh crawl paths and fresh tree bites. There are two types of beaver biotopes in the territory of north-western Lithuania chosen for the study: large and small natural rivers. The monitoring of beaver sites was carried out by investigating the studied area along Luoba – a large natural river and Guntinas – a small natural river. The number of beavers hunted in Skuodas district is 3.4% of Lithuania. During the examination, fourteen beaver sites were discovered, which were located in beds of Luoba and Guntinas rivers. There were 60% more beavers in the Guntinas than in Luoba. The average distance between active beaver sites is 279 meters. During the study, after counting the gnawed woody plants near the beaver habitats, the main plants used in beaver’s diet were identified: willow (30%), aspen (21%), and birch (18%).

Creation of the "Berezivskyi" landscape reserve of local importance as a component of preservation of natural landscapes, biotopes and species diversity of the Northeast of Ukraine

In the process of creating the "Berezivskyi" landscape reserve, surveys were conducted on xerophytic, meadow, and waterlogged habitats located on the slopes and the floor of a ravine. The ravine belongs to the basin of the Merla River. The proposed reserve area is situated in northern Kharkiv Oblast near the village of Berezivka, within the Krasnokutsk territorial community in Bohodukhiv District. Remnants of steppe ecosystems that once dominated this area have survived on the upper slopes but have been affected by human activity and are now primarily used for agriculture. The floristic diversity of the xerophytic vegetation averages 23-26 vascular plant species per 100 m², with some patches supporting up to 40 species. These areas hold phytocoenotic value due to the presence of state-protected plant species, including Adonis vernalis L., Colchicum bulbocodium Ker Gawl., Crocus reticulatus Steven ex Adams, Pulsatilla pratensis (L.) Mill. s.l., and Stipa capillata L. The proposed reserve is also significant for the conservation of Marmota bobak (Müller, 1776), a species listed in Ukraine’s Red Data Book in 2021. A small stream flows along the ravine floor, partially dammed by Castor fiber L., with its lower reaches connected to an artificial pond. These water bodies provide vital habitats for breeding amphibians such as Lissotriton vulgaris (Linnaeus, 1758), Pelopylax ridibunda (Pallas, 1771), Rana arvalis (Nilsson, 1842), Bufotes viridis (Laurenti, 1768), Pelobates vespertinus (Lichtenstein, 1823), and Bombina bombina (Linnaeus, 1758). Additionally, a large population of Lacerta agilis (Linnaeus, 1758) inhabits the ravine slopes, with Natrix natrix (Linnaeus, 1758) encountered along the stream banks. All these amphibian and reptile species are included in the appendices of the Bern Convention. The landscape and phytocoenotic diversity within the proposed reserve contribute to a diverse avifauna and entomofauna. Eighteen bird species have been identified to date; though common to Kharkiv Oblast, they require protection under the Bern Convention. One bird species, Grus grus (Linnaeus, 1758), is protected at the national level. Additionally, two insect species listed in Ukraine’s Red Data Book, Xylocopa valga (Linnaeus, 1767) and Hamearis lucina (Linnaeus, 1758), have been recorded, though further studies of the entomofauna are necessary. The primary goal of the proposed reserve is to conserve landscapes typical of the Ukrainian Forest-Steppe, particularly remnant steppe ecosystems, as habitats for rare and endangered species protected at regional, national, and pan-European levels. Another important objective is the restoration of herbaceous biotopes that have experienced heavy grazing impacts in the past, mainly along the ravine floor and lower gentle slopes. The area has additional conservation value because, at the time of writing, it has remained unaffected by the destructive impacts of ongoing hostilities.

Influence of land use intensity on ecological corridors and wildlife crossings’ effectiveness: comparison of 2 pilot areas in Austria

Human development and induced activities significantly affect the natural functioning of ecosystems and hence landscape connectivity. Ecological corridors are essential for maintaining structural as well as functional connectivity in cultural landscapes for wildlife, while providing interchange between core areas. In two pilot areas in the north-western and eastern part of Austria, ecological corridors were delineated using a geographic information system (GIS). The pilot areas are key to preserving ecological connectivity and are located along important international migration corridors (Bohemian Forest-Northern Alps corridor, Alpine-Carpathian corridor). Both areas are situated in highly human-altered and therefore dissected as well as fragmented landscapes. A one-year monitoring campaign using camera traps was carried out at selected locations along proposed ecological corridors in the cultural landscape and at wildlife crossings structures (WCSs) at intersections with road infrastructure. The monitoring was focused on mammals with a total of 18 species being observed. The most abundant species were roe deer, European hare and wild boar. European otter, European beaver, golden jackal and wildcat have only rarely been observed. Mammal species richness was positively correlated with the presence of vegetation cover and the coefficient of ecological stability (CES). The insights obtained can be used for recommendations and support in planning the planting of vegetation (use of grasslands, scattered and continuous woody vegetation, agroforestry systems) on the sites and in the vicinity of ecological corridors. The green bridges (wildlife overpasses) were used more frequently as well as by a larger number of mammal species compared to other studied WCSs showing characteristics that are less favourable for animals. The effectiveness of WCSs is mainly influenced by human activities, resulting in the recommendation to limit them on WCSs located along the routes of ecological corridors. We point out that actual wildlife migration corridors are likely to differ from designated data-driven ecological corridors generated by spatially explicit models, because these generally do not take into account all factors relating to the effectiveness of corridors. Our results suggest, that the application of the concept of functional connectivity is able to enhance the quality of ecological corridor designations, since usually they are based only on the concept of structural connectivity. For this reason, further studies are needed to help understanding factors and their specificities influencing the interplay between structural and functional connectivity of ecological corridors.

A national scale floodplain model revealing channel gradient as a key determinant of beaver dam occurrence and inundation potential can anticipate land-use based opportunities and conflicts for river restoration

A national scale floodplain model revealing channel gradient as a key determinant of beaver dam occurrence and inundation potential can anticipate land-use based opportunities and conflicts for river restoration

The Impacts of Beaver Dams on Groundwater Regime and Habitat 6510

Changes in land usage, increasing climatic uncertainty, and dynamic development of the rate of natural population growth of the Eurasian beaver will lead to increasing benefits and disadvantages from beaver activity. During three growing seasons from 2020 to 2022, four cross-sections were marked on unused sub-irrigation systems with the periodic occurrence of beaver dams, located on organic soils in parts of the facility protected by the Habitats Directive (natural habitat 6510) in Central Poland. Periodic water table measurements in wells, the beds of adjacent ditches, and the riverbed were carried out. Identification of the states and structures of plant communities was done using the botanical-weight analysis of several samples with an area of 1 m2. Beaver dams increased water levels in the river, ditches, and groundwater depth in over 78% of events in 2020–2022 years. A large impact of precipitation on the hydraulic conditions in the meadow was observed. In the studied area, since a moderately moist habitat (6510) is protected within the Natura 2000 network, phenomena increasing soil moisture, in the absence of mowing of meadows and the occurrence of expansive herbaceous vegetation that tolerates increased moisture, may lead to the disappearance of these habitats, especially in the zone near the riverbed.

Using Earth observation to support the predictive accuracy of species distribution models in ecological restoration: a case study of Poland beavers (Castor fiber)

Abstract. The ability of Earth observation and remote sensing to identify the potential of species to restore ecosystems is a critical element in combating habitat degradation and biodiversity loss. Historical climate data and current species occurrence, coupled with geospatial modelling methods, can significantly aid in decision-making to support ecosystem restoration. We chose Eurasian beavers (spp. Castor fiber) as our case species, which are known ecosystem engineers that create wetland habitats and significantly alter/reinforce the morphology, dynamics, and hydraulics of riverine landscapes. To investigate their ecosystem restoration potential, we applied species distribution modelling (SDM) to determine their current and future distribution scenarios. Our SDMs used current and simulated future environmental data along with different classes of rasters such as elevation, inland swamps, water bodies, natural seasonally or permanently wet grasslands, open mires, riparian mixed forests, riparian swamp broadleaved forests, riparian swamp coniferous forests, watercourses, protected areas, and urban and built-up areas derived from Google Earth Engine to predict areas suitable for beaver habitats. Further, by using the zonation method, we were able to develop a stepping stone model to prioritize habitat conservation efforts. We provide habitat projections according to time periods of "2041–2060", "2061–2080" and "2081–2100", and to different climate change scenarios (SSP126, SSP245, SSP370, and SSP585). Thus, using a potential nature-based solution, we have employed remote sensing data and tools to develop a holistic framework for not only quantifying the ecosystem restoration potential of beavers but will also provide a new direction for understanding species-specific importance in climate change mitigation.

The Ecology and Evolution of Beavers: Ecosystem Engineers That Ameliorate Climate Change

Beavers, Castor canadensis in North America and Castor fiber in Eurasia, are widely referred to as nature's engineers due to their ability to rapidly transform diverse landscapes into dynamic wetland ecosystems. Few other organisms exhibit the same level of control over local geomorphic, hydrologic, and ecological conditions. Though freshwater ecosystems are particularly vulnerable to changing climate, beavers and their wetland homes have persisted throughout the Northern Hemisphere during numerous prior periods of climatic change. Some research suggests that the need to create stable, climate-buffered habitats at high latitudes during the Miocene directly led to the evolution of dam construction. As we follow an unprecedented trajectory of anthropogenic warming, we have the unique opportunity to describe how beaver ecosystem engineering ameliorates climate change today. Here, we review how beavers create and maintain local hydroclimatic stability and influence larger-scale biophysical ecosystem processes in the context of past, present, and future climate change.

Ecosystem engineering at the regional scale—Beaver impact on floodplain pondscapes

Ecosystem engineering at the regional scale—Beaver impact on floodplain pondscapes

Comparative study on quality parameters of dry-cured beaver (Castor fiber) and nutria (Myocastor coypus) sausages

Comparative study on quality parameters of dry-cured beaver (Castor fiber) and nutria (Myocastor coypus) sausages

Methods for live-trapping beaver (Castor spp.)

Effective live-trapping of beaver (Castor spp.) has been and will continue to be necessary for introductions, re-introductions, translocation for the preservation of populations, removal of nuisance beaver, and to obtain animals for fur breeding, zoological gardens and research. The aim of this study was therefore to review the existing knowledge about live-trapping through a literature study, contact with individuals involved in live-trapping, and personal experience. Before starting live-trapping, the area used by the beaver should be determined by careful reconnaissance. Beaver are usually captured either in unbaited traps placed at sites frequently visited by beaver, or in traps baited with castoreum or an aspen twig. Human scent on traps and around the trap site may be reduced by adding mud, water or scent. Usually Bailey or Hancock traps are used for live-trapping beaver. The Hancock trap is preferable because of its greater catch efficiency and versatility. Other traps reviewed are the Breathe Easy trap, Scheffer-Couch trap and different types of cage traps. Other methods used for live-trapping of beaver are snares (often considered highly effective), the Byelorussian trapping method, nets and seines, landing nets, pits and enclosures. Capture methods involving the destruction of lodges/dens and dams have often been employed in the past. Such methods require special permission in most countries and are usually not to be recommended. The Eurasian beaver (C. fiber Linnaeus, 1758) is reportedly more difficult to live-trap than its North American counterpart (C. canadensis Kuhl, 1820). New, effective methods for live-trapping of beaver also need to be developed.