Characteristics of Beaver Ponds and Landforms Induced by Beaver Activity, S Part of the Tuchola Pinewoods, Poland

Currently, there are only two species of beavers described—the North American beaver (Castor canadensis) and Eurasian beaver (Castor fiber). Their natural habitats are confined to the northern hemisphere but instances of beaver introduction to regions of the world they do not normally inhabit have also been recorded. The activity of beavers leads to changes in the natural environment linked to hydrological and geomorphological and plant cover transformations. Beavers live in natural and artificial water reservoirs and rivers. If the water level in the river is too low, they build dams to create a comfortable living environment. This paper aims to present changes in the relief of the valley inhabited by beavers in which sediments accumulate. During the field study, detailed measurements of dams and of the spatial range of beaver ponds were made, and the thickness and spatial distribution of accumulated sediments were determined. In addition, measurements of geomorphological forms in beaver ponds were also made. The samples of sediments were subject to grain-size distribution analysis, the results of which allowed calculating sediment parameters. Beavers appeared in the Gajdówka valley in the southern part of the Tuchola Forest (Poland) in 2008. In 2008–2011 they built 17 beaver dams that impounded ponds. The beaver ponds and beaver dams were of different sizes. They either flooded the whole flat bottom of the valley or only raised the level of water in the riverbed. A characteristic feature of beaver ponds is that they capture sediments. Different landforms were created in the course of the formation and disappearance of beaver ponds. It was established that these include alluvial fans, levees, sand shadow dunes and microterraces formed by deposition and erosion. They do not occur in all ponds. Points at which mineral sediments are supplied to the watercourse, including beaver burrows and erosion hollows, are presented together with the points at which sediments are transferred from ponds upstream to ponds downstream the watercourse. Beaver activity during valley colonization shows changes in the landscape caused by their presence and in particular their impact on the relief and deposition of sediments. Analysis of contemporary changes in the morphology of the Gajdówka Valley leads to the conclusion that beaver activity has had an intense impact on the terrain relief of the valley inhabited by beavers.

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.

A spatial ecological analysis of the reintroduction of the Eurasian beaver

As ‘nature’s ecological engineers’ beavers can intentionally modify their habitat by building structures. This ability can have wider environmental benefits, including benefits for other habitats and species. However, this ability to modify the environment can sometimes be destructive, bringing beavers into conflict with land managers and others. To understand the complex connections between Eurasian beavers and ecosystems, this study was based on R language analysis tool that used land cover types, river network distribution and observational record studies of Eurasian beavers to find their most preferred environmental resources and potential habitats. The results found that reintroduced Eurasian beavers have a high potential for settlement and dispersal in restored areas.

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.

INTRODUCTION OF MAMMALS IN YAKUTIA: ANALYSIS OF EFFECTIVENESS, PROSPECTS AND NEGATIVE CONSEQUENCES

Attempts of intentional introduction of mammals into the territory of Yakutia are analyzed. Within the period between 1930 and 2020 a total of 8 foreign and one native species were introduced. Two foreign species (the muskrat and American mink) naturalized successfully, as well as the sable, a reintroduced species. Naturalization of the musk-ox, which was introduced in 1996, is progressing successfully, and with proper protective measures its abundance can be expected to increase and range to cover the entire tundra zone of Yakutia. Attempts to introduce the Eurasian beaver, raccoon dog, steppe polecat, and domestic yak have failed. Efforts on the introduction of the wood bison continue, but its reproduction rate and specifics of its winter behavior and feeding habits point to certain problems in its adaptation to new climatic conditions. Intentional introduction of foreign species is a potential danger for the ecosystems of the North, especially attempts at reconstruction of paleoufauna by introducing the species typical for paleolandscapes, and not the contemporary fauna of the region. Efforts aimed at "increasing the biodiversity" without a comprehensive biological analysis can lead to disturbance of the balance of the northern ecosystems.

Genetic structure of Eurasian beaver in Romania: insights after two decades from the reintroduction

Once exploited for fur, meat, and extracting the yellowish exudate called castoreum, the Eurasian beaver disappeared from Romania during the eighteenth century. After, the reintroductions carried out two decades ago are currently thriving in the Danube River basin. Using nine nSSR markers, we analysed samples from 98 individuals, and we found no genetic substructure, suggesting high dispersal and gene flow capabilities. The stepwise mutation model (SMM) indicated the existence of a recent genetic bottleneck, though the Eurasian beaver retains high levels of genetic diversity and population growth facilitated variation in nSSR loci. A fine-scale spatial correlation in females was detected, contrasting with males’ dispersal on longer distances. While the movement and establishment of individuals’ new territories were made under natural predation pressure, the mix following natural expansion improved the fitness and could contribute to a higher genetic diversity than the source population. With any reintroduction, a focus on capturing individuals from various geographic origins, as well as securing many and suitable founding individuals (adults, subadults, and juveniles) with mixed origins, could secure the post-genetic bottleneck recovery and higher genetic diversity. Beyond this conservation success, future management strategies should consider building a National Action Plan (NAP) for the species, including a permanent genetic monitoring programme for Eurasian beaver.

The response of a brown trout (Salmo trutta) population to reintroduced Eurasian beaver (Castor fiber) habitat modification

Globally, freshwaters are the most degraded and threatened of all ecosystems. In northern temperate regions, beaver (Castor spp.) reintroductions are increasingly used as a low-cost and self-sustaining means to restore river corridors. River modifications by beavers can increase availability of suitable habitat for fish, including salmonids. This study investigated the response of a population of brown trout (Salmo trutta) to reintroduced Eurasian beaver (Castor fiber) habitat modifications in northern Scotland. The field site comprised two streams entering a common loch; one modified by beavers, the other unaltered. Electrofishing and PIT telemetry surveys indicated abundance of post-young-of-the-year (post-YOY) trout was higher in the modified stream. Considering juvenile year groups (YOY and post-YOY) combined, abundance and density varied with year and season. In the modified stream, fork length and mass were greater, there was a greater variety of age classes, and mean growth was positive during all seasons. Beavers had profound effects on the local brown trout population that promoted higher abundances of larger size classes. This study provides important insight into the possible future effect of beavers on freshwater ecosystems.

On parasite fauna of the European beaver

The purpose of the research is identification of the current parasitological situation for Eurasian beavers inhabiting the Central Russia.Materials and methods. The work was carried out on hunting farms and in specially protected areas of the Central Russia. Potentially infective material was collected, recorded and preserved from animals during 2015–2021. The age of the animals was determined by their weight and physiological state of the rodents’ teeth and internal organs, and the sex was determined by their genitals. The animals were examined according to the method of complete and partial helminthological dissection per Skryabin.Results and discussion. A total of 41 animals were examined. Three forms of parasitism on animals were identified in natural habitat, namely, the trematode Stichorchis subtriquetrus, the nematode Travassosius rufus, and the ectoparasite Platypsyllus castoris. The stichorchosis causative agent localized in the animal’s large intestine was diagnosed in 35 rodents (85.4%). The helminth infection was 96% in the Eurasian beaver and 68.7% in the Canadian beaver. The nematode infection in stomach was detected in 31 animals (75.6%). The infection by T. rufus was 88% in the Eurasian beaver, and 56.3% in the Canadian beaver. The infected animals were delivered from the Vladimir, Moscow, Ryazan, Tula and Yaroslavl Regions. The beaver beetle P. castoris was found in 6 animals (14.6%). The infection rate was 8% in the Eurasian beaver, and 25% in the Canadian beaver. Animals with wingless arthropods have been identified in the Moscow and Ryazan Regions.