Behavior Of Beavers Research Articles

Human-beaver Engagements Seen Through Multiperiod Settlement Sites at Rautalampi, Hämeenniemi and Kitee, Hiidenniemi, Finland

The aim of this article is to investigate the relationship between beavers and humans in the prehistoric times. This is studied through animal bone assemblages excavated from two multi-period settlement sites in Northern Savonia and North Karelia, Finland, and is supplemented with ethnographic and folklore material. The theoretical framework uses perspectives from social zooarchaeology, relational ontology and multispecies archaeology and the research questions are answered with zooarchaeological analysis, age estimates and beaver ethology. This study shows that the hunted beavers were adults who could have established their own colonies, modified the landscape to suit their needs and had their first litter. Beavers had different ways of being, engaging and being present in a world that sometimes led to direct and indirect encounters between humans and beavers. The hunters had knowledge that based on the behaviour of beavers, and they used it to find the animals to engage with them.

Beavers and flood alleviation: Human perspectives from downstream communities

AbstractNatural flood management (NFM) methods work with natural processes to reduce flood risk, while often providing additional benefits such as water quality improvement or habitat provision. Increasingly, the activity of an animal—beavers—is recognised to potentially provide flow attenuation, along with multiple benefits for the environment and society, but there can also be associated challenges. We use Q‐Methodology to elicit and understand human perspectives of beavers and their potential role in flood management among communities living downstream of beavers at three sites in England (Cornwall, Yorkshire and the Forest of Dean). This is the first time a study has focused on downstream communities as the primary stakeholders. We identify diverse perspectives that exhibit a range of value judgements. We suggest a catchment‐based approach to beaver management and public engagement may facilitate deeper recognition of contextual perspectives in decision‐making and enable knowledge dissemination with communities. Further, we examine the relationship between beavers and other NFM methods through these perspectives. In doing so we identify features that relate to the unique element of relying on the natural behaviour of beavers for flood management, rather than human flood managers being the primary decision‐makers.

Assessment of the effect of beaver foraging activities on the alteration of waterside forests in northern and middle taiga of Russian Karelia

The territory of the Republic of Karelia is latitudinally elongated and traversing two boreal subzones such as the northern and middle taiga. Pine and spruce stands predominate in the northern taiga, while forests in middle taiga are more diverse, represented by secondary stands, and often dominated by deciduous species. These factors define the foraging behaviour of beavers and their role in alteration of riparian forests. Dispersing in the northern taiga, beavers tend to choose waterside areas with a higher proportion of deciduous species. However, such habitats occupy less than 1% of the forested area in this subzone, so the overall effect of beaver foraging on forest stands would be minor. On the other hand, inside beaver colonies, stand alteration is far more pronounced than changes in colonies in the middle taiga, and the effects are the following: 1) waterside forests in the northern taiga lose 2.5 times more deciduous trees than those in the middle taiga (61.4 and 26.3 %, respectively); 2) in waterside stands, aspen is totally removed, the share of conifers is doubled, and the share of birch is reduced (in the middle taiga, the share of birch around beaver colonies slightly increases, and the share of aspen is reduced by a factor of 1.5); 3) beavers in the north of Karelia consume thick birch trees more often than in the south of the region; 4) the regeneration capacity of damaged trees in the north is lower than in the south of Karelia.
 Key words: beavers, foraging activities, waterside forests, northern and middle taiga, tree stands

Local knowledge about a newly reintroduced, rapidly spreading species (Eurasian beaver) and perception of its impact on ecosystem services.

Conflicts caused by reintroduced native species are increasing; however, there is a knowledge gap concerning ecological knowledge and perception of local community members regarding the impact of these species on local ecosystem services and livelihoods. We studied local knowledge about beavers and the perception of their impact on ecosystem services and local livelihoods, and the perception of their general harmfulness and usefulness in Hungary and Romania in three ecologically distinct, diverse rural landscapes. Structured interviews were carried out with 45 knowledgeable and 45 randomly selected local informants. We found that locals were knowledgeable about legal status, biology and behavior of beavers and their diverse impact on nature and ecosystem services. Perceptions included mostly negative impacts on provisioning services, while both negative and positive impacts on regulating and cultural services were perceived, including some contradictory impacts of the species. In spite of the actual and anticipated potential future harms caused by beavers, most people appreciated its precise building mastery and ‘cute’ nature. We argue that communication between nature conservationists and locals should reflect this complexity of perceptions, while reciprocal learning could help to moderate local conflicts and develop adaptive management strategies.

Recolonizing lost habitat—how European beavers (Castor fiber) return to south-western Germany

For the last decades, the European beaver (Castor fiber) has been recolonizing its original habitats. Reintroductions of beavers from different relict populations into southern Germany have resulted in several admixed populations, which are spreading out along various river systems. The eastern part of the German state of Baden-Wurttemberg is a melting pot of colonization waves originating from various introduced populations. The aim of this study was to exemplify origins and dispersal behaviour of beavers in this region using genetic fingerprint methods. Sequence analysis of hypervariable region 1 (HV1) of the mitochondrial control region and fragment length analyses at 11 microsatellite loci resulted in genetic profiles for 84 samples. The study region is being populated from three different local origins of beavers: the north of the Main-Tauber district, the Neckar River near the city of Mosbach and the Danube tributaries in the east. Main-Tauber samples were most diverse, including microsatellite alleles and HV1 haplotypes specific to C. f. albicus (from the German Elbe relict population). In view of the geographical proximity of this region to a release site of C. f. albicus in the Spessart area, this finding strongly suggests gene flow between beaver populations of different provenience. Two remaining local origins at the Neckar and Danube tributaries are closely related to each other, thus possibly descending from the same original (admixed) population. This study is intended to serve as a starting point for follow-up fine-scale research into dispersal behaviour of European beavers currently recolonizing their original habitats.

Castor canadensis and urban wetland governance ⿿ Fairfax County, VA case study

Nonhuman power is evident in urban ecologies, from droughts to tree diseases to everyday encounters with wildlife. Some urban environmental governance literature takes up questions of nonhuman agency, generally focusing on human-environment relations and their influence on decision-makers involved in planning, politics, and management. However, results from current research on a wetland restoration project suggest that there is more to nonhuman agency in environmental governance than its effects on human actors. This restoration project, located in a Washington D.C. Metro Area park, involved the installation of a berm and a water control system for the management of a hemi-marsh habitat. Resident beavers (Castor canadensis) emerged from the planning and proposal process as major players influencing the project design and implementation. The research traces the development of this urban wetland, drawing on assemblage theories of power to analyze how the elements of the managing apparatus (dispositif)⿿including animal ethology, technological expertise, environmental ethics, and the concept of biodiversity⿿function to govern the space. Nonhuman agency in the network compelled park managers to incorporate beaver behavior and perception into the governing apparatus. Both humans and nonhumans emerge from this dispositif as coproducers of place and as political subjects playing a part in urban ecology governance decisions. The research shows that beavers not only exert their agency on the ecological network in the wetland, but also that their perceptual worlds (umwelt) form part of the logic of governance that guides management decisions. Ultimately, this research suggests that critical social theory frameworks coupled with nonhuman ontologies will help us to better understand the lively and productive human-environment relationships that are at the core of urban ecosystems.

Attempt to manage after-effects of beaver impounding activities in drainage systems: One trial assay

When there is a high population density of beavers, they readily occupy open drains. By impounding these drains, the animals also dam up the subsurface drainage systems that empty into them. This paper provides the results from a trial conducted in a beaver-obstructed stretch of the open drain, Žiedupis, and its environs in the Nevėžis River basin in Lithuania. Studies were carried out on the functioning of pond drains installed in beaver dams, the behaviour of beavers in reacting to the lowered water levels, the condition of the tile drain pipes operating under damming, and the hydrological conditions of the soils drained by these drains. The trial was conducted in soils with a light texture. The weather conditions were generally rather drier than average. It was found that pond drains were able to maintain water in ponds at the desirable levels that benefit the functioning of subsurface drainage systems. However, they did not prevent beavers from building new dams, and did not encourage the animals to abandon the beaver site. Possible reasons for beaver expansion into open drains, as well as ways to avoid or mitigate the harm from their damming of drainage systems, are also discussed in the paper. Copyright © 2010 John Wiley & Sons, Ltd. Quand il y a une forte densité de population de castors, ils occupent volontiers les fossés. En occupant ces fossés, les animaux tassent aussi les drains enterrés qui s'y déversent. L'article présente les résultats d'un essai mené sur tronçon du collecteur ouvert obstrué par les castors, Žiedupis dans le bassin du fleuve Nevėžis en Lituanie. Des études ont été menées sur le fonctionnement de drains de vidange mis en place dans les barrages de castors, le comportement des castors en réaction à la baisse des niveaux d'eau, le comportement des drains sous le tassement, et les conditions hydrologiques des sols drainés par ces drains. L'essai s'est déroulé dans des sols à texture légère. Les conditions météorologiques étaient généralement plutôt plus sèches que la moyenne. Il a été constaté que ces drains ont été en mesure de maintenir l'eau au niveau souhaitable bénéficiant du fonctionnement des systèmes de drainage souterrain. Toutefois, ils n'ont pas empêché les castors de construire de nouveaux barrages, et n'encouragent pas les castors à abandonner leurs sites. Les raisons possibles pour l'expansion du castor dans les fossés, ainsi que les façons d'éviter ou d'atténuer les effets dommageables du tassement des drains enterrés, sont également discutées dans l'article.

Central Place Foraging by Beavers (Castor canadensis) in a Complex Lake Habitat

Beavers (Castor canadensis) are important as ecosystem engineers and are useful model organisms for testing central-place foraging theory. Much previous work has done this in controlled situations, whereas here we tested predictions in a complex natural habitat by collecting data on beaver-cut and uncut trees in sites at various distances from an isolated beaver lodge on a large reservoir. The most basic theoretical predictions are that selectivity of predators should increase with distance from the central place and that preferred prey size should increase with distance. Consistent with the first prediction, beavers were more selective for preferred tree species when foraging far from shore or at sites some distance from their lodge than when near the shore or at sites near their lodge. Consistent with both predictions, beavers were more selective for particular sizes of trees and selected larger sizes of trees as distance from the shore increased. Overall, beavers showed a preference for intermediate tree sizes, avoiding both very large and very small trees, but as distance from shore increased, beavers cut fewer trees from the smaller end of this size range and more from the upper end in such a manner as to increase both selectivity and mean size. Similarly and within this same size range, as distance from the lodge through the water increased, beavers cut larger trees at greater distances due to reduced cutting of small trees and increased cutting of larger ones. In this case, however, overall selectivity did not increase, just an increase in the size selected. Overall, then, our study shows that central-place foraging theory can predict the behavior of beavers foraging in a complex natural landscape, and the patterns observed have implications for how beavers might influence tree species composition in forests.

If You Build It, They Will Come - Management Planning for a Suburban Beaver Population in Arizona

Management for beaver now ranges from lethal removal of nuisance individuals to reintroduction of individuals for wetland restoration and to increase wildlife and habitat diversity. Management, or lack thereof, is driven largely by stakeholder concerns at the local and regional level. In many cases with management of beaver and other species, there are unclear visions of how wildlife populations may exploit resources after successful restoration or with changing landscape conditions (e.g., habitat quality and competition). With increasing conversion of the modern-day landscape, natural resource managers must make pragmatic decisions on the potential effects habitat alteration has on system stability. In 2000, the United States Army Corps of Engineers received approval from Congress to construct the Tres Rios Ecosystem Restoration and Flood Control Project in Phoenix, Arizona. Upon completion, this multi-phased, 7-mile (11.3-km), 1,500-acre (607-ha) project is designed to include a 4.25-mile (6.8-km) flood protection levee, an effluent pump station, and development/maintenance of emergent wetlands, riparian corridors, and open water marshes to replace existing non-native saltcedar. In 2000, Tres Rios constructed a demonstration area onsite that used reclaimed wastewater from the 91st Avenue Treatment Plant to establish wetland habitat. Simultaneously, we began the Tres Rios Beaver Research Project to determine the possible effects beaver have on riparian and wetland habitats. Studies within this project found that existing non-lethal management techniques were generally ineffective; however, topical application of fructose and polyethylene glycol showed promise as a technique to increase palatability of invasive Tamarisk spp., while palatability of native tree species could be reduced by application of an herbivore repellent. Other studies developed new techniques for anesthetizing beaver and increasing radio transmitter retention time on beaver. Through monitoring movement of beaver and using landscape genetic techniques to explore population diversity, researchers found deviations from published literature on beaver, suggesting that density-dependent factors may be driving beaver behavior and movement in this environment. We describe the planning process involved in developing these research studies to address stakeholder concerns.

An extensive study of the foraging ecology of beavers (Castor canadensis) in relation to habitat quality

The objective of this study was to examine the foraging behaviour of the beaver (Castor canadensis Kuhl, 1820) and to explain its selection of terrestrial woody plant species according to central place foraging theory. Limitations in variety of food items in most studies with regard to size and (or) distance from the central place and information on availability of forage choices give a partial view of the subject. In this study, the theory is tested in a natural environment with high variability in food items with regard to these factors. Foraging choices by beavers were inspected by measuring variables on cut and uncut trees of every species encountered within 1 m of trail systems made by 25 beaver colonies in Kouchibouguac National Park in New Brunswick, Canada, thereby quantifying the availability of the different food items. The effect of habitat quality (food availability) on the foraging behaviour of beavers was also tested. The results of this study suggest that with increasing distance from the pond, beavers in high-quality habitats selected fewer, but larger, trees and are more species selective. This selectivity was diminished in habitats of lower quality. The results of this study are consistent with the predictions of the central foraging theory.

BEAVERS AS MOLECULAR GENETICISTS: A GENETIC BASIS TO THE FORAGING OF AN ECOSYSTEM ENGINEER

Ecological genetics is increasingly recognized as critical to understanding interactions among organisms and ecosystem processes. Using a common garden with pure and hybrid cottonwood trees of known genotype, two years of field surveys, and a cafeteria feeding experiment, we link introgression of Fremont genetic markers, condensed tannins (a genetically based plant trait), and foraging by beavers. These data support two major arguments. First, hybridization is an important mechanism for the transmission of ecologically functional traits. Second, links between a genetically based plant trait in a dominant riparian-forest tree species and the foraging behavior of beavers, an ecosystem engineer, emphasize that genetically based plant traits can directly and indirectly link population, community, and ecosystem processes.

Reintroduction of the European beaver (Castor fiber) to Norfolk, U.K.: a preliminary modelling analysis

AbstractAn existing spatial population model, developed to assess the reintroduction of the European beaver Castor fiber to Scotland, was applied to predict the likely result of reintroducing beavers to Norfolk, England. A habitat analysis was conducted using the Land Cover Map (classified satellite imagery developed by the Institute of Terrestrial Ecology) to predict the location of areas suitable for beavers. The model was used to simulate population processes within these areas and dispersal between them following a range of reintroduction scenarios. To represent uncertainty regarding the probable behaviour of beavers in Norfolk, the habitat analysis and model were applied using three sets of parameter values (high, medium and low) derived from the literature. It was predicted that Norfolk could support between 18 and 40 beaver families. Using high or medium parameter values, beaver populations were predicted to expand following reintroduction and spread to new areas. Using low parameter values populations were predicted to decrease, risk extinction and not colonize new areas. This analysis is a preliminary investigation into the likely fate of beavers in Norfolk. Checking the estimates of habitat availability in the field would enable greater confidence to be placed in these predictions.

Food Caching Behavior of Beavers (Castor canadensis): Selection and Use of Woody Species

Food Caching Behavior of Beavers (Castor canadensis): Selection and Use of Woody Species

Sex differences in behavior of beavers living in near-boreal lake habitat

Comparative studies of how female and male North American beavers (Castor canadensis) allocate time provide a basis for understanding their life history. I studied the behavior of beavers living in lake habitats of a near-boreal region to determine how animals of each sex allocated time during their active periods. Markov time-budget estimates revealed that over the open-water season, adult females and males spent 91 and 86%, respectively, of time during active periods feeding, traveling, and being in the lodge. Adult females spent most of their time feeding in late spring and summer. In late summer through fall, they spent more time provisioning, working on lodges, and constructing winter food caches. In contrast, adult males spent less time feeding and more time traveling, being in the lodge, and working on the lodge in late spring and early summer. As the season progressed, adult males traveled less and spent more time feeding and working on the lodge. Overall, the results suggest that there is a division of labor in this monogamous species. Adult females seemed to function primarily as providers of energy to kits. In contrast, adult males seemed to function primarily in protection and provisioning of kits, territory maintenance, and construction and maintenance of structures.

Behavior of beaver in lakes with varying water levels in Northern Minnesota

We studied the effects of winter water drawdowns (2.3 m) on beavers in Voyageurs National Park, Minnesota, USA. Our study was designed to sample areas within the park that differed in water drawdown regime. Lodges were counted and beavers were livetrapped and radio-implanted to study behavior, movements, and mortality. Active beaver lodge density, determined by aerial survey in 1984 and 1986, was greatest along the shoreline of the drawdown reservoir. In winter beavers living on the drawdown reservoir spent less time inside their lodges than did beavers from stable water environments, foraged more above ice, and they were unable to fully use stored food. Only one case of starvation in the drawdown reservoir was documented, but beavers in reservoirs that were drawn down survived winter in poorer condition than did beavers living in areas in which water levels remained high. In spite of an increasing population and lack of widespread mortality, winter water drawdowns did alter beaver behavior. To reduce these impacts, total annual water fluctuation should not exceed 1.5 m, and winter drawdown should not exceed 0.7 m. Possible management alternatives and costs are discussed.

Foraging Behavior of Beavers (Castor canadensis) in North Dakota

Foraging Behavior of Beavers (Castor canadensis) in North Dakota