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Rurek, Mirosław. "Characteristics of Beaver Ponds and Landforms Induced by Beaver Activity, S Part of the Tuchola Pinewoods, Poland". Water 13, n.º 24 (18 de dezembro de 2021): 3641. http://dx.doi.org/10.3390/w13243641.
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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.
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Jung, Thomas S., e Jennifer A. Staniforth. "Unusual Beaver, Castor canadensis, Dams in Central Yukon". Canadian Field-Naturalist 124, n.º 3 (1 de julho de 2010): 274. http://dx.doi.org/10.22621/cfn.v124i3.1090.
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North American Beavers (Castor canadensis) are remarkable for their ability to build dams and modify their habitat. Dams are typically made of the boles and branches of trees and large shrubs, and reinforced with mud and rocks. Here, we report two unusual Beaver dams in central Yukon, Canada, that are made primarily of medium-sized rocks. This observation points to the adaptability of Beavers in using available materials to build their dams.
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Malison, Rachel L., Kirill V. Kuzishchin e Jack A. Stanford. "Do beaver dams reduce habitat connectivity and salmon productivity in expansive river floodplains?" PeerJ 4 (1 de setembro de 2016): e2403. http://dx.doi.org/10.7717/peerj.2403.
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Beaver have expanded in their native habitats throughout the northern hemisphere in recent decades following reductions in trapping and reintroduction efforts. Beaver have the potential to strongly influence salmon populations in the side channels of large alluvial rivers by building dams that create pond complexes. Pond habitat may improve salmon productivity or the presence of dams may reduce productivity if dams limit habitat connectivity and inhibit fish passage. Our intent in this paper is to contrast the habitat use and production of juvenile salmon on expansive floodplains of two geomorphically similar salmon rivers: the Kol River in Kamchatka, Russia (no beavers) and the Kwethluk River in Alaska (abundant beavers), and thereby provide a case study on how beavers may influence salmonids in large floodplain rivers. We examined important rearing habitats in each floodplain, including springbrooks, beaver ponds, beaver-influenced springbrooks, and shallow shorelines of the river channel. Juvenile coho salmon dominated fish assemblages in all habitats in both rivers but other species were present. Salmon density was similar in all habitat types in the Kol, but in the Kwethluk coho and Chinook densities were 3–12× lower in mid- and late-successional beaver ponds than in springbrook and main channel habitats. In the Kol, coho condition (length: weight ratios) was similar among habitats, but Chinook condition was highest in orthofluvial springbrooks. In the Kwethluk, Chinook condition was similar among habitats, but coho condition was lowest in main channel versus other habitats (0.89 vs. 0.99–1.10). Densities of juvenile salmon were extremely low in beaver ponds located behind numerous dams in the orthofluvial zone of the Kwethluk River floodplain, whereas juvenile salmon were abundant in habitats throughout the entire floodplain in the Kol River. If beavers were not present on the Kwethluk, floodplain habitats would be fully interconnected and theoretically could produce 2× the biomass (between June–August, 1,174 vs. 667 kg) and rear 3× the number of salmon (370,000 vs. 140,000) compared to the existing condition with dams present. The highly productive Kol river produces an order of magnitude more salmon biomass and rears 40× the individuals compared to the Kwethluk. If beavers were introduced to the Kol River, we estimate that off-channel habitats would produce half as much biomass (2,705 vs. 5,404 kg) and 3× fewer individuals (1,482,346 vs. 4,856,956) owing to conversion of inter-connected, productive springbrooks into inaccessible pond complexes. We concluded that beaver dams may limit the total amount of floodplain habitat available for salmon rearing in the Kwethluk river and that the introduction of beavers to the Kol river could be detrimental to salmon populations. The introduction of beavers to other large alluvial rivers like those found in Kamchatka could have negative consequences for salmon production.
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Butler, David R., e George P. Malanson. "The geomorphic influences of beaver dams and failures of beaver dams". Geomorphology 71, n.º 1-2 (outubro de 2005): 48–60. http://dx.doi.org/10.1016/j.geomorph.2004.08.016.
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Clifford, Hugh F., Gillian M. Wiley e Richard J. Casey. "Macroinvertebrates of a beaver-altered boreal stream of Alberta, Canada, with special reference to the fauna on the dams". Canadian Journal of Zoology 71, n.º 7 (1 de julho de 1993): 1439–47. http://dx.doi.org/10.1139/z93-199.
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There were different macroinvertebrate assemblages on the face of and in beaver dams compared with beaver ponds and main stream sites. The beaver dam featured a large proportion of simuliid larvae compared with the main stream sites of this stream and with areas of other studies of beaver-altered streams. The fauna of the dams was typical of fast-flowing habitats, whereas animals of the main stream sites (including the beaver ponds) were more characteristic of slow-flowing or lentic habitats. Cluster analysis separated the dam and main stream sites for each sampling date and year of our study based on the composition of the macroinvertebrates. Although the invertebrate assemblages of the dams differed from those of the main stream sites, both habitats included similar functional feeding groups, except for a shredder found only at the dams. There are similarities between the beaver dam fauna and the faunas of debris dams, woody snags, and lake outlets. Beaver dams are important in supporting large populations of simuliids and generally in maintaining a lotic fauna in slow-moving, low-gradient boreal streams.
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Majerova, M., B. T. Neilson, N. M. Schmadel, J. M. Wheaton e C. J. Snow. "Impacts of beaver dams on hydrologic and temperature regimes in a mountain stream". Hydrology and Earth System Sciences Discussions 12, n.º 1 (22 de janeiro de 2015): 839–78. http://dx.doi.org/10.5194/hessd-12-839-2015.
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Abstract. Beaver dams affect hydrologic processes, channel complexity, and stream temperature by increasing inundated areas and influencing groundwater-surface water interactions. We explored the impacts of beaver dams on hydrologic and temperature regimes at different spatial and temporal scales within a mountain stream in northern Utah over a three-year period spanning pre- and post-beaver colonization. Using continuous stream discharge, stream temperature, synoptic tracer experiments, and groundwater elevation measurements we documented pre-beaver conditions in the first year of the study. In the second year, we captured the initial effects of three beaver dams, while the third year included the effects of ten dams. After beaver colonization, reach scale discharge observations showed a shift from slightly losing to gaining. However, at the smaller sub-reach scale, the discharge gains and losses increased in variability due to more complex flow pathways with beaver dams forcing overland flow and increasing surface and subsurface storage. At the reach scale, temperatures were found to increase by 0.38 °C (3.8%), which in part is explained by a 230% increase in mean reach residence time. At the smallest, beaver dam scale, there were notable increases in the thermal heterogeneity where warmer and cooler niches were created. Through the quantification of hydrologic and thermal changes at different spatial and temporal scales, we document increased variability during post-beaver colonization and highlight the need to understand the impacts of beaver dams on stream ecosystems and their potential role in stream restoration.
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Puttock, A. K., A. M. Cunliffe, K. Anderson e R. E. Brazier. "Aerial photography collected with a multirotor drone reveals impact of Eurasian beaver reintroduction on ecosystem structure". Journal of Unmanned Vehicle Systems 3, n.º 3 (setembro de 2015): 123–30. http://dx.doi.org/10.1139/juvs-2015-0005.
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Beavers are often described as ecological engineers with an ability to modify the structure and flow of fluvial systems and create complex wetland environments with dams, ponds, and canals. Consequently, beaver activity has implications for a wide range of environmental ecosystem services including biodiversity, flood risk mitigation, water quality, and sustainable drinking water provision. With the current debate surrounding the reintroduction of beavers into the United Kingdom, it is critical to be able to monitor the impact of beavers upon the environment. This study presents the first proof of concept results showing how a lightweight hexacopter fitted with a simple digital camera can be used to derive orthophoto and digital surface model (DSM) data products at a site where beavers have recently been reintroduced. Early results indicate that analysis of the fine-scale (0.01 m) orthophoto and DSM can be used to identify impacts on the ecosystem structure including the extent of dams and associated ponds, and changes in vegetation structure due to beaver tree-felling activity. Unmanned aerial vehicle data acquisition offers an effective toolkit for regular repeat monitoring at fine spatial resolution, which is a critical attribute for monitoring rapidly changing and difficult to access beaver-impacted ecosystems.
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Jones, Benjamin M., Ken D. Tape, Jason A. Clark, Allen C. Bondurant, Melissa K. Ward Jones, Benjamin V. Gaglioti, Clayton D. Elder, Chandi Witharana e Charles E. Miller. "Multi-Dimensional Remote Sensing Analysis Documents Beaver-Induced Permafrost Degradation, Seward Peninsula, Alaska". Remote Sensing 13, n.º 23 (30 de novembro de 2021): 4863. http://dx.doi.org/10.3390/rs13234863.
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Beavers have established themselves as a key component of low arctic ecosystems over the past several decades. Beavers are widely recognized as ecosystem engineers, but their effects on permafrost-dominated landscapes in the Arctic remain unclear. In this study, we document the occurrence, reconstruct the timing, and highlight the effects of beaver activity on a small creek valley confined by ice-rich permafrost on the Seward Peninsula, Alaska using multi-dimensional remote sensing analysis of satellite (Landsat-8, Sentinel-2, Planet CubeSat, and DigitalGlobe Inc./MAXAR) and unmanned aircraft systems (UAS) imagery. Beaver activity along the study reach of Swan Lake Creek appeared between 2006 and 2011 with the construction of three dams. Between 2011 and 2017, beaver dam numbers increased, with the peak occurring in 2017 (n = 9). Between 2017 and 2019, the number of dams decreased (n = 6), while the average length of the dams increased from 20 to 33 m. Between 4 and 20 August 2019, following a nine-day period of record rainfall (>125 mm), the well-established dam system failed, triggering the formation of a beaver-induced permafrost degradation feature. During the decade of beaver occupation between 2011 and 2021, the creek valley widened from 33 to 180 m (~450% increase) and the length of the stream channel network increased from ~0.6 km to more than 1.9 km (220% increase) as a result of beaver engineering and beaver-induced permafrost degradation. Comparing vegetation (NDVI) and snow (NDSI) derived indices from Sentinel-2 time-series data acquired between 2017 and 2021 for the beaver-induced permafrost degradation feature and a nearby unaffected control site, showed that peak growing season NDVI was lowered by 23% and that it extended the length of the snow-cover period by 19 days following the permafrost disturbance. Our analysis of multi-dimensional remote sensing data highlights several unique aspects of beaver engineering impacts on ice-rich permafrost landscapes. Our detailed reconstruction of the beaver-induced permafrost degradation event may also prove useful for identifying degradation of ice-rich permafrost in optical time-series datasets across regional scales. Future field- and remote sensing-based observations of this site, and others like it, will provide valuable information for the NSF-funded Arctic Beaver Observation Network (A-BON) and the third phase of the NASA Arctic-Boreal Vulnerability Experiment (ABoVE) Field Campaign.
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Majerova, M., B. T. Neilson, N. M. Schmadel, J. M. Wheaton e C. J. Snow. "Impacts of beaver dams on hydrologic and temperature regimes in a mountain stream". Hydrology and Earth System Sciences 19, n.º 8 (11 de agosto de 2015): 3541–56. http://dx.doi.org/10.5194/hess-19-3541-2015.
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Abstract. Beaver dams affect hydrologic processes, channel complexity, and stream temperature in part by inundating riparian areas, influencing groundwater–surface water interactions, and changing fluvial processes within stream systems. We explored the impacts of beaver dams on hydrologic and temperature regimes at different spatial and temporal scales within a mountain stream in northern Utah over a 3-year period spanning pre- and post-beaver colonization. Using continuous stream discharge, stream temperature, synoptic tracer experiments, and groundwater elevation measurements, we documented pre-beaver conditions in the first year of the study. In the second year, we captured the initial effects of three beaver dams, while the third year included the effects of ten dams. After beaver colonization, reach-scale (~ 750 m in length) discharge observations showed a shift from slightly losing to gaining. However, at the smaller sub-reach scale (ranging from 56 to 185 m in length), the discharge gains and losses increased in variability due to more complex flow pathways with beaver dams forcing overland flow, increasing surface and subsurface storage, and increasing groundwater elevations. At the reach scale, temperatures were found to increase by 0.38 °C (3.8 %), which in part is explained by a 230 % increase in mean reach residence time. At the smallest, beaver dam scale (including upstream ponded area, beaver dam structure, and immediate downstream section), there were notable increases in the thermal heterogeneity where warmer and cooler niches were created. Through the quantification of hydrologic and thermal changes at different spatial and temporal scales, we document increased variability during post-beaver colonization and highlight the need to understand the impacts of beaver dams on stream ecosystems and their potential role in stream restoration.
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Nummi, Petri, Wenfei Liao, Juliette van der Schoor e John Loehr. "Beaver creates early successional hotspots for water beetles". Biodiversity and Conservation 30, n.º 10 (4 de junho de 2021): 2655–70. http://dx.doi.org/10.1007/s10531-021-02213-8.
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AbstractBeavers (Castor spp.) are ecosystem engineers that induce local disturbance and ecological succession, which turns terrestrial into aquatic ecosystems and creates habitat heterogeneity in a landscape. Beavers have been proposed as a tool for biodiversity conservation and ecosystem restoration. So far, most research has compared biodiversity in beaver wetlands and non-beaver wetlands, but few studies have explored how beaver-created succession affects specific taxa. In this study, we investigated how water beetles responded to different successional stages of wetlands in a beaver-disturbed landscape at Evo in southern Finland. We sampled water beetles with 1-L activity traps in 20 ponds, including: 5 new beaver ponds, 5 old beaver ponds, 5 former beaver ponds, and 5 never engineered ponds. We found that beaver wetlands had higher species richness and abundance than non-beaver wetlands, and that new beaver wetlands could support higher species richness (321%) and abundance (671%) of water beetles compared to old beaver wetlands. We think that higher water beetle diversity in new beaver ponds has resulted from habitat amelioration (available lentic water, shallow shores, aquatic vegetation, and low fish abundance) and food source enhancement (an increase of both dead and live prey) created by beaver dams and floods. We conclude that using beavers as a tool, or imitating their way of flooding, can be beneficial in wetland restoration if beaver population densities are monitored to ensure the availability of newly colonizable sites.
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Malison, Rachel L., Lisa A. Eby e Jack A. Stanford. "Juvenile salmonid growth, survival, and production in a large river floodplain modified by beavers (Castor canadensis)". Canadian Journal of Fisheries and Aquatic Sciences 72, n.º 11 (novembro de 2015): 1639–51. http://dx.doi.org/10.1139/cjfas-2015-0147.
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Beavers (Castor canadensis) may strongly influence juvenile salmon production by damming spring brooks that are primary rearing habitats on expansive floodplains of large Pacific Rim salmon rivers. We studied three floodplain rearing habitats in the Kwethluk River, Alaska: free-flowing (beaver-free, n = 3) and beaver-influenced (below beaver dams, n = 4) spring brooks and early-successional beaver ponds (n = 4). We analyzed juvenile coho (Oncorhynchus kisutch) and Chinook (Oncorhynchus tshawytschwa) salmon movement, survival, densities, and growth using a multistate robust capture–mark–recapture design. Survival (46% to 80%) and densities (0.9 fish·m−2) were highest in beaver-free spring brooks. Ponds had lower salmon densities, producing less biomass per unit area than beaver-influenced or beaver-free spring brooks (1.87 ± 0.57 g·m−2 vs. 2.98 ± 1.22 and 3.23 ± 0.73 g·m−2). However, ponds covered 2× greater area than either type of spring brook and therefore produced more salmon biomass at the floodplain scale than either type of spring brook (175 kg vs. 149 kg in beaver-influenced spring brooks and 140 kg in beaver-free spring brooks). We conclude that beaver damming of floodplain spring brooks produces bigger juveniles and more total biomass, but spring brooks produce significantly more, albeit smaller, coho and Chinook juveniles. Thus, the presence of beavers on the floodplain increases habitat variation, which provides a larger range of growth opportunities for juvenile salmon.
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Loates, Bethany M., e Glen T. Hvenegaard. "The Density of Beaver, Castor canadensis, Activities along Camrose Creek, Alberta, within Differing Habitats and Management Intensity Levels". Canadian Field-Naturalist 122, n.º 4 (1 de outubro de 2008): 299. http://dx.doi.org/10.22621/cfn.v122i4.635.
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Beaver (Castor canadensis) occupy a variety of habitats in North America, but prefer Aspen (Populus tremuloides) and willow (Salix spp.) for food and construction materials. Beaver landforms, such as dams, can cause many problems for landowners, resulting in varied management efforts, such as dam dismantling and Beaver removal. The goal of this study was to compare the density of Beaver activity along Camrose Creek, Alberta, among a variety of habitats and management intensities. Along this 35 km creek there were an average of 0.46 food caches/km, 0.57 lodges/km, and 3.06 dams/km (of which 1.66/km were altered by people and 1.40/km were unaltered). There were more caches, lodges, and unaltered dams in Trembling Aspen forests compared to other habitats. Areas with some management had more food caches and either altered or unaltered dams than areas with no management.
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Pollock, Michael M., Shari Witmore e Erich Yokel. "Field experiments to assess passage of juvenile salmonids across beaver dams during low flow conditions in a tributary to the Klamath River, California, USA". PLOS ONE 17, n.º 5 (24 de maio de 2022): e0268088. http://dx.doi.org/10.1371/journal.pone.0268088.
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Across Eurasia and North America, beaver (Castor spp), their dams and their human-built analogues are becoming increasingly common restoration tools to facilitate recovery of streams and wetlands, providing a natural and cost-effective means of restoring dynamic fluvial ecosystems. Although the use of beaver ponds by numerous fish and wildlife species is well documented, debate continues as to the benefits of beaver dams, primarily because dams are perceived as barriers to fish movement, particularly migratory species such as salmonids. In this study, through a series of field experiments, we tested the ability of juvenile salmonids to cross constructed beaver dams (aka beaver dam analogues). Two species, coho salmon (Oncorhynchus kisutch) and steelhead trout (O. mykiss), were tracked using passive integrated transponder tags (PIT tags) as they crossed constructed beaver dam analogues. We found that when we tagged and moved these fishes from immediately upstream of the dams to immediately downstream of them, most were detected upstream within 36 hours of displacement. By the end of a 21-day field experiment, 91% of the displaced juvenile coho and 54% of the juvenile steelhead trout were detected on antennas upstream of the dams. In contrast, during the final week of the 21-day experiment, just 1 of 158 coho salmon and 6 of 40 (15%) of the steelhead trout were still detected on antennas in the release pool below the dams. A similar but shorter 4-day pilot experiment with only steelhead trout produced similar results. In contrast, in a non-displacement experiment, juveniles of both species that were captured, tagged and released in a pool 50 m below the dams showed little inclination to move upstream. Further, by measuring hydraulic conditions at the major flowpaths over and around the dams, we provide insight into low-flow conditions under which juvenile salmonids are able to cross these constructed beaver dams, and that multiple types of flowpaths may be beneficial towards assisting fish movement past instream restoration structures. Finally, we compared estimates of the number of juvenile salmonids using the pond habitat upstream of the dam relative to the number that the dam may have prevented from moving upstream. Upstream of the dams we found an abundance of juvenile salmonids and a several orders of magnitude difference in favor of the number of juveniles using the pond habitat upstream of the dam. In sum, our study suggests beaver dams, BDAs, and other channel spanning habitat features should be preserved and restored rather than removed as perceived obstructions to fish passage.
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Barnes, D. M., e A. U. Mallik. "Use of woody plants in construction of beaver dams in northern Ontario". Canadian Journal of Zoology 74, n.º 9 (1 de setembro de 1996): 1781–86. http://dx.doi.org/10.1139/z96-197.
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Newly formed beaver dams were studied in the Chapleau Crown Game Preserve of northern Ontario to determine if beavers (Castor canadensis Kuhl) showed any preference in their choice of woody plants in building the dams. Application of Neu's utilization–availability technique showed that beavers exhibited a high preference for alder (Alnus spp., plant species not commonly used as food) stems with diameters of 1.5–3.5 cm and a lesser preference for food-tree stems with diameters of >4.5 cm. We maintain that beavers used large food-tree stems only because they became more accessible after dam construction. Since the alder stems available close to the water's edge accounted for most of the stems of the preferred size, 1.5–3.5 cm, we postulated that selection of woody stems by beavers for construction purposes was based on size rather than on species.
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Dalbeck, Lutz, Joyce Janssen e Sophie Luise Völsgen. "Beavers (Castor fiber) increase habitat availability, heterogeneity and connectivity for common frogs (Rana temporaria)". Amphibia-Reptilia 35, n.º 3 (2014): 321–29. http://dx.doi.org/10.1163/15685381-00002956.
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Beavers (Castor fiber), as typical ecosystem engineers, alter living conditions especially for amphibians through the building of dams and felling of trees, thereby changing the hydroperiod and substantially affecting forest succession stages. In this study we quantify the effects of beavers on the availability of amphibian breeding waters in the Hürtgenwald, a woodland area in the Central European Rhenish Massif, its colonisation by common frogs (Rana temporaria) and the effects of age and succession stage of beaver ponds on ovipositional site selection. In 2013, beaver ponds comprised about half (49%) of all lentic water bodies but contained 82.5% of all common frog egg masses. Mature beaver ponds (>6 years old) harboured approximately half of the egg masses (), but new beaver ponds (1-3 years old) can also be home to large breeding aggregations. Abandoned beaver ponds are of minor importance as ovipositional sites for common frogs. High egg mass counts were also found in artificially-dammed ponds (). We believe that common frogs prefer occupied beaver ponds as ovipositional sites because of high insolation and a permanent hydroperiod, which lead to rapid tadpole emergence. Beaver ponds are generally located in close proximity to each other, facilitating movement and rapid colonisation by common frogs. Our research provides additional evidence to show that beavers enhance habitat availability, heterogeneity and connectivity, thereby fostering amphibian populations at a landscape level. As natural elements of small streams, beaver ponds must be taken into account in the context of the EU Water Framework Directive.
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Piętka, Sławomir, e Wojciech Misiukiewicz. "Impact of European Beaver (Castor fiber L.) on Vegetation Diversity in Protected Area River Valleys". Conservation 2, n.º 4 (13 de outubro de 2022): 613–26. http://dx.doi.org/10.3390/conservation2040040.
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The aim of the study was to evaluate the impact of European beaver (Castor fiber L.) on vegetation diversity and the expansion of non-native plant species in areas surrounding watercourses in Polesie National Park, Poland. The investigation was carried out within six watercourses inhabited by beavers and four comparison watercourses where beaver were absent. European beaver living in the park had a small excursion range, reaching a maximum distance of 25 m from the watercourse so that effects on vegetation diversity were limited to the immediate vicinity of the watercourse. Beaver significantly influenced diversity of the tall tree and forest floor vegetation, while it did not significantly modify the diversity of the low tree and shrub layer. Five alien plant species were documented. The alien species most strongly associated with beaver activity was devil’s beggartick (Bidens frondosa L.), which occurred in the immediate vicinity of beaver dams. Other alien species most benefiting from the presence of beaver were giant goldenrod (Solidago gigantea Aiton) and black cherry (Prunus serotina Ehrh.). Our study confirmed hypotheses found in literature according to which beaver activities that reduce the proportion of native species can promote the expansion of plant alien species.
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Dalbeck, Lutz. "A review of the influence of beaver Castor fiber on amphibian assemblages in the floodplains of European temperate streams and rivers". Herpetological Journal, Volume 30, Number 3 (1 de julho de 2020): 135–46. http://dx.doi.org/10.33256/hj30.3.135146.
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Once widespread throughout Eurasia and hunted nearly to extinction, the Eurasian beaver Castor fiber has returned to large parts of its former range, largely through active conservation measures. Beavers can substantially alter small, low order streams and their floodplains through dam construction, burrowing activities and tree felling. Therefore, it is presumed they can significantly influence amphibian distributions, species richness and numbers. We undertook a literature review to compare the available data addressing the effects of beaver dams on amphibians in streams of central temperate and boreal Europe. All 19 amphibian species occurring in the study region were found in beaver ponds, despite their distinctly different habitat requirements. Amphibian species acting as pioneers / early colonisers were under-represented in beaver ponds compared to typical forest species. Open country and ubiquitous species showed intermediate patterns. Beaver ponds in headwater streams often supported the entire spectrum of species occurring in the surrounding landscape, and species numbers in beaver modified headwater streams were comparable to those in floodplains of larger natural rivers. In small headwater streams, beavers tended to be the primary providers of essential habitat for amphibians. In contrast, beaver ponds in the floodplains of larger rivers appeared to have less effect and supported lower average species numbers compared to beaver ponds in headwater streams. We propose that beavers and their habitat creating activities are pivotal determinants of amphibian species richness in the headwater streams, which account for 60–80 % of the water bodies in catchment areas in temperate Europe. By creating habitat for endangered amphibian species, beavers and their ability to modify habitats offer extensive opportunities to implement many aspects of the European Water Framework Directive across the continent and to restore amphibian habitats, contributing to their long-term conservation.
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Wigley, T. Bently, e Edward E. Gbur. "Landowner Characteristics Associated With Willingness To Try Beaver Control". Southern Journal of Applied Forestry 16, n.º 3 (1 de agosto de 1992): 138–39. http://dx.doi.org/10.1093/sjaf/16.3.138.
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Abstract We used a survey of Arkansas landowners to identify characteristics of landowners who tried controlling beavers (Castor canadensis). Landowners most likely to try control were those who had damage and dams on their land and were willing to pay for control. A model is presented thatuses these dichotomous variables to predict the probability of landowners trying beaver control. South. J. Appl. For. 16(3):138-139.
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Hart, James, Matteo Rubinato e Tom Lavers. "An Experimental Investigation of the Hydraulics and Pollutant Dispersion Characteristics of a Model Beaver Dam". Water 12, n.º 9 (19 de agosto de 2020): 2320. http://dx.doi.org/10.3390/w12092320.
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Beavers have influenced the world’s ecosystem for millions of years. Their dams create ponds and wetlands that provide a large range of hydraulic and ecological benefits to the natural world, including mitigation against flooding and improving water quality. As beavers are now being reintroduced to many parts of the world, it is important to fully understand the impact of their dams on the flow characteristics of the water-courses on which they are built. This paper investigates the relationship between the physical properties of a model beaver dam and its fundamental hydraulics and pollutant dispersion characteristics. The first objective of this paper was to develop a modelling framework to relate discharge to flow-depth for dams with a combination of porous and impermeable sections. The second objective was to utilize a similar framework to predict the down-stream concentration distribution of an up-stream pollution event passing through such systems. The ability to model these parameters for dams with variable lengths of porous and impermeable sections is important as the porosity of beaver dams can vary with depth, depending on which sections are constructed from branches, rocks, or compacted mud. The analysis and modelling developed in this paper show that a single, general relationship can be obtained between discharge and flow-depth regardless of the presence of sections that are both porous or impermeable, provided the relative depths of these sections are known and accounted for. It is also shown that the Nominal Residence Time and the Advection Dispersion Equation can be used to predict pollutant transport in such systems. These two equations have previously been shown to have limitations when applied to some complex systems, so demonstrating they can be applied to a porous dam with combinations of porous and impermeable sections at the relative discharges investigated is noteworthy.
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Čanády, Alexander, Peter Krišovský, Bálint Bajomi, Attila Huber, Dávid Czabán e Milan Olekšák. "Is new spread of the European beaver in Pannonian basin an evidence of the species recovery?" European Journal of Ecology 2, n.º 2 (1 de dezembro de 2016): 44–63. http://dx.doi.org/10.1515/eje-2016-0015.
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Abstract Abstract: During fieldwork from 6 June to 20 July 2016, the first records of the European beaver (Castor fiber) in south-eastern Slovakia were made. Beavers are mainly nocturnal animals, and as such, they are rarely observed; therefore, our observations were based on searching for beaver presence signs: damaged trees, dams, signs of food consumption (chewed/felled trees) and footprints in the mud. The southern part of the Košická kotlina basin, from the city of Košice down to the state border and the surrounding villages in Hungary, was checked. We found two beaver locations via feeding signs in the vicinity of the Slovakia–Hungary state border, at the villages of Milhosť (Miglécnémeti) and Buzica (Buzita), in Slovakia. According to our calculations, the present total beaver population in Hungary is between 4,000 and 5,000 and 14,600–18,300 beavers with potential support. For Slovakia, we estimated the potential population size to be 7,700–9,600. Our findings in northern Pannonian lowland (Slovakia–Hungary border) are an important evidence of beaver expansion. Although we don’t know the exact origin of investigated population, these new records indicate the possibility of merging the populations of different origin, which could enable gene flow and increase the genetic diversity. This could lead to improved recovery of species and its stabilisation in nature. However, it is necessary to carry out a detailed investigation of the presence of beaver in these regions in future.
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Ahmed, Fatima, Eric Liberda, Andrew Solomon, Roger Davey, Bernard Sutherland e Leonard Tsuji. "Indigenous Land-Based Approaches to Well-Being: The Amisk (Beaver) Harvesting Program in Subarctic Ontario, Canada". International Journal of Environmental Research and Public Health 19, n.º 12 (15 de junho de 2022): 7335. http://dx.doi.org/10.3390/ijerph19127335.
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The act of decolonizing knowledge systems involves recovering and renewing traditional, non-commodified cultural patterns, such as the sustenance of intergenerational relationships and traditional practices. A decline in beaver harvesting, which was once an integral part of the Omushkego Cree culture, has resulted in an overabundance of beavers and dams, which has negatively affected communities by increasing the local flooding events and impacting the water quality. The aim of the Amisk (beaver) program was to reconnect the Elders and youth to revitalize traditional on-the-land activities and, in the present case, beaver harvesting and associated activities within the community. The program and evaluation were built using a two-eyed seeing (Etuaptmumk) and community-based participatory research approach. Salivary cortisol, a biomedical measure of stress, was collected before and after participation in the program. Photovoice, along with semi-directed interviews, were employed to identify the key elements of well-being from a First Nations’ perspective. For the beaver harvesting activities, the changes observed in the cortisol concentrations were not statistically significant (p = 0.094). However, the act of beaver dam removal was associated with a statistically significant increase in the post-participation cortisol concentration (p = 0.021). It was noteworthy that increased stress during the removal of the beaver dams–as indicated by the elevated post-activity cortisol levels–were not reflected in a decrease in the qualitative measures (semi-directed interviews and photovoice) of well-being from an Indigenous perspective. In fact, there was a noted increase in the subjective well-being of the participants, which highlights the importance of multiple perspectives when assessing well-being, especially in Indigenous peoples. However, the cortisol findings of the present pilot project need to be interpreted with caution, due to the limited sample sizes.
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Washko, Susan, Nigel Willby e Alan Law. "How beavers affect riverine aquatic macroinvertebrates: a review". PeerJ 10 (29 de abril de 2022): e13180. http://dx.doi.org/10.7717/peerj.13180.
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Background As ecosystem engineers, the construction of dams by beavers alters stream habitat physically and biologically, making them a species of interest for habitat restoration. Beaver-created habitat changes affect a wide range of aquatic invertebrate species. However, despite numerous individual studies of how beavers affect aquatic macroinvertebrate assemblages, there has been no evaluation of the consensus of these effects across studies. Methodology We collated and examined studies comparing beaver-created ponds to nearby lotic reaches to determine general trends in aquatic macroinvertebrate richness, density, biomass, and functional composition between habitats. From this evidence, we highight knowledge gaps in how beaver activity affects aquatic macroinvertebrates. Results Overall, in the majority of studies, aquatic macroinvertebrate richness was higher in nearby lotic reaches compared to beaver-created ponds, but richness at coarser scales (gamma diversity) increased with the addition of beaver ponds due to increased habitat heterogeneity. Functional feeding group (FFG) patterns were highly context-dependent, though predator taxa were generally more abundant in beaver ponds than adjacent lotic reaches. Site-specific geomorphological changes, coupled with dam or riparian zone characteristics and resulting differences in basal food resources likely shape other FFG responses. Conclusions We identify a lack of long-term studies at single or multiple sites and conclude that fine-scale approaches may improve our understanding of the dynamics of macroinvertebrates within the freshwater realm and beyond. Due to the context-dependent nature of each study, further systematic studies of beaver engineering effects across a wider variety of environmental conditions and wetland types will also help inform land and species management decisions, such as where to prioritize protection of beaver habitats in the face of a global freshwater biodiversity crisis, or where to restore beaver populations to deliver maximum benefit.
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Grudzinski, Bartosz P., Hays Cummins e Teng Keng Vang. "Beaver canals and their environmental effects". Progress in Physical Geography: Earth and Environment 44, n.º 2 (15 de setembro de 2019): 189–211. http://dx.doi.org/10.1177/0309133319873116.
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Beaver canals and their environmental effects are much less studied than beaver dams, despite being widespread in some beaver-inhabited areas. In this study, we completed a systematic review of previous research on the structure and ecosystem effects of beaver canals to provide an increasingly holistic understanding of these landscape features. Specifically, we: 1) summarized why, where, when, and how beaver develop canals; 2) chronicled all published descriptions on beaver canal morphology; and 3) summarized the literature on the environmental effects of beaver canals. Thirty-one relevant studies were identified and incorporated into this review. Beaver canals have been identified in numerous environments ranging from largely undeveloped mountainous regions to heavily developed agricultural landscapes. Beaver primarily develop canals to increase accessibility to riparian resources, facilitate transport of harvested resources, and to decrease predation risk. As with beaver dams, beaver canals exhibit large structural variability, particularly in lengths, which can be over 0.5 km. Widths of about 1 m and depths of about 0.5 m are common. Beaver canals alter watershed hydrology by creating new aquatic habitats, connecting isolated aquatic features, and diverting water into colonized areas. Beaver canals have been identified as favored habitats for several biotic species and are sometimes used during critical life stages (e.g. dispersal). In addition to increasing overall floral and faunal species richness and diversity, beaver canals may benefit biota by mitigating habitat fragmentation and climate change impacts. Based on the results of this review, incorporating beaver canals into stream restoration practices may be environmentally beneficial.
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Połeć, Katarzyna, Antoni Grzywna, Monika Tarkowska-Kukuryk e Urszula Bronowicka-Mielniczuk. "Changes in the Ecological Status of Rivers Caused by the Functioning of Natural Barriers". Water 14, n.º 9 (9 de maio de 2022): 1522. http://dx.doi.org/10.3390/w14091522.
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Introducing the European beaver to the catchment area, which adjusts the habitat to its own needs (by building dams), may have a positive impact on the ecology, geology, and hydromorphology of rivers and intensify the water self-purification process. In this study, a comparative assessment of the ecological status was made between the areas where the species Castor fiber L. occurs (habitat type A) and the areas unaffected by the influence (habitat type B). For this purpose, the Macrophyte River Index (MIR) and the Hydromorphological River Index (HIR) were calculated, along with the floristic indicators of biodiversity: species richness and Margalef, Shannon–Wiener, and Simpson indices. Only 35% of the sites met the standard of good ecological status. The presence of hypertrophic species and anthropogenic modifications of the river bed had a negative impact. The spread of beavers has a significant positive effect on changes in hydromorphological conditions and water levels in the river. The water levels in habitat types A and B were 0.504 and 0.253 m, respectively. There were statistically significant differences in the HIR values between habitat types A and B, which were 0.585 and 0.535, respectively. In habitats of type A, the heterogeneity of the current and bed material as well as the diversity of elements accompanying the tree stands increased. Research has shown greater species richness and greater biodiversity of macrophytes in the habitats of beaver dams. The research confirmed the significant influence of the European beaver on changes in the environment. The activity of beavers intensifies the processes of introducing wetland and rush species to forest areas.
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Neumayer, Michael, Sonja Teschemacher, Sara Schloemer, Volker Zahner e Wolfgang Rieger. "Hydraulic Modeling of Beaver Dams and Evaluation of Their Impacts on Flood Events". Water 12, n.º 1 (19 de janeiro de 2020): 300. http://dx.doi.org/10.3390/w12010300.
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There is a general agreement on the impact of beaver dams regarding the increasing diversity of habitats and the improvement of the water quality, whereas the retention effect during flood events is still being discussed. In this study, we modeled 12 beaver dam cascade scenarios in two catchments for eight flood events with a two-dimensional (2D) hydrodynamic model. The implementation of the potential cascades in the model is based on the developed three-stage model for predicting location-dependent dam cascades in Bavaria. A Bavaria-wide questionnaire regarding dam occurrences and characteristics in combination with a detailed survey of 51 dams was used to set up a prediction scheme. It was observed that beaver dams are most likely built in rivers with riparian forest, with widths from 2 to 11 m and depths smaller than 1 m. The hydraulic model results showed larger inundation areas (>+300%) for the beaver dam scenarios. There is a noticeable peak attenuation and translation for elevated peak discharges (five times the annual mean discharge: up to ≤13.1% and 2.75 h), but no remarkable effect could be observed for flood events with return periods of more than 2 years. We conclude from the results that beaver dam cascades can have an impact on runoff characteristics, but do not lead to relevant peak reductions during flood events and therefore cannot be counted as flood mitigation measure.
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Woelfle-Erskine, Cleo Assan. "The watershed body: Transgressing frontiers in riverine sciences, planning stochastic multispecies worlds". Catalyst: Feminism, Theory, Technoscience 3, n.º 2 (19 de outubro de 2017): 1–32. http://dx.doi.org/10.28968/cftt.v3i2.28840.
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In conversation with Eva Hayward’s writing on transgender embodiment, this paper explores how beaver modify landscapes differently than human engineers, and how human engineering might be transformed through riverine collaborations with beavers. Considering the body variously as a body of water — a river, which draws together all of the above and underground water in a watershed — as like our own trans bodies, and as a slippery double for the psyche of an Anthropocene engineer, July Cole and I argued that thinking with beaver as stochastic transgressors against Manifest Destiny engineering projects could transfigure engineers approaches to their work and river restoration more broadly. What if, rather than trapping beavers into service as “ecosystem engineers,” we assert that humans should engineer as beavers do, in ways that create porous boundaries between land and water and up- and downstream, by way of stick-and-mud, leaky, temporary dams? Here, I theorize a transfigured watershed body through human-beaver-salmon encounters at three salmon recovery sites in the Pacific west: a Karuk-led project on the Klamath river, agency-led beaver relocation projects in the Methow and Yakima watershed, and a citizen science-agency collaborative project in the beaverless Salmon Creek and Russian River watersheds. All three stories concern river and salmon recovery in the Pacific West, where either humans or beavers have initiated collaborative projects to raise water tables, keep rivers from going dry, and improve salmon habitat. These scientists and local knowledge holders’ encounters with beavers and their ponds thick with salmon are inspiring them to change how they undertake habitat restoration projects and also spurring some to reconsider the proper task of human ecologists and engineers, into a mode inspired by beavers themselves.
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Swift, Troy P., e Lisa M. Kennedy. "Beaver-Driven Peatland Ecotone Dynamics: Impoundment Detection Using Lidar and Geomorphon Analysis". Land 10, n.º 12 (3 de dezembro de 2021): 1333. http://dx.doi.org/10.3390/land10121333.
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This investigation focused on remotely detecting beaver impoundments and dams along the boreal-like peatland ecotones enmeshing Cranberry Glades Botanical Area, a National Natural Landmark in mountainous West Virginia, USA. Beaver (Castor spp.) are renowned for their role as ecosystem engineers. They can alter local hydrology, change the ratios of meadow to woodland, act as buffers against drought and wildfire, and influence important climate parameters such as carbon retention and methanogenesis. The Cranberry Glades (~1000 m a.s.l.) occupy ~300 ha, including ~40 ha of regionally rare, open peatlands. Given the likely historical role of beaver activity in the formation and maintenance of peatland conditions at Cranberry Glades, monitoring of recent activity may be useful in predicting future changes. We analyzed remotely sensed data to identify and reconstruct shifting patterns of surface hydrology associated with beaver ponds and dams and developed a novel application of geomorphons to detect them, aided by exploitation of absences and errors in Lidar data. We also quantified decadal-timescale dynamics of beaver activity by tallying detectable active impoundments between 1990–2020, revealing active/fallow cycles and changing numbers of impoundments per unit area of suitable riparian habitat. This research presents both a practical approach to monitoring beaver activity through analysis of publicly available data and a spatiotemporal reconstruction of three decades of beaver activity at this rare and imperiled “Arctic Island” of the southern High Alleghenies.
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Brooks, Marjorie L. "Unlocking the biogeochemical role of beaver in state-transition of landscapes in Yellowstone's northern range". UW National Parks Service Research Station Annual Reports 41 (15 de dezembro de 2018): 55–64. http://dx.doi.org/10.13001/uwnpsrc.2018.5649.
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Extirpation of wolves from the Greater Yellowstone Ecosystem in the 1920s hypothetically triggered a trophic cascade in which browsers, released from wolf (Canis lupus) predation, over-browsed riparian zones. Eventually, vast meadow-wetland complexes transitioned to grass-lodgepole systems. By 1954, beaver (Castor canadensis) virtually abandoned the Greater Yellowstone Ecosystem. In 2000, Colorado State University established experimental dams with browsing exclosures for Long Term Environmental Research in Biology (LTREB) on three streams in Lamar Valley to compare hydrologic effects of pseudo-beaver dams and browsing on willow (Salix spp.) productivity and state transitions. In 2015, beaver began recolonizing the region. I investigated how the biogeochemical role of beaver versus their hydrologic influence affects the underlying mechanisms of state transition: nutrient cycling, productivity, and stream respiration. Analyses of the 2017 field samples show that beaver streams trend toward higher nutrient levels and higher variances than the LTREB sites. The data tentatively support the role of beaver as keystone species in state transitions, although more data are needed. The unexpected and late May notice from the NPS to obtain an independent research permit—approved late August—curtailed my 2018 research to a brief field bout in September. Analysis of 2018 samples is underway.
Featured photo from Figure 1 in report.
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Brooks, Marjorie L. "Unlocking the biogeochemical role of beaver in state-transition of landscapes in Yellowstone's northern range: Tantalizing insights, initial results, and evolving research design". UW National Parks Service Research Station Annual Reports 42 (15 de dezembro de 2019): 70–79. http://dx.doi.org/10.13001/uwnpsrc.2019.5741.
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Extirpation of wolves from the Greater Yellowstone Ecosystem in the 1920s hypothetically triggered a trophic cascade in which herbivores over-browsed riparian zones once released from the fear of wolf (Canis lupus) predation. Eventually, vast meadow-wetland complexes transitioned to grass-lodgepole systems. By 1954, beaver (Castor canadensis) virtually abandoned the Greater Yellowstone Ecosystem. In 2000, Colorado State University established experimental dams with browsing exclosures for Long Term Environmental Research in Biology (LTREB) on three streams in Lamar Valley to compare hydrologic effects of pseudo-beaver dams and browsing on willow (Salix spp.) productivity and state transitions. In 2015, beaver began recolonizing the region. I investigate how the biogeochemical role of beaver versus their hydrologic influence affects the underlying mechanisms of state transition: nutrient cycling, productivity, and stream respiration. Analyses of the 2017 field samples showed that beaver streams trend toward higher nutrient levels and higher variances than the LTREB sites. These trends continued in 2018 and 2019. The data tentatively support the role of beaver as keystone species in state transitions. Interannual modeling of nutrient dynamics, comparisons of stream metabolism, and genetic identification of microbial communities are underway. Similarly, analyses of the repeated measures collected across the month of July 2019 are underway.
Featured photo from figure 1 in report.
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Lokteff, Ryan L., Brett B. Roper e Joseph M. Wheaton. "Do Beaver Dams Impede the Movement of Trout?" Transactions of the American Fisheries Society 142, n.º 4 (julho de 2013): 1114–25. http://dx.doi.org/10.1080/00028487.2013.797497.
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Pollock, Michael M., Timothy J. Beechie, Joseph M. Wheaton, Chris E. Jordan, Nick Bouwes, Nicholas Weber e Carol Volk. "Using Beaver Dams to Restore Incised Stream Ecosystems". BioScience 64, n.º 4 (24 de março de 2014): 279–90. http://dx.doi.org/10.1093/biosci/biu036.
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Wohl, Ellen. "Landscape-scale carbon storage associated with beaver dams". Geophysical Research Letters 40, n.º 14 (26 de julho de 2013): 3631–36. http://dx.doi.org/10.1002/grl.50710.
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Gurnell, Angela M. "The hydrogeomorphological e•ects of beaver dam-building activity". Progress in Physical Geography: Earth and Environment 22, n.º 2 (junho de 1998): 167–89. http://dx.doi.org/10.1177/030913339802200202.
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A characteristic of beaver ecology is their ability to build dams and, thus, to modify the landscape to increase its suitability for their occupation. This ability gives beaver great significance as a geomorphic agent. In order to review the hydrogeomorphological effects of beaver dam-building activity, this article places a context on the likely distribution and magnitude of beaver activity by considering the spatial and temporal variability of distributions of beaver and the habitat characteristics which might favour the establishment of substantial beaver populations. A description is then given of the nature and potential dimensions of instream structures built by beaver and the environmental conditions under which dam building has been observed to occur. The hydrogeomorphological impact of dam building is then appraised both locally and at the landscape scale, illustrating the very significant process modification caused by beaver. While the European beaver, Castor fiber, is the main focus of this review, it necessarily draws extensively on the much larger literature concerning the North American beaver (Castor canadensis).
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Macfarlane, William W., Joseph M. Wheaton, Nicolaas Bouwes, Martha L. Jensen, Jordan T. Gilbert, Nate Hough-Snee e John A. Shivik. "Modeling the capacity of riverscapes to support beaver dams". Geomorphology 277 (janeiro de 2017): 72–99. http://dx.doi.org/10.1016/j.geomorph.2015.11.019.
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Kramer, Natalie, Ellen E. Wohl e Dennis L. Harry. "Using ground penetrating radar to ‘unearth’ buried beaver dams". Geology 40, n.º 1 (janeiro de 2012): 43–46. http://dx.doi.org/10.1130/g32682.1.
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St-Pierre, Mathilde Lapointe, Julie Labbé, Marcel Darveau, Louis Imbeau e Marc J. Mazerolle. "Factors Affecting Abundance of Beaver Dams in Forested Landscapes". Wetlands 37, n.º 5 (29 de junho de 2017): 941–49. http://dx.doi.org/10.1007/s13157-017-0929-x.
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Medwecka-Kornas, Anna, e Renata Hawro. "Vegetation on beaver dams in the Ojców National Park (Southern Poland)". Phytocoenologia 23, n.º 1-4 (15 de dezembro de 1993): 611–18. http://dx.doi.org/10.1127/phyto/23/1993/611.
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Janzen, Kimberely, e Cherie J. Westbrook. "Hyporheic Flows Along a Channelled Peatland: Influence of Beaver Dams". Canadian Water Resources Journal / Revue canadienne des ressources hydriques 36, n.º 4 (janeiro de 2011): 331–47. http://dx.doi.org/10.4296/cwrj3604846.
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Meentemeyer, Ross K., e David R. Butler. "HYDROGEOMORPHIC EFFECTS OF BEAVER DAMS IN GLACIER NATIONAL PARK, MONTANA". Physical Geography 20, n.º 5 (setembro de 1999): 436–46. http://dx.doi.org/10.1080/02723646.1999.10642688.
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Weber, Nicholas, Nicolaas Bouwes, Michael M. Pollock, Carol Volk, Joseph M. Wheaton, Gus Wathen, Jacob Wirtz e Chris E. Jordan. "Alteration of stream temperature by natural and artificial beaver dams". PLOS ONE 12, n.º 5 (17 de maio de 2017): e0176313. http://dx.doi.org/10.1371/journal.pone.0176313.
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DAVIES, NEIL S., JOHN C. GOSSE, ALEXANDRA ROUILLARD, NATALIA RYBCZYNSKI, JIN MENG, ALBERTO V. REYES e JARLOO KIGUKTAK. "WOOD JAMS OR BEAVER DAMS? PLIOCENE LIFE, SEDIMENT AND LANDSCAPE INTERACTIONS IN THE CANADIAN HIGH ARCTIC". PALAIOS 37, n.º 6 (28 de junho de 2022): 330–47. http://dx.doi.org/10.2110/palo.2021.065.
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ABSTRACT During the mid-Pliocene (Zanclean, ca. ∼ 3.9 Ma), parts of the Canadian High Arctic experienced mean annual temperatures that were 14–22°C warmer than today and supported diverse boreal-type forests. The landscapes of this vegetated polar region left behind a fragmented sedimentary record that crops out across several islands in the Canadian Arctic Archipelago as the Beaufort Formation and correlative strata. Paleoecological information from these strata provides a high-fidelity window onto Pliocene environments, and prominent fossil sites yield unparalleled insights into Cenozoic mammal evolution. Significantly, many of the strata reveal evidence for life-sediment interactions in a warm-climate Arctic, most notably in the form of extensive woody debris and phytoclast deposits. This paper presents original field data that refines the sedimentological context of plant debris accumulations from the anactualistic High Arctic forests, most notably at the ‘Fyles Leaf Beds' and ‘Beaver Pond' fossil-bearing sites in the ‘high terrace deposits' of central Ellesmere Island. The former is a remarkably well-preserved, leaf-rich deposit that is part of a complex of facies associations representing lacustrine, fluvio-deltaic and mire deposition above a paleotopographic unconformity. The latter yields tooth-marked woody debris within a peat layer that also contains a rich assemblage of vertebrate and plant fossils including abundant remains from the extinct beaver-group Dipoides. Here we present sedimentological data that provide circumstantial evidence that the woody debris deposit at Beaver Pond could record dam-building in the genus, by comparing the facies motif with new data from known Holocene beaver dam facies in England. Across the Pliocene of the High Arctic region, woody debris accumulations are shown to represent an array of biosedimentary deposits and landforms including mires, driftcretions, woody bedforms, and possible beaver dams, which help to contextualize mammal fossil sites, provide facies models for high-latitude forests, and reveal interactions between life and sedimentation in a vanished world that may be an analogue to that of the near-future.
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Szostak, Marta, e Jadwiga Jagodzińska. "The hydrological modeling in terms of determining the potential European beaver effect". Geodesy and Cartography 66, n.º 1 (1 de junho de 2017): 105–16. http://dx.doi.org/10.1515/geocart-2017-0006.
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Abstract The objective of the paper was the hydrological analysis, in terms of categorizing main watercourses (based on coupled catchments) and marking areas covered by potential impact of the occurrence and activities of the European beaver Castor fiber. At the analysed area – the Forest District Głogów Małopolski there is a population of about 200 beavers in that Forest District. Damage inflicted by beavers was detected on 33.0 ha of the Forest District, while in the area of 13.9 ha the damage was small (below 10%). The monitoring of the beavers’ behaviour and the analysis of their influence on hydrology of the area became an important element of using geoinformationtools in the management of forest areas. ArcHydro ArcGIS Esri module was applied, as an integrated set of tools for hydrographical analysis and modelling. Further steps of the procedure are hydrologic analyses such as: marking river networks on the DTM, filling holes, making maps of the flow direction, making the map of the accumulation flow, defining and segmentation of streams, marking elementary basins, marking coupled basins, making dams in the places, where beavers occur and localization of the area with a visible impact of damming. The result of the study includes maps prepared for the Forest District: the map of main rivers and their basins, categories of watercourses and compartments particularly threatened by beaver’s foraging.
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Smith, Michael E., Charles T. Driscoll, Barbara J. Wyskowski, Carol M. Brooks e Christina C. Cosentini. "Modification of stream ecosystem structure and function by beaver (Castor canadensis) in the Adirondack Mountains, New York". Canadian Journal of Zoology 69, n.º 1 (1 de janeiro de 1991): 55–61. http://dx.doi.org/10.1139/z91-009.
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Stream ecosystem structure and function were studied in an acidic second-order Adirondack Mountain stream system with current beaver activity. Acid-neutralizing capacity, pH, dissolved organic carbon, Fe2+, and Mn2+ values were elevated and [Formula: see text], Aln−, and dissolved oxygen concentrations were decreased following water transport through the beaver impoundment. Upstream acidity was primarily ameliorated by [Formula: see text] and Fe retention in the impoundment during the low-flow summer period. High Fe and Al sediment concentrations were present during low-flow periods immediately downstream of the beaver dam. During the high-flow period, Fe and Al concentrations were highest 0.25 km downstream of the dam, owing to slow metal hydrolysis–oxidation kinetics during spring snowmelt. The immediate downstream site exhibited significantly lower invertebrate richness and diversity and collector–filterer, Plecoptera, and Trichoptera densities, but significantly higher total invertebrate, Diptera, Ephemeroptera, predator, and collector–gatherer densities. Significant differences were noted primarily during April and July. Our results indicate that beaver dams modify stream ecosystems longitudinally and temporally and ameliorate stream acidity. Current lotic ecosystem paradigms like the river continuum concept should incorporate "patch" occurrences such as those created by beaver.
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Brick, Philip, e Kent Woodruff. "The Methow Beaver Project: the Challenges of an Ecosystem Services Experiment". Case Studies in the Environment 3, n.º 1 (31 de dezembro de 2019): 1–14. http://dx.doi.org/10.1525/cse.2017.001057.
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This case explores the Methow Beaver Project (MBP), an ambitious experiment to restore beaver (Castor canadensis) to a high mountain watershed in Washington State, USA. The Pacific Northwest is already experiencing weather regimes consistent with longer term climate projections, which predict longer and drier summers and stronger and wetter winter storms. Ironically, this combination makes imperative more water storage in one of the most heavily dammed regions in the nation. Although the positive role that beaver can play in watershed enhancement has been well known for decades, no project has previously attempted to re-introduce beaver on a watershed scale with a rigorous monitoring protocol designed to document improved water storage and temperature conditions needed for human uses and aquatic species. While the MBP has demonstrated that beaver can be re-introduced on a watershed scale, it has been much more difficult to scientifically demonstrate positive changes in water retention and stream temperature, given hydrologic complexity, unprecedented fire and floods, and the fact that beaver are highly mobile. This case study can help environmental studies students and natural resource policy professionals think about the broader challenges of diffuse, ecosystem services approaches to climate adaptation. Beaver-produced watershed improvements will remain difficult to quantify and verify, and thus will likely remain less attractive to water planners than conventional storage dams. But as climate conditions put additional pressure on such infrastructure, it is worth considering how beaver might be employed to augment watershed storage capacity, even if this capacity is likely to remain at least in part inscrutable.
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Stakheev, Valeriy V., Vlalimir Yu Shmatko, Nikita V. Panasyuk e Aleksey V. Kleshchenkov. "CURRENT STATUS OF POPULATION AND ECOLOGICAL PECULIARITIES OF THE EURASIAN BEAVER CASTOR FIBER L. IN ROSTOV REGION". South of Russia: ecology, development 13, n.º 2 (1 de julho de 2018): 196–202. http://dx.doi.org/10.18470/1992-1098-2018-2-196-202.
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Aim. Are considered the issues of distribution, the current state, and some ecological peculiarities of the Eurasian beaver Castor fiber in the Rostov region in the south of their range. Methods. The materials presented in the study were collected predominantly in the spring-summer months, based on the information from hunting specialists. Was used the method of counting the number of inhabited settlements. Was also considered the confinement of the animal to certain stations, as well as to the width of the river bed. Results. Over the past two decades, this species has significantly expanded its distribution in the region and settled along the right bank of the Don River up to its mouth. Currently, the number of beavers in the Rostov region is estimated at over 2300 individuals. At the same time, the overwhelming majority of them inhabit the administrative regions located in the north of the region and are more connected with the rivers of Seversky Donets, Kalitva, Chir, the middle course of the Don River. Conclusion. In the Rostov region, the beaver demonstrates the main elements of occupying the territories, which is expressed in the prevalence of construction of burrows over the construction of huts, as well as the absence of dams and canals. In the near future, there is a probable increase in the density of the population of the beaver in the lower reaches of the Don, as well as the colonization of the rivers of the northern part of the Azov Sea.
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Hägglund, Åsa, e Göran Sjöberg. "Effects of beaver dams on the fish fauna of forest streams". Forest Ecology and Management 115, n.º 2-3 (março de 1999): 259–66. http://dx.doi.org/10.1016/s0378-1127(98)00404-6.
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Brooks, Marjorie L. "Beaver and state transition in Yellowstone". UW National Parks Service Research Station Annual Reports 40 (15 de dezembro de 2017): 23–30. http://dx.doi.org/10.13001/uwnpsrc.2017.5561.
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Extirpation of wolves from the Greater Yellowstone Ecosystem (GYE) in the 1920shypothetically triggered a behaviorally-mediated trophic cascade in which elk (Cervus elaphus), released from the fear of wolf (Canis lupus) predation, over-browsed riparian zones. Eventually, vast areas of meadow-wetland complexes transitioned to grass-lodgepole systems. The importance of beaver (Castor canadensis) in wetland losses has received less attention. Beaver abandoned most of the GYE by the 1950s, possibly due to resource limitations. Researchers from Colorado State University established an experimental system for Long Term Environmental Research in Biology (LTREB) along several streams in the Lamar Valley of Yellowstone sixteen years ago. To evaluate effects of hydrologic changes and elk browsing on productivity of willows (Salix spp.) and state transition, they built small experimental dams with browsing exclosures. In 2015, beaver began recolonizing the region. I am investigating how their biologic as well as hydrologic impacts affect the underlying mechanisms of state transition: nutrient cycling, productivity, and stream respiration. I posit that beaver are keystone species, meaning that the sustained recovery of wetland-meadow complexes is unlikely without the higher levels of riparian productivity triggered by the biological influence of beaver.
Featured photo by Ben Amaral on Unsplash. https://unsplash.com/photos/rohY54N6auU
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Ecke, Frauke, Oded Levanoni, Joachim Audet, Peter Carlson, Karin Eklöf, Göran Hartman, Brendan McKie et al. "Meta-analysis of environmental effects of beaver in relation to artificial dams". Environmental Research Letters 12, n.º 11 (1 de novembro de 2017): 113002. http://dx.doi.org/10.1088/1748-9326/aa8979.
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Filonenko, Yu. "Zoogenic landforms within the river Ubort basin". Bulletin of Taras Shevchenko National University of Kyiv. Geography, n.º 62 (2014): 28–31. http://dx.doi.org/10.17721/1728-2721.2014.62.7.
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The causes and features of appearance of the most common zoogenic landforms in the river Ubort basin within Ukraine are analyzed. Particularly, such zoogenic landforms as beaver dams, huts, holes and channels; muskrat huts and holes; brock, fox and hamster holes and hillocks; dog holes; molehills and mole labyrinths; ground and soil anthills are investigated. The characteristic of the size and density of these landforms within particular areas of the investigated region is made.
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Revel, Jean-Paul. "The WAIS and byways of the GOPHER". Microscopy Today 2, n.º 4 (julho de 1994): 3–5. http://dx.doi.org/10.1017/s1551929500065469.
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The Gopher, although as industrious as the Beaver and the skilled architect of complex subterranean mazes which should inspire as much awe as the dams and lodges built by beavers, is rarely revered as the mascot of Institutes of Higher Education. In real life many, my wife and I included, relentlessly pursue the garden variety gopher who dares to intrude and destroy prized plants, or for that matter even plants we do not care about. It is my job to deal with them and I do it like a Daemon that's BinHex-ed. However there is a highly prized and very beneficial, if virtual, species of GOPHERS. These creatures, created at the U. of Minnesota (home of the Golden Gophers), put their tunneling ability to good use, digging out otherwise hard to find information and so performing great services on the latter day wonder of electronic communication, the Information Superhighway, the Internet.