Beaver Activity Research Articles

Assessing controls on sedimentation rates and sediment organic carbon accretion in beaver ponds

Beaver dams trap sediment, promote channel-floodplain connectivity, modify biogeochemical cycling and organic carbon (OC) storage, and influence geomorphic form. Beaver-related sediment accumulation has been investigated at longer timescales (e.g., > 1000 years) and shorter timescales (< 10 years), but we lack information on sedimentation and sediment-associated OC accretion rates over multiple decades in relatively persistent beaver ponds (10–100 years old). We coupled field surveys of 45 beaver ponds with historical aerial imagery and radiometric dating with 7Be, 210Pb, and 14C to calculate sedimentation rates, mean sediment depth, and sediment OC content at two study sites in the southern Rocky Mountains, USA. Sedimentation rates in beaver ponds (median = 5.7 cm yr−1, mean = 11.6 cm yr−1) decreased with pond age. Incised, single threaded reaches had greater variability in mean sediment depth compared to less incised reaches. In less incised reaches, mean sediment depth and beaver dam height increased with pond age, indicating more stable dams and depositional environments. Sediment OC content within beaver ponds (median = 0.8 %, mean = 1.7 %) increased with finer sediment grain size distributions. Sediment OC accretion rates in ponds ranged between 0.13 and 23 Mg C ha −1 per year. We used Monte Carlo simulations to estimate it would take ∼100 years or more of uninhibited beaver activity for deposition to laterally reconnect adjacent terraces in the incised study reaches, a common objective within many stream restoration projects. Our findings show that beaver ponds in complex, multi-threaded reaches better retain fine sediment over longer timescales, highlighting the need to incorporate geomorphic context when considering whether beaver can help restore incised river channels and floodplain connectivity, retain fine sediment, and store OC on the landscape.

Can beavers help improve terrestrial invertebrate diversity?

On a global scale, species biodiversity is declining rapidly, including that of terrestrial invertebrates. Environmental heterogeneity is viewed as a key factor promoting biodiversity, and previous studies have shown how beavers can have a profound effect on both habitat heterogeneity and abundance and diversity of a plethora of water-related and terrestrial organisms. However, less is known about the effects of beavers and successional stages on the terrestrial invertebrate community. Here, we review existing knowledge and outline research trajectories to improve our understanding of how beavers affect the terrestrial invertebrate community with special focus on the importance of each successional stage that beavers provide on terrestrial invertebrates. Although beavers can have a large impact on the terrestrial invertebrate community, more studies are needed that take into consideration successional stages and with standardized sampling designs. A better understanding of how beaver activity affects the terrestrial invertebrate community can help in conservation of endangered species and restoration of biodiversity in terrestrial habitats.

The Impact of Beaver Dams on the Dynamic of Groundwater Levels at Łąki Soleckie

Areas excluded from agricultural production are susceptible to the presence of beaver families. The most significant changes occur during the initial period, when agricultural utilization is abandoned and beavers establish their presence on the land. During this period, some parcels remain uncultivated, while agricultural activities persist in neighboring areas. This situation is accompanied by the destruction of beaver dams, especially during periods of abundant water resources, and notably during intensive fieldwork. The article presents field studies aimed at determining the extent to which constructed and operational beaver dams contribute to changes in groundwater levels in drained peatland areas. In order to protect and sustainably use peat soils, it is necessary to maintain their high moisture content by ensuring a high groundwater level elevation. This can be achieved through the use of existing damming structures in the area (levees, weirs). Beaver dams can also serve a similar function, blocking the outflow of water from peat lands by raising the water level and consequently retaining it naturally. The specific objective was to develop principles for verifying factors influencing the effects of beaver dam construction on groundwater levels in fields within their range of influence. The water table levels within the study area during rainless periods were influenced by water levels in ditches, dependent on beaver activity in the nearby river. Beaver activities, manifested through dam construction, were influenced by periodic water resources in the river, defined by the cumulative monthly precipitation. Factors affecting groundwater levels in rainless periods on the plots also included the distance from the river cross-section and the permeability of soils expressed by the filtration coefficient of the active layer. Beaver dams had the greatest impact on stabilizing the water table in the soil profile closest to the river.

Effects of a beaver dam on the benthic copepod assemblage of a Mediterranean river

As known “ecosystem engineers”, beavers influence river hydrology, geomorphology, biochemistry, and biological assemblages. However, there is a lack of research regarding the effects of beaver activities on freshwater meiofauna. In this study, we investigated the taxonomic and functional composition of the benthic copepod assemblage of a segment of the Tiber River (Italy) where a beaver dam, created about 7 weeks before our survey, had formed a semi-lentic habitat upstream and a lotic habitat downstream of the dam. We also analyzed the copepod assemblage before and after a flood event that destroyed the beaver dam, providing a unique opportunity to observe changes in a naturally reversing scenario. Our analyses revealed that, while the taxonomic composition and functional traits of the copepod assemblage remained largely unchanged across the recently formed semi-lentic and lotic habitats, substantial differences were evident between the dammed and undammed states. The dammed state showed lower copepod abundances, biomass, and functionality than the undammed one. These results highlight the role of beaver dams in changing the composition and functionality of meiofaunal assemblages offering insights into the dynamic interactions within aquatic ecosystems.

Full floodplain connectivity: Realising opportunities for ‘Stage 0’ river restoration

AbstractContinued declines in freshwater biodiversity and the challenges of climate change are creating greater interest in river restoration projects. Increasing recognition of the interaction between biological, geomorphological and hydrological processes has led to the development of ‘Stage 0’ river restoration. Stage 0 reaches are typically multi‐thread anabranching systems connected to the floodplain and its ecosystems. It is suggested that the defining characteristic of Stage 0 conditions is that of connectivity (longitudinal, lateral and vertical) at base flows. The methods or mechanisms that can re‐create such reaches are described, namely valley floor reset, beaver activity, beaver dam analogues and the use of large wood in the channel and floodplain. The scope for wider adoption of Stage 0 is then discussed and recommendations for expanding this approach across temperate regions with a long history of river modification and higher population densities are presented.

Beaver dam analogs did not improve beaver translocation outcomes in a desert river

Stream restoration programs employ beaver‐related restoration techniques, including beaver translocations and installation of beaver dam analogs (BDA), to create complex in‐stream habitat. We investigated whether BDA installations improved the probability of translocated beavers surviving and colonizing a section of a degraded desert river. We translocated beavers fitted with tracking devices to the Price River, Utah, United States, for 2 years before and after BDAs were installed. We monitored survival and site fidelity of beavers to estimate apparent survival (φ), using model selection to evaluate models with BDA, flow, and other factors hypothesized to relate to apparent survival. We found similar apparent survival 8 weeks post‐release of pre‐BDA (φ = 0.50 ± 0.08 SE) and post‐BDA beavers (φ = 0.41 ± 0.06 SE). There were 15 predator‐caused mortalities and 39 beavers emigrated out of the study site. Top models indicated apparent survival was negatively related to mean flow. Of the 70 BDAs constructed, beaver activity was detected on only two structures and the number of intact natural dams decreased due to monsoon floods. Our results suggest BDAs may not improve survival and site fidelity of translocated beavers in desert river systems. Instead, the dynamic flow of desert rivers and negative relationship between flow and apparent survival suggest the timing of release may be an important consideration for successful beaver translocation. Additional research is needed to understand how habitat, food availability, individual behavior, and resident conspecifics influence beaver translocation success.

An overview of the current state of the beaver’s environmental activity

A review of scientific publications devoted to the study of the impact of beaver foraging and construction activities on the plant communities of small rivers in different natural zones has been conducted. Based on the analysis of publications devoted to the study of the beaver's environmental activity, its key role in the successional processes of phytocenoses of riverine biotopes in all natural zones within the native and acquired range is noted. The stages of succession transformations initiated by the beaver's vital activity are considered. The degree of succession transformations depends, first of all, on the density of populations and their stages of maturity. The successions are highly intensive, multidirectional and do not reach the final stage, but are concentrated in the floodplains of small rivers and streams, in the coastal strip of other reservoirs. The vital activity of beavers determines the floristic, faunal, and ecologicaltopological diversity of coastal biogeocenoses. An increase in the proportion of groups of aquatic and wetland plant species was noted, and an increase in biological diversity was revealed in the beaver pond backup zone, regardless of zonal factors. However, being strongly transformed, the coastal vegetation remains zonally conditioned, does not become azonal.

Functional requirements for an intelligent system for monitoring the impact of beaver activity on ecosystems

The consequences of beaver activity affect the condition of natural and anthropogenic systems. The paper presents a brief description of possible consequences of beaver settlement in the natural territory. The monitoring of the number of individuals, the control of the environment and the possibility of forecasting its changes require the development of specialized software tools. The paper presents a description of the main functionalities of such a system and a list of users to whom they are available. These include the detection of beaver habitats, the prediction of environmental changes due to the construction of dams and reservoirs, and the regulation of animal fishing processes. In addition, lists of data are presented, the use of which will make it possible to realize the presented functionalities. The proposed intelligent system will allow forest specialists to monitor the state of natural areas, to specify the list of measures to ensure the preservation of natural and anthropogenic objects. From the point of view of state management, it is possible to create an up-to-date and constantly updated register of beavers and to control their fishing.

Beaver-related restoration: An opportunity for sandy lowland streams in a human-dominated landscape

The expansion of beavers into human-dominated landscapes can help improve the ecological status of degraded streams. This study aimed to assess the changes in the ecological status of a degraded sandy-bottom stream under the influence of processes generated by the activity of a European beaver. We assumed that the processes in the beaver dam-and-pond complex significantly improved the physical, chemical, and bacteriological properties of water and improved the ecological status of a small lowland stream in a human-dominated landscape. To achieve these objectives, water for quality assessment, benthic invertebrates, and fish samples were collected, and the forms of land use and the natural values of the stream were analysed. In the upstream zone of the sandy-bottom stream flowing in a human-dominated landscape, the inflow of pollutants caused a significant reduction in water quality. The amount of nutrients was high and the amount of dissolved oxygen was low. Similarly, the number of meso- and psychrophilic bacteria was significantly higher than in the reference stream. The building activity of beavers initiated a series of positive environmental changes, and beaver ponds improved the self-purification of water in a polluted stream. In the lower part of the studied stream, after the stream passed through the beaver wetland system, the water quality improved, which was indicated by a significant improvement in physicochemical, microbiological, and biotic indicators, that is based on macrozoobenthos and fish. By constructing dams, beavers flooded large areas and created habitats for plant and animal species associated with wetlands, including amphibians, birds, and mammals. The improvement of the ecological status of the stream, combined with the preservation and restoration of wetland habitats in the catchment area, enables the use of ecosystem services provided by the streams in the human-dominated landscape and their surroundings.

A bibliometric literature review in beaver management: when does the beaver become a resource?

Abstract Freshwater ecosystems are some of the most biodiverse habitats, but they are among the most endangered due to human activities. In this context, beavers represent a nature‐based solutions to preserve and repair freshwater ecosystem, given their important role as ecosystem engineers. However, in an environment modified by humans, beaver activities frequently create conflicts masking the positive effects of this rodent. Therefore, the management of beaver populations and human–beaver conflicts is needed. This article investigates the literature about beaver management through a bibliometric analysis to understand past, current, and future response. Moreover, it quantifies the number of studies that consider beavers as a resource, and it identifies the emerging themes in the field. The bibliometric analysis was performed considering a total of 415 documents with the software VOSviewer and the R web interface for bibliometrix Biblioshiny. The analysis presented here provides a complete view of past, present, and future management approaches and responses at the base of beaver management strategies. Three main results emerged. Firstly, a rising tendency in the number of publications about beavers that are directly linked to the populations development and spread has detected. Secondly, only 4.3% of scientific literature has referred to beaver‐related restoration. Thirdly, the ‘human perceptions’ has resulted in the emerging field investigated. Findings suggest that there is a lot of research interest about beaver management. The beaver is still poorly managed as a tool for freshwater ecosystem restoration. The management is shifting from studies focused more so on beaver ecology to others mainly focused on the beaver effects and the human dimension. This review provides a starting point for future research on beavers and suggests the development of socio‐ecological management models that consider benefits and impacts of beavers. This will help the decision‐making process of conservation and restoration initiatives.

Equivalent impacts of logging and beaver activities on aboveground carbon stock loss in the southernmost forest on Earth

The conservation of forest landscapes is crucial for global climate strategies, and the forest in Tierra del Fuego, located in Patagonia, represents the southernmost example on Earth. These ecosystems are critical for Chile’s roadmap toward carbon neutrality. Unfortunately, these ecosystems have been impacted by logging and beaver activities. Currently, the precise contribution of each driver to forest cover and carbon stock loss remains insufficiently quantified, impeding effective policymaking and the implementation of strategies to safeguard and enhance carbon stocks in these ecosystems. In this study, we conducted an assessment of forest carbon stock loss resulting from both logging and beaver activities in Chilean Tierra del Fuego from 1986 to 2019. While beavers have received significant attention for their substantial contribution to forest cover loss (56.1% forest cover, ≈ 1.4 MtC), our findings suggest that logging has nearly equally contributed to carbon stock depletion (43.8% forest cover, ≈ 1.2 MtC). Consequently, the prevailing focus on beavers has obscured the ongoing logging-induced carbon stock loss. The implications of our study highlight the urgency for comprehensive consideration of both drivers in Chile’s climate strategy to fulfill the country’s mitigation commitments.

The positive response of small terrestrial and semi-aquatic mammals to beaver damming

Ecosystem engineers, such as the Eurasian beaver, Castor fiber, transform habitats, thereby creating favourable conditions for other species and increasing biodiversity. Multiple studies have revealed that beaver ponds are valuable habitats for invertebrates and vertebrates, including other mammals, but the impact of watercourse damming on the fauna of small terrestrial rodents and shrews has not yet been documented. We tested the hypothesis that the presence of beaver dams and consequent flooding enrich the small mammal assemblage both quantitatively and qualitatively. We live-trapped small mammals at nine beaver-modified sites on 300-metre transects alongside dammed watercourses, starting from the dam through to the pond to the sections with unmodified lotic conditions. The abundance and species richness of trapped small mammals were highest near the dams and declined with distance. Additionally, five out of 12 trapped species significantly decreased their abundance with linear distance along the shoreline from the dam and none revealed the opposite trend. Four species were more abundant on plots subjected to beaver-related inundation (especially Sorex minutus and Micromys minutus), while none were present solely on uninundated plots. Among the semi-aquatic species, two water shrews benefited from beaver activity in different ways. Neomys milleri occurred only in flooded sections, while N. fodiens preferred unmodified sections, but was the most numerous species closer to the dams, as per known patterns of competitive displacement observed in Central Europe. An important factor affecting small mammals, the herbaceous layer cover, appeared to be interdependent with damming. We provide the first unequivocal evidence that the presence of beaver dams facilitate the abundance and diversity of small mammals, presumably due to increased food abundance, availability of shelter and habitat connectivity. Beaver-created wetlands may act as potential refuges for species most susceptible to the consequences of anthropogenic climate change.

Cadastral and landscape modeling of lakes as a prerequisite for protected and recreational nature resource management

The cadastral information about the lakes of the nature reserve fund (NRF) should be based on landscape-geographic principles using modern geo-information systems.Within the research, based on the instrumental field research and the use of software packages ArcGIS Desktop and ReefMaster Software, a bathymetric map of Lake Serednie (Nobel National Natural Park, Ukraine) and other spatial models were developed. The main hydrological and morphometric parameters of the lake basin were calculated, a landscape map of the natural aquatic complex was created and its landscape metric analysis was carried out at the level of aquatic tracts and facies. The research revealed changes in the level regime and shoreline of the lake caused by the long dry periods of 2016-2021 and life activity of beavers. The created integrated cadastral landscape model of the lake with limnology parameters should serve as a basis for the recreational nature use, monitoring and geo-ecological certification of the reservoirs of the NRF.

Consequences of the activities of Eurasian beaver on local plants and vegetation cover – an overview

Abstract The Eurasian beaver has a significant impact on biotic and abiotic resources, thus it is known as an “ecosystem engineer”. Currently, the beaver population in Eurasia is estimated at more than 1.4 million individuals due to successful reintroductions in many countries. The recognition of its impact on ecosystems is increasing every year, therefore this article summarizes the current knowledge of how the Eurasian beaver affects the local flora and vegetation in the area where it settles. Beavers initiate a transformation of their closest surroundings with the dams and ponds they create by forming wetlands, and the newly developed vegetation is richer in plant species than previously. Beaver activities lead to a decrease in local woody plant resources and an increase in the species diversity of herbaceous plants. Beavers also cause damage to agricultural crops when they feed on cultivated plants. Observed changes can vary over time and landscape scales due to local conditions and persistence of beaver occurrence. Understanding how beavers affect plants and vegetation may be helpful not only in the protection of the species itself, but also in better management of the areas where they occur.

Channel Gradient as a Factor in the Distribution of Beaver Dams and Ponds on Small Rivers: A Case Study in the Northern Extremity of the Volga Upland, the East European Plain

A very noticeable increase in the beaver population (mainly the Eurasian beaver (Castor fiber L.)) in the East European Plain since the end of the 20th century through reintroduction contributed to the emergence of a large number of beaver dams and ponds, which resulted in the transformation of the channels and the hydrological regime of small rivers. In this paper, for the first time in the Middle Volga region, regularities in the distribution of beaver dams and ponds on small rivers were revealed based on a topographic survey of the river channel, regulated by beaver activity in recent decades. The materials of the paper were obtained during field (geodetic) work in August and September of 2022 in the valleys of two small rivers typical for the north of the Volga Upland, Morkváshinka River (16.6 km) and Morkváshka River (7.8 km), with subsequent statistical processing. According to the results obtained, all the dams we encountered were located in the sections of their channels with relatively small (up to 1%) and medium (1–3%) average gradients. In the upper reaches of the rivers, the expansion of beaver activity is limited to the large gradients of their channels. Along the entire length, there is an alternation of sectors with a “natural” (not regulated by beavers) channel and a cascade of beaver ponds. Drained (at the time of the survey) sectors without dams, as well as those with preserved and destroyed dams, were also identified on the Morkváshinka River. On the whole, 26–48% of the length of the studied rivers has been transformed by beaver activity. The average number of dams per kilometer of the watercourse is 3.7–5.1. The most favorable channel gradients for beaver activity are 3.6–16.6 m/km, or 0.36–1.66%. The average gradient of the channel, above which no beaver dams and related ponds were found in these rivers, is 30 m/km, or 3%. An increase in the channel gradient upstream of the rivers is reflected in the size of beaver dams and ponds. The beaver dams and ponds are slightly larger in the sections of the rivers with a relatively small average gradient than in the sections with a medium average gradient of the channel.

The mammal fauna of the Mykhailivska Tsilyna Nature Reserve: assessment of diversity and factors of its support

At the time of the creation of the Mykhailivska Tsilyna Nature Reserve (1928), it was a completely forestless steppe area with an area of 202.2 hectares. Presumably, 17 mammal species from 11 families and 5 orders were distributed in its territory, and 1 species (steppe marmot) had already disappeared. Of them, 8 species belonged to the steppe faunal core, 3 species were confined to floodplain meadows, and 6 species were widespread. Fifteen species occurred permanently and two species were recorded with a varying frequency. In the early 1950s, substantial changes took place in and around the nature reserve. A ditch was dug around the perimeter of the reserve and a forest belt was planted. Two much bigger and deeper ponds were created on the site of a small pond. A house and a brick stable were built on the steppe area, and apple trees and an alley of ornamental shrubs were planted. After the reserve was granted republican status in 1947, its environmental protection regime changed, and this had a notable impact on the vegetation. After grazing and mowing were banned, a thick layer of dead plant remains on the ground surface, reaching 5–10 cm in thickness, appeared in most of the reserve’s territory. At that time, an absolute protected regime was established on an area of about 100 hectares. The rest of the area was periodically mowed. In the early 1980s, the ponds were heavily overgrown with aquatic and wetland vegetation, and the banks were overgrown with trees and bushes. Fish were introduced into the ponds. The woody vegetation in the forest belt also grew substantially and became dense. Since 1998, the nature protection regime in the reserve has changed: the ‘periodically mowed steppe’ was mown annually for four years, and there was a break in the fifth year. All this affected the fauna and mammal population of the reserve. In 2009, the area of the reserve was increased to 880 hectares. As a result, a pond (300 x 33 m) appeared in its territory, located near the village of Stepove. A small pond (70 x 12 m) was formed in a ravine in the northern part of the reserve because of the activity of beavers. As of 2023, 24 mammal species from 16 families and 5 orders were recorded here. Of them, 4 species belong to steppe species, 2 to hydrophilic species, 5 to forest species, 12 species are widespread, and there is 1 synanthropic species. Eighteen species occur permanently in the reserve, five species visit the reserve regularly, and one synanthropic species settles in during the warm period of the year.

Beavers ecosystem altering: Influence of beaver dams on aquatic invertebrates in newly created beavers ponds and small mountain river

Beaver-created ponds constitute an important element of small water retention in forest catchments and preserving biodiversity as breeding sites for vertebrates and invertebrates. In many areas, these habitats disappear as a result of drainage melioration, drainage formed from agricultural and developmental needs, and liquidation by littering and backfilling. This study was carried out from 2017 to 2019 to understand the transformations of river valley as a result of the beaver activity in the context of newly created ponds and mountain stream and to assess the changes and biodiversity. Beavers modified in-stream habitat by constructing dams, thus creating a series of interconnected dam ponds. Organic matter retention was higher in beaver ponds relative to unmodified river section. In beaver ponds, the invertebrate aquatic assemblages was highly variable. A total of 56 taxa were identified, and significant seasonal variability of benthos assemblages. The values of diversity indices confirmed the instability of benthos assemblage in beaver ponds (variability of species amongst years and sites), which may be related to the short period of their existence. Lotic macroinvertebrate assemblages were common in the beaver-modified section of stream, with some lentic taxa also being present. The unmodified section of stream had more abundant collectors- gatherers and predators and no filter feeders, while scrapers were more abundant in modified section. The environmental variables which significantly influenced invertebrate occurrence were pH, nitrates, iron and the content of organic matter. The results contribute to ecological characteristics of these aquatic environments, and enable determining their functioning in forest areas.

The Influence of Eurasian Beaver (Castor fiber L.) Activity on the Transformation and Functioning of Riparian Phytocoenoses in the Southern Boreal Zone (European Russia)

The reintroduction of Eurasian beaver (Castor fiber L.) results in significant changes in ecosystems. The purpose of this study is to assess the impact of the environment-forming activity of C. fiber on the riparian phytocoenoses of the Raifa forest sector of the Volga-Kama State Nature Biosphere Reserve (Middle Volga region, European Russia) after the reintroduction. Phytoindication methods of ecological–coenotic groups and indicator values were used to assess changes in environmental conditions under the influence of beaver activity. The influence of the beaver reintroduction factor on the increase in the moisture regime (by three points according to the Tsyganov indicator values) and the illumination of habitats, the richness of soils in nitrogen, and the acidity and salt regime of soils (by one point) was revealed. Under the conditions of fodder and construction activities of the beaver, an increase in the proportion of aquatic and wetland groups from 10.2% to 28.2% and boreal plant species from 15.0% to 27.6% was detected. An expansive nature of the change in the degree of landscape occupancy with wetland plants was noted. A decrease in the degree of landscape occupancy (3 to 2 points) of the distribution of ruderal species in the riparian zones of the waterbodies of the reserve due to the activity of the beaver was revealed. Based on phytoindication and ecological–coenotic analyses, it was shown that the reintroduction of C. fiber into the waterbodies of the Raifa forest sector of the reserve is responsible for maintaining the necessary microclimatic conditions for the preservation of natural southern boreal communities. The results obtained can be used for predictive assessment of the influence of the beaver on riparian (small rivers and lakes) plant communities of forest ecosystems in the Middle Volga region of European Russia and other regions of the planet with similar environmental conditions.

Responses of insectivorous bats to tree felling in forested wetlands

AbstractForested wetlands provide habitat for a diversity of wildlife and create complex vegetation structure within forests. Current best management practices in New England have limited disturbances in forested wetlands due to concerns for wetland function and water quality. As a result, forested wetlands often have large, mature trees that were formerly rare under natural disturbance regimes. Our goal was to determine whether experimentally felling trees within forested wetlands is an effective management action to improve foraging habitat for insectivorous bats. In the winter of 2019 while the ground was frozen, we felled all trees in an area of approximately 0.1 ha in each of 3 forested wetlands to simulate a natural disturbance, similar to that caused by beaver activity or windthrow. The following spring and summer of 2019 and 2020, we monitored bat activity in the 3 treated forested wetlands as well as 3 untreated forested wetlands. We found that for all species recorded, bat activity was higher in treated wetlands than in untreated wetlands. We also found Lasiurus borealis and Lasionycteris noctivagans had a delayed response to treatments, with higher activity in the second year after treatments. Our findings suggest that managing forested wetlands consistent with historic patterns of forest disturbance and regeneration is beneficial to insectivorous bats. The positive response by bats to tree felling indicates that promoting age‐class and structural diversity in forest canopies without flooding or soil disturbance is an appropriate consideration with respect to best management practices in forested wetlands.

Beaver activity and red squirrel presence predict bird assemblages in boreal Canada

AbstractWetlands and predation in boreal ecosystems play essential roles throughout the breeding season for bird assemblages. We found a positive association of beaver activity and a negative influence of American red squirrels (Tamiasciurus hudsonicus) on bird assemblages. We used a multispecies hierarchical model to investigate whether bird communities differ between two major wetland habitats in boreal Canada: beaver ponds and peatland ponds. In addition to including variables such as forest cover and latitude, we adopted a structural equation model approach to estimate the occupancy of American red squirrels and its potential influence on bird communities. Using automated recording stations deployed at 50 ponds, we detected 96 bird species in 2018 and 2019. Bird species were grouped into four taxonomic guilds according to their habitat successional requirements: early successional species, late successional species, generalists, and wetland species. Beaver ponds harbored higher species richness, a pattern driven primarily by early successional species. The occupancy of almost a quarter of the species was lower in the presence of red squirrels. Late successional species responded positively to the cover of forest surrounding the pond. Our results highlight the value of considering acoustic data of red squirrels to quantify habitat quality in boreal forests. We conclude that beaver activity shapes bird assemblages through modification of their habitat, and that some bird guilds are associated negatively with the presence of American red squirrels.