Beaver Library

For thousands of years, beavers had a big influence on the Dutch ecosystem and the people that lived there. This is the conclusion of research by archaeologist Nathalie Brusgaard. The rodents were used for food, clothing and tools, and created a landscape hospitable to many other species.

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 aimed at testing the hypothesis that the presence of beaver dams and consequent flooding enriches 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 distance from the dam and none revealed the opposite trend. Four species were more abundant on plots subjected to damming (especially Sorex minutus and Micromys minutus), while none were present solely on undammed plots. Among the semi-aquatic species, two water shrews benefited from beavers’ activity in different ways. Neomys milleri occurred only in flooded sections, while N. fodiens preferred unmodified sections, but was the most numerous closer to the dams, following the already 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 beaver dams facilitate the abundance and diversity of small mammals, presumably due to increased food abundance, availability of shelters and habitat connectivity. Beaver-created wetlands may act as potential refuges for the species most susceptible to the consequences of anthropogenic climate change, while revealing a critically low range-shift capacity.

Beaver are ecosystem engineers capable of converting free-flowing lotic habitats into a series of lentic ponds, thereby enhancing the wetland area of a riverscape. Process-based riverscape restoration using beaver reintroductions and mimicry (beaver dam analogues, BDAs) are increasingly used to restore  functions, the provisioning of services, and improve the resiliency of ecosystems across North America and Europe. Beaver can create breeding habitat for a wide range of species within the highly imperilled class Amphibia by increasing wetland area, increasing emergent vegetation, prolonging wetland hydroperiod, and creating deep ponds.

The engineering activities of the Eurasian beaver Castor fiber have far-reaching effects on the components of an environment and therefore modify the functioning of the ecosystem. The wetlands thereby created are the most conspicuous effect of beaver activity and attract water-related species. However, there is some evidence suggesting that beavers influence not only aquatic ecosystems but also the terrestrial habitats adjacent to these wetlands and the organisms occurring there. Because the impact of beavers on terrestrial birds is still poorly understood, this study evaluates the assemblage of birds wintering on beaver sites (N = 65) and paired reference sites (N = 65) in temperate forests of central Europe. We investigated the correlations between beaver presence, parameters of wetland areas, terrestrial vegetation characteristics, distance from the water’s edge and bird species richness and abundance. We found a greater species richness and abundance of wintering birds on beaver sites than on watercourses unmodified by this ecosystem engineer (by 38% and 61%, respectively). Species richness and abundance were higher in the terrestrial habitats near the edges of beaver ponds, but for some species this tendency also held in forests growing at some distance from beaver wetlands. Greater species richness was related to beaver presence, but also increased with a more open canopy and greater forest floor diversity, whereas bird abundance was correlated only with canopy openness.

Rivers and streams, when fully connected to their floodplains, are naturally resilient systems that are increasingly part of the conversation on nature-based climate solutions. Reconnecting waterways to their floodplains improves water quality and quantity, supports biodiversity and sensitive species conservation, increases flood, drought and fire resiliency, and bolsters carbon sequestration. But, while the importance of river restoration is clear, beaver-based restoration—for example, strategic coexistence, relocation, and mimicry—remains an underutilized strategy despite ample data demonstrating its efficacy. Climate-driven disturbances are actively pushing streams into increasingly degraded states, and the window of opportunity for restoration will not stay open forever. Therefore, now is the perfect time to apply the science of beaver-based low-tech process-based stream restoration to support building climate resilience across the landscape. Not every stream will be a good candidate for beaver-based restoration, but we have the tools to know which ones are. Let us use them.

Wetlands are declining worldwide, and there is a great need for their restoration and creation. One natural agent of wetland engineering is beavers. The study was conducted in Finland to address facilitation of waterbird communities by between beaver activity. The article also evaluates how the results of the study have been used in management.

The research gathered in this paper discusses the beaver’s effects on: wetland carbon cycling, riparian forest structure, and biodiversity. This thesis also covers the relationship between beaver populations and the existence of wetlands, particularly the way in which beavers are an essential part of wetland ecosystems.

The aim of this paper was to test whether the space use of Eurasian beavers seasonally varies and whether the pattern comprises diverse habitats.

A study that suggests a high density of the biological signaling field is a sign of possible depletion of food resources, and can explain how beavers can have such a large range.

We aimed to recognise beaver-produced ecosystem services and quantify their theoretical value for the entire Northern Hemisphere.

Study that finds beaver-induced changes to habitat quality, stability, and connectivity may increase spotted frog population resistance and resilience to seasonal drought, grazing, non-native predators, and climate change.

The goal of this study was to evaluate factors such as cattle grazing that may limit the occurrence of dam-building beavers in northern New Mexico.

A review by the University of Southampton of how the reintroduction of beaver will affect fish in Scotalnd

In-depth report on how beaver could provide benefits to local residents and visitors well into the millions of dollars per year in Utah.

This review summarizes how beaver impact ecosystem structure and geomorphology, hydrology and water resources, water quality, freshwater ecology, and humans and society.

Study on how beaver engineering and foraging has the potential to create unique and highly heterogeneous wetland and stream habitats

Demonstration on how beavers physically altered isolated shallow-water wetlands which then influenced aquatic invertebrates