Historically, beavers were widespread across Europe, Asia, and North America, but were severely reduced due to hunting for fur and other body parts. Recent decades have seen natural expansions and reintroductions, particularly in Europe, leading to population recoveries estimated at over 1.5 million Eurasian beavers currently [5]. Several European countries, including Italy, have experienced significant comebacks. In particular, the extinction of the species in Italy dates back to between the 16th and 17th centuries. After an absence of more than 400 years, the species was recorded in North-Eastern regions in 2018 and 2020, and subsequently in 2021 in Tuscany and in 2023 in South-Eastern regions. Recent research has highlighted high landscape connectivity for the Eurasian beaver in Italy, particularly in areas characterised by relatively dense forest cover, which is an important factor influencing habitat suitability for the Eurasian beaver and facilitating its expansion [6].

The diet of this species includes herbaceous and woody species with a preference for Salix spp. and Populus spp. Nevertheless, their preference can change based on local tree species abundance and to complement nutrients.  This activity can influence the succession, structure, and composition of vascular plant communities. For example, some studies have indicated different cyclical successions caused by the Eurasian beaver, such as the development from inundated forest to swamp forest and back [7]. Another possible effect caused by this mammal on forest structure concerns its controlling activity on large mature trees, especially if they have relatively soft wood like poplar, willow, or birch, as beavers can consume them as food; however, relatively small diameters are likely to be the most selected, but this trend shifts as it moves away from water bodies.

Furthermore, some studies have focused on the resprouting potential of some species, showing that the regrowth on incompletely felled trees can favour a multi-layered forest. One indirect effect is the immediate reduction of living biomass and the accumulation of deadwood. Canopy gaps formed after this species fell trees also increase light availability, thus favouring the regeneration of a range of tree species, as well as the development and growth of young trees [8]. On the other hand, outcomes may impact tree diversity and forest composition, as beavers can favour conifers by selectively feeding on broadleaves in mixed riparian forests and have been reported to potentially decrease tree diversity.

These animals offer a wonderful insight into the intricate web of holistic relationships that nature is made of: they have a multi-layered effect, both direct and indirect. They are “result-oriented” and determined, as proven by the eight beavers in the Czech Republic. The municipality of the area where they settled, in fact, wanted to build a dam on the Klabava river to protect the population of the endangered crayfish: they have tried for seven years but never managed, mostly because of bureaucracy. Beavers managed in less than seven days, having the government save more than three million euros. Another proof that nature is smarter than humans!

Cover image: Beavers’ impact on many parts of the food web. Photo by sharkolot from Pixabay.