How do wolves and humans shape beaver spatial behaviour and ecosystem impacts?

Promoting the recovery of keystone species such as the beaver and wolf is regarded as a key strategy for halting
or even reversing the ongoing decline in Europe’s biodiversity, as these species can have outsized effects on
ecosystems. Beavers ecologically engineer watercourses and river valleys, and shape riparian woody
vegetation through their foraging. Through their selective foraging on trees, beavers alter forest composition
and structure within ca. 60 m of a water’s edge by resetting succession, and shifting tree stands to being
dominated by conifers and deciduous trees less preferred by beavers. Whereas wolves by hunting and killing
herbivores can indirectly affect woody plant communities (their prey’s food). The beaver can comprise up to
45% of the wolf’s diet in some areas of Poland, suggesting there is great potential for wolves to modify the
distributions and ecosystem impacts of beavers. Yet we have at best only a partial picture of how they interact
with one another.
A key way large carnivores like the wolf shape ecosystems is through the fear they inspire in prey. The
perceived risk of predation can cause behavioural changes in prey that can cascade down food chains to the
prey’s food species, whose survival and/or abundance can increase as a consequence. But it remains unclear
how wolves impact beaver behaviour, if at all. Understanding such predator-prey interactions in Europe can
be particularly complicated, as wolves and beavers are recolonising landscapes that have been transformed by
humans. Human impact can greatly modify how wolves and beavers interact with one another. This all means
that European riparian systems, landscapes crucial for conservation and agriculture, are shaped by an
interaction between three keystone species that we know little about. A key question arising from this story is
what role do wolves play in suppressing beavers and their impacts in Europe’s human dominated landscapes?
Do wolves suppress the distributions and behaviour of beavers as they can do those of their ungulate prey, or
do humans alter or prevent these impacts? The aim of the project is to understand how wolf risk and human
activities shape beaver behaviour, and hence their impacts on woody tree communities.
1) In the first step, the project aims to understand how wolf risk and human activities shape beaver
distributions across the landscape. We will inventory beavers using drone and aquatic surveys. We will
then assess levels of wolf and human activity across the riparian landscape using camera trap and GIS
analyses. By relating beaver occurrence to wolf and human activity, we will be able to determine how
wolves and humans shape beaver distributions.
2) In the second step, the project aims to understand how wolf risk and human activities shape beaver foraging
behaviour. We will assess beaver foraging activity via a terrestrial field survey and camera trapping. By
relating beaver foraging behaviour to wolf and human activity, we will determine how wolves and humans
shape the distances beavers forage away from water.
3) In the third step, the project aims to understand how wolf risk and human activities indirectly shape the
beaver’s impacts on tree communities along watercourses. To this end, we will carry out woody tree
vegetation surveys in beaver territories but also at control sites without beavers. By relating the forest
composition at both types of sites to the gradients of wolf and human activities across the landscape, we
will be able to determine whether wolves and humans are reducing the beaver’s impacts on woody tree
communities.
The field work will work will be carried out at two study sites, one in Poland, Białowieża Forest, and one in
the Netherlands, near Groningen. The former site hosts wolves, and the latter does not. By comparing the data
collected at sites with and without wolves, we will be able to determine the role of the wolf in curtailing beaver
distributions, foraging behaviour and ecological impacts. The field work in the Netherlands will be part of a
6-month fellowship hosted by the University of Groningen.
In recent years the landscape of fear has been a hot topic in ecology, with studies suggesting the fear inspired
by large carnivores can suppress the behaviour and ecological impacts of ungulates and medium sized
carnivores. Here we aim to extend this framework to the beaver, which is an important prey species for
the wolf. The project aims to reveal whether the wolf excludes the beaver, and its ecological impacts and
conflicts from parts of our landscapes, and whether humans are reducing these effects of the wolf. This
knowledge will pave the way for better informed management of wolves, beavers and riparian landscapes, and
help us to fine-tune wolf and beaver ecological functionality and potentially mitigate beaver conflicts where
desired. As both species are often heralded as saviours of biodiversity, this knowledge is urgently needed to
predict the ecological effects of the ongoing wolf and beaver recolonisations of Europe’s human dominated
landscapes.