Tall shrub tundra
The tall shrub tundra is a mosaic of willow thickets and open grasslands, representing a green, productive oasis of the Varanger Peninsula. It is here we find the greatest biological diversity.
With a warmer climate, we expect the thickets to encroach into the grasslands. What will then happen to the grassland species? And can browsing animals come to their rescue?
The composition of grasslands and willow thickets make the tall shrub tundra in the river valleys a hot spot for many different animal species.
Here animals find good access to nutrient rich food plants and protection from predators and bad weather. But climate change is threatening the biological diversity in these areas.
The river is flooding every spring. Leaving behind silt, sand, and organic matter on the grasslands. The constant flooding disturbance coupled with animal activities cause many different nutrient-rich forb and grass species to thrive there.
The willow thickets serve as good hiding places for animals such as hares, ptarmigan, and other birds.
Photo: Eeva Soininen
Both meadows and willow thickets are good grazing areas for reindeer, moose, and small rodents.
Insects and decomposers also benefit from the nutrient-rich food.
Small rodents like the tundra vole often eat grass and fresh shoots that sprout from the ground.
Photo: Geir Vie
In a single meadow, we have recorded almost 60 different species of grasses and herbs!
Photo: Eeva Soininen
Can you see which animal is hidden in the shrubs here?
Photo: Geir Vie
Climate changes are giving us warmer summers that last longer.
In northern and alpine areas, we see that thickets have begun to take over larger areas that were previously also covered by meadows.
We also expect to see greater thicket growth here in Varanger. This threatens the great species diversity in the lush river valleys.
But aren't more green bushes and thickets good for the climate?
Not necessarily. Even though they absorb CO2, the dark bushes also absorb a lot of heat and can actually contribute to making the temperatures even higher.
Meadows that are grazed, on the other hand, bind CO2 which is stored in the ground. Allowing reindeer to graze here is therefore a good climate measure!
A shrub tundra without meadow vegetation does not have as great a variation in habitats and will not be able to provide living spaces for as many species.
In addition, other species, such as birds of prey, are in turn dependent on the species in the tall shrub tundra, such as small rodents. If the meadows disappear, it can therefore have major consequences for the entire ecosystem.
Photo: Eeva Soininen og Geir Vie
How can we prevent the thickets from taking over the meadows in the river valleys?
The best tool we have to avoid overgrowth is something that already appreciates the tall shrub tundra – namely the browsing animals!
Even though small rodents are just that: small – they play an important role in keeping thicket growth in check. More about small rodents
In the winter, they stay in tunnels under the snow and live on, among other things, willow shoots. This prevents many bushes and thickets from growing large.
Animals that brows on bushes and thickets will have better access to food as the climate warms.
At the same time, browsing from, for example, reindeer limits the spread of willow thickets. As soon as an area is without browsing animals, we see that the thickets spread.
In this way, the reindeer help us to cope with climate changes, while they get a good meal. A win-win situation there, indeed! More about moose and reindeer
Photo: Leif Einar Støvern.
Photo: Geir VieHave you noticed that some tall shrubs and trees on the Varanger Peninsula look like they come straight from the savannah?
Here it's the reindeer that have been at work, but they have only eaten as high up on the tree as they can reach – the rest is left in peace to grow further.
We have set up small cages over some meadows and willow bushes to see what happens to the vegetation when it is not grazed on. These cages are called exclosures.
Every year we record which plant species and how much of each species we find in fixed areas inside and outside the exclosures.
In this way, we can monitor how the meadows change from year to year.
Grazing animals such as reindeer, moose, small rodents,
hares and ptarmigan are monitored by counting droppings
at fixed locations annually.
Photo: Eeva Soininen
With a ruler, we can measure how much the plants grow each year. Photo: Leif Einar Støvern
Can you spot the researcher in the willow thicket?
Photo: Eeva Soininen
Here is one of our researchers busy counting plant species in an exclosure. Photo: Hans Ivar Hortman
We record birds by standing at specific places and using bird song to count which species are present.
We register all the species we hear over the course of 20 minutes, before moving on to the next location.
The redpoll is one of the most common birds in the willow thickets. Photo: Geir Vie
Knowledge about the tall shrub tundra can help us counteract the impact of climate changes
Knowledge about the meadows in the tall shrub tundra shows that overgrowth can be prevented through, for example, the management of reindeer and moose.
Preserving the tall shrub tundra will strengthen the biological diversity of plants living there.
It will also affect the species that eat the plants, as well as predators that in turn live off the plant eaters.
Therefore, the conservation of the tall shrub tundra is important for the populations of, among others, small rodents, moose, ptarmigan, and hare.
