“The main thing is to reduce the existing plant biomass,” says Guy Pe’er. The fewer dry grasses or shrubs there are, the less chance there is of them catching fire. The prerequisite for this is that the animals are used according to their feed preferences. Cattle, for example, are less well suited to scrubland. Their stomachs do not tolerate herbaceous plants. So where trees and shrubs are to be nipped in the bud, goats and sheep are the better choice. This is because they also eat twigs, young trees and bark. Cattle and horses, on the other hand, prefer to eat grass (see info box). “It is usually most effective when different herbivores with different food spectrums are used,” says Pe’er.
Which animal eats what?
goats are ideally suited to reopening dry locations that are in danger of becoming overgrown. They cover a higher proportion of their feed requirements than other grazing animals with leaves, bark and woody shoots (on average around 60 percent, and even more in winter). Goats eat bushes up to two meters high, thin trunks are crushed, and they do not disdain thorny bushes such as sloe, hawthorn and roses or conifers such as pine.
Bovine do well in both dry and wet habitats. Their diet includes grasses, herbaceous plants and woody plants. However, cattle often do not adequately contain emerging shoots. The combination of cattle with other animal species such as goats is therefore ideal.
horses feed more selectively than cattle and focus more on grasses. They prefer nutrient-rich, young forage plants, but also eat fibre-rich, older greens. Horses are not very effective at reducing undergrowth, but it can be slowed down if they are grazed all year round. Horses are particularly well suited to habitats where some ground clearance is desired – because they roll on the ground or paw the ground with their hooves. The areas are important for the germination of many specialized plants.
sheep have contributed over the centuries to the emergence of nutrient-poor grasslands, heaths and sandy habitats. Many of these habitats, which are among the most species-rich in Central Europe, can therefore best be preserved if this extensive grazing by migrating flocks of sheep is maintained. Sheep tend to scorn woody plants, which is why, in contrast to goats, they can also be used to graze orchards. Sheep have a much more selective diet than cattle or horses – preferring young forage and avoiding older and harder grasses.
bison get by without human care and maintenance and can therefore be used well in regions where agricultural use has been abandoned. Bison are similar to cattle in terms of feeding habits, but are somewhat better adapted to digesting woody food. Studies on the choice of food revealed a maximum of 30 percent woody plants, especially in winter. In summer, their diet consists mainly of grasses and herbs. Bisons are able to stem the growth of trees and shrubs. Trees up to ten centimeters thick are pushed over or trampled on during the moult.
If you allow different animal species to graze an area, mosaic-like landscapes will form over time. The animals use certain areas and avoid others, creating a landscape that alternates forests, islands of trees and open spaces. Fires can still break out there. But they cannot spread as devastatingly as in a monoculture or in a bushy area.
The study is part of the GrazeLife project, which was commissioned by the EU Commission and is intended to evaluate different forms of grazing to determine whether they prevent fires, contribute to climate adaptation and increase biodiversity. “Fire management in Europe should focus much more on fire prevention,” says Pe’er. So far, politicians have primarily invested in firefighting, i.e. in expensive fire-fighting aircraft and other fire-fighting technology. “However, there is strong evidence that this fire suppression policy leads to more combustible biomass and more intense and frequent fires in the long term.”