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Across Europe, many natural landscapes are undergoing rapid
change. Warmer temperatures and increased
rainfall are accelerating the growth
of shrubs and trees, gradually turning open habitats into dense woodland. While
this process, known as ecological succession, is natural, it can threaten
species that depend on light, open environments, such as wildflowers and
insects. Traditionally, land managers have controlled this by cutting back
vegetation. However, new research suggests that large grazing animals like horses
and cattle may offer a more natural and effective solution.
This approach, known as trophic rewilding, involves introducing free-ranging herbivores into landscapes and allowing them to shape vegetation through their natural behaviour. A recent five-year study carried out in Denmark at the Mols Laboratory has provided valuable insight into how this works in practice. Researchers from Aarhus University tracked the movements of feral horses (Equus ferus caballus) and cattle (Bos taurus) across a 120-hectare rewilding site to understand how their grazing patterns influence vegetation.
Using GPS collars fitted to the animals and satellite data measuring vegetation growth (NDVI), the researchers were able to link where the animals spent their time with how the landscape changed over several years. The results showed that both horses and cattle preferred open grassland areas over dense woodland. In these frequently used areas, grazing and trampling reduced plant biomass and slowed the growth of shrubs and trees. As a result, these patches remained open for longer, supporting species that rely on sunlight and low vegetation.
However, the animals did not use the landscape evenly. Instead, they created a patchwork of heavily grazed and lightly grazed areas. This uneven grazing pattern is important because it increases habitat diversity, leading to a more varied and resilient ecosystem. Rather than maintaining a uniform landscape, the animals’ natural choices produced a dynamic mosaic of habitats.
Interestingly, the study also found that horses and cattle are not as similar as they are often assumed to be. While both species preferred similar grazing areas during times of abundance, their behaviour diverged when food became scarce. They began to use different parts of the landscape and exploit different food sources. This difference in “functional roles” is beneficial, as it enhances the overall impact on vegetation and promotes biodiversity more effectively than a single species would.
Another key finding was the influence of human-made structures. Both horses and cattle were strongly attracted to an artificial shelter within the study area, particularly the horses. This had a noticeable effect on grazing patterns, concentrating activity in specific areas. The researchers highlighted that the placement of infrastructure such as shelters or water troughs can unintentionally shape animal movement and, therefore, vegetation patterns. This is an important consideration for future rewilding projects.
The study also examined how the system responded to extreme weather, specifically the severe European drought of 2018. Areas that were heavily grazed showed the greatest decline in vegetation during the drought but also recovered the fastest afterwards. This ability to recover, known as resilience, suggests that grazing animals may help ecosystems better withstand climate extremes. However, when the herbivore population was later reduced by around two-thirds, the landscape became generally greener, indicating that the continued presence of grazing animals is essential to maintain open habitats.
Overall, the research demonstrates that year-round grazing by horses and cattle can effectively slow vegetation succession and prevent landscapes from becoming overly dense. For horse owners and equine science students, this highlights an important ecological role for horses beyond sport and recreation. When managed appropriately, horses can act as powerful agents of environmental change, contributing to biodiversity conservation and sustainable land management.
At the same time, the study emphasises that rewilding is not about leaving animals entirely unmanaged. Animal welfare remains a priority, with populations carefully monitored to ensure that the land can support them. This balance between natural processes and responsible management is key to the success of rewilding initiatives.
In summary, horses and cattle do more than graze; they actively shape the landscapes they inhabit. By understanding their behaviour and ecological impact, we can use them to create healthier, more diverse environments in a changing world.
For more details,see:
Kristensen, Jeppe Å., Robert Buitenwerf, Emilio Berti, Oskar L. P.Hansen, Simon D.Schowanek, Rasmus Ejrnæs, Morten D. D.Hansen, Kent Olsen, Signe Normand, and Jens-Christian Svenning.
Space-Use by Feral Cattle and Horses Shapes Vegetation Structure in a Trophic Rewilding Area.”
Ecological Applications2026: 36(1): e70170
https://doi.org/10.1002/eap.70170
