Migrations of wild bison have been shown to benefit the ecosystem

2025/08/29 Galarraga Aiestaran, Ana - Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Zoologia
• Ekologia

Yellowstone’s bison group migrations improve soil nutrient cycles and are beneficial for the health of grazing ecosystems. This is confirmed in a study published in the journal Science. Therefore, it is concluded that the restoration of bison would be effective for the restoration of ecosystems.

Historically, North America had tens of millions of wild bison species, and their seasonal migrations transformed the continent’s vast grassland ecosystems. Today, there are no more than 400,000 bisons left, and almost all of them live in private lands or within parks and reserves, in small groups. Although the studies suggested that the expansion of bison habitats and the promotion of migration would have led to the improvement of ecosystems, they could not say for sure, since they all live in restricted areas. Now, however, the restoration of bison migrations in Yellowstone’s northern ecosystem has allowed researchers to have a natural laboratory to study how large herbivores shape landscape and ecosystems.

Thus, between 2015 and 2022, the impact of bison dynamics on the carbon and nitrogen cycle, plant communities and soil microbiology has been studied in three main habitats divided into 16 zones. Thus, they have observed that bison stabilize plant production, increase the nitrogen content of the soil, and improve the nutritional quality of pastures. These benefits are even more pronounced in places where bison density was higher than commonly recommended, especially in humid and nutrient-rich areas.

According to the authors, the findings show that the ecological value of large migratory herbivores lies not only in their size, but also in their number, density and freedom of migration. And they confirm that the restoration of wild bison in vast areas would be useful to restore the ecosystem.