Interplay of competition and facilitation in grazing succession by migrant Serengeti herbivores

A groundbreaking study reveals that the migration of herbivores in Serengeti National Park is governed by a dynamic interplay of competition and facilitation, characterized as a 'push-pull' mechanism. Large-bodied zebras are nudged ahead of wildebeest due to competitive grazing, while their consumption of grass facilitates the arrival of smaller gazelles. This balance was observed through an 8-year study involving camera-trap surveys, GPS-collared herbivores, and fecal DNA metabarcoding, providing unprecedented insights into the mechanisms regulating large-scale ungulate migrations. Natural experiments, such as wildfires and rainfall, further demonstrated how these forces can disrupt or strengthen grazing succession patterns.

Anderson, T. M., Hepler, S. A., Holdo, R. M., Donaldson, J. E., Erhardt, R. J., Hopcraft, J. G. C., Hutchinson, M. C., Huebner, S. E., Morrison, T. A., Muday, J., Munuo, I. N., Palmer, M. S., Pansu, J., Pringle, R. M., Sketch, R., & Packer, C. (2024). Interplay of competition and facilitation in grazing succession by migrant Serengeti herbivores. Science, 383(6684), 782–788. https://doi.org/10.1126/science.adg0744