Floral communities in tundra and montane grasslands are shaped by both grazing and soil nutrients. Our study, conducted at two northern sites as part of the Nutrient Network, shows how bottom-up and top-down forces interact to influence flower abundance and diversity.
Nitrogen addition generally reduced flower abundance, while phosphorus and potassium increased it. Excluding grazers boosted flower abundance, especially when combined with nutrients. Yet grazing also maintained species richness and diversity by keeping tall competitive plants in check.
These results highlight that management of grazing and nutrient inputs can strongly influence floral resources, with likely consequences for pollinators and the stability of high-latitude ecosystems. We are currently investigating the consequences of nutrient- and grazing-driven changes in floral resources on flower visitor assemblages.
The paper was recently published in Oikos Volume 2025, Issue 7.
Reference: Johanson, N., Olde Venterink, H., Carvalheiro, L. G., Eskelinen, A., & Virtanen, R. (2025). Long‐term nutrient addition and grazing exclusion determine flower abundance, diversity and community composition in high‐latitude grasslands. Oikos, e11562. https://doi.org/10.1002/oik.11562
Text and photograph: Nicolina Johanson, 2024