| Effects of herbivores on plant production has been a central question in ecology during the last decades1, due to its importance for understanding dynamic processes in natural ecosystems1, and its fundamental role for designing sustainable management regimes of domestic grazers. Managed grazing covers more than 25% of the global land surface, and this can locally be much higher like in Sweden, where more than 50% of the area is grazed by reindeer. The overall aim of this project is thus to reveal how present reindeer management regimes influence the productivity of reindeer summer pastures, and communicate this information back to the practitioners. To be able to do this, our project will use an interdisciplinary approach with novel methods and an active dialog with practitioners. This includes a novel use of more than 200 years old historical reindeer pens, and combining differences in reindeer densities between summer pastures of different districts, with new data from national inventories and satellite images, which makes it possible to study the effect of reindeer across the entire Swedish tundra. The specific objectives of the proposed project are: • Examine the effect of present reindeer grazing regimes on productivity of summer pastures at large spatial scales. • Investigate the importance of vegetation shifts for the effect of reindeer on pasture productivity. • Reveal the mechanisms behind positive effects of reindeer on the productivity of forage plants using historical reindeer pens as centuries-long ecological experiments. This project will improve our understanding of the effects of reindeer on the summer pastures. An increased understanding of the effect of reindeer on summer pasture productivity is necessary for an evidence-based management of the summer pastures. |