In full (EN)

Abstract:
Large herbivores regulate ecosystem structure and functioning across Earth’s biomes, but vegetation community responses to herbivory depend on complex interactions involving the timing and intensity of herbivory pressure and other, often abiotic, controls on vegetation. Consequently, reindeer-driven vegetation transitions in the Arctic occur heterogeneously between and even within landscapes.

Here, we employed drone surveys to investigate drivers of spatial heterogeneity in vegetation responses to reindeer herbivory by mapping change comprehensively across a landscape at the fine scale inherent to plant-herbivore interactions. We conducted our surveys on the Yamal Peninsula, West Siberia in coordination with Indigenous Nenets mobile pastoralists managing a reindeer herd of hundreds of animals, including 13 animals with GPS collars. The surveys mapped the focal landscape immediately before the herd arrived, immediately after they had left the site, and one month after the herd’s activity. Using structure-from-motion (SfM) photogrammetry in a novel workflow that accounts for spatially variable uncertainty in the SfM reconstructions, we detected significant decreases in canopy height over 0.4% of the site after the herbivory event and significant increases in canopy height over 3% of the site one month later.

Vegetation responses diverged depending on the amount of herbivory pressure, which was derived from the collar GPS data. In areas with higher reindeer activity, there were initial decreases in canopy height strongly suggesting trampling and defoliation, including signs of browsing around the edges of erect shrubs, and subsequent growth instead predominantly in low-lying vegetation one month later. Areas with lower herbivory pressure within the same habitat types showed strikingly little change throughout the study period. Due to our spatially comprehensive approach, we were able to pinpoint immediate and lagged effects of an herbivory pulse, ultimately demonstrating how herbivory can shape the productivity and distribution of vegetation communities within a landscape.

Spiegel, M.P., Kerby, J., Ehrich, D., Volkovitskiy, A., Terekhina, A., Violetta Filippova, Shklyar, K., Sokolova, N., Sokolov, A. and Macias-Fauria, M. (2025). Drone mapping links reindeer browsing during an herbivory pulse to divergent vegetation community responses. Environmental Research Ecology. doi: https://doi.org/10.1088/2752-664x/adb03f