Responses of tundra carbon cycling and storage to reindeer-induced vegetation shifts : Can reindeer alter how much carbon tundra ecosystems store?

Summary, in English

In this presentation, I will summarize our findings on the effects of reindeer-induced vegetation transitions on carbon cycling processes and storage. These are monitored in subarctic Northern Norway alongside reindeer pasture rotation fences. At these sites, a yearly pulse of intensive reindeer grazing has turned the vegetation from shrub-dominated towards graminoid-dominated. We monitor the development of ecosystem carbon storage and demonstrate how reindeer grazing can alter the location and total amount of ecosystem carbon. At one of the sites, we also monitor carbon cycling processes on a zone that has recently become graminoid-dominated and show that many of the processes in soils respond to changes in grazing intensity even faster than vegetation-driven processes. The presented data acts as evidence of the potential of grazers to shape tundra processes and carbon storage. It also highlights the need for further studies on the site-specific carbon cycling responses to grazing. This could improve predictions of ecosystem changes across the tundra. Grazer-induced differences in carbon sequestration rates could be incorporated into land-use management, which aims to increase carbon sequestration in tundra soils.