Disturbance, recovery and tundra vegetation change: Final report project 17/92 - to Svalbard Environmental Protection Fund

During the last 20 years, Svalbard’s climate has grown warmer, Svalbard reindeer almost doubled in population size, and Svalbard pink-footed geese increased dramatically in both number and spatial extent. All three factors can strongly influence tundra vegetation, but sufficiently long-term and spatially extensive studies on Svalbard’s vegetation are lacking, preventing us to appraise the impact of changes in climate and herbivore densities. Svalbards miljøvernfond allowed us to move away from this position, by providing funding for a new programme of work to trace, literally, earlier steps made. Since 1997, as part of a long-term study of the reindeer population (Albon et al. 2017), vegetation work commenced in one of Svalbard’s most productive area, the Colesdalen-Reindalen valley system. Part of this work took place in a relatively confined area (Semmeldalen), revealing - among other aspects - a great sensitivity of tundra plant production to current summer’s temperature conditions (Van der Wal and Stien 2014). Other parts covered the ‘reindeer study area’, with vegetation transects walked in most of its valley. About 10 years on, when realising the scale and potential impact on the vegetation by the expanding pink-footed goose population, we also started to investigate their disruption of tundra vegetation and recovery thereof, through the initiation of a short-term experimental vegetation disturbance experiment in Adventdalen (Speed et al. 2010). Svalbards miljøvernfond provided us with the opportunity to capitalise on these two unique and by now historical research efforts, and embark, in 2018 and 2019, on a mission to reveal valley-wide vegetation change over a 20-year period and the drivers thereof, the findings of which we report here.