Herbivore-shrub interactions influence ecosystem respiration and BVOC composition in the subarctic
Brachmann, C. G., T. Vowles, R. Rinnan, M. P. Björkman, A. Ekberg and R. G. Björk. 2023.
Abstract
Arctic ecosystems are warming nearly four times faster than the global average which is resulting in
plant community shifts and subsequent changes in biogeochemical processes such as gaseous fluxes. Additionally,
herbivores shape plant communities and thereby alter the magnitude and composition of ecosystem respiration
and BVOC emissions. Here we determine the effect of large mammalian herbivores on ecosystem respiration and
BVOC emissions in two southern and two northern sites in Sweden, encompassing mountain birch (LOMB) and
shrub heath (LORI) communities in the south and low-herb meadow (RIGA) and shrub heath (RIRI) communities
in the north. Herbivory significantly decreased ecosystem respiration at RIGA and altered the BVOC composition
between sites. However, plant community composition had a larger effect on ecosystem respiration as RIGA had
35% higher emissions than the next highest emitting site (LOMB). Additionally, LOMB had the highest emissions
of terpenes with the northern sites having significantly lower emissions. Differences between sites were primarily
due to differences in exclosure effects, soil temperature and prevalence of different shrub growth forms. Our
results suggest that herbivory has a significant effect on trace gas fluxes in a productive meadow community and
differences between communities may be driven by differences in shrub composition.
