The impacts of shrub abundance on microclimate and decomposition in the Canadian Low Arctic
Skaarup, E. 2017.
Abstract
Increasing deciduous shrub abundance in the Arctic could alter the biotic and abiotic controls on
carbon (C) cycling in these ecosystems. Betula glandulosa (Michx.) leaf litter was decomposed
at three sites of differing shrub abundance in the Canadian Low Arctic for one year. Summer and
winter microclimate along with soil nutrients were monitored and lab incubations simulated
autumn temperatures and leaching conditions. At the high shrub site, warmer winter soil
temperatures contrasted with cooler summer temperatures likely due to deeper snow and greater
thickness of moss and organic soil layers compared to the other sites. However, surface mass
loss was significantly higher at the shrubbier site only after a full year suggesting that
microclimate was not the only influencing factor. At all sites, large mass losses (21-26%)
occurred between August and May with no significant differences among sites. The laboratory
study suggested that much of the mass loss occurred shortly after litterfall in autumn.
