Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2017

Erindi/veggspjald / Talk/poster E45

Effects of climate warming and herbivory on rate of decomposition in the high and low Arctic

Höfundar / Authors: Katrín Björnsdóttir (1,2), Isabel C. Barrio (1,3), Ingibjörg Svala Jónsdóttir (1,2)

Starfsvettvangur / Affiliations: 1. University of Iceland, 2. The University Centre in Svalbard, 3. Agricultural University of Iceland

Kynnir / Presenter: Katrín Björnsdóttir

Tundra ecosystems contain enormous amount of organic carbon and therefore play a crucial role in the global carbon cycle. If temperature changes follow current predictions, these carbon pools could potentially shift from a sink to a source of CO2 by the end of this century due to accelerated decomposition rates. The aim of this study is to examine how climate warming and herbivory affect decomposition rate within contrasting bioclimatic sub-zones in the Arctic. The impacts of warming and vertebrate herbivory on the decomposition rate was assessed in different habitats in high Arctic Svalbard and sub-Arctic Iceland, using open-top chambers to enhance temperature or fences to exclude grazing. To estimate decomposition rate, two types of commercially available tea was used to represent dead plant material. 1328 tea bags were buried into the ground in 178 plots (OTCs, controls and fences) and the decomposition rate estimated as weight loss over three months and one year. Preliminary results show that excluding herbivory did not affect decomposition rate in Iceland but the effect of warming on decomposition differed significantly between high and low Arctic. Decomposition was higher in warmed plots in Iceland, but surprisingly the opposite occurred in Svalbard. The results of this study will provide information on how future changes in climate warming and increasing herbivory pressure will affect decomposition processes in the Arctic.