Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2019

Erindi/veggspjald / Talk/poster V19

Tundra ecosystem respiration and soil organic matter - effects of different stages of degradation.

Höfundar / Authors: Arna Björt Ólafsdóttir (1), Gertrude Akello (2), Isabel C Barrio(3), Ingibjörg S. Jónsdóttir (4)

Starfsvettvangur / Affiliations: 1. Líf- og umhverfisvísindadeild, 2. UNU-LRT, 3. Landbúnaðarháskóli Íslands, 4. Líf- og umhverfisvísindadeild

Kynnir / Presenter: Arna Björt Ólafsdóttir

Icelandic ecosystems have been shaped by isolation, extreme climate and frequent volcanic activity and during the last 1100 years by livestock grazing. Vegetation degradation and soil erosion escalated after the settlement, frequently resulting in ecosystem collapse which is believed to be largely driven by sheep grazing in later years. Shifts in plant communities to degraded states, driven by grazing, may have affected soil microbial communities and microbial activity with consequences for carbon cycling. In a warming climate it is important to understand these processes and potential feedback mechanisms. Yet, there is limited understanding of soil dynamics of the degraded tundra landscapes in Icelandic rangelands., The aim of this project is to assess microbial activity in soils of ecosystem at contrasting degradation states and in response to grazing cessation. In an existing grazing experiment we will test the hypothesis that soil carbon stocks and microbial abundance and activity is lower at highly degraded states than less degraded and that exclusion of sheep grazing may have an effect on soil quality. Preliminary results show that both carbon stocks and ecosystem respiration are lower in totally collapsed ecosystems (melur) than degraded but still intact Betula nana heaths. Three years of sheep grazing exclusion did not affect theses variables.