Disputas: Shea Allison Sundstøl

Shea Allison Sundstøl har til forsvar for graden philosophiae doctor (ph.d.) ved Fakultet for teknologi, naturvitenskap og maritime fag (TNM), innlevert avhandling med tittelen; “Ecology of alpine lichen heaths: Relationships between vegetation, soil temperature, and edaphic factors in southern Norway.”


01 Mar

Praktisk informasjon

  • Dato: 1. mars 2019
  • Tid: kl. 12.15 - 16.00
  • Sted: Campus Bø
  • Til å bedømme avhandlingen er oppnevnt:

    • Forsker Johan Asplund, Norges Miljø- og Biovitenskapelige Universitet
    • Professor Knut Rydgren, Høgskulen på Vestlandet

     

    Administrator:

    Førsteamanuensis Stefanie Reinhardt, USN

     

    Veiledere:

     

    Hovedveileder for doktorgradsarbeidet har vært Professor emeritus Arvid Odland, USN. Biveiledere har vært Førsteamanuensis Live Semb Vestgarden, USN og Professor Inger Hanssen-Bauer, Meteorologisk institutt.

     

     

    Program:

    Prøveforelesningen vil bli holdt i Auditorium 4-311A ved USN i Bø, fredag 1. mar 2019, kl.11.00 over emnet: “Functional traits as drivers of plant-soil interactions”

    Disputas avholdes samme sted, 4-311A fredag 1. mar 2019, kl.12.15  

     

    Prøveforelesning og disputas er åpen for alle interesserte.

Om avhandlingen:

Why do lichens grow where they do? What are the environmental conditions that lead to lichen-dominated heaths? How will climate change affect lichen distribution in alpine areas? A number of studies have recorded declines in lichens in many areas; why is this happening? These are some of the questions that I have attempted to answer with my research. Anyone who has spent time in the mountains has more than likely encountered areas that are covered with expanses of lichen vegetation, which are often called “reindeer lichens” or even “reindeer mosses”. Most people know that reindeer eat these to survive the winter. Lichens, which are not plants but are a symbiosis between a fungus and a photosynthetic bacteria or alga, play an important role in natural ecosystems - and not just for reindeer. Lichens fix both carbon (C) and nitrogen (N) from the air, can help regulate soil temperatures, and can grow in extreme environments.

In Norway, free-growing lichens (those that are not attached to trees or stones) are usually found on ridgetops and plateaus where there is little to no snow cover, and in areas with drier, more continental climates, especially in eastern Norway. Although most climate models predict less snow in the lowlands, snow depths are expected to increase in mountain areas. This is an important change because snow influences ecological parameters such as soil temperatures, nutrient cycling, and growing season length.

I have measured soil temperatures over a three-year period, and have recorded the vegetation in different landscape positions at three mountain areas in southern Norway: at Haukeli in Telemark, Imingfjell in Buskerud, and Lesja in Oppland. I have also taken soil samples and analysed them for both texture and macronutrient content. Using these data I have formulated a new theory about lichen heath formation and the environmental conditions that are most favourable to their development and distribution. I have also identified possible threats that a changing climate poses to these unique landscapes.

Shea Allison Sundstøl