Awarded King’s gold medal for PhD thesis
Top image: Pernille Bronken Eidesen doing fieldwork around Ny-Ålesund this summer. Photo: Eike Müller/UNIS.
UNIS associate professor Pernille Bronken Eidesen has been awarded His Majesty the King’s Gold Medal for her PhD thesis on Arctic-Alpine plants, which she defended at the University of Oslo (UiO) last December. Eidesen will receive the honors on 2 September 2008.
20 August 2008
Text: Eva Therese Jenssen
UNIS associate professor Pernille Bronken Eidesen has been awarded His Majesty the King’s Gold Medal for her PhD thesis on Arctic-Alpine plants. The thesis, which Eidesen defended last December at UiO, was considered the best PhD thesis out of 108 contenders at the Faculty of Mathematics and Natural Sciences in 2007.
Eidesen, who completed her PhD work at the National Centre for Biosystematics at UiO’s Natural History Museum, will receive the award at the UiO annual celebration on 2 September.
In its decision the award committee noted among other things that:
“Her dissertation is extraordinary in its innovation, scope and scientific quality. This is reflected by the fact that five out of the six articles (which encompasses her thesis) was already printed in highly profiled international journals: one in Science (ISI impact 30); three in Molecular Ecology (impact 4,8); and one in Journal of Biogeography (impact 2,9).
Arctic plants on the move
Today Arctic plants are widespread, but 20 000 years ago most of the Arctic was covered by ice. Eidesen’s thesis: “Arctic-alpine plants on the move: Individual and comparative phylogeographies reveal responses to climate change” investigates how Arctic plants survived the last glaciations and how they reestablished themselves in the Arctic environment.
By using DNA methods one can reveal a plant’s family tree, and by studying the family tree one can trace the plant’s ancestors and their habitat during the last glaciation, and what route the plants followed when the ice retreated.
“Refugee camps” around the Bering Strait
Eidesen studied genetic patterns in several plants and discovered that some areas have been important “refugee camps” for the plants during the different ice ages. The biggest of such refuges is in the area around the Bering Strait, in Northern America and in Eastern Siberia.
The White Arctic Bell-heather (Cassiope tetragona), which today grows in Finnmark, Northern Norway, is one of the plant species that have survived the last glaciation in this area, and has probably been spread from Alaska, through Canada, over Northern Greenland to Svalbard, and finally to Scandinavia – all this in the course of 15,000 years!
By studying the effects of previous climate changes we can also find out more about the ongoing global warming. Svalbard, as an isolated archipelago, was covered by ice during the last glaciation. This means that plants preferring warmer climates, must have established themselves at Svalbard after the ice retreated. Svalbard was therefore used as a model system to study plant distribution in the Arctic in one of the cooperative projects presented in Eidesen’s thesis.
The data shows that the plant colonization of Svalbard has taken place several times from several geographical areas. The results indicate that it has been much harder for plants to establish and survive in Svalbard, than spreading their seeds to the archipelago. This means that despite the long distances seeds must travel to arrive at Svalbard, the colonization will most likely increase as the global temperatures increase.