Tree response to climate change

We are investigating the glacial survival hypothesis of boreal tree species at high latitudes in Europe and use a combination of palaeoecological and DNA studies on ancient and contemporary material to address three important ecological questions:

  • How far north did tree species survive the Last Glacial Maximum in Europe?
  • Which routes did they follow and thus how current forest structure develop during the post-LGM warming?
  • What is the contribution of northern tree refugia for the geographical distribution, the genetic diversity and the adaptation we see today in trees?

Most of these analyses focus on Norway spruce (Picea abies), as we wanted to understand how interglacial spruce in western Norway relate to present day populations outside the glaciated area. Material we are investigating is Eemian spruce wood (130-114,000 years old), macrofossils, pollen and environmental DNA from lakes and peat from Nordic environments in Europe. The time frame is broad: from the previous interglacial (Eemian) to modern times.

A good explanation for how tree moved in the past is important for guiding forecasts for population movements in the 21st century and we hope this information will be useful in future studies to understand the source of genetic variation of trees at northern latitudes and how this affects their adaptation in extreme environments. This information can also help to identify genetic resources important for forest tree breeders and foresters who needs tree provenances with traits related to flexibility to changing climatic conditions.

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NGS sequencing on ancient lake sediments

Together with Barbara Wohlfarth and Tanja Slotte at Stockholm University we are using grants From SciLifeLab in Stockholm to test the utility of shotgun sequencing on lake sediments.  Postdoctoral fellow Engy Ahmed has testied barcoding and the metagenomic approaches  on lake sediments using the sequencing facilities available at the SciLifeLab Stockholm Genomics Platform.  We worked on Hässeldala lake sediment sequences that is an excellent record for testing the potential of environmental ancient DNA analysis and to address questions that cannot be resolve using classical paleoecological methods. The record covered the time interval between 17,000 and 11,000 years ago and document the dramatic environmental and climatic changes that characterized the end of the last ice age and the transition into the present interglacial in southern Sweden. Currently we are also working on a new sediment core from a vulcanic lake from southern Italy (Monticchio Lake).

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