My research interests focus on the origins and evolutionary history of extant biodiversity in polar (Arctic and Antarctic) areas, particularly plants and microbial groups, by applying population genetic, phylogeographic and molecular dating methods.
The evolutionary history of the flora of Greenland
Natural History Museum of Denmark, University of Copenhagen
Research on the origins of the Antarctic vascular flora
British Antarctic Survey
The two native Antarctic vascular plants, Colobanthus quitensis and Deschampsia antarctica, growing on Lagotellerie Island, Antarctica. We now know that C. quitensis likely arrived to the Antarctic Peninsula twice on a recent timescale (likely after the Last Glacial Maximum).
Highlighted previous research:
The origin and age of the largest plant genus in Antarctica, including several Antarctic endemic species
Genetic variation of Schistidium antartcici throughout Antarctica (for more info see here)
This phylogenetic study of Antarctic Schistidium mosses revealed a (multi-)million-year origin of several species of endemic moss, suggesting they have survived throughout the Last Glacial Maximum in Antarctica. This is the first evidence of long-term persistence of plants in Antarctica, a pattern consistent with many other endemic faunal groups.
The study further informs on the adaptive potential of Antarctic plants to survive climate change (throughout both warmer and colder conditions) over both historical and contemporary timescales. Lastly, evidence for increased genetic diversity in the northern maritime Antarctic compared to other regions point at the region including potential refugial areas throughout the Last Glacial Maximum, a finding of relevance to climate research as well as for prioritizing areas for conservation of Antarctic biota.
Refuges of Antarctic biodiversity
Two of the figures in the review; one showing an overview of some of the biological evidence for long-term survival across the Antarctic (left), and the other the relative timescales of in situ survival for the dominant biota (right). For more info see here or ask for a copy here
In recent years it has been realized that much of the terrestrial Antarctic biota is unique to the continent, carrying signals of its evolutionary radiation on multi-million-year timescales, some even pre-dating the final breakup of Gondwana and the geographic isolation of Antarctica. However, for terrestrial life to have existed continuously on the continent over these timescales, appropriate ice-free land must have existed through the multiple glacial cycles that took place throughout the Miocene, Pliocene and Pleistocene eras. This challenges current glaciological reconstructions, which present a model of complete obliteration of most currently ice-free areas of ground at successive glacial maxima, with those remaining not providing viable refugia for the majority of the contemporary terrestrial biota. In this chapter, we consider the requirement for refugia across all regions of Antarctica, and the likely form that such refugia may have taken.
Biogeography of plants with global distributions
The biogeographic studies on two of the most globally widespread plants Ceratodon purpureus and Bryum argenteum revealed the timescales and frequency with which these two species dispersed across the globe. In particular, the study on Ceratodon purpureus revealed the importance of global wind patterns for both dispersing spores over a long distance, but also restricting dispersion as wind systems can act as self-enclosed and isolated transport systems.
Arctic bryophyte research: recent advances and future priorities
In this review the future directions and priorities for Arctic bryophyte research were highlighted, with a focus on the importance of improving museum collections to advance scientific knowledge in the Arctic.
Biogeograpic patterns of plants with bipolar distributions
Bipolar distributions are very common among the Antarctic flora (~45% of the moss flora has this distribution. The studies on four bipolar mosses of Polytrichaceae and the moss Tetraplodon fuegianus revealed that bipolar dispersal events can occur on million-year timescales, and usually occur form the Northern Hemisphere to the Southern Hemisphere, but that the other way around can occur as well.
Despite its extreme survival abilities the peat moss Chorisodontium aciphyllum is of likely recent origin in Antarctica
The peat bank-forming moss C. aciphyllum is known to be the oldest sub-fossils of any extant plant in Antarctica (~5000-5.500 years old). It is also known for starting to grow new shoots from a peat core which had been frozen for more than 1500 years, revealing the longest survival and viability of any multicellular eukaryotic organism known. Despite this, we found almost no genetic variation between its populations in Antarctica, implying the plant has not been present here on a long-term (glacial) timescale - unlike many other terrestrial species.