Floristic turnover in Iceland from 15 to 6 Ma - Extracting biogeographical signals from fossil floral assemblages
- Autor(en)
- Fridgeir Grímsson, Thomas Denk
- Abstrakt
Aim: This study aims to document the floristic changes that occurred in Iceland between 15 and 6 Ma and to establish the dispersal mechanisms for the plant taxa encountered. Using changing patterns of dispersal, two factors controlling floristic changes are tested. Possible factors are (1) climate change, and (2) the changing biogeography of Iceland over the time interval studied; that is, the presence or absence of a Miocene North Atlantic Land Bridge. Location: The North Atlantic. Methods: Species lists of fossil plants from Iceland in the time period 15 to 6 Ma were compiled using published data and new data. Closest living analogues were used to establish dispersal properties for the fossil taxa. Dispersal mechanisms of fossil plants were then used to reconstruct how Iceland was colonized during various periods. Results: Miocene floras of Iceland (15-6 Ma) show relatively high floristic turnover from the oldest floras towards the youngest; and few taxa from the oldest floras persist in the younger floras. The frequencies of the various dispersal mechanisms seen in the 15-Ma floras are quite different from those recorded in the 6-Ma floras, and there is a gradual change in the prevailing mode of dispersal from short-distance anemochory and dyschory to long-distance anemochory. Two mechanisms can be used to explain changing floral composition: (1) climate change, and (2) the interaction between the dispersal mechanisms of plants and the increasing isolation of proto-Iceland during the Miocene. Main conclusions: Dispersal mechanisms can be used to extract palaeogeographic signals from fossil floras. The composition of floras and dispersal mechanisms indicate that Iceland was connected both to Greenland and to Europe in the early Middle Miocene, allowing transcontinental migration. The change in prevalence of dispersal modes from 15 to 6 Ma appears to reflect the break-up of a land bridge and the increasing isolation of Iceland after 12 Ma. Concurrent gradual cooling and isolation caused changes in species composition. Specifically, the widening of the North Atlantic Ocean prevented taxa with limited dispersal capability from colonizing Iceland, while climate cooling led to the extinction of thermophilous taxa.
- Organisation(en)
- Institut für Paläontologie
- Externe Organisation(en)
- Nordic Volcanological Center - NordVulk, University of Iceland, Swedish Museum of Natural History
- Journal
- Journal of Biogeography
- Band
- 34
- Seiten
- 1490-1504
- Anzahl der Seiten
- 15
- ISSN
- 0305-0270
- DOI
- https://doi.org/10.1111/j.1365-2699.2007.01712.x
- Publikationsdatum
- 09-2007
- Peer-reviewed
- Ja
- ÖFOS 2012
- 105117 Paläobotanik
- Schlagwörter
- ASJC Scopus Sachgebiete
- Ecology, Geography, Planning and Development
- Sustainable Development Goals
- SDG 13 – Maßnahmen zum Klimaschutz
- Link zum Portal
- https://ucrisportal.univie.ac.at/de/publications/e6ee5ebd-bd71-437c-9c55-88c67acdea33