Arctic wildlife dispersed by sea ice

New research with the participation of Aarhus University shows that sea ice can play an important role in the dispersal of plant and animal species in the remote Arctic regions. This gives rise to asking a question. What happens when the ice melts?

2016.09.26 | Christina Troelsen

Sea ice that drifts with the currents between the coasts in the Arctic regions also plays a role as a means of transport for the dispersal of plant and animal species. This is demonstrated in new research with the participation of Aarhus University. Photo: Inger Greve Alsos

This is what the dominant sea ice routes look like in the North Atlantic region today. They are mainly controlled by wind and ocean currents and, in some periods, they can change due to shifts in wind patterns and ocean gyres. (Figure: Biology Letters)

In some of the most outlying Arctic islands in the North Atlantic region, the variation in nature is greater than it is further south. There is no other connection between these remote islands than drifting sea ice, so the obvious explanation is that the ice acts as a means of transport for plant and animal species.

A group of researchers consisting of biologists and geologists from Norway, Denmark and Iceland decided to study and determine the importance of sea ice for the dispersal of species in the Arctic regions. The results of the study have just been published in the Royal Society journal Biology Letters.

The spread followed sea ice routes

First, the researchers analysed data on the occurrence of plant species in East Greenland, Iceland, the Faroe Islands and Svalbard from the end of the last ice age up to recent times, and reconstructed the most likely routes of species spread based on distribution and genetics. Then they examined a reconstruction of sea ice in the same period and compared this with data on finds of driftwood as an independent source of knowledge on how ice can spread biological material.

The results of the interdisciplinary collaboration showed that the most likely routes are located in areas with the most sea ice and where most driftwood is found today.

“Our study confirms the theory that ice can act as a travelling platform for the spread of seeds, small plants and other organisms, and in some cases also larger animals,” says Professor Marit-Solveig Seidenkrantz from the Department of Geoscience, Aarhus University, who is one of the researchers behind the study.

“It is therefore natural to ask how the ongoing climate change with a consequent reduction of sea ice will impact nature in the Arctic. If it means reduced spread of species and thus less genetic variation, this will be important to take into consideration in relation to nature management in the Arctic in the future,” concludes Professor Seidenkrantz.

Not all bad news for the Arctic

As the climate warms, we see at the moment that plant and animal species not indigenous to the Arctic are moving further north, and in some cases they are threatening to outperform the Arctic species. If spread via sea ice diminishes in the future, it may also have the positive effect that the Arctic species will be protected against competition from the south.

According to the researchers, further studies and a better understanding of the role of sea ice as a travelling platform are needed to allow more accurate predictions of the development in the future.

The role of sea ice for vascular plant dispersal in the Arctic was published on 21 September 2016 in the Royal Society journal Biology Letters.

For more information, please contact

Professor Marit-Solveig Seidenkrantz
Department of Geoscience
Aarhus University
mss@geo.au.dk
+45 2778 2897

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