Warming may have actually allowed moose to colonize the Alaskan tundra. Scientists have discovered that warming that occurred in the 20th century allowed these mammals to move north as their shrub habitat increased.
Moose have an iconic wildlife present throughout Alaska. However, these animals were absent from tundra regions earlier in the 20th century. Previously, researchers believed that overhunting was the reason why moose were absent from this area.
Now, though, scientists found that this may not be the case. There are very short plants in the tundra landscape. Moose, though, need to forage on shrubs sticking above the snow during the winter to survive. In this latest study, the researchers looked at whether a lack of available shrub vegetation was an alternative explanation for the previous absence of moose in the tundra.
The research team used recent changes in shrub cover and relationships between shrub height and summer temperature to estimate the available moose habitat in Arctic Alaska around 1860 so that they could compare it to that available in 2009.
So, what did they find? It turns out that average shrub height has increased since 1860 from about 1.1 m to about 2 m. This, in turn, means that the amount of forage available sticking above the snow has greatly increased. In fact, prior to the 20th century, it's likely that the shrubs were too short and sparse in the tundra to support moose.
Of course, the average shrub height in 1860 is only an estimate, which limits the study. However, the findings do point out the fact that it's certainly possible that shrubs have grown in the past several years, which could be the result of warmer temperatures.
"Although scientists have been anticipating changes to wildlife in response to the observed changes in climate and vegetation of the Arctic, this is one of the first studies to demonstrate it," said Ken Tape of the University of Alaska, one of the researchers involved in the study. "We showed that the large-scale northward shift of moose was likely in response to their increasing shrub habitat in the tundra."
The findings were published in the April 13 issue of the journal PLOS One.
