25 January 2012

The vegetation is changing in Siberia

As reported by the National Oceanic and Atmospheric Administration:
The pair of images above shows a site on the Siberian tundra near Russia’s Yenisey River in the summers of 1966 (top) and 2009 (lower). In the 43 years that passed between the first image and the second, shrubs colonized virtually all of the previously open tundra surrounding a cluster of lakes...

At the site Frost studies, the tundra is often patterned with bald spots—circles of bare ground where seasonal frost heave can uproot plant seedlings. These frost circles, sometimes called “frost boils,” give the tundra in the top center of the images its speckled look. The bare spots create an open canvas for shrubs to colonize, presuming they can withstand the seasonal frost heave. At this site, the colonizing shrubs are usually alders...
The conversion of tundra to dense, tall shrubland triggers a cascade of changes in how the ecosystem functions. Observations from Europe, Alaska, and Siberia in recent decades have shown plant communities became less diverse as mosses, lichens, and other shorter-growing plants disappeared under the shade created by shrubs. The loss of lichens, in particular, could pose a problem for caribou and reindeer, which forage on them extensively.

The change from tundra to shrubland can also affect the thawing of permafrost...
More at the link.  Via NASA's Earth Observatory.

1 comment:

  1. Sounds like what they need is an animal that eats the shrubs. They need woolly mammoths. They would crop back the shrubs which would allow the diverse lichens and grasses to grow again.

    This is similar to how the shortgrass prairie has been killed off by invasive mesquite trees. People have seriously argued that south Texas needs elephants. They would crop back the trees and leave behind a more diverse ecosystem

    It's called megafauna restoration.


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