Climate Change Transforming Alaska's Landscape -- Ancient Lakes And Wetlands Being Replaced By Forest

In a paper published in the August 2005 issue of the NRC ResearchPress' Canadian Journal of Forest Research, Eric Klein and hiscolleagues document a significant landscape shift from wetlands towoodland and forest in the Kenai Peninsula Lowlands.

The trend fits within a global picture of drying wetlands in northernlatitudes, with similar changes already appearing in lower latitudes.Klein, a biologist who did his graduate research with Alaska PacificUniversity, says the transformation of Alaska's landscape correspondswith an increase in temperatures over the past 100 years. "When youlook at the climatologic data, it shows a warming trend. This is justone of the physical manifestations of that trend that is hard torefute."

The researchers compared aerial photos of the Kenai Peninsula taken in1950 and 1996. Combined with extensive field study and analysis ofvegetation, the research confirms that the Kenai Peninsula is becomingwoodier and dryer. In the areas studied, wooded areas increased from 57percent to 73 percent from 1950 to 1996, while wetland areas decreasedfrom 5 percent to 1 percent.

The results confirm what the researchers could see for themselves."It's very clear when you fly over closed basin lakes, many of whichare the kettle ponds left after the glaciers receded," says Klein."They have a kind of apron, or area between the water and matureforest, and you can see it getting larger as the water goes down."

Global temperatures have increased by about 0.6°Cover the past 100 years. The rate of temperature increase from 1976 tothe present has been double that from 1910 to 1945 -- greater than atany other time during the last 1,000 years.

Over the past 30 years, temperatures in the Kenai Peninsula have increased 0.7°C.In the last 15 to 25 years, species such as dwarf birch, blueberriesand black spruce have grown up in areas where wetlands had existed for8,000 to 12,000 years. "These areas used to be soggy bogs with sphagnumpeat moss, and no shrubs or trees," says Dr. Ed Berg, an ecologist withthe U.S. Fish and Wildlife Service. "The evidence for this is that whenyou dig down into the peat, you don't see any stems or shrubs. Had theygrown there in the past, they would have been preserved because peatpreserves things very well."

Wetlands are hotspots for biodiversity. The shift to woodland andforest means loss of many types of wetland vegetation and fewerhabitats for migratory birds. The greater forest cover also creates acontinuous swath of vegetation that helps wildfires to spread morequickly.

Similar drying is happening outside the Kenai Peninsula. "It'scertainly happening in Alaska on a very broad scale," says Dr. Berg."Much of the interior is showing the same kind of drying pattern."

If the warming trend continues, Alaska's lakes and wetlands willcontinue to disappear, creating a dryer landscape in the long term.

Klein says that Alaska's transformation is another piece of evidence inthe climate change puzzle. "The bottom line is that a change ishappening," he says. "There is an overall environment shift occurringin Alaska, and especially in the northern hemisphere. I think it's abioindicator of climate change and what is happening to the planet as awhole."

The Canadian Journal of Forest Research is a scientific peer-reviewedjournal published by the NRC Research Press, the publishing arm of theCanada Institute for Scientific and Technical Information (CISTI).

For the complete article, see http://pubs.nrc-cnrc.gc.ca/cgi-bin/rp/rp2_abst_e?cjfr_x05-129_35_ns_nf_cjfr8-05.

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